J

11:1

3.9 .. prﬁuru

:.n

Link.
a. 2....
' >l1- .0

:1... ,
. 1.1:...
1.121.. I. .r. . . .

.X. .. 3)..

.. .1911
:.Hsn|l\htd~.5!;1 r

. .v . vita.

u . i.
an 1.1.»."433
I».

a
if
:11

31...... iv-ﬁ. ‘ . .
2:34.31 , V , I . .4 w). 5"
i . u x .3. .ylzap‘?

. . . . . i: (t

‘ n. : .
spun;

Ilbl f’

.wrla. )
.quu‘:

3;;
“55$:

3
:‘i

.1: a

.15.»!
nr-Lw .

 

TWIERSWY
l
l; l

Illllljilll ll llllllllllllllllll

31 93 01415 0837

 

 

 

 

This is to certify that the

thesis entitled

CANOPY AND CROPPING INFLUENCE ON VINE GROWTH, PHYSIOLOGY,
AND CLUSTER DISEASE INCIDENCE OF SEYVAL AND VIGNOLES
GRAPEVINES.

presented by
Russell Paul Smithyman

has been accepted towards fulfillment
of the requirements for

Masters degree in Horticulture

 

 

<35 ' (”61/ /

Major professor

Date Aug. 5, 1994

 

0-7639 MS U is an Afﬁrmative Action/Equal Opportunity Institution

 

 

 

 

 

 

 

 

LIBRARY
Mlchlgan State
Unlverslty

 

 

 

 

PLACE ll RETURN BOXto roman” mum your record.
TO AVOID FINES rotum on or baton dd. din.

DATE DUE DATE DUE DATE DUE

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

CANOPY AND CROPPING INFLUENCE ON VINE GROWTH,
PHYSIOLOGY, AND CLUSTER DISEASE INCIDENCE OF
SEY VAL AND VIGNOLES GRAPEVINES

By

Russell Paul Smithyman

A THESIS

Submitted to
Michigan State University
in partial fulﬁllment of the requirements
for the degree of

MASTER OF SCIENCE

Department of Horticulture

1994

.I

3

i

‘N

a“ r '
n. l J,
7w“
“*1 :

ABSTRACT

CANOPY AND CROPPING INFLUENCE ON VINE GROWTH,
PHYSIOLOGY, AND CLUSTER DISEASE INCIDENCE OF
SEY VAL AND VIGNOLES GRAPEVINES

By

Russell Paul Smithyman

Seyval and Vi gnoles grapevines were subjected to decreasing pruning seventies to increase
the level of fruitful (clusters) and vegetative (apical meristems) sinks during anthesis in an effort to
reduce fruit-set, cluster compactness and Botrytis incidence. Fruit-set appears to be influenced
more by cluster number than apieal meristems. Due to their large cluster size, Seyval showed a
signiﬁcant response to greater fruitful sink competition. However, the small clusters of Vi gnoles
were insufﬁcient in inﬂuencing f ruit-set at pruning seventies that produced sufﬁcient vegetation for
fruit and wood maturity. Increased shoot numbers per vine facilitated early ﬁlling of the trellis area
with foliage. However, a limit existed where vegetative sink competition adversely affected light
penetration into the eanopy, leaf production after veraison, and eane cold hardiness. Three eanopy
I conﬁgurations (severely pruned, full trellis, and hedging), providing three levels of shoot
production, were compared to examine their influence on shoot and leaf growth as well as leaf area
formation. Both the full trellis and hedging systems increased early ﬁlling of the trellis area with
foliage and yield, but canopy density beeame a problem in the hedged vines after veraison. A
moderate pruning severity, accompanied by post-set thinning in Seyval appears to be the best
method for creating a sufﬁcient sink competition to reduce berry-set, cluster compactness, and

thus, Botrytis infection.

Dedieated to missed days in the woods and streams of Michigan.

ACKNOWLEDGMENTS

I would like to express my sincere appreciation to Dr. Stan Howell for his guidance,
encouragement, and assistance during my tenure on this project. The opportunity to study
viticulture under his tutelage has been enlightening and gratifying. I would like to thank the
members of the guidance committee: Dr. E. Hanson and Dr. D. Dickman.

I am deeply indebted to Doug Welsh for the use of his vineyard, and to his family for
allowing me into their home during my trips to Penn Valley. Thanks are also due Dave Miller for
his support as a coworker and friend.

Lastly, I wish to thank my wife, Jenn, for helping me prepare this manuscript. Her

patience and moral support during this endeavor was appreciated.

TABLE OF CONTENTS

Ease
LIST OF TABLES ........................................ xii
LIST OF FIGURES ........................................ x
INTRODUCTION ......................................... 1
LITERATURE REVIEW ..................................... 4
Leaf Area ............................................ 4
Canopy Design ............. - ............................ 5
Carbohydrate Sinks ...................................... 6
Flower Initiation and Differentiation ........................... 7
Bloom and Fruit Set ..................................... 8
Berry Development ...................................... 9
Cultural Practices to Inﬂuence Fruit-Set ........................ 9
Chemical Influence on Fruit-Set ............................ 10
Cultural Control of Botrytis ............................... 11
Statement of Objectives .................................. 12
Literature Cited ........................................ 14

Chapter I. Inﬂuence of Canopy Configuration on Canopy Development, Yield, Fruit
Composition, and Cane Quality of Seyval Grapevines.

Abstract ............................................ 23
Introduction .......................................... 24
Materials and Methods ................................... 27
Results and Discussion .................................. 30
Conclusions .......................................... 35
Literature Cited ........................................ 37

Chapter II. Inﬂuence of Canopy Configuration on Shoot Growth, Leaf Development,
and Leaf Area of Seyval Grapevines.

Abstract ............................................ 54
Introduction .......................................... 54
Materials and Methods ................................... 58
Results and Discussion .................................. 61
Conclusions .......................................... 67
Literature Cited ........................................ 69

Chapter III. The Use of Carbohydrate Sink Competition to Reduce Fruit Set and
Botrytis Rot in Seyval Grapevines.

Abstract ............................................ 88
Introduction .......................................... 88
Materials and Methods ................................... 91
Results and Discussion .................................. 96
Conclusions .......................................... 99
Literature Cited ........................................ 101

Chapter IV. The Use of Carbohydrate Sink Competition to Reduce Fruit Set and
Botrytis Rot in Vi gnoles Grapevines.

Abstract ............................................ 118
Introduction .......................................... 1 18
Materials and Methods ................................... 120
Results and Discussion .................................. 124
Conclusions .......................................... 128
Literature Cited ........................................ 130
CONCLUSIONS ......................................... 150

Appendix 1. Inﬂuence of Cane Characteristics on Primary
Bud and Periderm Cold Hardiness .............................. 153

vi

 

 

LIST OF TABLES

Table Page
CHAPTER I

1. Inﬂuence of pruning treatments on vine yield from
1988 - 1993 of Seyval grapevines at Fenn Valley vineyards .......... 40

2. Inﬂuence of pruning treatments on node number at pruning
and cluster number at harvest from 1988 - 1993 of Seyval
grapevines at Fenn Valley vineyards .......................... 41

3. Inﬂuence of pruning treatments on cluster wt., berry wt., and
berries/cluster at harvest from 1989 - 1993 of Seyval grapevines
at Fenn Valley vineyards ................................. 42

4. Inﬂuence of pruning treatments on fruit composition and
vine sugar production at harvest from 1989 - 1993 of Seyval
grapevines at Fenn Valley vineyards .......................... 43

5. Inﬂuence of pruning treatments on incidence of Botrytis rot
within and among clusters at harvest from 1989 - 1993 of
Seyval grapevines at Fenn Valley vineyards ..................... 44

6. Inﬂuence of pruning treatments on vine size and growth
per node retained at pruning from 1988 - 1993 in Seyval
at Fenn Valley vineyards ................................. 45

7. Inﬂuence of pruning treatments on shoot population
measured after verasion from 1991 - 1993 in Seyval at
Fenn Valley vineyards ................................... 46

8. Inﬂuence of pruning g treatments on cane quality as
assessed after leaf fall from 1991 - 1993 in Seyval at Fenn
Valley vineyards ....................................... 47

9. Inﬂuence of pruning treatments on occurrence of shootless
nodes to Seyval grapevines measured just past burst from
1991 - 1993 at Fenn Valley vineyards ......................... 48

vii

to

IQ

CHAPTER II

Inﬂuence of pruning system in 1993 on the yield components
and the fruit quality indices of Seyval grapevines at

Fenn Valley vineyards ................................... 72
Inﬂuence of pruning treatments in 1993 on the vine size

indices of Seyval grapevines at Fenn Valley vineyards .............. 73
Inﬂuence of pruning system in 1993 on shoot leaf area at

harvest of Seyval grapevines at Fenn Valley vineyards ............. 74
Inﬂuence of pruning system in 1993 on vine leaf area at

harvest of seyval grapevines at Fenn Valley vineyards .............. 75

CHAPTER III

Inﬂuence of pruning severity and time of cluster thinning
on the vine size indices averaged from 1992 — 1993 of
Seyval grapevines at Fenn Valley vineyards ..................... 103

Inﬂuence of pruning severity and time of cluster thinning
on fruit set averaged from 1992 - 1993 of Seyval grapevines
at Fenn Valley vineyards ................................. 104

Inﬂuence of pruning severity and time of cluster thinning
on the vine size and yield indices averaged from 1992 - 1993
of Seyval grapevines at Fenn Valley vineyards ................... 105

Inﬂuence on increasing crop levels retained at
thinning on yield (kg) in 1993 of Seyval grapevines
atFenn Valley vineyards ............................. . . . 106

Inﬂuence of pruning severity and time of cluster thinning on
the yield components and fruit quality indices averaged from
1992 - 1993 of Seyval grapevines at Fenn Valley vineyards .......... 107

CHAPTER IV
Inﬂuence of the number of nodes retained and cane
length on the vine size and shoot and cane characteristics
of Vignoles grapevines at Fenn Valley vineyards in 1992 ............ 133
Inﬂuence of the number of nodes retained and eane

length on the vine size and shoot and cane characteristics
of Vignoles grapevines at Fenn Valley vineyards in 1993 ............ 134

viii

Inﬂuence of the number of nodes retained and cane
length on the yield and the components of yield of
Vignoles grapevines at Fenn Valley vineyards in 1992 .............. 135

Inﬂuence of the number of nodes retained and
eane length on the yield and components of yield of
Vignoles grapevines at Fenn Valley vineyards in 1993 .............. 136

Inﬂuence of the number of nodes retained and
cane length on fruit set and quality of Vi gnoles
grapevines at Fenn Valley vineyards in 1992 .................... 137

Inﬂuence of the number of nodes retained and cane
length on fuit set and quality of Vi gnoles grapevines at
Fenn Valley vineyards in 1993 ............................. 138

LIST OF FIGURES

Figure

IQ

CHAPTER I

Effect of canopy configuration on seasonal canopy
development averaged from 1991 - 1993 of Seyval
grapevines at Fenn Valley vineyards, expressed as

Page

leaf layer number ...................................... 49

Frequency distribution averaged from 1991 - 1993
of the number of contacts (leaves and fruit) measured
at bloom by point quadrat for Seyval grapevines pruned

to three canopy configurations .............................. 50

Frequency distribution averaged for 1991 - 1993
of the number of contacts (leaves and fruit) measured
at verasion by point quadrat for Seyval grapevines pruned

to three canopy configurations .............................. 51

Frequency distribution averaged for 1991 — 1993
of the number of contacts (leaves and fruit) measured
at harvest by point quadrat for Seyval grapevines pruned

to three canopy configurations ..................... p ......... 52

CHAPTER II

1993 Standard for ﬂowers per cluster

measurements in Seyval grapevines .......................... 76

Standard for primary shoot leaf area measurement

in Seyval grapevines .................................... 77

Standard for lateral shoot leaf area measurements

in Seyval grapevines .................................... 78

Inﬂuence of canopy configuration on primary shoot
length (cm) in Seyval grapevines at Fenn Valley vineyards

during the 1993 growing season ............................ 79

10.

11.

Inﬂuence of canopy configuration on primary shoot
leaf production in Seyval grapevines at Fenn Valley
vineyards during the 1993 growing season ..................... 80

Inﬂuence of canopy configuration on lateral shoot
production in Seyval grapevines at Fenn Valley vineyards
during the 1993 growing season ............................ 81

Inﬂuence of canopy conﬁguration on lateral shoot leaf
production in Seyval grapevines at Fenn Valley vineyards
during the 1993 growing season ............................ 82

Inﬂuence of canopy configuration on lateral shoot
growth (cm) in Seyval grapevines at Fenn Valley vineyards
during the 1993 growing season ............................ 83

Inﬂuence of canopy configuration on total shoot
vegetative growth (cm) in Seyval grapevines at Fenn
Valley vineyards during the 1993 growing season ................ 84

Inﬂuence of canopy configuration on total leaves per shoot
in Seyval grapevines at Fenn Valley vineyards
during the 1993 growing season ............................ 85

Inﬂuence of eanopy conﬁguration on leaf area production
in Seyval grapevines at Fenn Valley vineyards
during the 1993 growing season ............................ 86

CHAPTER III

1992 standard for ﬂowers per cluster measurements
in Seyval grapevines .................................... 108

1993 standard for ﬂowers per cluster measurements in
Seyval grapevines ...................................... 109

Effect of pruning severity on the 1992 season canopy
development of Seyval grapevines at Fenn Valley vineyards,
expressed as leaf layer number ............................. 110

Effect of pruning severity on the 1993 season canopy

development of Seyval grapevines at Fenn Valley vineyards,
expressed as leaf layer number of Seyval ...................... 1 1 1

xi

Inﬂuence of pruning severity on the total vegetative
length per shoot (primary + lateral) of Seyval grapevines
at Fenn Valley vineyards during the 1993 growing season ........... 112

Inﬂuence of pruning severity on the total leaves per shoot
(primary + lateral) of Seyval grapevines at Fenn Valley
vineyards during the 1993 growing season ..................... 113

Inﬂuence of pruning severity on the lateral number
per shoot (primary + lateral) of Seyval grapevines

at Fenn Valley vineyards during the 1993 growing season ........... 114

1992 percentage Botrytis rot as a function of the

number of benies set per cluster in Seyval grapevines .............. 115

1993 percentage Botrytis rot as a function of the

number of benies set per cluster in Seyval grapevines .............. 116
CHAPTER IV

1992 standard for ﬂowers per cluster measurements
in Vignoles grapevines ................................... 139

1993 stande for ﬂowers per cluster measurements
in Vi gnoles grapevines ................................... 140

1991 and 1992 combined Vignoles primary bud
hardness evaluation ..................................... 141

1991 and 1992 combined Vignoles peridenn
hardness evaluation ..................................... 142

Inﬂuence of pruning severity on primary shoot length
(cm) in Vignoles grapevines at Fenn Valley vineyards
during the 1993 growing season ............................ 143

Inﬂuence of pruning severity on primary shOot leaf production
in Vignoles grapevines at Fenn Valley vineyards
during the 1993 growing season ............................ 144

Inﬂuence of pruning severity on lateral shoot production

in Vignoles grapevines at Fenn Valley vineyards
during the 1993 growing season ............................ 145

xii

10.

11.

Inﬂuence of pruning severity on lateral leaf production
in Vignoles grapevines at Fenn Valley vineyards
during the 1993 growing season ............................ 146

Inﬂuence of pruning severity on lateral shoot length
(cm) in Vignoles grapevines at Fenn Valley vineyards
during the 1993 growing season ............................ .147

Inﬂuence of pruning severity on total vegetative length per
shoot (primary + lateral) in Vi gnoles grapevines at Fenn
Valley vineyards during the 1993 growing season ................ 148

Inﬂuence of pruning severity on total leaves per

shoot (primary + lateral) in Vi gnoles grapevines at Fenn
Valley vineyards during the 1993 growing season ................ 149

xiii

!J

10.

11.

APPENDIX

Inﬂuence of cane diameter on the primary bud
cold hardiness of Seyval grapevines ........................ 155

Inﬂuence of cane diameter on the periderm
cold hardiness of Seyval grapevines ........................ 156

Inﬂuence of intemode length on the primary bud
cold hardiness of Seyval grapevines ........................ 157

Inﬂuence of intemode length on the periderm
cold hardiness of Seyval grapevines ........................ 158

Inﬂuence of periderm color on the primary bud
cold hardiness of Seyval grapevines ........................ 159

Inﬂuence of periderm color on the periderm
cold hardiness of Seyval grapevines ........................ 160

Inﬂuence of lateral status on the primary bud
cold hardiness of Seyval grapevines ........................ 161

Inﬂuence of lateral status on the periderm
cold hardiness of Seyval grapevines ........................ 162

Inﬂuence of node position along the cane on
the primary bud cold hardiness of Seyval grapevines ............. 163

Inﬂuence of node position along the cane on
the periderm cold hardiness of Seyval grapevines ............... 164

Inﬂuence of cane characteristics on primary bud cold
hardiness of Seyval grapevines at Fenn Valley vineyards .......... 165

Inﬂuence of eane characteristics on periderm cold
hardiness of Seyval grapevines at Fenn Valley vineyards .......... 166

xiv

Introduction

VineyardManagememﬂoals

The viticulturalist’s objective is to manage each grapevine to produce the greatest
consistent yield of high-quality fruit, while maintaining vine health. Cultural management
research has increased the understanding of canopy conﬁguration, structure, and function.
However, few practices have been adopted commercially by growers because of
differences in cultivars, climates, and soils. An understanding of specific circumstances of
cultivar growth, localized environment and costs of production are required if the

viticulturalist’s objective is to be achieved.

Cmpﬂontmlandlargeﬂusteredﬂnltivars

Many phylloxera resistant grape cultivars are economically important in Michigan
viticulture. However, because their growth and fruiting habits often differ from the widely
cultivated Vitis labruscana Bailey grapevines, dormant-season balanced pruning, a proven
method of controlling crop level and maintaining fruit quality of V. labruscana (11,44), can
fail to provide adequate crop control for many large clustered hybrid cultivars
(22,36,37,46). Some cultivars can produce three or four heavy (>500 gm) clusters per
shoot as well as fruitful lateral shoots (59). Fruitful shoots can also arise from base buds
that are not counted in the balanced pruning practice (46,57). For such high producing
cultivars, increasing the pruning severity is insufficient to control crop load and maximize
ﬁlling of the trellis space with leaves early in the growing season (46,57). Overproduction
is detrimental to vegetative growth and fruit maturity (11,22,25,26,31,44,46,61,64,
90,96), but can be corrected by cluster thinning (22,26,36,37, 61,96) so that, a balance

1

2

between vegetative growth and fruiting is produced. However, thinning increases labor
and production expense for such cultivars. Severe pruning is presently employed to limit
cluster thinning costs. Such pruning delays canopy formation early in the growing season;
maximum leaf area for the trellis space is not reached until well after bloom. The potential
loss of photosynthesis due to the delay in canopy formation is of concern. A more cost-
effective method of crop control and canopy management that would better utilize vine

capacity would be very useful.

(1118th

Even with successful cropping procedures, pathogens can upset the balance
achieved between vegetation and fruit, causing damage to vine health and fnrit quality.
Cultivars differ in their vulnerability to different pathogens. Seyval has a serious harvest
season cluster rot problem due primarily to Botrytis cinerea Pers. The most serious
infections occur post-veraison during fruit ripening after rains, when the foliage layers are
fully developed and drying of the clusters is inhibited. Cluster exposure and berry contact
within the cluster inﬂuence Botrytis rot incidence and intensity of infection (54). At
present, an extensive chemical spray schedule is needed to prevent infection. However,
many important fungicides are being banned or their use limited. Cultural practices are
needed that would reduce cluster rot infection and decrease dependance on the use of
chemicals normally applied for control.

The cultivars Seyval (S.V. 5276) and Vignoles (Ravat 51) were chosen for this
study because both are of importance in Michigan’s wine industry and both have serious
cluster rot problems. In addition, Seyval is easily overcropped because it forms large,
compact clusters. Seyval is managed using severe balanced pruning and ﬂower cluster
thinning (37). It is recommended that a 15+10 balanced pruning formula with thinning to

1.5 clusters per shoot be employed to control crop level (61).

3

Vignoles is by contrast, a small-clustered cultivar that also bears compact clusters
susceptible to Botrytis infection. Because of the smaller clusters, balanced pruning alone is
sufficient for crop control. A 15+15 pruning formula on a High Cordon training system is
recommended (28). More practical cultural methods need to be investigated in the
production of both these cultivars. Importantly, information learned on these two should
provide a basis for similar problems in other cultivars such as Chancellor and Pinots noir,

gris and blanc.

Literature Review

meArea

The photosynthate produced during the vegetative season must drive the processes
of vegetative growth, fruiting, and ﬂower bud development for next years crop. Reserves
must also be stored over the winter for cold hardiness, and initiation of growth and
development, until a new canopy is producing photosynthate the following spring. Equally
as signiﬁeant is the mobilization and transport of assimilate between different organs of the
vine in order to carry out these processes.

Leaf development is important for fruit and shoot maturity. A leaf number greater
than 10 per shoot is necessary for optimal fruit ripening and shoot weight (87,93). Leaf
photosynthesis is greatest when the leaf is fully expanded, and then gradually declines
shortly thereafter (56). The amount of photosynthate produced by each leaf is important
for the development of the subtending bud (24,79). Over 80 percent of the assimilate a
cluster collects is produced by the leaves on the same side of the shoot (47,48). Buttrose
(8) found that as leaf number was reduced, root dry weight decreased most severely,
followed by reductions in berry development, and then trunk and shoot carbohydrate
reserves. Increasing the number of leaves per shoot increases berry sugar, weight, and
coloration at harvest (87). However, the production of each new leaf adds to the vine leaf
area and the formation of leaf layers within the canopy.

The leaf area of the vine is critical because it produces the assimilate necessary for
crop ripening and wood maturity. A minimum leaf area of 7-14 cmA2 per gram of fruit is
needed for adequate fruit ripening (31,83). Smart showed that a dense canopy can reduce
light levels to 1% of the solar radiation in the fruiting and renewal zone (80), and an
optimal eanopy has no more than three leaf layers (81). Light penetration into the canopy is

important for photosynthesis (35,78), f ruitf ulness (27,74), ﬂower bud formation (74,80),

5

fruit set (15,68), fruit quality (63,65,82), yields (74), and wood hardiness (25,74,85).
Thus, it is evident that a maximum leaf area exists where light penetration into the canopy is
restricted to the point that vine productivity and conditions begin to diminish. The
maintenance of this leaf area is important to maximize the amount of assimilate produced in
the vegetative season for vine growth and development.

When this maximum leaf area to facilitate vine grth is established is of great
interest. l4C-labeled assimilates move from the leaves to the perennial portions of the vine
in autumn, and then reappear in the shoot growth the following spring (73). This new
growth is dependent on the remobilization of stored carbohydrates from the previous year
(98,99). Photosynthesis increases up to the fourth week after anthesis and then declines
until harvest (53). Cluster development is slow until the leaf area is established (95).
Thus, it is important to ﬁll the trellis area with vegetative growth as early as possible to

facilitate vine growth and development without creating a dense canopy later in the season.

Canopyﬂeaign

Manual labor for pruning and thinning has become increasingly scarce and costly.
Much attention has been focussed on minimal pruning management techniques to reduce
labor. Mechanical hedging, selective hand pruning, or no pruning, increase the number of
buds retained for potential shoot production from the previous years vegetative growth
compared to conventional pruning. Downton and Grant (20) showed that an increase in
shoot number resulted in a change in vine morphology; smaller shoots were produced
compared to spur pruned vines. Minimally pruned vines had a greater leaf area and higher
photosynthetic rates before bloom, but little leaf production after, as spur pruned vines had
a greater leaf area at harvest. The total amount of carbon ﬁxed per vine was similar
between treatments, but proportioned differently. Minimally pruned vines allocated more
photosynthate to fruit ripening than to wood maturity. They concluded that minimally

6

pruned vines lose less of their fixed carbon from the previous year due to pruning. This
was supported by Ruhl and Clingeleffer (69), who found that minimally pruned vines
stored more carbohydrates in old wood but less in their canes and roots. Without any other
crop control, minimal pruning increases yield as a function of increased cluster number, but
brix are usually lower (41). Increasing shoot number increases both canopy density (81)
and the labor expense incurred by cluster thinning fruitful varieties.

Mechanical hedging has been suggested as an alternative to hand, balanced pruning,
since it may increase labor efﬁciency three to six-fold (75,83). Continuous use of hedging
requires the vineyard to be uniform in vine size and vigor (45) and without eane selection
or shoot positioning, it has been shown to be useful for only a few years (45,55,66). It
increases the amount of vegetation per foot of trellis space (43,45,55), allowing for earlier
ﬁlling of the canopy. However, mechanical pruning for more than one to three years
results in reduced yields, fruitfulness and fruit quality (43,45,55). Mechanical hedging
may be a viable alternative when it is done in conjunction with selective hand pruning

techniques (66).

CarlnlrydrateSinks

The organs competing for photoassimilates are termed sinks and the control of
assimilate transport is determined by the relative position of the source leaves and sink
organs, and the relative strength of the sink organs to accumulate assimilates (48). From
bud-burst to bloom, the rapidly expanding leaves and shoot apex are the primary sinks for
stored carbohydrates (95). Flower clusters compete for carbohydrates during bloom (60).
After anthesis, the shoot apex and the developing clusters become the strongest sinks
(15,24,60). At harvest, the vine storage sinks compete for assimilate. Only by balancing
the source to sink ratio, can productive grapevines be maintained.

An excessive crop creates a situation where the total fruiting sink is greater than any

Ull ll

mot
clux'

Hilc‘l

F”

i WES.

7

other sink. In response to excess crop, vine size decreases as shoot growth diminishes
(22,25,26,61,64). Overcropping negatively effects fruit quality, beny weight, cluster
weight, and berries per cluster (26,31,62). Fruit and wood maturity are delayed
(2,5,61,92,97). The increased competition from high crop levels can inﬂuence
morphological characteristics such as a decrease in shoot length, leaf size, cluster size,
cluster weight, and berry weight (4,30,90). These canopy reductions improve canopy
microclimate (63,64) and increase photosynthetic efﬁciency through reduced shading (83).
Lateral shoots supply assimilate to clusters on the main shoot, but when fruitful, the mid-
season clusters they produce draw assimilate from the main shoot (34). In total, an

excessive crop level disrupts the source to sink balance, and is detrimental to vine growth

and health.

El 1.. . IE’EI ..

Each node formed on a grapevine shoot contains three partially developed shoots
with leaf and ﬂower primordia for the following year (95). The apical buds formed late in
the growing season are the least mature along the cane in the fall. Because the basal buds
of a shoot are close in proximity to the storage and fruiting sinks, they accumulate
carbohydrates later than the more apieal nodes, and are less fruitful in most cultivars (95).
The French-American hybrids have fruitful basal buds (46,57). The leaf subtending each

developing bud is the main source of assimilate for that bud (24,79). Thus, the light
intensity on that leaf and bud is important during ﬂower bud development (40,79), and
Shading can decrease vine f nritf ulness (27,74).

Flower initiation begins in early summer, when each bud begins to swell (58,84).
BUds mature throughout the vegetative season. Differentiation from vegetative to fruiting
Plimordia occurs in late summer until the vine acclimates to winter. The calyx, corolla,

Slamws, and pistil are differentiated the following spring (72). Two carpels makeup the

8

pistil with two ovules in each carpel. With development of the stamens and differentiation

of the pollen, the perfect inﬂorescence are ready to bloom.

BloonLandEmitzset

The basal clusters are the ﬁrst to bloom, six to eight weeks after bud burst.
Blooming lasts one to three weeks, with temperature being the controlling factor (95).
High relative humidity and rain hamper pollination, while moisture stress decreases fruit set
for up to four weeks following bloom (1). Grape ﬂowers are either self-pollinated or aided
by insects and wind (95). Fruit set is best at temperatures between 20 and 30 C (9,86).

Two theories exist as to what regulates fruit set in grape vines. One suggests that
growth hormones are transported to the cluster to induce set (88,89), while the other
proposes that carbohydrate supply determines fruit set (49). Inna-vine competition for
carbohydrates and growth hormones by vegetative (90) and fruiting sinks ( 17) have been
shown to have a negative effect on fruit set Reducing sink competition and growth
hormone sources by removing shoot tips, increases fruit set (15,76). Decreasing
assimilate sources by leaf removal during bloom decreases fruit set (10). Thinning ﬂower-
clusters increases pollen genuinability and fruit set (94). Within-cluster competition
decreases fruit set (37). Mullins (49) demonstrated that fruit set can occur in ﬂowers
cultured in vitro on a medium of sucrose and nutrients, suggesting that fruit set is regulated
by assimilate supply. Roper et. al. (67) suggest that competition for photosynthate may be
the limiting factor in cranberry fruit set.

Strawberry fruit set and initial growth is not limited by the ability of receptacles to
mobilize current source leaf assimilates; and early fruit grth is not related to pool sizes
( l9). Nitsh (51) removed the achenes of strawberries and the receptacle ceased to enlarge.
However, if the berry was coated with a lanolin paste containing auxin, it enlarged

normally. It is assumed the strawberry receptacle requires auxin for normal growth (52).

barn
Cmm
l'ariet
full cc
stems]

and ne

H
en‘r

Emily;
Bﬁﬂd

Crumb;

9

In grapevines, a direct correlation is reported between berry size and seeds per
berry (12). Seed number has little relationship with auxin or abscisic acid content (9).
Coombe (14) found increased auxin levels and improved fruit set in girdled vines.
Varieties that undergo normal set contain higher auxin levels and greater berry size with a
full complement of developing seeds than varieties that are stimulative parthenocarpic or
stenospermocarpic (95). A competition for carbohydrates and growth hormones exists,

and needs further experimentation to determine optimum cultural practices.

BerrsLDeyelornnem

When the benies become active sinks, many of their tissues become meristematic
and growth begins. Those berries that have not initiated this process generally abscise.
Berry development follows a double sigmoid growth curve consisting of three stages (18).
Coombe (18) suggests that cell division before verasion and cell expansion after anthesis
are the major determinants of the increase in weight of ﬂeshy fruits. Some contributions
are made by cell division after anthesis and an increase in concentration of solutes. Little is
known about the inﬂuences upon early cell division and its differences may commonly
contribute to fruit size variation. Early availability of carbohydrates and growth hormones

would appear to be of great importance during this time.

Manipulating the carbohydrate source/sink balance, can alter fruit set in grapevines.
Shoot tipping at bloom (13,15,76), girdling (5,13), ﬂower-cluster thinning (91,92), and
the application of growth regulators (5,13,16) increase fruit set. Heavy pruning (91) or
leaf removal during bloom decreases fruit set (10). Increasing the light intensity for
photosynthesis promotes fruit set (68). It follows that vine training to allow more light

reception into the canopy could increase fruit set (‘77).

1O

Pruning is presently the most cost effective way to control crop level. Balanced
pruning uses the one-year-old cane prunings as an estimate of vine size to determine the
vines capacity for growth and production (3). Capacity is defined as the vines ability for
total vegetative and reproductive growth (95). Vegetative growth can then be balanced with
expected crop level to maintain vine size and sufficiently ripen the fruit (26).

As stated earlier, easily overcropped cultivars, such as Seyval, require thinning.
Thinning increases the ratio of leaves to fruit, improving the nutrition of both the vine and
fruit (95). Some cultivars are ﬂower-cluster thinned (37). Flower-cluster thinning
increases pollen gerrninability, fruit set (94), and shoot growth (22,37). Post-set thinning
decreases fruit set by increasing the fruiting and vegetative sink competition for assimilate
and growth hormone (17,90), as well as reducing pollen quality. Reduced fruit set
decreases cluster compactness. Post-set thinning reduces berries per cluster in Seyval, and
a compensatory increase in berry size and fruit quality follows (29). Vegetative vigor and
the development of laterals decreases as thinning is delayed until after fruit set (29). The
period for source/sink manipulation of fruit set is suggested to extend from bloom to two

weeks post-set (10).

ﬂlemicallnﬂuencemEnukSet

The use of growth regulators is an altemative to hand thinning. Both ethephon and
gibberellic acid have been used as berry abscission agents (36,37,91). Ethephon’s
effectiveness is dependant upon environmental conditions, time of application,
concentration, and cultivar (91). Gibberellic acid response has not been consistent (36,37).
Chlormequat (CCC) application increases fruit set under good conditions (5,16) by
diverting organic nutrients from the shoot tips to the developing ovaries (60). More
partially seeded berries are set (5). Roubelakis and Kliewer (68) were unable to induce

fruit set with CCC applications during poor light and temperature regimes.

11

Culturalﬁomroloﬁﬂatgztis

The control of Botrytis cinerea Pers. is a costly endeavor for the vineyard manager.
Cluster infection usually occurs late in the growing season, decreasing yield and fruit
quality. B. cinerea survives the winter by forming sclerotia either on the surface or within
plant tissue. Clusters and dead wood retained in the vineyard from the previous season can
be an important source for inoculum in the spring the following year. The fungus lives
most of its life as a saprophyte, getting nutrients from dead or dying plant parts (39). It
may infect grape ﬂowers and remain latent in these tissues until the clusters begin to mature
(42). The spores of B. cinerea require prolonged periods of free water and nutrients on
the berry surface for germination (39,50). Enzymes produced by the fungus can destroy
the integrity of the berry in less than 24 hours (39).

The grape berry’s main protection to Botrytis infection is its skin. The cuticle
membrane and the epicuticular wax, provide the primary physical barrier to pathogen
invasion (2). For berry infection to occur, the pathogen must ﬁnd a weakness on the berry
surface where it can bypass the cuticle membrane, or directly penetrate the surface (6). The
epicuticular wax layer inﬂuences the retention of pesticides, the water retention of the berry
surface, and the adhesive ability of plant pathogens (2). Percival et al. (54) found that
berries of exposed clusters and those having little berry contact, produced more epicuticular
wax and cuticle. Infection can be reduced by improving the microclimate within the canopy
(39,70,71).

By reducing the periods of free water within the canopy and increasing cluster
exposure through canopy management, disease pressure within the vineyard can be
reduced (39). leaf removal in the fruiting zone decreases infection (21,23,33,54). Since
the leaf area is the source for photoassimilate, defoliation can have a detrimental affect on

fruit quality (10,25,38), vine growth (7,32), and hardiness (25,38,85). Grapevines are

1")

able to compensate for the loss in leaf area by producing lateral shoots and increasing their
photosynthetic efficiency (7,10,32). However, fruitful laterals draw assimilate from the
main shoot (34). Defoliation in moderation can improve the canopy microclimate at the
expense of assimilate production. The canopy microclimate can be improved to decrease

Botrytis cinerea incidence, through better design (70,71,81).

Statement of Objectives

An efﬁcient canopy maintains enough leaf area to produce quality fruit and a
sufﬁcient number of mature buds. It allows for adequate light penetration into the fruiting
zone of the canopy to ripen fruit and inhibit Botrytis infection. Some cultivars are more
susceptible to cluster rot because they bear compact clusters. This cluster structure holds
moisture within, facilitating infection. More economical practices are needed to address
this problem.

Seyval and Vignoles are valuable cultivars for white wine production in the state of
Michigan. However, their growth habits pose some problems in producing quality fruit.
Seyval produces large, compact clusters that have a tendency to contract Botrytis at
harvest. Presently it is recommended that Seyval be severely pruned and cluster thinned to
control overcropping. This inhibits early filling of the trellis area. Vignoles is a small
clustered cultivar that also has a tendency to contract Botrytis rot at harvest The removal
of reproductive and vegetative sinks diverts photoassimilate to retained sinks. The time of
cluster and whole shoot removal inﬂuences assimilate supply per alternate sink during the

critical period of fruit set.

13

II 1.. [I' I, .

H

L)

or

To investigate economical pruning techniques that will allow for expedient ﬁlling of the
trellis for optimum fruit ripening in Seyval.

To explore the effect of post-set cluster thinning to ﬁnd an optimum method for
decreasing Botrytis rot and improving fruit quality in Seyval.

To examine the effect of post-set pruning on fruit set and Borryris infection in
Vi gnoles.

II I“! l' I l [1' I .

. Hedging is a viable practice for pruning Seyval grapevines and maintaining quality

yields and vine health.

A canopy constructed of optimally spaced shoots will have superior architecture for
fruit and wood maturity.

. Increasing the amount of fruiting sinks at fruit set will decrease the number of berries

SCI.

Increasing the number of vegetative sinks at fruit set will decrease the number of benies
set.

Decreasing the number of benies set by post-set thinning and pruning will decreases the
amount of Bonytis rot.

The loss in yield in Seyval because of the decrease in fruit set can be overcome by
retaining more clusters per vine during thinning.

By using the competition among fruiting and vegetative sinks, I believe that more

economical and environmentally sound canopy management practices can be adopted to

improve fruit quality and health of the vine.

to

Literature Cited

. Alexander, D. 1965. The effect of high temperature regimes or short period of water

stress on development of small fruiting Sultana vines. Austral. J. A gr. Res.
16:817-823.

Baker, EL. 1982. Chemistry and morphology of plant epicuticular waxes. In:
Cutler, D.F., Alvin K.L., Price, C.E. (Eds): The Plant Cuticle, 139-161.
Acedemic Press, Toronto.

Bell, H.K., R.P. Larson and A.L. Kenworthy. 1958. Balanced pruning of the
Concord grape - another look under present-day conditions. Quarterly Bull. Mich.
Agr. Exp. Station. Michigan State Univ. 40:915-919.

Bravdo, B., Y. Hepner, C. Loinger, S. Cohen, and H. Tabacman. 1984. Effect of
crop level in a high yielding Cari gnane vineyard on growth, yield, and wine
quality. Am. J. Enol. Vitic. 35:247-252.

Brown, K., D.I. Jackson, and GE Steans. 1988. Effects of Chlormequat,
girdling, and tipping on beny set in Vitis vinifera L. Am. J. Enol. Vitic.
39(1):91-94.

Bulit, J., and D. Dubos. 1988. Botrytis bunch rot and blight. In: Pearson, R.C.,
Goheen, A.C. (Eds): Compendium of grape diseases, 13-15.
APS Press, St. Paul.

Buttrose, MS. 1966. The effect of reducing leaf area on the growth of roots, stems,
and berries of Gordo grapevines. Vitis. 5:455-464.

Buttrose, MS. 1968. The effect of varying berry number on Gordo grapevines with
constant leaf area. Vitis 7:299-302.

Buttrose, MS. and CR. Hale. 1973. Effect of temperature on development of the
grapevine inﬂorescence after budburst. Am. J. Enol. Vit. 24: 14—16.

10. Candolﬁ-Vasconcelos, MC. and W. Koblet. 1990. Yield, fruit quality, bud fertility

and starch reserves of the wood as a function of leaf removal in Vitis vinifera -
Evidence of compensation and stress recovering. Vitis. 29:199-221.

11. Cawthon,D.L. and JR. Morris. 1977. Yield and quality of Concord grapes as

affected by pruning severity, nodes per bearing unit, training system, shoot
positioning, and sampling date in Arkansas. J. Amer. Soc. Hort. Sci.
102:760-767.

12. Cawthon, D.L. and JR. Morris. 1982. Relationship of seed number and

maturity to berry development, fruit maturation, hormonal changes, and uneven
ripening of Concord grapes. J. Amer. Soc. Hort. Sci. lO7(6):1097-1104.

14

13.

14.

15.

16.

17.

18.

19.

20.

21.

22.

24.

25.

26.

15

Coombe, B.G. 1959. Fruit set and development in seeded grape varieties as affected
by defoliation, topping, girdling, and other treatments. Am. J. Enol. Vitic.
10:85-100.

Coombe, B.G. 1960. Relationship of growth and development to changes in sugar,
auxin, and gibberellins in fruit of seeded and seedless varieties of Vitis vinifera.
Plant Physiol. 35:241-250.

Coombe, B.G. 1962. The effect of removing leaves, ﬂowers and shoot tips on fruit
set of Vitis vinifera L. J. Hort. Sci. 37: 1-15.

Coombe, B.G. 1970. Fruit set in grapevines: The mechanism of the CCC effect.
J. Hort. Sci. 45:415-425.

Coombe, B.G. 1973. Regulation of set and the development of the grape beny.
Acta. Horticulture 34:261-273.

Coombe, B.G. 1976. The development of ﬂeshy fruits. Ann. Rev. Plant
Physiol. 27(2):507-528.

Darnell, R.L. and CC. Martin. 1988. Role of assimilate translocation and
Carbohydrate accumulation in fruit set of strawberry. J. Amer. Hort. Sci.
113(1): 114-1 18.

Downton, W.J.S. and W.J.R. Grant. 1992. Photosynthetic physiology of spur
pruned and minimal pruned grapevines. Aust. J. Plant Physiol. 19:309-316.

English, J.T., C.S. Thomas, J.J. Marois, and W.D. Gubler. 1989. Microclimates of
grapevine canopies associated with leaf removal and control of Botrytis bunch rot.
Phytopathology. 79(4):395-40l.

Fisher, K.H., O.A. Bradt, J. Wiebe and V.A. Dirks. 1977. Cluster thinning ‘de
Chaunac’ French hybrid grapes improves vine vigor and fruit quality in Ontario. J.
Amer. Soc. Hort. Sci. 102(2):l62-165.

Gubler, W.D., J.J. Marois, A.M. Bledsoe, L.J. Bettiga. 1987. Control of
Botrytis bunch rot of grape with canopy management. Plant. Dis. 71(7):599-601.

Hale, CR, and PJ. Weaver. 1962. The effect of developmental stage on direction
of translocation of photosynthate in Vitis vinifera . Hilgardia 33:89-131.

Howell, G.S., B.S. Stergios and SS. Stackhouse. 1978. Interrelation of
productivity and cold hardiness of Concord grapevines. Am. J. Enol. Vitic.
29: 187-191.

Howell, G.S., T.K. Mansfield and J.A. Wolpert. 1987. Inﬂuence of training
system, pruning severity, and thinning on yield, vine size and fruit quality of Vidal
blanc grapevines. Am. J. Enol. Vitic. 38(2): 105-1 12.

29.

30.

31.

32.

33.

34.

35.

36.

37.

38.

39.

16

Howell, G.S., D.P. Miller, C.E. Edson and R.K. Streigler. 1991. Inﬂuence of
training system and pruning severity on yield, vine size, and fruit maturity of
Vignoles grapevines. Amer. J. Enol. Vitic. 42(3):]91-198.

Howell, G.S. May 1992. Pruning and training Vignoles grapevines in
Michigan. Vintner & Vineyard. Coop. Ext. Serv. Pub. 6(1):1-6.

Hunter, D.M. and J.T.A. Proctor. 1985. Effects of timing of thinning inﬂuence on
Seyval blanc fruit yields and quality. Presented at 10th Annual meeting of the
American Society for Enology and Viticulture/Eastern section, Mississauga, Ont.
(August 1985).

Kaps, ML. and GA. Cahoon. 1989. Berry thinning and cluster thinning inﬂuence
on vegetative growth, yield, fruit composition, and net photosynthesis of Seyval
blanc grapevines. J. Amer. Soc. Hort. Sci. 114(1):20-24.

Kliewer, W.M. and RJ. Weaver. 1971. Effect of crop level and leaf area on
growth, composition and correlation of ‘Tokay’ grapes. Am. J. Enol. Vitic.
23: 172-177.

Kliewer, W. M and R. D. Fuller. 1973. Effect of time and severity of defoliation on
growth of roots, trunk and shoots of Thompson Seedless grapevines. Am. J.
Enol. Vit. 24: 59-64.

Kliewer, W.M. and A.M. Bledsoe. 1987. Inﬂuence of hedging and leaf removal on
canopy microclimate, grape composition, and wine quality under Califomia
conditions. Acta. Hort. 206: 157-168.

Koblet, W. 1977. Translocation of photosynthate in grapevines. In: Proc. OIV
symp. on the quality of the vintage. pp.45-51. OVRI, Stellenbosch, South Africa.

Kriedemann, P.E., B.R. Loveys, and W.J.S. Downton. 1975. Internal control of
stomatal physiology and photosynthesis. 2. Photosynthetic responses to phaseic
acid. Aust. J. Plant Physiol. 2:553-567.

Looney, NE. and DP. Wood. 1977. Some cluster thinning and gibberellic acid
effects on fruit set, berry size, vine growth, and yield of DeChaunac grapes.
Canadian J. Plant Sci. 57:653-659.

Looney, NE 1981. Some growth regulator and cluster thinning effects on berry set
and size, berry quality, and annual productivity of ‘De Chaunac’ grapes. Vitis
20: 22-35.

Mansﬁeld, T.K. and GS. Howell. 1981. Response of soluble solids accumulation,
fruitfulness, cold resistance, and the onset of bud growth to different defoliation
stress at verasion in Concord grapevines. Am. J. Enol. Vitic. 32:200—205.

Marios, J.J. 1987. Botrytis bunch rot of grapes. Oregon Dpt of Agr.: The Wine
Advisory Board Research Report June (S):1-6.

43.

45.

47.

49.

51.

52.

53.

17

May, P. and A.J. Antcliff. 1963. The effect of shading on f ruitfulness and yield of
the Sultana J. Hort. Sci. 38:85-94.

. McCarthy, M.G., and RM. Cirami. 1990. Minimal pruning effects on the

performance of selections of four Vitis vinifera cultivars. Vitis 29:85-96.

. McClellan, W.D. and W.B. Hewitt. 1973. Early Botrytr's rot of grapes: Time of

infection and latency of Botrytis cinerea Pers. in Vitis vinifera L. Phytopathology.
63: 1 151-1 157.

Morris, J.R., D.L. Cawthon, and J.W. Flemming. 1975. Effect of mechanical
pruning on yield and quality of Concord grapevines. Ark. Farm Res. pub.

24(3):1-12.

Morris, JR. and D.L. Cawthon. 1980. Yield and quality responses of Concord
grapes to training systems and pruning severity in Arkansas.
J. Amer. Soc. Hort. Sci. 105:307-310.

Morris, JR. and D.L. Cawthon. 1981. Yield and quality responses of
Concord grapes to mechanized pruning. Am. J. Enol. Vitic. 32(4):280-282.

Morris, J.R., C.A. Sims, J.E. Bourque and J.L. Oakes. 1984. Inﬂuence of training
system, pruning severity and spur length on yield and quality of six French-
American hybrid grape cultivars. Am. J. Enol. Vitic. 35:23-27.

Motomura, Y. 1990. Distribution of l4C-assimilates from individual leaves on
clusters in grape shoots. Am. J. Enol. Vitic. 41:306-312.

Motomura, Y. 1993. 14C-assimilate partitioning in grapevine shoots: Effects of
shoot pinching, girdling of shoot, and leaf -halving on assimilate partitioning from
leaves into clusters. Am. J. Enol. Vitic. 44: 1-7.

Mullins, M. G. 1967. Regulation of fruit set in the grapevine. Aust. J. Biol. Sci.
20: 1 141-1 147.

Nelson, KB. 1951. Factors inﬂuencing the infection of table grapes by Botrytis
cinerea (Pers). Phytopathology. 41:319-326.

Nitsch, JP. 1950. Growth and morphogenesis of the strawberry as related to auxin.
Amer. J. Bot. 37:211-215.

Nitsch, JP. 1953. The physiology of fruit growth. Ann. Rev. Plant Physiol.
4:199-236.

Pandey, RM. and H.L. Farmahan. 1977. Changes in the rate of photosynthesis and
respiration in leaves and berries of Vitis vinifera grapevines at various stages of
berry development. Vitis. 16:106-111.

55.

57.

59.

61.

65.

I8

Percival, D.C., J.A. Sullivan, and K.H. Fisher. 1993. Effect of cluster exposure,
berry contact and cultivar on cutical membrane f orrnation and occurrence of bunch
rot (Botrytis cinerea Pers.:Fr.) with 3 Vitis vinifera L. cultivars. Vitis 32:87-97.

Pollock, J.G., ES. Shepardson, NJ. Shaulis, and DE. Crowe. 1977. Mechanical
pruning of American hybrid grapevines. Trans. ASAE 20(5):817-821.

Poni, S., C. Intrieri, and O. Silvestroni. 1994. Interactions of leaf age, fruiting and
exogenous cytokinins in Sangiovese grapevines under non-ini gated conditions. 1.
Gas exchange. Am. J. Enol. Vitic. 45(1):71-78.

Pool, R.M., C. Pratt, and H.D. Hubbard. 1978. Structure of base buds in relation to
yield of grapes. Amer. J. Enol. Vit. 29:36-41.

Pratt, C. 1971. Reproductive anatomy of grapes - A review. Amer. J. Enol. Vitic.
22292-109.

Pratt, C. 1974. Vegetative anatomy of cultivated grapes- -A review. Amer. J. Enol.
Vit. 25:131- 150.

Quinlan, JD. and R.J. Weaver. 1970. Modiﬁcation of pattern of the photosynthate
movement within and between shoots of Vitis vinifera L. Plant Physiol.
46: 527-530.

Reynolds, A.G., R.M. Pool and LR. Mattick. 1986a. Effect of shoot density and
crop control on growth, yield, fruit composition and wine quality of ‘Seyval blanc’
grapevines. J. Amer. Soc. Hort. Sci. 111(1):55-63.

. Reynolds, A.G., R.M. Pool andL.R. Mattick. 1986b. Inﬂuence of cluster exposure

on fruit composition and wine quality of ‘Seyval blanc’ grapes. Vitis 25:85-95.

. Reynolds, A.G., and DA. Wardle. 1989a. Impact of various canopy management

techniques on growth, yield, fruit composition and wine quality of
Gewurtztraminer. Am. J. Enol. Vitic. 40:121-129.

Reynolds, AG. and DA. Wardle. 1989b. Effects of timing and severity of summer
hedging on growth, yield, fruit composition, and canopy characteristics of ‘De
Chaunac’ 1. Canopy characteristics and growth parameters. Am. J. Enol. Vitic.
40:109-120.

Reynolds, AG. and DA. Wardle. 1989c. Effects of timing and severity of summer
hedging on growth, yield,fruit composition, and canopy characteristics of ‘De
Chaunac’ 2. Yield and fruit composition. Am. J. Enol. Vitic. 40:299-308.

Reynolds, AG. and DA. Wardle. 1993. Yield component path analysis of Okaagan
Reisling vines conventionally pruned or subjected to simulated mechanical pruning.
Am. J. Enol. Vitic. 44(2):]73-179.

67.

69.

70.

71.

72.

74.

75.

76.

79.

19

Roper, T.R., EJ. Stang, and GM. Hawker. 1992. Early season leaf removal
reduces fruit set and size in cranberry (Vaccinium macrocarpon Ait.).
Hort. Science. 27(1):75.

Roublelakis, K.A. and W.M. Kliewer. 1976. Inﬂuence of light intensity and growth
regulators on fruit set and ovule fertilization in grape cultivars under low temprature
conditions. Am. J. Enol. Vitic. 27(4):163-167.

Ruhl,E.H. and PR. Clingeleffer. 1993. Effect of minimal pruning and virus
inoculation on the carbohydrate and nitrogen accumulation in Cabernet franc vines.
Am. J. Enol. Vitic. 44(1):81-85.

Savage, SD. and MA. Sall. 1983. Botrytis bunch rot of grapes: The inﬂuence of
selected cultural practices on infection under California conditions. Plant Dis.
67: 77 1-774.

Savage, SD. and MA. Sall. 1984. Botrytis bunch rot of grapes: Inﬂuence of trellis
type and canopy microclimate. Phytopathology. 74:65-70.

Scholefield, PB. and RC. Ward. 1975. Scanning electron microscopy of the
developmental stages of the Sultana inﬂorescence. Vitis. 14: 14-19.

. Scholefield, P.B., T.F. Neales, and P. May. 1978. Carbon balance of the Sultana

vine (Vitis vinifera L.) and the effects of autumn defoliation by harvest-pruning.
Aust. J. Plant Physiol. 5:561-570.

Shaulis, N., and R. Smart. 1974. Grapevine canopies: management microclimate
and yield responses. In: Proc. XIXth International Hort. Congress. pp. 255-265.
11-18 Sept, Warsaw.

Sims, C.A., R.P. Johnson, and RP. Bates. 1990. Effects of mechanical pruning on
the yield and quality of Muscadine grapes. Am. J. Enol. Vitic. 41(4):273-276.

Skene, K.G.M. 1969. A comparison of the effects of “Cycocel” and tipping on fruit
set in Vitis vinifera . Austr. J. Biol. Sci. 22: 1305-131 1.

Smart, RE. 1973. Sunlight interception by vineyards. Am. J. Enol. Vitic.
24(4): 141-147.

Smart, R.E. 1974a. Photosynthesis by grapevine canopies. J. Applied Ecology
1 1:997- 1006.

Smart, R.E., NJ. Shaulis, and ER. Lemon. 1982b. The effect of Concord
vineyard microclimate on yield. 2. The interrelations between microclimate and
yield expression. Am. J. Enol. Vitic. 33:109-116.

Smart, RE. 1984. Some aspects of climate canopy microclimate, vine physiology
and wine quality. In: Proc. First Intl. Symp. Cool Climate Vitic. Enol. D.A.
Heatherbell, P.B. Lombard, F,W. Bodyfelt, and SF. Price (eds.). pp 1-18. June
1984, Eugene, Oregon. Oregon State Univ.

85.

89.

91.

95.

20

. Smart, RE. 1985. Principles of grapevine canopy microclimate manipulation with

implications for yield and quality. A review. Am. J. Enol. Vitic. 36(3):230-239.

. Smart, RE. 1987. Inﬂuences of light on composition and quality of grapes. Acta

Horticulture. 206237-47.

Smart, R.E., J.K. Dick, I.M. Gravett and BM. Fisher. 1990. Canopy management
to improve grape yield and wine quality - principle and practices.
S. Afric. J. Enol. Vitic. 11:3-17.

Srinivasan, C. and MG. Mullins. 1981. Physiology of ﬂowering in the grapevine:
A review. Am. J.Enol. Vitic. 32(1):47-63.

Stergios, B.G. and GS. Howell. 1977. Effects of defoliation, trellis height, and
cropping stress on the cold hardiness of Concord grapevines. Am. J. Enol. Vitic.
28( l):34»42.

Tukey, L.D. 1957. Effects of controlled temperature following bloom on berry
development of the Concord grape. Proc. Am. Soc. Sci. 71: 157-166.

Weaver, R.J. 1958. Effect of leaf to shoot ratio on fruit quality and shoot
development in Cari gnane and Zinfandel wine grapes. Am. Soc. Enol. Vitic.
14:1-12.

Weaver, R.J., S.B. McCune, and CR. Hale. 1962. Effect of plant regulators on
fruit set and beny development in certain seeded and seedless varieties of Vitis
vinifera. Vitis 3:84-96.

Weaver, R.J., W. Shindy, and W.M. Kliewer. 1969. Growth regulator induces
movement of photosynthate products into fruits of ‘Black Corinth’ grapes.
Plant. Physiol. 44:183-188.

Weaver, R.J. and RM. Pool. 1968. Effect of various levels of cropping on Vitis
vinifera grapevines. Am. J. Enol. Vitic. 19: 185-193.

Weaver, R.J. and RM. Pool. 1971b. Chemical thinning of grape clusters
(Vitis vinifera L.). Vitis. 10:201-209.

Winkler, A.J. 1929. The effect of dormant pruning on the carbohydrate metabolism
of the vine. Hilgardia. 4: 153-173.

. Winkler, AJ. 1930. The relation of number of leaves to size and quality of table

grapes. Proc. Am. Soc. Hrt. Sci. 27:158-160.

Winkler, A.J. 1958. The relation of leaf area and climate to vine performance and
grape quality. Amer. J. Enol. 9: 10-23.

Winkler, A.J., J.A. Cook, W.M. Kliewer and LA. Lider. 1981. General
Viticulture. University of California Press, Berkeley.

21

96. Wolpert, J.A., G.S. Howell, T.K. Mansfield. 1983. Sampling Vidal blanc grapes:
1. Effect of training system, pruning severity, shoot exposure, shoot origin, and
cluster thinning on cluster weight and fruit quality. Amer. J. Enol. Vit. 34:72-76.

97. Wolpert,J.A. and GS. Howell. 1985. Cold acclimation of Concord grapevines. 1.
Variation in cold hardiness within the canopy. Am. J. Enol. Vitic. 41:330-341.

98. Yang, Y.S. and Y. Hori. 1979. Studies on retranslocation of accumulated
assimilates in ‘Delaware’ grapevines. I. Retranslocation of 14C-assimilates in the
following spring after 14C feeding in summer and autumn.

Tohoku J. of Agr. Res. 30(2):43-56.

99. Yang, Y.S., Y. Hori, and R. Ogata. 1980. Studies on retranslocation of accumulated
assimilates in ‘Delaware’ grapevines. II. Retranslocation of assimilates
accumulated during the previous growing season. Tohoku J. of Agr. Res.

31(2): 109-119.

CHAPTER I

INFLUENCE OF CANOPY CONFIGURATION ON CANOPY DEVELOPMENT,
YIELD, FRUIT COMPOSITION, AND CANE QUALITY OF SEYVAL GRAPEVINES

22

Abstract

Seyval grapevines were trained to three canopy configurations in 1988. One
treatment ﬁlled the trellis (Full Trellis) early by spacing 45 buds along the cordon. Another
simulated a hedge (Hedge) by hand pruning four inches around the cordon. A control was
used where vines were balanced pruned to 8 nodes per 454 g. cane prunings. All vines
were ﬂower cluster thinned to 15 clusters per 454 g. cane prunings. Vine size and yield
indices, as well as fruit quality, were evaluated each year. Canopy development was
measured using point quadrat analysis taken during the 1991-1993 growing seasons. Cold
hardiness evaluations were made in March of 1992-1994. The full trellis and hedge
treatments had a larger number of nodes retained and earlier ﬁlling of the trellis area with
foliage. However, hedging produced poorly spaced shoots that were less winter hardy.
The full trellis treatment increased yield as a function of increased berries per cluster and
cluster weight, as well as cane cold hardiness. Hedging increased yield by developing
more clusters after thinning, but produced a higher incidence of Botrytis rot. There were
no other differences in fruit quality between treatments. A canopy structure that fills the

trellis early with properly spaced shoots appears to be the best canopy conﬁguration for

Seyval grapevines.

Introduction

Seyval is an important white wine grape cultivar across the Eastem United States.
It is cold hardy, disease resistant, and phylloxera resistant. It does, however, form large,
compact clusters susceptible to cluster rot under Michigan conditions and the large clusters
can lead to overcropping. Crop levels are usually maintained by severe balance pruning
and ﬂower-cluster thinning. Reynolds et al. (12) suggested an optimal cropping level of 17
clusters per 500 grams of cane prunings in New York state. Severe pruning reduces the
thinning expense incurred by the grower, but results in a later ﬁlling of the canopy and thus
potential loss of photosynthesis. The current suggested balanced pruning formula is 15+10
(15 nodes retained for the ﬁrst 454 gm of dormant one year cane prunings, and 10 nodes
retained for each additional 454 gm). This results in a canopy that does not ﬁll the trellis
area until after fruit set

Grapevine canopy development and density have been areas of recent interest and
research. Spring shoot growth is dependant on the remobilization of carbohydrates stored
in roots, trunks, cordons, and canes from the previous year (31,32), and cluster
development is slow until leaf area is established (30). Shoots become net exporters of
carbohydrates during anthesis (11). Cell division before anthesis and cell expansion after
anthesis are the major determinants of the increase in weight of grape berries (3). Thus, it
seems important to fill the trellis area with vegetative growth and leaf surface as early as
possible to facilitate vine growth and fruit development.

Increasing the number of nodes retained at pruning is the most common method
used to establish an early full canopy (22). There are potential negatives. Increased shoot
numbers can form a dense canopy that reduces light levels to 1% of the solar radiation in

the fruiting zone (21,22). Light penetration into the canopy is important for photosynthesis

24

25

(20), fruitfulness (6,18), ﬂower bud formation (18,21), fruit set (2,16), fruit quality
(13,15,23), yields (18), and wood hardiness (5,18,26). It appears that an optimum leaf
area exists above which light penetration into the canopy is restricted to the point that vine
productivity begins to diminish, and below which the canopy is ineffective as a light trap
for photosynthesis. A method to quickly establish and maintain this optimum leaf area to
maximize the amount of assimilate produced in the vegetative season, and maximize vine
productivity, fruit quality, and composition, plus insure vine growth and cold hardiness
needs to be investigated for a large f ruited, overproducing cultivar such as Seyval.

Mechanical hedging, selective hand pruning, or no pruning at all, increase the
number of nodes retained for potential shoot production from the previous years vegetative
growth, but, increasing shoot number increases canopy density (4). These minimally
pruning management techniques also change vine morphology. They increase the leaf area
before and decrease leaf production after bloom (4). Minimally pruned vines partition fixed
carbon differently than conventionally pruned vines (4). They store more carbohydrates in
old wood and less in their canes and roots (17). However, some of these methods have
increased labor efficiency (19,25).

Mechanical hedging has received increasing attention in the United States, since the
pioneering efforts of the Australian researchers. This is suggested to be a cost effective
alternative to hand pruning. Hedging leaves more nodes in the canopy area, increasing the
amount of vegetation per foot of row and per square foot of canopy space (8,9,10). With
no further crop control, increasing shoot number produces more clusters per vine, and thus
greater sink competition. This in turn results in morphological characteristics such as
reduced shoot length, leaf size, cluster size, cluster weight, and berry weight (1,7,29).
This improves canopy microclimate (13,14) and increases photosynthetic efficiency
through reduced shading (25). However, hedging alone has shown only to be useful for a

few years before yields, fruitfulness, and fruit quality diminishes (8,9,10). Given the

26

differences in climate and limitations of sunlight and carbon assimilation between the North
Eastern United States and Australia, an objective evaluation of the limitations of this
technology deserves effort particularly for Seyval. Since thinning is required to control
overcropping in Seyval, the crop level can be managed so that the inﬂuence of canopy
conﬁguration and decreasing pruning severity on canopy development, can be further
investigated. Reducing labor expenses by mechanical hedging would greatly decrease the

cost of producing this variety.

[3.1:]...

1. To evaluate alternative pruning techniques that may allow expedient ﬁlling of the trellis
for optimum fruit ripening in Seyval.

2. To determine the results of increasing bud numbers and balanced cropping (based on
the previous years vine size) on canopy development, yield, fruit composition
and quality in Seyval.

3. To evaluate balanced cropping with a set pruning number of buds retained, designed to
space shoots at optimal distances from each other along the cordon in Seyval. ,

4. To analyze the impacts of hedging in conjunction with balanced cropping by cluster
thinning in Seyval.

Materials and Methods

PlamMaterial

The experiment was established in March of 1988, 4.5 miles East of Lake Michigan
(42-15’ latitude) at Fenn Valley vineyards in Fennville Mi. Mature, bearing Seyval
grapevines planted in 1975 on an Oshtemo sandy-loam soil were used in the experiment.
Rows were spaced 3.0 meters apart with vines 2.4 meters apart within rows. The vines
were trained to a bilateral cordon on the top wire, 1.8 meters high (Hudson River Umbrella

training system).

Huninglreatments

The three canopy configurations initiated in 1988 consisted of: 1) a full trellis
treatment (FT) spacing 45 buds along the cordon with ﬁve-node canes and two-node spurs;
2) a mechanically pruned hedge (SH) was simulated by hand pruning four inches around
the cordon; and 3) a control (C) (the current standard cultural method) was employed to
ensure a typical rate of canopy development In all cases an 8+8 balance pruning formula
(8 buds retained for every 454 grams of dormant one year cane prunings) was used.

The control and full trellis vines were pruned to 45-nodes and the live one-year cane
prunings weighed to estimate the previous year’s vine size. The node number for the
control vines was then set for the duration of the growing season following the procedures
stated above. Because hedged vines retained a larger number of nodes, a method was
devised to estimate the weight of retained wood. After pruning the hedge treatment, the
live canes were weighed and nodes counted. The remaining live nodes of canes on the vine
were counted. A weight was assigned to the number of nodes over 45 retained on the vine,
based on a node weight calculated in 1992 (113 gm per 52 nodes) and 1993 (113 gm per

50 nodes). This weight and the weight of cane prunings were added producing the vine

27

size estimate for each (SH) vine.

Since pruning is not sufficient for optimal crop control in Seyval, cluster thinning
was also required. The weight of live one-year-old canes at pruning (vine size) was used
to determine cluster number after thinning. All vines were ﬂower-cluster thinned just prior
to or during bloom to 15-clusters per 454 grams of dormant cane prunings.

At bud burst, nodes that did not produce a shoot (shootless nodes) were counted.
Percent blind nodes, vegetativeness (vine size (gm) per shoot), count shoots (nodes
retained at pruning minus blind nodes), and non-count shoots (total shoots minus count
shoots) were calculated for each vine. Treatment comparisons of pruning data were

analyzed each year and over years for the years applicable.

II E l l E . : l' :

Prior to harvest each year, Botrytis incidence assessments of each sample vine were
taken. Vine rot and within cluster rot were subjectively evaluated using a one to ﬁve
making where 1=0-20%; 2=21-40%; 3=41-60%; 4=6l-80%; and 5:81-100% of the
clusters on the vine or benies within the cluster were rotten. Treatment vines were
harvested each year within ten days of October 1. Each sample vine was hand harvested
with the cluster number noted and the fruit placed into an individual bin. Each bin was then
weighed in the ﬁeld and a cluster weight calculated. Apical berries were taken from
clusters of all sample vines within a treatment replication to create a 100 beny sample.
From these samples pH, titratable acidity, soluble solids, and a berry weight were
measured and the number of berries per cluster calculated. The number of non-count
clusters per vine was calculated from the number of clusters harvested minus the number
retained after bloom thinning. Treatment comparisons of harvest data were analyzed each
year and over the years 1989,1991, 1992, and 1993. Using the harvest and pruning data,

shoots per cluster (total shoots/ harvest cluster number), productivity (yield per previous

29

year’s vine size), and crop load (yield per current season’s vine size) were calculated for
every sample vine and analyzed each year and over years. Fruitfulness (gm fruit per shoot)

was calculated and analyzed during 1991-1993.

Canopy Measrrrem enIS' Boint eradrat Analysis

Point quadrat assessments were taken at three times during the growing season in
1991-1993. A thin metal rod was inserted into the canopy to determine the number of
leaves above the fruiting zone (24). Five insertions along the cordon were made on each
treatment vine at bloom, veraison, and harvest. Insertions were always made from the
West side of the canopy. A frequency distribution of the number of contacts and a seasonal

history of leaf layer formation were developed.

ColdﬂardinessEvaluaticns

Prior to pruning in 1993-1994, a cold hardiness evaluation was taken of the
previous season’s vegetative growth. Previous work with Seyval (28) and a re-evaluation
of that work (Appendix 1) has led to a deﬁnition of Seyval cane characteristics closely
associated with cold hardiness. Classiﬁcations were created from hardiness analyses done
on Dec 19, 1991 and Jan 22, 1992 on Seyval canes (Appendix 1). Periderm and primary
bud T50’s were determined for variations within four cane characteristics, and over node
positions along the cane. Canes having a medium diameter (7-10 mm), medium intemode
length (6-8 cm), and dark brown periderm were found to have superior cane and primary
bud cold hardiness. Persistent laterals and node position (2-9) did not have any inﬂuence
on cold hardiness. Total one-year-old canes were counted on each treatment vine and each
cane given an excellent, acceptable, or poor classiﬁcation. Excellent canes consisted of ten
or more live nodes with the optimal characteristics stated above. Acceptable canes had ﬁve

or more living nodes but failed in one of the optimal characteristics. Canes with less than

30

ﬁve live nodes or failing at least two optimal characteristics were placed in the poor cold
hardiness category. Samples of Seyval canes within the three classiﬁcations were collected
in December, January, and March. Periderm and primary bud cold hardiness were
signiﬁcantly different among the treatments at the 0.01 level over the three dates. Excellent
canes were superior while poor canes were inferior to acceptable canes. Using the three
classiﬁcations was a rapid and effective way to evaluate the relative cold hardiness of each

treatment vine.

13.”. I!I'

A randomized complete block design was used with four blocks. Two rows,
containing two blocks each, of self-rooted Seyval grapevines were utilized. Within each
block, the treatments consisted of ﬁve sample vines. A guard row was situated outside and
between the two treatment rows, and a guard vine separated each treatment Comparisons
between treatments were done using the MST AT-C statistical computer package. Analysis
was by ANOVA, with mean separations calculated using Duncan’s Multiple Range Test
(27). Comparisons over years were made where applicable. Point quadrat frequency
distributions were calculated using the MSTAT-C computer package. In the spring of 1990
a portion of the experiment was accidentally pruned by the grower, and thus, the treatments
were analyzed using only two replications that year, and were not considered in the

analysis over years. The experiment was terminated after pruning in March of 1994.

Results and Discussion

y' IT“ ”5.: .. E
Vine yield was favored by increased node number retained. Both (FT) and (SH)

vines had improved yields (25-30 percent; over a ton per acre) over the control (Table 1).

31

While (C) and (SH) yields ﬂuctuated among years, the (FT) consistently produced 7 kg or
more fruit per vine. Normally, these differences in yield might be the result of increased
cluster number or cluster weight, composed of berry weight and number. Although large
differences in nodes retained provided conditions favorable for large variations in cluster
number, this variable was eliminated by the process of cluster thinning based on vine size.
As a result, no signiﬁcant differences were observed in cluster number at harvest (Table 2).
The yield differences are, therefore, due to cluster weight and must be a result of variations
in berry weight and/or the number of berries per cluster (Table 3). The (FT) system
improved the components of yield compared to the other two treatments. Its average
weight per cluster was the highest every year and 50 g heavier over years. Although
occasional years (1989 and 1993) show a berry weight response, the major response is
berry number per cluster. The (FT) treatment produced 10 percent more berries per cluster
over years. Importantly, when both berry weight and beny number per cluster were
signiﬁcant, it was always for the (FT) treatment.

It was surprising to note minimal differences in cluster weight of (C) and (SH)
vines, contrasting previous work (1,7,29). Since the vines were ﬂower cluster thinned
near bloom each year, many more shoots per cluster existed in the (SH) canopy than the
(C) at that stage. The greater leaf area at bloom may explain this response. The
fnritfulness data suggest a reduced yield per node, but that was expected based on the
thinned treatment response.

Treatments did not affect soluble solids , pH, or titratable acidity (Table 4). The
(C) berries appeared to accumulate the highest percent of soluble solids in each year, but
were signiﬁcantly greater only in 1989. The grams sugar per vine data are highly
signiﬁcant, but vary from year to year. Early, the best treatment is the (SH). However,
over time it becomes clear that the better choice is the (FT) treatment. It produces the most

sugar per vine over years. Interestingly, the (FT) also was the best at vegetative production

and yield.

Bottytis cinerea infection of the clusters was the most noticeable fruit quality
variant among canopies (Table 5). Subjective ratings on the day of harvest, showed that
the amount of Botrytis rot was severe across treatments every year. The average loss of
crop was nearly 25 percent. Severe pruning produced adventitious shoots from secondary
and tertiary buds, as well as vigorous laterals from basil nodes. This created dense
microclimates immediately surrounding clusters of control canopies during fruit ripening.
A dense canopy inhibits air ﬂow and chemical penetration to the clusters. In 1989 and
1993 the higher amount of rot incidence in (C) clusters inﬂuenced yield. Rot within
clusters was significantly lower for (FT) and (SH) in 1989, and for (FT) compared with
(C) in 1991. The number of clusters with vine rot was significantly lower for (FT) and
(SH) in 1989 and 1993. The (FT) treatment showed the least amount of vine rot in 1993.
Over years, vine and cluster rot incidence were signiﬁcantly lower for (PT) compared to
(C). Clusters on the (FT) canopy consistently had less Botrytis rot infection. Proper shoot
spacing created an optimal eanopy density limiting Botrytis rot infection in years of high

incidence.

if y . G l E

Canopy conﬁgurations were achieved in the second year (1989). Although all the
vines began the study at about 250-275 grams of cane prunings per meter of row, and yield
varied by 30 percent, vine size differences were very small and seldom significant (Table
6). Vine size was similar among treatments in all of the years except in 1992. In that year,
(FT) produced an average of 200 more grams of cane prunings per vine than the other two
treatments. Averaged over years, the (FT) produced 60 grams more than (C) and 100 gm
more than (SH). The (FT) treatment had the largest vine size and was also the treatment

with the highest consistent yield.

33

There was a strong vegetative response by the vine to varying node number at the
same cluster number. The full trellis and hedged systems increased node numbers within
the canopy 4 and 10 fold, respectively from the control. Control vines produced the most
vegetative growth as measured by both kilograms of cane prunings per node or shoot
retained (Table 6). This supports Ruhl and Clingeleffer’s (l7) findings on carbohydrate
partitioning of reserves, but was more likely due to two factors: 1) the stimulation of non-
count shoot production by (C) vines, which resulted in two-thirds of the total shoot number
per vine, from non-count positions; and 2) the competition for stored reserves, nutrients
and water, among the large number of primary shoots arising from count positions in the
other treatments, resulting in shootless nodes on (SH) vines.

Shoot numbers among treatments did not vary as widely as the number of nodes
retained due to adventitious shoot growth and shootless nodes. Adventitious shoots
comprised much of the (C) canopy. These non-count shoots formed either along the
cordon, or from secondary and tertiary buds when a primary shoot was present. Over
years, (C) vines produced twice as many shoots from non-count sites as they did from
count positions (Table 7). less than ten were produced each year by (FT) vines and very
few produced by (SH). Whatever was gained by adventitious shoots on (SH) vines, was
negated by the loss of count shoots during the growing season. Even taking into account
the non-count shoot contribution, total shoot number was highly significant among
treatments over years. The (C) vines produced the least amount of shoots and hedging the
most. The large number of non-count shoots exemplifies the severe pruning practice of the
(C) treatment.

Another response to the differing bud populations per vine was the cane maturation
and acclimation to cold. Cane quality varied with the number of nodes retained in the
canopy (Table 8). Hedging produced the fewest number of excellent and the most poor

quality canes each year. In 1993 (FT) vines matured signiﬁcantly more excellent and

34

acceptable quality canes than the other two treatments. Over years, the treatments each
matured signiﬁcantly different numbers of excellent quality canes. The (FT) vines had the
most (1 l) and (SH) vines the least (4) excellent quality canes. The (FT) vines had a greater
number of acceptable canes and (SH) vines had a greater number of poor quality canes over
the other two treatments. These data are signiﬁcant whether expressed as direct data (Table
8) or as percentage of total canes per vine (data not shown). Whether data derived from
canes can express accurately characteristics of older vine tissues is not known. However,
this does pose a concern (not heretofore deﬁned) about vine culture with systems of large
bud numbers. With the canopies fully developed in the later years of the study,
competition between shoots became evident. Nearly half of the (SH) buds failed to
produce a shoot in 1992 and 1993 (Table 9), supporting the position that excess shoots can
weaken a vine’s cold resistance.

According to Smart (22), an optimal canopy has no more than three leaf layers.
Point quadrat assessments taken during the 1991-1993 growing seasons, showed that
increased shoot number per vine increased leaf layer number each year (Figs. 1, 2, and 3).
The (SH) vines produced a greater average leaf layer number throughout the growing
season each year. The (SH) canopies averaged 2 layers at bloom, and over 3 layers from
veraison to harvest The (C) and (FT) canopies never obtained an average of 3 layers in
any year. The (FT) canopies were also superior to (C) canopies each year. They
continually had nearly half a leaf layer advantage. Most leaf layer production for (SI-I)
canopies occurred between bloom and veraison, while (C) and (FT) canopies increased
their rate of leaf layer production from veraison to harvest

The (C) vines never completely ﬁlled the canopy with foliage during any of the
growing seasons (Figs. 4-12). Gaps in the canopy still existed at harvest The (SH) and
(FT) vines ﬁlled the trellis area by veraison each year (Figs. 412). However, (SH)

canopies formed shaded areas at bloom each year. Hedging improved canopy formation

35

early in the growing season, consistent with prior work on hedging systems (8,9,10).
However, increased shading occurred after veraison each year, contradictory to previous
results with hedging systems (13,14,25). The upright growth of small shoots in hedged
canopies caused the added leaf layer formation. The long, well developed shoots of control
and full trellis canopies angled below the cordon later in the growing season exposing fruit
and older leaves, and avoided leaf layer formation above the fruiting zone. The full trellis
canopy was superior because it increased ﬁlling of the trellis with vegetation early in the
growing season and allowed for further leaf development during ripening without

substantial shading.

Conclusions

The treatments established three unique canopy architectures. Severe pruning and
hedging were compared with a constant pruning level created to optimally space shoots
along the cordon. Cluster number was consistent among treatments due to balanced
cropping based on vine size. Thus, yield responses reﬂected differences in cluster
weights. The full trellis and hedged systems increased yield by increasing cluster weight
resulting from greater numbers of berries per cluster. Although the hedged canopies
contained greater node numbers, the response of increased berry number was greatest in
the full trellis treatment

Retaining more nodes than currently recommended at pruning, increased shoot
number within the canopy. With more shoots, canopies filled the trellis area with foliage
earlier in the growing season. Creating a canopy that spaced shoots at optimum distances,
increased light penetration and cane maturity, resulting in greater cane cold hardiness and
deterrence to rot Hedging increased canopy formation before bloom, but shading became

a problem after veraison. With poor light levels within the canopy, hedged vines ripened

36

fruit at the expense of vegetation and poor cane cold hardiness resulted. Dead wood
accumulated in the canopy area and optimal spacing declined each year. Because of poor
wood maturity, hedged vines would also be more susceptible to environmental stresses and
disease. If hedging is the preferred method of pruning in Seyval, then cordon renewal is
suggested for maintenance of vine health after four to ﬁve years. No advantages to vine
growth were observed in the hedging system compared to the full trellis canopy. Thus,

optimal shoot spacing should be the major consideration during pruning.

Literature Cited

1. Bravdo, B., Y. Hepner, C. Loinger, S. Cohen, and H. Tabacman. 1984. Effect of
crop level in a high yielding Cari gnane vineyard on growth, yield, and wine
quality. Am. J. Enol. Vitic. 35:247-252.

1°

Coombe, B.G. 1962. The effect of removing leaves, ﬂowers and shoot tips on fruit
set of Vitis vinifera L. J. Hort. Sci. 37:1-15.

3. Coombe, B.G. 1976. The development of ﬂeshy fruits. Ann. Rev. Plant Physiol.
27(2):507-528.

4. Downton, W.J.S. and W.J.R. Grant. 1992. Photosynthetic physiology of spur
pruned and minimal pruned grapevines. Aust. J. Plant Physiol. 19:309-316.

5. Howell, G.S., B.S. Stergios and SS. Stackhouse. 1978. Interrelation of
productivity and cold hardiness of Concord grapevines. Am. J. Enol. Vitic.
29:187-191.

6. Howell, G.S., D.P. Miller, C.E. Edson and R.K. Streigler. 1991. Inﬂuence of
training system and pruning severity on yield, vine size, and fruit maturity of
Vignoles grapevines. Amer. J. Enol. Vitic. 42(3):191-198.

7. Kaps, ML. and G.A. Cahoon. 1989. Berry thinning and cluster thinning inﬂuence
on vegetative growth, yield, fruit composition, and net photosynthesis of Seyval
blanc grapevines. J. Amer. Soc. Hort. Sci. 114(1):20-24.

8. Morris, J.R., D.L. Cawthon, and J.W. Flemming. 1975. Effect of mechanical
pruning on yield and quality of Concord grapevines. Ark. Farm Res. pub.
24(3): 1-12.

9. Morris, JR. and D.L. Cawthon. 1981. Yield and quality response of Concord grapes
to mechanized pruning. Am. J. Enol. Vitic. 32(4):280-282.

10. Pollock, J.G., E.S. Shepardson, NJ. Shaulis, and DE. Crowe. 1977. Mechanical
pruning of American hybrid grapevines. Trans. ASAE 20(5):817-821.

11. Quinlan, JD. and R.J. Weaver. 1970. Modiﬁcation of pattern of the photosynthate
movement within and between shoots of Vitis vinifera L. Plant Physiol.
46:527-530.

12. Reynolds, A.G., R.M. Pool and LR. Mattick. 1986a. Effect of shoot density and
crop control on growth, yield, fruit composition and wine quality of ‘Seyval blanc’
grapevines. J. Amer. Soc. Hort Sci. 111(1):55-63.

13. Reynolds, A.G., and DA. Wardle. 1989a. Impact of various canopy management

techniques on growth, yield, fruit composition and wine quality of
Gewurtztraminer. Am. J. Enol. Vitic. 40: 121-129.

37

38

14. Reynolds, AG. and DA. Wardle. 1989b. Effects of timing and severity of summer
hedging on growth, yield, fruit composition, and canopy characteristics of ‘De

Chaunac’ 1. Canopy characteristics and growth parameters. Amer. J. Enol. Vitic.
40: 109-120.

15. Reynolds, AG. and DA. Wardle. 1989c. Effects of timing and severity of summer
hedging on growth, yield,fruit composition, and canopy characteristics of ‘De
Chaunac’ 2. Yield and fruit composition. Am. J. Enol. Vitic. 40:299-308.

16. Roublelakis, K.A. and W.M. Kliewer. 1976. Inﬂuence of light intensity and growth
regulators on fruit set and ovule fertilization in grape cultivars under low temprature

conditions. Am. J. Enol. Vitic. 27(4):163-167.

l7. Ruhl,E.H. and PR. Clingeleffer. 1993. Effect of minimal pruning and virus
inoculation on the carbohydrate and nitrogen accumulation in Cabernet franc vines.

Am. J. Enol. Vitic. 44(1):81-85.

18. Shaulis, N., and R. Smart. 1974. Grapevine canopies: management microclimate
and yield responses. In: Proc. XIXth International Hort Congress. pp. 255-265.

11-18 Sept, Warsaw.

I9. Sims, C.A., R.P. Johnson, and RP. Bates. 1990. Effects of mechanical pruning on
the yield and quality of Muscadine grapes. Am. J. Enol. Vitic. 41(4):273-276.

20. Smart, R.E. 1974a. Photosynthesis by grapevine canopies. J. Applied Ecology

11997-1006.

21. Smart, R.E. 1984. Some aspects of climate canopy microclimate, vine physiology
and wine quality. In: Proc. First Intl. Symp. Cool Climate Vitic. Enol. D.A.
Heatherbell, P.B. Lombard, F,W. Bodyfelt, and SF. Price (eds.). pp 1-18. June

1984, Eugene, Oregon. Oregon State Univ.

22. Smart, RE. 1985. Principles of grapevine canopy microclimate manipulation with
implications for yield and quality. A review. Am. J. Enol. Vitic. 36(3):230-239.

23. Smart, R.E. 1987. Inﬂuences of light on composition and quality of grapes.

Acta Hortic. 206:37-47.

24. Smart, R-E., C.M. Seaver. 1988. Handbook for Canopy Management Workshop.
Pesented at 2nd International Cool climate Viticulture and Oenology Symposium,
Matua Valley Vineyard Kumeu, New Zealand. (Jan. 1988). pg. 1-20.

25- Smart, R- E., J.K. Dick, I.M. Gravett and BM. Fisher. 1990. Canopy management

to improve grape yield and wine quality - principle and practices.
S. Afric. J. Enol. Vitic. 11:3-17.

26- Stergios. B.G. and cs. Howell. 1977. Effects of defoliation, trellis height, and
cropping stress on the cold hardiness of Concord grapevines. Am. J. Enol. Vitic.

28(1):34-42.

30.

31.

39

Steel,R.G.D. and J.H. Torrie. 1980. Principles and Procedures of Statistics: A
Biometric Approach. McGraw-Hill Book Company, New York, NY.

Striegler, R.K., and GS. Howell. 1991. The inﬂuence of rootstock on the cold
hardiness of Seyval grapevines: 1. Primary and secondary effects on growth,
canopy development, yield, fruit quality and cold hardiness. Vitis. 30: 1-10.

Weaver, RJ. and RM. Pool. 1968. Effect of various levels of cropping on
Vitis vinifera grapevines. Am. J. Enol. Vitic. 19:185-193.

Winkler, A.J., J.A. Cook, W.M. Kliewer and LA. Lider. 1981. General
Viticulture. University of California Press, Berkeley.

Yang, Y.S. and Y. Hori. 1979. Studies on retranslocation of accumulated
assimilates in ‘Delaware’ grapevines. I. Retranslocation of l4C-assimilates in the
following spring after 14C feeding in summer and autumn.

Tohoku J. of Agr. Res. 30(2):43-56.

. Yang, Y.S., Y. Hori, and R. Ogata. 1980. Studies on retranslocation of accumulated

assimilates in ‘Delaware’ grapevines. II. Retranslocation of assimilates
accumulated during the previous growing season. Tohoku J. of A gr. Res.
31(2):109-119.

$8.093”. 03:35. 302 9:00:30 9:0: 0:523 553. 3:233 0:022

.85 sausage 6: 3 5e .4... C so a 232:2» 822, n.

00.00.30. 02 >_co cc 0000.. 0.0 300 000:» .009 .0 e805. c. .03 .0 use—ca 3:3 2 02". 0.038005 0.00 ~
605.22 000520.020 m; 9:520. 05> 3:25 0+0 :0 to. 80.020 .0 .025: 05 8 9.6.0000 .3 003 .05. no.0

.5200 05 Eat «:60. :05 v 0 02050 00:00 02662 50.23 200:0 9:30: 0:0... 9.0: 02238800 003 20.500... 090: >
.0053! 0095.082". m4 @5520. 05> 3:33

0+0 :0 .2 28020 .o .382. 05 2 9.2080 .00 003 .30. no.0 0:333: no 532 2 e055 9.03 «05> 2:0; :9... x

60520.. 0025.202“. m4 2 00:55 .2020 .030: 0:0 0+0 8 00:33 00:3 .9500 3

.80?va 0:0 80.. 9.0% 05 cc 0000.. 0.0 0:008 002C >

 

.. . me me ~ .. me n em

a m: a So so.» a: we a 2.0 0.: s 3222 .3 ones:
a 82 o «to 8.0 no to e 3.3 m: x as «an; :3

e no.» o «3. a: 3.0 03 a so.» 2g. 3 8+8 .9280

 

> 32>.me $529; $529; 40529; €523 3539; 3539.4 335.2 amaze
x 22> 22> 22> 22> 22> 2o; 2253:
t 82 we? 53 one. one. one.

0210:; >0=0> 5.0“.
“0 00:32.06 _0>>0m .0 003-003 :8: 20; 05> co 8:05.00: 9555 Lo 00:03:... .w mam]:

41

.005 00:0... 0.00.0.2 302 0:00:00 0:.00 030. 55.3 :0..0.0000 c005.

 

 

 

 

 

 

 

 

 

 

 

.0... 28.5.5.0 .2. .o 5.. .0. .0. 80 o... .0 202......» 0020.. n.
00.02.00. 03. >50 :0 00000 0.0 0.00 000:5 .000. .0 00.0.2 5 .0.0 .0 05:30 .0500 0. 000 0.0.0585 0.00 N
0007.00. 0:0 000. 0.00.. 0:. :0 00000 0.0 0:005 000:... >
000590.020 0.. 0550.0. 05> 00:0.0 0+0 :0 .0. 0.0.00.0 .0 .0050: 0.... 0. 050.0000 .00 003 .0>0. 00.0 500.00
0:. 50.. 00.00. :05 v 0 00.0.00 00:00 00.650. :0.:3 0.00:0 0:0... 0500 00:0..050000 003 505.00.. 0000... x
000503.020 0.. 0550.0. 05> 00:0.0 0+0 :0 .0. 0.0.00.0 .0 .0050:
0:. 0. 050.0000 .00 003 .03. 00.0 0520000: 00 50.0. 0. 00:20 0.03 005> 050.... :0”. 3
0050.0. 000E0.0.00.0 0.. 0. 00:5... .2050 .030: 0:0 0+0 0. 00:0.0 0.03 00:.> .0..:00 >
m: 00 00 .0 .. x
.. a 00. a me o I n
m: 00 00 cm
.. 000. one o 2 000.
0.. mm C 0.
.. a .3 n .9 o 0. 000.
m... 00 mm 0.
. . a 0. n 0.. o 0 .00.
N 00 00 2.
~ .0. 3. mm 000.
m: 8 om 0.
. . a 00 a .3. o 0 000.
2. 00 mm .0
m: 0. 0.. 00 000.
n. 0.0 0 .2020 0 082 0 .2020 0 082 0 .2020 0 082
x 008: a. 0.0.. .3“. > .228

 

.00.0>0:.> >0..0> ::0u. .0 00030020 .0100 .0 0007000. 50.. .0020: .0

.0050: .3050 0:0 0500.0 .0 .0050: 000: :0 2:05.00: 05:20 .0 00:05.5 .0 m..m<h

.005 00:00. 0.0502 302 0.000000 0500 030. 5003 05.0.0000 000.2

 

 

 

 

 

 

 

 

 

 

.0... 08.5.0.0 .2 .o ..:. .0. .0. #0 o... .0 0.8.50.0 829. .
00.05.00. 03. >50 :0 00000 0.0 0.00 0000.: .000. .0 00.05. 5 .0.0 .0 0500.0 .0500 0. 000 0.205005 0.00 N
0007.00. 0:0 000— 0.0g 00. :0 00000 0.0 0:005 000.: >
000505.020 0.. 0550.0. 05> 0000.0 0+0 :0 .0. 0.0.00.0 .0 .0050: 00. 0. 050.0000 .00 003 .0>0. 00.0
000.00 00. 50.. 00.00. 00:. v 0 00.0.00 00:00 00>050. 00.03 0.0000 0:00 0500 00000050000 003 505.00.. 0000... x
000520.050 0.. 0550.0. 05> 0000.0 0+0 :0 .0. 0.0.00.0 .0 .0050:
00. 0. 050.0000 .00 003 .0>0. 00.0 0520000: 00 50.0. 0. 0000.0 0.03 005.. 050... =0“. 3
0050.0. 000520.050 0.. 0. 00:50. .2050 .030: 0:0 0+0 0. 00:50 0.03 005> .9500 >
.. e. 0.: a 00. a 03
0: 8.0 0.0 00.0 > x
.. n 80 a 0.0 a New I
2 0.: v C 00
. n .0.. a 000 n 00..
.. a. NE a 000 n 8. 30.
0: 00. 00. 00.
2. 00.. m . .0 00..
. o .00 m .3. n 80 ~00.
. a a: a mom a 8.
m: 00.. 00.. 6.0
. a 80 a 03 a $0 .00.
~ 0 . . 00. . .0.
N 8.0 8.0 00..
N 000 :0 $0 80.
.. am 0.: a .0. a 00
. a. 0.0 a 30 0 000
. a 80 a 30 a 80 000.
u. .00 .2020 5.0. .50. .0020 5.0. .50. .2020 5.0. 5.0.
00:50 .3 >000 .3 .2050 00.000 .3 >000 .3 .2050 000.00 .3 500 .3 0.00.0
x 0W00I 3 0.._0..P =0“. > .5500

 

.00.0>05> >0..0> :00”. .0 00:.>000.0 .0100 .0 0000.000.
50.. .0020: .0 .0.00.0.00...00 0:0 ...3 >000 ...3 3.00.0 :0 2:05.02. 0500.0 .0 00:00:...

.0 .303.

43

 

 

 

 

 

 

 

 

 

 

.00. 00:00 25.3: :02 0.08000 058 0:2 50..; 8.0.0000 :00: .0.... 38.....0.» .8 .o .0.. 0... .C .00 0... .0 00250.0 08.0.. n.
3.02.00. 2.. 08 S 0000.. 0.0 0.0.. 80... .80. .0 020.2 s .20 .o 8.00... 0.00.. o. 0.... 0.0.058... 0.00 0
.8208. 0:0 000. 200.. 0... E 088 0.0 0000... $0... >
00520.05 50. 00.... u 05> .00 .0000 050.0 x
0000.20.00... 0.. 00.0.0.0. 05> 0000.0 0+0 :0 .0. 0.0.00.0 .0 .0050: 00. 0. 006.0000 .00 003 .0>0. 00.0
000.00 00. 50.. 00.00. 000. v 0 00.0.00 00000 0.5050. 00.03 0.0000 0000 00.00 0002350000 003 505.00.. 0000... 3
000500.020 0.. 00.0.0.0. 05> 0000.0 0+0 :0 .0. 0.0.00.0 .0 .0050: 00. 0. 00.0.0000 .00 003 .0>0. 00.0 00.200000 0.. 0.0.0. 0. 0000.0 0.03 0003 0.00... :0“. >
0050.0. 000030.020 0.. 0. 0000.0. 0.00.0 .0300 0:0 0+0 0. 0000.0 0.03 00:3 .0030 0
.. a 0.00. 0 0.00. o 0.00
0.. .0... 8.0 00.0
0.. 0.... 00.0 0.0 0 x
0.. 0... 0.... 00. -
.. 0 .00. 0 0.00. o 0.00
0.. 00.0 . .0... $0
0.. .0... .0... .0....
0.. 0... 0.0. 0.0. 000.
0.. 0..... 0.0.. 0.0..
0.. .0... 00.0 00.0
0.. 00.0 8.0 8.0
0.. 00. o... 0.0. 000.
.. 00 0.00. 0 0.00. n 0.0...
0.. .0... 00.0 00...
0.. 00.0 B... 00...
0.. .00 0.0. .00. .00.
0 .00 0.0.. 0.0.0
0 Z... 0.... 0....
0 00.0 .5... I...
0 0.0. 0.0. 0.00 000.
.. 0 0.8. 0 0.00 a 0.00
0.. 00.. 0.... 00..
0.. 00.0 00... No.0
. 0 0.0. 0 0.0. 0 .0. 000.
u. 0.0 x .0000 .50 <. :0 000.. x .0000 0.0 E 0.. 00.... 0 E0 0.0 E :0 00....
s 0000: > 0...... =0. 0 .0008

 

00.0.8... 0...; 0:0“. .0 02.380... .0100 .0 08.08. .02.

.8200 .0 0000000... .0000 05> 000 00.000058 00.. 00 8:05.02. 0500.0 .0 8000...... .0 .305

.60... 095“. 03222 302 953.50 9.8: 2.5.. 55.3 c3233 522

.35 28:53 .2. 3 .C x; .C 4.... 2.. a £855.» 822,

4068232 oz: >_co :0 Emma 2a «in 39:. .39 .o 5222 c. .03 .o 9.755 3:8 2 26 80363:. San

dam—wamw 0cm GOQF 30> 0...: CO 00062 26 QCGOE 80:...
6.030.— 050; 05> 05 :0 2053.0 uO .v‘oOOruOOﬂm Ucﬂ

”38-8"”. ”$8-93 u<.o¢.o~um u$o~-ou. 22.3 95.52 m; a 8.2. 33.2.. 202.833 «a; .2 2.5

£on 203 9033.0 05 55:5 «2:3 .0 «voowéoum new ”ioowécuw

”$8-83 ”xovémuu ”38.0"? 22; 9:52 m; a as»: 8.333 202.833 «a; .2 3.3.0 555,
.ouo:\2o~m:_o m4 9:522 05> 3:35 n+0 ca .2 223.0 .o .352: 0..: 2 @5283 “on ma; .0>0. 35
.828 2: E2. mama. soc. v a 222:0 3:3 335...: so...) 835 new; 9:2. 35.3583 «a! 225:: wane:

635223.". m; 95:22 05> non—ea o+o ca .8 223.0 .o .383:
05 2 9.6.88 .3 ma; .0>0. no.0 .3583: mv 532 o. 3:35 22> 35> 9:9; =3”.
.3589 ouoEESmau m... 2 3:55 3320 .030: new 95 2 ocean 20! 35> .2200

u
N

>

 

 

 

 

 

 

 

 

 

 

. na 3 a am a to > x
. an «.m a 5 a ad I
.. g mm o a; a «a
m: o.~ 2.. ed 83
m: we «.9 m6
2 to o.~ m.~ «m3
2 .3 .1 «a
. 8 3 n 3 a on 33
~ 2 0.0 3
~ «a 90 5. 82
.. a mm a R a 3
.. a va n 3 a we 33
n. .3 x .2". 3 “om x .8 3 8m x 8m 3 8m
05> .3520 05> .0320 05> .3330
> a8: a 2...: .3“. . .228

 

6213c; >o=u> econ. 3 3539.5 313.3 39.39 E2. 825:. .a

283.0 93.5 new 55.3 8. 0258 .o 8:029... co 8:253: 9555 .0 8:02.... .n meE.

45

.30... omcmm 03:32 392 $58.50 9.3: 252 55.3 5:833 582

 

 

 

 

 

 

 

 

 

 

 

 

.85 23.253 .0: .o A... $F .C $m 05 «a .58:sz 83.9 m
$23.32 95 >25 :o 823 2w 2% oon. .89 .0 new: 5 «ca 3 9555 .523 2 can 229:8... Sac N
6878? Ba 83 2mg 05 :o 083 2a 289: 085 >
6852236 9F @5522 was 8:95 n+0 ca 8. 223.0 .0 .3E:: 05 2 9.2085 .8 was .26. no.0
.5200 on. E9. mans so... v a 0223 8:8 3362 :02: 235 9.2. as? 3:22.583 was .2953: omuor x
63:223.". m.F @5522 was 2:56 o+o ca .2 223.0 .0 39:5:
2: 2 9.283 «ow «a; .0>0. no.0 @5233: mv £22 2 3.53 22: 85> 9:2» =3“. 3
.8522 26520520 mF 2 02.55 8520 830: new o+o 2 3.55 22: 35> .9200 >
. . 9 9 an vF a 0F
.. on em. usv > x
. n vvd a vmd nu med I
. n N cm 3 a 3
. . o v n FF w Fm
w: Bio med omd mmaF
. . n F m FF w 3
. . o m n 0F m cm
. 2 Fee a mud n and «2:
m: o F v F om
.. n o 9 3 a on
we end vvd mmd meF
.. o m n FF a mm
m: and mvd no.0 2::
N x. v F mm F
N Fed v0.0 wFF aomF
an F m o N F N
me mad Fm.o Fwd oomF
n. gm 3 .8 $529: :3 a. $529: .3 :3 85%...
Saga .3 So: .8 mum 82w .3 ova: .8 cam 89% Ba ova: 5a 35
£39m .mo> £390 .mo> 2.5 £320 dc> £320 .mo> 2.5 £320 .25 £320 do> 0:5
x manor 3 «=3; =3“. > .9300
@8783 E9: 3330.3 on: 305 .8 5320 .wEgocs >c=u> 53m
S .938 c. $3.39 E0: 9553 “a 3582 one: Ba 532m 93 on.» 05> :0 2:25am: 9.253 .0 00:022. .0 mqmﬁ.

03., macaw. 29:22 :62 @5850 9.3: 2.6. 55.3 5.3.33 522
.35 28:29.». .9. .o A... .x; .C «on 2.. a 28:29.». 329, u.
68.5.93... mF 3.53». 9..., 32:... n+0 cm .2 293.0 .o 59...... m5 2 9.6.88 .3 mm; .92 no.0
.898 9.. ES. menu. so... v a 3650 «2.8 3.68m. 50...; 23% 2.9. 9...»: 8223688 on; 20.53.. ouuo: n
6358236 mF 3.52m. 05> umcaa o+o ca .2 9836 .o .325:
on. 2 9.6.88 .3 mm; 55. no.0 .ocEmouoc 9 £92 2 no.5... 22, 85> m___o..F =3”. >
.3532 30:35.36 mF o. 3:55 .0520 .252. 93 0+» 2 3:2... 22; 35> 6.2.00 x

 

 

 

 

 

 

 

 

 

I m 8 n 9‘ 0 cm
2 n o n o a mm x
I m Fm n ov o FF I
.. m mu n av n vm
. . o o n m a mm
. . m mu a CV o m mmmF
2 a mo nu mv 2 mm
2 o o n v m E
I m on an an n vF mmmF
mc mv om mm
. . n o an F u 3
2. m vv an on 9 S meF
M. .9m 22°F 2.30.52 ano 3.3 230.52 .560 :32. 2500-52 2.30
N 025: > maoﬁ :9. x .9200
$239.5 >23) cam“.
E _m>>mw 5 89-39 E9. 5282, .23 3582.. c3238 .85.. co 2:953: 955... .o 09.02.... .F m._m<._.

47

.000... 0000K 200.05. 302 0.000000 00.00 030. 0.5.3 02.0.0000 000.2
.05 08:00.0 .8 .o A... 0.. .C 0.0 o... .0 580.000 820., u.
00.000.00.000 00050.0: 0.00 00.000 00. .0 0.2 .000. .0 00:0. .0 00000 02. m 00.... 000. .0 020.0000 00000 3:000 .000 n
00.000.00.000 00050.0: 0.00 .00500 05 .0 000 00:0. .00 00000 00.. 0.0E .0 m .0 000.0000 00000 3:000 0.00.0003. >
00.000.00.000 00050.0: 0.00 .06000 5.3 00000 00.. 0.08 .0 OF .0 000.0000 00000 3:000 00.003 x
000220.020 0F 00.0.0.0. 003 0000.0 0+0 :0 .0. 0.0.00.0 .0 .00050 05 0. 00.0.0000 .00 003 .000. 00.0
000.00 00. 0.0.. 00.00. 000. w 0 00.050 00000 00000.0. 00.03 0.0000 0000 00.00 0000:05300 003 0000000.. 0000... 3
000880.020 0F 00.0.0.0. 003 0000.0 0+0 00 .0. 0.0.00.0 .0 .00500
00. 0. 00.0.0000 .00 003 .0>0. 00.0 00.0.0000: 00 0.0.0. 0. 0000.0 0.03 000.0 0...0.... :0". >
00530. 0000.20.00? 0F 0. 0000.0. .2020 .030: 000 0+0 0. 0000.0 0.03 0003 .00000 0

 

 

 

 

 

 

 

 

.. 0 F0 0 0F 0 0F

.. 0 FF 0 «F 0 FF x
.. 0 v 0 FF 0 0 I
.. 0 F0 0 3 0 NF

. 0 0F 0 cm 0 0F

.. 0 v 0 0F 0 0 000F
.. 0 F0 0 0F 0 0F

00 0F NF FF

.. 0 v 0 FF 0 0 ~00F
.. 0 F0 0 0F 0 x.
00 0 0F 0

. o 0 0 0 0 0 FO0F

n. 0.0 ~ .000 H 0.00.0002 x 20:83 N .000 4 0.000002 x .00..00xm N .000 » 0.00.0002 0. 20:00.6
3 0000: > 059.250 0 0.0000

 

00.00.30... 00:00) 000“.

.0 .0100 0. 000739 0.0.. :0. .00. .000 00000000 00 3:000 0000 00 0.000002. 00.020 .0 0000000.

.0 m..m<._.

.00... 0000.... 0.00.3.2 302 0.000030 00.00 0.00. 0.0:... 02.0.0000 000.2
.00.. 03:00.0 .0.. .o .0.. 0... .0. 0.0 o... .0 080......» 0029. n.

0000.20.020 m.F 00.0.0.0. 00.0 0000.0 0+0 00 .0. 0.0.00.0 .0 80.000 00. 0. 00.0.0000 .00 00... .0>0. 00.0
000.00 0... .00.. 00.00. 000. v 0 00.0.30 00000 00>00.0. 00.0... 0.0000 0000 00.03 0000._00.0000 003 .000..00.. 0000... u

.0000.0.0.03.0 0F 00.0.0.0. 003 0000.0 0+0 00 .0. 0.0.03.0 .0 30.030
0... 0. 00.0.0000 .00 00.... .0>0. 00.0 00.200000 0.. 0.0.0. 0. 0003.0 0.0... 000... 050.... :3“. >
00520. 0000.0.0.03_0 0F 0. 0000.... 3.00.0 .0300 000 0+0 0. 0000.0 0.03 000... .0..000 x

 

 

 

 

 

 

.. .. .. .. .. .. 0.. .. 0.00
a 0.. a 0.. a 0+ 0 00 a 00 a F. 00 a 00 N 0000:
n a. 00 0 F. n... 0 n. 00 0. a. 3:30.30
0 .F 0 m a 00 a v a m a. 00 a 0 x .2060
0. 2.2.. .x. 05>... 0. 05>... 0. 05>...
93> .26 000.9... 00 0. 00 0. F0 0.

 

.0000: 00:0 .0023 00 0000203 00.0..00... >0_.0> 000“. .0 000759 .00.. .050

030 .000 .03.. 00.30000. 00030090 .0....00 0. 00000 00000000 .0 0000.030 00 0.000000: 0500.0 .0 0000000. .0 39...:

 

49

 

 

 

 

 

 

 

amen: _ coma.m> _ E85 0
who
ﬂ
”.9
n .I
wmé mm.
m
1N m
N
n
rm
$9 I h
AEV ..|I. wmd
6V II. N
v

395:: .26. Km. 3 nommmaxo .mEm>oc_> >m=m> Emu E 35536 31mm .0 mm?
-59 Ea: 395% «558.9% 30:8 353% cc 8:923:00 >858 B Baum .F .9“.

 

:oEomE En. 909:8

 

 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

x .r' ,-"

n‘
I

.......
.

.P

 

 

I!)
G)

r ,7 .r .r r .. .r
.r "
-

*-

.9 -' n ‘ I‘ I.
‘. ’2 __.> ...
4. I.
.- I

I

 

 

£9 3 EV I Q E

 

O
V

 

 

 

 

 

 

 

. o
a} Pr . . Q,
.. .. ... ... . r... ... . .. ...... .... . . .
f. .....1 r. 5...... r.... ...... .f/z... . ..
...... x. . ... .... ... .. I
. .. . . . . . .. .. .. .
... .. . r... ...... .. . I. I... .. . .... .... I
.r .. . f .. x .... ... ....
I... ... .. r... ... .. r. .... u. . I. ... . . . '
.. ._ .. .. ... ... . .. ....
7.. ... .. . 7. J.K., Iv... 3.... ....- ..A.... I
... . . .... ... .. .. .. .
.x . . .... .... .1 .. r J.,] xxx! . .-
.... ... .. ... ..... .. ... .1. . .l
.... x. 4 .. I .... .. I”... ...... .
... .. .... .... .. . .2 . .-
Ti .... A .. r. 1 .. r ... f ,
.. x .. ... - II F
... . r. J . r ... ...t . I
.... . . . . ... ... . .. .... .
r . ..... .. .. .. .
... ... . T. u A { r I. I . . . .
.... .3 ... ... . .... ...! . 1-
!, .... J . r! .4 I: r .I. .. I
.. . .. .. .. . ,
r... .....I.A . . r! . cl r! .... In... . . . .
.1. K ... .... . .. II I F
7.; .... ... .. ... 1. .I
. .1; ...... al.. ..a. a}! .,
ﬂint-C ...j 71”» punt. J . r04. ’1'! .4 an T
r .. .. ... . . . . . ...
.. ... .13.... r/......
I... .1 .r. ... .. .... ...: .
7... ..... r... .f. j .. r.. .... .4 ..
v .. ... . .. .... .I
.. .... v. ... ... r. .... ..+ ,.
r!... I... I... on... .. ... ...! .... I
f... 1 .. .....z... . .. I
.. .. s .. ‘ .. .
. v..- l-cvff‘ .. Mn! .. '
.... . .... ,. .. H I
,. . .. :8
r ...: ...: . I
.. ...
I. -./ . '
... .... . .
... .... .
r. .... ..
. ...
T , ........ u 8
.2 . . .
'
.I
.l
I
l
1
T
T
I
II-
I
I
.I
1

 

 

ID
V.

.388 9: E can a 3:398. 209:8 QoN .mcozmsgcoo 30:3 025
o. 855 $5535 _m>>mw .2 $635 Eon .3 883 .m 8539: as: new
$23: 209:8 6 59:5: 05 6 m8 759 ES. 80905 cogntﬁﬁ 3:262“. .N .9".

(0/0) Aouenbajd

 

coEmmc. En. $0250

 

 

 

 

 

 

ID

If
a _. ‘ .
e _.- . -
. .-" 3. 1’. .... .

 

 

 

_ 4‘ I

 

‘.
I

 

 

2' -

 

2' n
.
n o . l‘
1’ . -' .
v" I.’ j u" I '

 

 

O
,—

 

’.

 

. ‘2'

 

.. .‘ I.

.‘ .-
.. ’ .
. .lv’ ‘1.

ID
...

 

 

 

 

 

 

 

O
N
(0/0) AouanbeJd

 

LO
N

51

 

 

 

 

 

 

O
CO

 

$9 I F: I Q E

 

 

 

 

 

 

 

 

 

 

 

TIIIITTII'IIIUIIUIIItIIFri—IIIIIrIUIIIIU

 

 

 

.80ch m5 5 gun a 25352 202:8 oboN .mcozmszcoo >358 025 2 8.55
85536 826m .2 .2820 Eon B :85? a 3532: c5: 2:... «26m:
202:8 .0 82:3: 2: 8 39.59 .2 3855 5:39:36 55:62“. .m .9...

:o_:om:_ Lon 2o2:oo
m N _. o

          

w m v

:3 l2 2
(%) AouanbaJd

L0
N

 

_!fmv I F: I 6: @— mm

0v

.>no:mo 05 :_ now a 2:328: 222:8 QoN .mcozﬁzmzcoo >358 09.5 2 oocan
mo:_>on§m _m>>om :2 8526 ES 3 «moan: E oosmmoEcS: o:m
wo>moc 202:8 :o 5:83: 2: B 89-59 :2 835% :ozonEmﬁ 3:269“: .v .9“.

CHAPTER II

INFLUENCE OF CANOPY CONFIGURATION ON SHOOT GROWTH, LEAF
DEVELOPMENT, AND LEAF AREA OF SEYVAL GRAPEVINES

53

Abstract

Seyval grapevines were trained to three canopy configurations in 1988. One treatment
ﬁlled the trellis early (Full Trellis) by spacing 45 buds along the cordon. Another simulated
a hedge (Hedge) by hand pruning four inches around the cordon. A control was used
where vines were balanced pruned to 8 nodes per 454 g. cane pnmings. All vines were
flower cluster thinned to 15 clusters per 454 g. cane prunings. Shoot measurements were
taken throughout the 1993 growing season, including a leaf area measurement at harvest.
The full trellis and hedge treatments had a larger number of nodes retained and increased
shoot and leaf development early in the growing season. The full trellis vines provided
higher yields by producing heavier clusters with larger benies. Full trellis and hedged
vines also produced a greater leaf area through verasion. But, by harvest, severely pruned
vines obtained a leaf area equal to the other treatments. This resulted from new leaf
production from laterals. The full trellis vines also produced many new leaves during fmit
ripening, however, hedging showed little leaf production after veraison. Severe pruning
caused an increase in Botrytis bunch rot in 1993, but, no other significant differences in
fruit quality or vine size were observed. A canopy structure that exhibits early shoot and
leaf development with properly spaced shoots and yet allows for new leaf production
during fruit ripening, appears to be the best canopy configuration for Seyval grapevines.

Introduction

Seyval is an important white wine grape cultivar across the Eastern United States.
It has numerous desirable characteristics. It is cold hardy, disease resistant, and phylloxera

resistant. It does, however, f onn large, compact clusters susceptible to cluster rot under

54

55

Michigan conditions and the large clusters can lead to overcropping. Crop levels are
usually maintained by severe balance pruning and ﬂower-cluster thinning. Reynolds et al.
(19) suggested an optimal cropping level of 17 clusters per 500 grams of eane prunings in
New York state. Severe pruning reduces the thinning expense incurred by the grower, but
results in a later ﬁlling of the eanopy and thus potential loss of photosynthesis. The current
suggested balanced pruning formula is 15+10 (15 nodes retained for the first 454 gm of
dormant one year cane prunings, and 10 nodes retained for each additional 454 gm). This
results in a canopy that does not fill the trellis area until after fruit set.

The photosynthate produced during the vegetative season must drive the processes
of vegetative growth, fruiting, and ﬂower bud development for next years crop. Reserves
must also be stored over the winter for cold hardiness, and initiation of growth and
development until a new canopy is producing photosynthate the following spring. Equally
as signifieant is the mobilization and transport of assimilate between different organs of the
vine in order to carry out these processes.

Grapevine shoot development has been an area of recent interest and research.
Spring shoot growth is dependant on the remobilization of carbohydrates stored in roots,
trunks, cordons, and canes from the previous year (38,39), and cluster development is
slow until leaf area is established (37). Shoots become net exporters of earbohydrates
during anthesis (18). Cell division before anthesis and cell expansion after anthesis are the
major determinants of the increase in weight of grape berries (4). Thus, it seems important
to fill the trellis area with vegetative growth and leaf surface as early as possible to facilitate
vine growth and fruit development

Leaf development is important for fruit and shoot maturity. A leaf number greater
than 10 per shoot is necessary for optimal fruit ripening and shoot weight (34,36). Leaf

photosynthesis is greatest when the leaf is fully expanded, and then gradually declines
Shortly after ( 17). The amount of photosynthate produced by web leaf is important for the

56

development of the subtending bud (6,27). Over eighty percent of the assimilate a cluster
collects is produced by the leaves on the same side of the shoot (14,15). Buttrose (2)
found that as leaf number was reduced, root dry weight decreased most severely, followed
by reductions in berry development, and then trunk and shoot carbohydrate reserves.
Increasing the number of leaves per shoot increases berry sugar, weight, and coloration at
harvest (34). However, the production of each new leaf adds to the vine leaf area and the
formation of leaf layers within the canopy.

The leaf area of the vine is critical because it produces the assimilate necessary for
crop ripening and wood maturity. A minimum leaf area of 7-14 cm"2 per gram of fruit is
needed for adequate fniit ripening (10,31). Smart showed that a dense canopy can reduce
light levels to 1% of the solar radiation in the fruiting and renewal zone (28), and an
optimal canopy has no more than three leaf layers (29). Light penetration into the canopy is
important for photosynthesis (11,26), f ruitfulness (8,25), flower bud formation (25,28),
fruit set (3,23), fruit quality (20,22,30), yields (25), and wood hardiness (7,25,32).
Thus, it is evident that a maximum leaf area exists where light penetration into the canopy is
restricted to the point that vine productivity begins to diminish. The maintenance of this
leaf area is important to maximize the amount of assimilate produced in the vegetative
season for vine growth and development. When this maximum leaf area to facilitate vine
growth is established is of great interest.

Mechanieal hedging, selective hand pruning, or no pruning at all, increase the
number of buds retained for potential shoot production from the previous years vegetative
growth. These minimally pruning management techniques change vine morphology. They
increase the leaf area before bloom and decrease leaf production after (5). Minimally
pruned vines partition fixed carbon differently than conventional pruned vines (5). They
Store more carbohydrates in old wood and less in their canes and roots (24). Increasing

Shoot number increases canopy density (7) and the labor expense incurred by cluster

thinning fruitful varieties.

Mechanical hedging has received increasing attention in the United States, since the
pioneering efforts of the Australian researchers. This is suggested to be a cost effective
alternative to hand pruning. Hedging leaves more buds in the canopy area, increasing the
amount of vegetation per foot of row and per square foot of canopy space (12,13,16).
With no further crop control, increasing shoot number yields more clusters per vine, and
thus increased sink competition and higher crop levels. This in turn results in
morphological characteristics such as reduced shoot length, leaf size, cluster size, cluster
weight, and berry weight (1,9,35). Whole canopy microclimate improves (20,21) and
photosynthetic efficiency increases through reduced shading (31). However, hedging
alone has shown only to be useful for a few years before yields, fruitfulness, and fruit
quality diminish (12,13,16). Given the differences in climate and limitations of sunlight
and carbon assimilation between the North Eastern United States and Australia, an
objective evaluation of the limitations of this technology deserves effort and Seyval would
seem to be a good eandidate for this effort. Since thinning is required to control
overcropping in Seyval, the crop level can be managed so that the inﬂuence of canopy
configuration and decreasing pruning severity on shoot and leaf development, can be
further investigated. Reducing labor expenses by mechanical hedging would greatly
decrease the cost of producing this variety.

E‘ l:l"'

1. To determine the results of increasing bud numbers and balanced cropping (based on
the previous years vine size) on vegetative growth, yield, and fruit composition and
quality in Seyval.

58

to

To evaluate balanced cropping with a set pruning number of buds retained, designed to
space shoots at optimal distances from each other along the cordon in Seyval.

3. To analyze the impacts of hedging in conjunction with balanced cropping by cluster
thinning in Seyval.

4. To measure the impact of these pruning/cropping strategies on shoot, lateral, and leaf
development in Seyval.

5. To measure the impact of these pruning/cropping strategies on leaf area formation in
Seyval.

Materials and Methods

ElantMaterial

The experiment was performed during the 1993 growing season, 4.5 miles East of
Lake Michigan (42-15’ latitude) at Fenn Valley vineyards in Fennville Mi. Mature, bearing
Seyval grapevines planted in 1975 on an Oshtemo sandy-loam soil were used in the
experiment. Three unique canopy configurations were initiated in 1988. Rows were
spaced 3.0 meters apart with vines 2.4 meters apart within rows. The vines were trained to
a bilateral cordon on the top wire, 1.8 meters high (Hudson River Umbrella training

system).

Burningffreatments

The three canopy configurations consisted of: 1) a full trellis treatment (FT)
spacing 45 buds along the cordon with five-node canes and two-node spurs; 2) a
mechanically pruned hedge (SH) was simulated by hand pruning four inches around the
Gordon; and 3) a control (C) (the cunent standard cultural method) was employed to ensure
a typical rate of canopy development In all cases an 8+8 balance pruning formula (8 buds

retained for every 454 grams of dormant one year cane prunings) was used.

59

The control and full trellis vines were pruned to 45-nodes and the live one-year cane
prunings weighed to estimate the previous year’s vine size. The node number for the
control vines was then set for the duration of the growing season following the procedures
stated above. Because hedged vines retained a larger number of nodes, a method was
devised to estimate the weight of retained wood After pruning the hedge treatment, the
live mnes were weighed and nodes counted. The remaining live nodes of canes on the vine
were counted. A weight was assigned to the number of nodes over 45 retained on the vine,
based on a node weight of 113 gm per 50 nodes. This weight and the weight of cane
prunings were added producing the vine size estimate for each (SI-1) vine.

Since pruning is not sufficient for optimal crop control in Seyval, cluster thinning
was also required. The weight of live one—year-old canes at pruning (vine size) was used
to determine cluster number after thinning. The treatments were ﬂower-cluster thinned just
prior to or during bloom to lS-clusters per 454 grams of dormant cane prunings. At bud
burst, nodes that did not produce a shoot (shootless nodes) were counted. Percent blind
nodes, vegetativeness (vine size (gm) per shoot), count shoots (nodes retained at pruning
minus blind nodes), and non-count shoots (total shoots minus count shoots) were

calculated for each vine.

II E l l E . C l' !
Treatment vines were harvested October 1. Each sample vine was hand harvested,
the cluster number recorded and the fruit placed into an individual bin Each bin was then
weighed in the ﬁeld and a cluster weight calculated. Apical berries were taken from
clusters of all sample vines within a treatment replication to create a 100 berry sample.
From these samples pH, titratable acidity, soluble solids, and a berry weight were
measured and the number of berries per cluster calculated. Using the harvest and pruning
data, shoots per cluster (total shoots/ lmvest cluster number) was calculated.

 

ShootandieaLMeasurements

During the 1993 growing season, detailed shoot and leaf measurements were taken
on one vine from each treatment block The vines were selected to conform to an average
vine size range (0.57-0.91 kg). Within each sample vine, six shoots were randomly
flagged along the cordon for vegetative measurements during the growing season. These
included: 1) primary shoot length (PSL); 2) primary shoot leaf number (PSLF); 3) lateral
number; 4) lateral length (LL); and 5) lateral leaf number (LLF); measured on May 26
(WK3 weeks after bud burst), June 2 (WK4), June 9 (WKS), June 16 (WK6), June 30
(WK8), July 29 (WK12), and September 23 (WK21) one week prior to harvest.
Additional calculated data included total leaves per shoot (T SLF=PSLF+LLF) and total
vegetative shoot length (PSL+LL). Treatment comparisons were made at appropriate dates
and over dates on those variables measured or calculated.

At thinning, three of the sample shoots were defruited while one cluster was
retained on the other three. Shoot development with and without a fruiting sink, was
compared for the remainder of the growing season. A standard curve was developed to
allow rapid determination of flower number per cluster based on cluster length. Thirty
clusters were randomly sampled from guard vines just prior to bloom. Rachis length was
calculated using the length of rachis from the lowest basal arm to the tip added to the length
of the lowest basal arm. Flowers of each sample cluster were counted and a strong
correlation was found (Fig. 1). The rachis length of clusters on sample shoots was
measured and an estimated flower number calculated. At harvest, berry pedicles of sample
shoot clusters were counted and the percentage of berries set analyzed.

A count of shoots longer than 10 cm and bearing three or more leaves was taken
two weeks prior to harvest. Primary leaves per vine (PSLF*SC), lateral leaves per vine
(ILF‘SC), and total leaves per vine (T SLF‘SC) were then calculated and compared
between treatments. A leaf area standard curve was developed for primary shoot and lateral

61

leaves at WK21 by sampling 100 primary shoot leaves and 50 lateral leaves randomly from
guard vines. The mid-rib length and area was measured for each leaf. A strong curvilinear
relationship was found between mid-rib length and leaf area for primary shoot (Fig. 2) and
lateral leaves (Fig. 3). Mid-rib lengths of leaves from sample shoots were measured
WK21 and leaf area calculated using the standards. Leaf area was calculated on a per leaf,
per shoot, per vine, per cluster, and per yield basis for comparison. Leaf area
accumulation per vine over the 1993 growing season was calculated using the average leaf

area and number of both primary and lateral leaves in each treatment.

E' 112' II'

A randomized complete block design was used with four blocks. Two rows,
containing two blocks each, of own rooted Seyval grapevines were utilized. Within each
block, the treatments consisted of five sample vines. A guard row was situated outside and
between the two treatment rows, and a guard vine separated each treatment. Comparisons
between treatments were done using the MST AT-C statistical computer package. Analysis
was by ANOVA, with mean separations calculated using Duncan’s Multiple Range Test

(33). Leaf area regressions were calculated using the Delta Graph computer package.

Results and Discussion

If 1:. ll lE .: l'
Vine yield was favored by a decrease in pruning severity (Table 1). The (FT) and

(SH) vines produced 3540 percent more fruit than (C). Normally, these differences in

62

yield might be the result of increased cluster number or cluster weight. Although large
differences in nodes retained provided conditions favorable for large variations in cluster
number, this variable was eliminated by the process of cluster thinning based on vine size.
As a result, no significant differences were observed in cluster number at harvest (Table 1).
The yield differences are, therefore, due to cluster weight, and must be a result of
variations in berry weight and/or the number of berries per cluster (Table 1). The (FT)
system improved the components of yield compared to the other two treatments. Its
average weight per cluster was 17-27 percent heavier. Since there were no signiﬁcant
differences in the percent berry set or number of benies per cluster among treatments, the
major response was berry weight in 1993. The (FT) treatment produced berries nearly 10
percent greater than the other treatments.

The minimal differences in cluster weight of (C) and (SH) vines contrast with
previous work (1,9,35). Since the vines were ﬂower cluster thinned near bloom each year,
many more shoots per cluster existed in the (SH) canopy than the (C) at that stage. The
greater leaf area at bloom may explain this response. The fruitfulness data suggest a
reduced yield per node, but that was expected based on the thinned treatment response.

Fruit composition data provided little basis for discrirrrinating among treatments
(Table 1). There were no differences among soluble solids , pH, and titratable acidity.
Botrytis cinerea infection of the clusters was the most noticeable fruit quality variant among
canopies. Subjective ratings performed the day of harvest showed that the amount of
Botrytis rot was severe across all treatments. The average loss of crop was nearly 25
percent. No signiﬁcant differences were observed in rot incidence within clusters,
however, the higher amount of rot incidence in (C) clusters expressing rot (vine rot),
inﬂuenced yield (Table 1). The (FT) vines showed less incidence of vine rot in 1993. The

full trellis canopy was the least conducive to Botrytis rot infection.

63

No signiﬁcant differences were found in vine size; however, increasing the number
of nodes retained reduced vegetative vine growth measured by kilograms of cane prunings
per node (Table 2). This result was likely due to two factors: 1) the stimulation of non-
count shoot production in (C) vines, which resulted in three—quarters of the total shoot
number per vine from non-count positions; and 2) the competition for stored reserves,
nutrients and water among the large number of primary shoots arising from count positions
in the (SH) canopies resulted in shootless nodes.

Adventitious shoots comprised much of the (C) canopy. These non—count shoots
formed along the cordon, or from secondary and tertiary buds when a primary shoot was
present. Since nearly all of the count shoots were needed to cany the crop load, non-count
shoots served as additional sources of photosynthate. Some of these adventitious shoots
produced ﬂower clusters. Because they developed as quickly as on non-count shoots, they
were thinned during bloom as well. The competition among shoots was most evident in
the hedged vines, as many buds failed to produce any growth. Less than ten non-count
shoots were produced by the (FT) vines and very few produced by (SH). Whatever was
gained by adventitious shoots on (SH) vines, was negated by the loss of count shoots
during the growing season. The (SH) vines also produced two to four times as many
shootless nodes as the other treatments. Even taking into account the non-count shoot
contribution and shootless nodes, total shoot number was highly signiﬁcant among
treatments (Table 2). The (C) vines produced the least amount of shoots and (SH) the
most The large number of non-count shoots exempliﬁes the severe pruning practice of the

(C) treatment; while the shootless nodes in hedged vines indicate vine capacity is attained.

ShootAssessmems

Because shoots begin exporting carbohydrates during anthesis, shoot development

ﬁn)“
him;

no

as!)

$2:
zﬁ_

\le
Sﬁggt
hm
Glut

64

early in the spring is important for overall vine production. Seyval clusters are very large
and become strong carbohydrate sinks at fruit set. Berry growth and most of the vegetative
growth in a season occurs between bloom and verasion (4). Laterals form just prior to
bloom and grow for the remainder of the season. Shoots thinned of fruit are sources of
photosynthate for various sinks within the vine. During the 1993 growing season, detailed
shoot measurements were taken on six sample shoots from one vine in each treatment
block. Shoots of (FT) vines were more developed before bloom. Between WK3 and
WK6, (FT) vines had a greater primary shoot length than (C) or (SH) (Fig. 4). This
suggests the (FT) shoots were able to utilize reserves better than the other treatments and
become self sufficient earlier. The earlier shoot and leaf development of the (FT) vines
coincides with early cell division in the beny (4), and may be the cause for their superior
berry weights. The (C) shoots caught up in length to (FT) shoots by WK12, and they both
averaged more than 40 cm longer than (SH) shoots at harvest. Shoot growth rate for each
treatment increased after WK6 and decreased again after WK12. Little primary shoot
growth was achieved by (SH) after veraison, while (C) and (FT) shoots continued to
grow.

Since intemode length remained consistent between treatments at every date, leaf
production was closely related to primary shoot length. The (FT) shoots averaged one
more leaf on WK4 (Fig. 5). At veraison, (C) and (FT) primary shoots averaged 5 more
leaves than (SH). This response continued through harvest, but as (FT) and (SI-l) primary
shoots stopped producing leaves, (C) primary shoots increased leaf number. New leaf
growth rate for each treatment increased after WK6 and decreased again after WK12.

Lateral growth began to appear during WK6. By WK12, (C) and (FT) shoots
produced over twice as many laterals than (SH) (Fig. 6). None of the canopies produced
new lateral shoots after verasion. The laterals of (C) and (FT) shoots produced more

leaves than (SH) shoots by verasion, and continued to produce more till harvest (Fig. 7).

65

They also had a greater rate of elongation between WK6 and WK8, and length at harvest
(Fig. 8). Rate of elongation after anthesis was inversely related to bud number. Shoots of
(SH) vines were considerably smaller with less leaves and lateral growth.

No differences were found in the total vegetative shoot length until WK21 when
(SH) shoots were inferior to the other two treatments (Fig. 9). Shoots of (SH) also had
fewer leaves per shoot than the (C) shoots on WK12 and WK21 (Fig. 10). Over dates
measured, (SH) shoots were inferior to (C) and (FT) shoots in length and leaf number,
while control and (FT) shoots were never significantly different from each other. This
agrees with previous work with hedging systems (1,9,35). Shoots with and without a
cluster were compared in each treatment and no significant differences or interactions were
found at any date. However, shoot and leaf measurements on defruited shoots were
signiﬁcantly greater than shoots bearing fruit over the year.

Canopy type inﬂuenced the rate of growth between veraison and harvest (Table 4).
At veraison the (SH) vines averaged 2800 leaves, 600-800 more than (C) or (FT). Only 12
percent (389 leaves) of the total (SH) leaf production was grown between veraison and
harvest. The (C) and (FT) vines produced 900 (31%) and 700 (24%) of their leaves during
this time respectively. Lateral shoots were responsible for the additional leaf production
after veraison. Laterals provided young, productive leaves during fruit ripening. The (C)
and (FT) canopies produced laterals that continued to produce leaves after veraison, while
(SH) shoots had little lateral leaf production. The lack of new leaf production after
veraison in (SH) vines suggests older, less photosynthetically efficient (17) leaves were
responsible for photosynthate production during fruit and wood ripening. Although, fruit
quality was not affected, wood maturity was a concern. The vegetativeness per shoot was

signiﬁcantly lower in (SH) vines (Table 2).

LeaLAreaMeasurements

The mid-ribs of leaves from sample vines were measured at harvest. The (SH)
primary shoot leaves were significantly smaller than those of the other two treatments
(Table 3). However, no differences among treatments were seen in lateral leaf area or the
whole shoot average area per leaf. Shoot leaf area was directly related to leaves per shoot
and inversely related to shoot number (Table 3.). The (SH) vines produced the fewest
leaves per shoot and the least leaf area per shoot. They produced a primary shoot leaf area
over 750 square centimeters smaller than the other two treatments and a 70 percent decrease
in lateral shoot leaf area from the control; leaf area per whole shoot was over 45 percent
smaller than (C) and (FT). The (FT) and (C) vines never varied signiﬁcantly in leaf
number or leaf area per shoot. Obviously, there exists a limit in the number of vegetative
sinks a vine can support and grow to full potential. Shoots with and without a cluster were
compared in each treatment and no signiﬁcant differences or interactions were found.
Thus, the crop level inﬂuence was over the entire vine and not limited to the shoot.

Leaf area per vine at harvest was calculated using the average area per leaf, total
leaves per shoot, and number of shoots per sample vine (Table 4). Although (SH) shoots
were less developed and possessed less leaf area, no significant differences among
treatments in the total number of leaves or leaf area per vine at harvest were observed
(Table 4). (SH) shoots averaged over 3000 leaves per vine with an area more than 16
meters square. However, it is interesting to note how the treatments achieved this leaf area.
Using the average leaf area for primary shoot and lateral leaves and the leaf number of each
of these at the dates counted, a seasonal history of leaf area development was constructed
(Fig. 11). Increasing the number of shoots within the canopy increased the leaf area from
pre-bloom until after veraison, supporting Downton and Grant’s results (5) on minimal
pruned vines. Lateral shoots produced the additional leaf area in the (C) and (FT) vines

from veraison to harvest. Leaf area per cluster was not signiﬁcantly different among

67

treatments, although (FT) and (SH) had 1000 and 1500 square centimeters less per cluster
than (C) respectively. Signiﬁcant differences among treatments did surface when leaf area
was expressed per gram of yield. The (FT) and (SH) vines produced over 10 cm"2 less
leaf area per gm yield than (C) vines (Table 4). However, all the treatments produced over
20 cm"2 of leaf area per gram of fruit, sufficient to adequately ripen fruit (10,31). A
greater leaf area, necessary to ripen fruit and wood in Michigan’s climate, was expected.
Canopy configuration and increased bud numbers increased the amount of leaf area through
veraison, though the leaf area response to increasing node number was limited. The (SH)

vines never achieved greater amounts of leaf area compared to the (FT) vines.

Conclusions

The treatments established three unique canopy architectures. Severe pruning and
hedging were compared with a constant pruning level created to loptimally space shoots
along the cordon. Increasing node number at pruning increased yield with no affect on pH,
titratable acidity, or soluble solids. Cluster number was consistent between treatments
because of balanced cropping based on vine size. Yield responses were due to an increase
in berry weight.

The greatest cause for a decrease in fruit quality or crop loss was Botrytis rot
infection. An average of 25 percent of the crop was lost between all of the treatments. The
adventitious shoots forming from secondary and tertiary buds, as well as vigorous laterals
from basil nodes, formed a dense leaf area immediately around the control clusters. A
dense canopy inhibits air ﬂow and chemical penetration to the clusters. Crop loss was
most severe in control vines, while the full trellis canopy was the most consistent in
avoiding rot infection due to optimally spaced shoots creating a low leaf density around the

clusters.

F-

v,

lit

68

It is evident that early shoot development is important for fruit development.
Severe pruning inhibited shoot and leaf area development and promoted adventitious shoot
growth early in the growing season. Because of greater shoot numbers, the hedged and
full trellis canopies developed earlier. However, the full trellis canopy conﬁguration was
superior because of optimal vegetative sink competition and leaf area development allowing
for better shoot development. This resulted in the full trellis vines yielding the heaviest
clusters with the largest berries. Full trellis vines seldom producing shoots from non-count
positions. In the hedging system, vines achieved their full capacity, since all of their
vegetative growth arose from count positions and shoot abortion occurred throughout the
growing season. Dead wood accumulated in the canopy and optimal shoot spacing
declined each year.

Because sufﬁcient source levels were available, the control and full trellis canopies
produced large primary shoot leaves and lateral shoots. The lateral leaves were an
important component of total leaf area. However, much of the leaf and leaf area production
by control canopies was produced after verasion. Small primary shoot leaves comprised
most of the leaf area of hedged canopies. Full trellis and hedged vines produced a greater
leaf area through verasion; however, new leaf production in hedged vines decreased
because of the lack of laterals. Laterals provided young, productive leaves during fruit
ripening. The full trellis canopy was superior because it increased shoot development early
in the growing season and allowed for further leaf area development during fruit and wood
ripening. This was not an advantage in 1993, since each treatment produced more than
enough leaf area to sufﬁciently ripen fruit. However, if crop levels were to be increased,
mid to late season leaf production could be crucial. Increasing node number per vine by
hedging showed no advantage over the full trellis system in production of leaf area or fruit.
Hand pruning to a set number of buds spaced along the cordon produced the best canopy

conﬁguration in this experiment.

to

10.

11.

l2.

13.

Literature Cited

. Bravdo, B., Y. Hepner, C. Loinger, S. Cohen, and H. Tabacman. 1984. Effect of

crop level in a high yielding Cari gnane vineyard on growth, yield, and wine
quality. Am. J. Enol. Vitic. 35:M7-252. '

Buttrose, MS 1968. The effect of varying berry number on Gordo grapevines with
constant leaf area. Vitis 72299-302.

. Coombe, B.G. 1962. The effect of removing leaves, ﬂowers and shoot tips on fruit

set of Vitis vinifera L. J. Hort. Sci. 37:1-15.

Coombe, B.G. 1976. The development of ﬂeshy fruits. Ann. Rev. Plant Physiol.
27(2):507—528.

Downton, W.J.S. and W.J.R. Grant. 1992. Photosynthetic physiology of spur
pruned and minimal pruned grapevines. Aust. J. Plant Physiol. 19:309-316.

Hale, CR, and P.J. Weaver. 1962. The effect of developmental stage on direction of
translocation of photosynthate in Vitis vinifera . Hilgardia 33289-131.

Howell, G.S., B.S. Stergios and SS. Stackhouse. 1978. Interrelation of
productivity and cold hardiness of Concord grapevines. Am. J. Enol. Vitic.
29:187-191.

Howell, G.S., D.P. Miller, C.E. Edson and R.K. Streigler. 1991. Inﬂuence of
training system and pruning severity on yield, vine size, and fruit maturity of
Vignoles grapevines. Amer. J. Enol. Vitic.

42(3): 191-198.

Kaps, M.L. and G.A. Cahoon. 1989. Berry thinning and cluster thinning inﬂuence
on vegetative growth, yield, fruit composition, and net photosynthesis of Seyval
blanc grapevines. J. Amer. Soc. Hort. Sci. 114(1):20-24.

Kliewer, W.M. and R.J. Weaver. 1971. Effect of crop level and leaf area on
growth, composition and correlation of ‘Tokay’ grapes. Am. J. Enol. Vitic.
23:172-177.

Kriedemann, P.E., B.R. Loveys, and W.J.S. Downton. 1975. Internal control of
stomatal physiology and photosynthesis. 2. Photosynthetic responses to phaseic
acid. Aust. J. Plant Physiol. 22553-567.

Morris, J.R., D.L. Cawthon, and J.W. Flemming. 1975. Effect of mechanical
pruning on yield and quality of Concord grapevines. Ark. Farm Res. pub. 24(3): 1-

Morris, J.R. and D.L. Cawthon. 1981. Yield and quality response of Concord
grapes to mechanized pruning. Am. J. Enol. Vitic. 32(4):280-282.

69

14. .\1

15. .\1

19. R

31.11

14.

15.

16.

17.

18.

19.

20.

21.

25.

26.

7O

Motomura, Y. 1990. Distrbution of 14C-assimilates from individual leaves on
clusters in grape shoots. Am. J. Enol. Vitic. 41:306-312.

Motomura, Y. 1993. 14C-assimilate partitioning in grapevine shoots: Effects of
shoot pinching, girdling of shoot, and leaf -halving on assimilate partitioning from
leaves into clusters. Am. J. Enol. Vitic. 4421-7.

Pollock, J.G., E.S. Shepardson, N.J. Shaulis, and DE. Crowe. 1977. Mechanical
pruning of American hybrid grapevines. Trans. ASAE 20(5):817-821.

Poni, S., C. Intrieri, and O. Silvestroni. 1994. Interactions of leaf age, fruiting and
exogenous cytokinins in Sangiovese grapevines under non-irri gated conditions. 1.
Gas exchange. Am. J. Enol. Vitic. 45(1):71-78.

Quinlan, J.D. and R.J. Weaver. 1970. Modification of pattern of the photosynthate
movement within and between shoots of Vitis vinifera L. Plant Physiol.
46: 527-530.

Reynolds, A.G., R.M. Pool and LR. Mattick. 1986a Effect of shoot density and
crop control on growth, yield, fruit composition and wine quality of ‘Seyval blanc’
grapevines. J. Amer. Soc. Hort. Sci. 111(1):55-63.

Reynolds, A.G., and DA. Wardle. 1989a. Impact of various canopy management
techniques on growth, yield, fruit composition and wine quality of
Gewurtztraminer. Am. J. Enol. Vitic. 40: 121-129.

Reynolds, A.G. and DA. Wardle. 1989b. Effects of timing and severity of summer
hedging on growth, yield, fruit composition, and canopy characteristics of ‘De
Chaunac’ l. Canopy characteristics and growth parameters. Amer. J. Enol. Vitic.
40:109-120.

Reynolds, A.G. and DA. Wardle. 1989c. Effects of timing and severity of summer
hedging on growth, yield,fruit composition, and canopy characteristics of ‘De
Chaunac’ 2. Yield and fruit composition. Am. J. Enol. Vitic. 40:299-308.

Roublelakis, K.A. and W.M. Kliewer. 1976. Inﬂuence of light intensity and growth
regulators on fruit set and ovule fertilization in grape cultivars under low temprature
conditions. Am. J. Enol. Vitic. 27(4): 163-167.

Ruhl,E.H. and PR. Clingeleffer. 1993. Effect of minimal pruning and virus
inoculation on the carbohydrate and nitrogen accumulation in Cabernet franc vines.
Am. J. Enol. Vitic. 44(1):81-85.

Shaulis, N., and R. Smart. 1974. Grapevine canopies: management microclimate
and yield responses. In: Proc. XIXth International Hort. Congress. pp. 255-265.
ll-18 Sept, Warsaw.

Smart, R.E. 1974a. Photosynthesis by grapevine canopies. J. Applied Ecology
1 1:997-1006.

27.

30.

31.

32.

33.

34.

35.

36.

37.

38.

39.

71

Smart, R.E., N.J. Shaulis, and ER. Lemon. 1982b. The effect of Concord vineyard
microclimate on yield. 2. The interrelations between microclimate and yield
expression. Am. J. Enol. Vitic. 33:109-116.

Smart, R.E. 1984. Some aspects of climate canopy microclimate, vine physiology
and wine quality. In: Proc. First Intl. Symp. Cool Climate Vitic. Enol. D.A.
Heatherbell, P.B. Lombard, F,W. Bodyfelt, and SF. Price (eds). pp 1-18. June
1984, Eugene, Oregon. Oregon State Univ.

Smart, RE. 1985. Principles of grapevine canopy microclimate manipulation with
implications for yield and quality. A review. Am. J. Enol. Vitic. 36(3):230—239.

Smart, R.E. 1987. Inﬂuences of light on composition and quality of grapes. Acta
Horticulture. 206:37-47.

Smart, R.E., J.K. Dick, I.M. Gravett and BM. Fisher. 1990. Canopy management
to improve grape yield and wine quality - principle and practices.
S. Afric. J. Enol. Vitic. 1123-17.

Stergios, B.G. and GS. Howell. 1977. Effects of defoliation, trellis height, and
cropping stress on the cold hardiness of Concord grapevines. Am. J. Enol. Vitic.
28( 1):34—42.

Steel, R.G.D. and J.H. Torrie. 1980. Principles and Procedures of Statistics:
A Biometric Approach. McGraw-Hill Book Company, New York, NY.

Weaver, R.J. 1958. Effect of leaf to shoot ratio on fruit quality and shoot
develeprnent in Carignane and Zinfandel wine grapes. Am. Soc. Enol. Vitic.
14:1-12.

Weaver, R.J. and RM. Pool. 1968. Effect of various levels of cropping on
Vitis vinifera grapevines. Am. J. Enol. Vitic. 19:185-193.

Winkler, A.J. 1930. The relation of number of leaves to size and quality of table
grapes. Proc. Am. Soc. Hrt. Sci. 27:158-160.

Winkler, A.J., J.A. Cook, W.M. Kliewer and LA. Lider. 1981. General
Viticulture. University of California Press, Berkeley.

Yang, Y.S. and Y. Hori. 1979. Studies on retranslocation of accumulated
assimilates in ‘Delaware’ grapevines. I. Retranslocation of 14C-assimilates in the
following spring after 14C feeding in summer and autumn.

Tohoku J. of Agr. Res. 30(2):43-56.

Yang, Y.S., Y. Hori, and R. Ogata. 1980. Studies on retranslocation of accumulated
assimilates in ‘Delaware’ grapevines. II. Retranslocation of assimilates
accumulated during the previous growing season. Tohoku J. of Agr. Res.

31(2): 109-119.

.50... 09.0.". 0.5.53. 302 9:00.50 050... 0..—5.00 55.! 5.3.0000 2.00.2
as 58.58.» .2. .o ”.... a... H... 8 a 88.588 822 n.
0050.2 0002.20.36 m... 0550.0. 05> coca... 0+0 :0 .0. 2803.0 .0 .BE:_. 05 2 9520000 .00

003 .0>0. no.0 000.00 0.... 50.. 03.00. ...05 v a 052:0 0050 00.652 :02... 0.00:0 0530... 0:0... 050: 0023050000 003 208.00.. 02.01 N

60582 0uo£20850 rev 05522 05> 00:20
0+0 :0 .0. 2203.0 .0 .095: 05 9 050.0000 .00 003 .0>0. no.0 05.5000: 9. 50.2 2 00.5.0 203 005., w...2.r ..an. .5
0050.0. 03:20.33 m; 2 0055: .8050 .030: 2.0 0+0 2 coca... 005., .2200 x

0092 0.03 05> 0..: :0 2203.0 .0 $007003
.28 ”$8.84 £8-88 ”4.8580 £863 22.3 8:8. r... a 8.3 8.333 5.2.8.8.. on; .2 2.5 3

 

 

.o/. .88. so; 282% o... 55.3 .352. .o «.878»...
o8 ”$8.8"... ”$8.88 secromum .....omou. 0.2.3 8:5. m... a 052. 02033.6 5.2.838 on; .2 .0820 55.3 >
.. 0: 2. 0c 0.. . 0.. 0c .. 0c .

o o.~ on at 8.0 So c 3.. no. 9:. 8 35 on a 3.0 N .258. .... 008:
o 3 Nu «.3 So So a mad I. 0.3. a 8.8,... on a «to a .8. use.» :3.
a mo c.~ no. on... E.» c 8.. 0o 93 n :3 cu o «3. x 8+0. .280
3 on. > on. 8.8 5.22 In .23 .5. .830 80 .53 .5. 8852 35>.va 3:53. 9.22%
05> .0820 0_n:_om 0.022.... >..0m .00...0m Fem 0.. .2020 .8020 22> 2.0.500...

 

.80.. .F ..00 00.0020... 02:05., >0..0> 5.0“. .0 005.5003 .0250»).
.0 000.05 5.020 53.. 05 use 2:050:60 503 05 :0 003 5 E020 05.5.0 .0 00:02.5 .. wam<k

73

..00._. 00:00. 0.00.22 ....02 9:00:30 0503 0:23.00 55.... 520.0000 0:00.).
.05 .8280 .8 .0 ”.... .... .... .00 .0 .8280 820., .
0050.0. 000520.020 0.. 0550.0. 05> 00:3... 0+0 :0 .0. 0.0.03.0 .0 .0023: 0:.0. 050.0000 .00 00.... .0>0. 00.0
000.00 0:. 20.. 0200. :05 v 0 00.0.30 00:00 00>022 :25... 0.00:0 05000: 0:0: 0503 00:0..020000 00.... 202.00.. 0000... ~
0050.0. 000520.020 0.. 0550.0. 0:... 00:3...
0+0 :0 .0. 0.0.03.0 .0 .0023: 0:. 0. 050.0000 .00 00; .0>0. 020 0550000: 0.. 50.0. 0. 00:3... 20.... 005> 05.0... =3“. >
0050.0. 000520.020 0.. 0. 00:5:. .0.03.0 .030: 0:0 0+0 0. 00:3... 005.. .2200 x

C. ii ... I. C .I CC ”C

 

o o 0 m. a m. 0 0.. a .. a e 0 00. 8.0 N .0200. .... 0000:

n 0 n 0.. n 0.. a I 8 o. 8 z n 0.. 00.0 . .0... 0......» =3".

0 00 0 0 0 ..0 0 8 0 0. 0 .0 0 2 00.0 x 6+0. .2250

069.0 0.02.0 .020 :0. 05> 088 .82 850.2. .053... .0353. a

2300202 2300 .00232 .00002 >0. 0~.0 05>. >0. 30 05>. 00002 020 05> 202.00....
60:0 000..oo:0 5o 000:0>_.0.000> 000:0>..0.000> 000.

 

.000. .. ..00 00.0020... .00.0>05> >0..0> ::0...
.0 005.6020 .0....00 .0 000.05 050 05> 0:. :0 000. 5 0202.02. 05:3... .0 00:02.5 .0 w..m<..

74

.38. 35m @3222 302 2.350 9:»: 2.628 55.3 c3838 «cue—2
.35 285cm.» .2 a 5; ..S 6 «.m a 285:9» 82...; n.
.8522 08,5332". m; 9:552 05> toga m+o ca .2 232:0 .o .383: 05 2 9.6803 .3 was .96. no.0
.5200 05 So: «:62 soc. v a 029.5 853 .3389. so...) 23;» 9:30: can: as»: unco._nEoooa an! “co—Eco: 0231 N
60582 32.38620 r...
@5582 05> vocaa o+m ca .2 923.0 .0 39:5: 05 2 9.288 .8 on: .0>0. no.6 .oszaouoc mc £82 2 ocean 35> 2.3:. .....u. >
.3538 08.5.0330 m; 2 3:55 .0520 .930: new 95 2 3:33 35> .2200 x

 

 

. . . .. .. : 9. 2. .
a not a «8 a 8: a 3 n 9 a n. on cm a no n 328. .3 .58...
an 28 no 39 a 83 na 8 na 9. as om S E a 3 > as 2:5 .3“.
a 89 a 88 a 9.9 a I a E a mm mm 3 a no x 8+8 .2500
$23 .85 31:3 $25 82m 695 .223 895 32E 32.3 33 553 .23 A953 33 $3.52 3.5.3
302 .2... 602m. .223 .095 baEtm 3230.. 3263 3263 302. 33 .025 .223 .096 EaEta 22:23:.
.28 :32 .53 :82 33 .28. .28 :82 33 \ .32 33

 

.82. .F .60 c2322..
.mEgocS >23) Eon. 8 $5335 .933 .0 32cm... 3 no.8 30. .002» :o mom? 5 6033 9:55 3 00:02.5 . .n m..m<._.

75

.005 09.0.. 0.0222 302 0:00:00 050: 05:28 55.3 5:90:00 0:005.
.35 28.590 .2 .o x... 0... ”C .00 .0 58:20.0 0022 n.
0050.0. 03:33.02". 0; 0550.0. 05> 00:2: 0+0 :0 ..o. 0.0.020 .o .0005: 0:. 2 050.0000 .00
m0; _0>0_ :20 .5080 0:. ES. 0200. :05 v 0 02050 00:00 00.650. :25: 0.00:0 05000: 0:0: 050: 00:53:82.0 003 £05.00... 0000... 0
0050.0. 000E2202o 0..
0550.0. 05> 00:2: 0+0 :0 .0. 20.020 .0 .350: 0:. 0. 050.800 .00 003 _0>0_ no.0 0520000: 00 50.0. o. 00:2: 00:3 0225 =0”. >
0050.0. 000520.020 m; o. 00:55 .8020 .032. 0:0 0+0 0. 00:2: 00:5 .2200 x

 

 

. 2 2 .. a: . .. . .. a:
n 3.0 003 9.0. a 000 0000 a 030 a B n 005 n 00 on N .0208 .... 02.0...
.n 0.8 300 00.0. 0 o: 0000 a 0000 n 00 an 2.8 as 8 S > 60. 2:0... =3“.
0 0.00 800 B0. 0 000 :00 a 080 0 ov a 08.. a i «m x 8+0. 6080
8.9 22> .2020 05> .830: 2 .830: .0 coaso> .0 320:0. .0..on820 82.0 .920. .03 Anseﬂczae
29.50. 10:50. 201:. 3.00.0) ES. 0520300.. 0520300.. .0952 .025 .002 .004 32.00.. .002 .00.. 20.500...
002 .00.. 00.< .00.. 002 .00.. £320 .00.. _0.o.r 3.0.. 05) .aE0m .085 .08... _0.o.r

 

.009 .F .80 00.0020:
00.03:; >0=0> ::0H. .0 00:30:05 .0>>0m .o .0030: .0 00.0 .00_ 05> :o 000? 5 80.03 05:3: .0 00:02.5 .0 M30...

76

..m

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

«5.21561? "3. 88.0 u 9}.
Es 152m... 5530
mm ow 3 S m o
_ > p » L . . p _ p p L . p h F p p p p o
r com
.1 o9.
f
f
o8
. r
0 com
0 w
\ o f
o r coop
8m.

353:3 >m=a> can".
5 85535 _m>>mw 5 9589335 5.3.0 .3 236: .2 235% 89 .F .9“.

HBQWHN HEMO'H

Leaf Area (cm‘2)

ééé

8888

O

77

PRIMARY SHOOT LEAF AREA

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

a . /
r 3 o

. o

I 0 %PO

. . o

: 07%.

3 ~/.

; 7° 0

3 e

1 ' .; o

2 0/ .0

1 o

1

3 '-

4 . o
E—v-F-FE Y T a Y A 1 a , r ﬁ ﬁ x
O 2 6 8 1O 12 14 16 18

Mid-Rib Length (CM)
H“2=0.9798 t(x)=(0.7377) ' (X‘1.9793)

Fig. 2. Standard for primary shoot leaf area measurements in Seyval grapevines at
Fenn Valley vineyards in 1993.

78

LATERAL SHOOT LEAF AREA

 

180

 

160

D

 

140‘

 

E;

 

§

L1LL1|4L llll 1111 11 A

 

Leaf Area (cm‘2)
O
O
A!

 

 

 

 

 

8888

L14 [All

 

 

 

 

 

 

 

 

O
I;

 

 

2 4 6 8 1O 12 14 16
Mid-Rib Length (cm)

0

R"2=0.9804 f(x)=(0.7591) " (x‘t .9629)

Fig. 3. Standard for lateral shoot leaf area measurements in Seyval grapevines at Fenn
Valley vineyards.

79

VN

.888 9.365 89 9: 9.26 «29823 >m=w> econ. «a $5586

.miow 5 A88 £90. 80% basin :0 5:939:50 .60ch .o 853:... 6 .9“.

595:
..N

-

hwmnm 03m W.M.—h; mxmm>>

or m_.

- p

com_m.m>
N F m

802m

 

 

C

 

 

I
O
N

l
O
V

r
O
Q

g 8
(ma) H19N5n Loon-rs Auvmud

é

 

 

 

mwowI I

w_._._wm._. .33“. ..ll

JOIPZOO ll

 

o:

80

:83» @5266 89 mg. 9.26 356:3 >o=w> econ. 3 8:32.05
_m>>mm s cozozuoa ﬁe. 605 >853 .8 5293928 .888 .o 853:... .m .9".

 

 

 

 

 

 

Pmem 03m Emit. wxmw>>
“$me com§m> 802m
PNLL ,m.FL_,_m.w.b__WFL...@....m_..Lm.._Lo
¢¢ CC OC To
. r
an m
a mm m
H w
i d
3%
r d
- M
r W
a f 9 .2w
1 H .A
,. m”.
a I
am ”cum
1.1111 a H
a i 1
mm

 

wwowI III mqﬁmh ...—Du. ll. ..OEPZOO ll. _

 

8]

.838 0::st 89 $5 05:6 3.98:3 >m=w> econ. La «05585
628m 5 8:885 605 .929 cc cozmszcoo 3058 Lo 00:25:. .o 9....

.513m 03m mwt< wxmmg

 

 

 

 

 

 

meEmI com_mLm> Eoo_m
rm 3. mw NF m m o o
p L L b L L L L L _ L _ L L _ L L F L L o
Cﬂ L... W
I N
I v
w
LL 9 we
r m
L
w m r
I 0..
m. w H
N..

 

wODMI I w_.jwm._. .33“. ll 405.200 II

 

 

HSBWHN WVHELV'I

.commmm 9:266 82 05 05:6 3.93:3 >e=m> 50¢ E 823399
_m>>mm E cozoanoa Law. 805 3.03. :0 5:93:50 .683 .o 8522. N .9".

hmem 03m me< mxmm>>

 

 

 

 

 

 

mate: :8 ﬁLm> £02m
vm rm m F m P N F . m m m o
> > IP — P p . o
L
H. or
H, m
, om a
, V
T 1.
low E
Y I:
s N
H n
\ we. own
, 3
, H
w \ 1| 8
m
00

 

meow: ll m...._mE.:E I .6528 II _

 

.633 65266 89 9.: 6566 366:3 >m=m> ccmm 6
352866 .965 5 A53 £266 696 666. :0 6293968 6960 6 coca—55 .m 6E

...mem 03m IMP”? mxmmz,

 

 

66361 com_m6> Eoo_m
em a 2 3 «L 4 a m m o
L L _ L L _ L L P L F 5 L L _ L L _ L L _ L L O
L
wow
6 we
:8
.3
18.
m H
8L

 

 

 

 

moowI III. m_._._wm._..._._3n_ ll. JOIPZOO Ill

 

 

(we) H.LMOUE) .LOOHS WHEN!

 

.688 65266 89 65 6566 666:3 6:05 56.... 6 $5636 613
5 A53 5266 626669 665m .99 05 :0 6:96:60 60:8 6 882.5 .m .mE

mezm 03m Eur—,1 wxmm>>

 

 

 

 

 

 

 

 

meamI com_mLo> 502m
6 6.3 9 «L 6_Lw__m,_o
, L3 ,0
m H
#« C c 1..I II.—
,om m
, V
, 1|
. A
.169 mas
L m
I H.
\\ .62 A
\\\ r ...:
\\ 9
\\ . w
\\\\\ ICON W
\,. x r H
, m
.romwmw
So
68: ...... 9465.33... II .65.on ::

85

:80me 65266 89 05 6560 666:3 >0=0> ::0u_ 6 856006
.013 5 60.6 :00 $60. .06. 05 :0 6669600 60:00 6 00:026. .0? .9".

...mem 03m me< wxmmg

 

 

 

 

60>sz :0066> £02m
em a 9 9 «L 0 0 m 0
L _ _ L L _ L L _ L L _ L L _ L L _ L L _ L L 0
mo.
L 0.
wow I.
, V
H .I
won m
woe w
r d
H 3
..rom H
, S
H H
...00 m
x 7 H12.
m H
00

 

 

 

 

MODmI II. m_.3mm._.._43u_ III. ..OEPZOO III _

 

86

vm

.668 65266 89 05 6566 «066:3 6.6) ::0n_ 6 356066

663 5 65> 66 66.606 666 60. :0 :5669600 60:60 6 00:62.5 .2 6E

...wmnm 03m mmt< mxmw>>

 

 

60261 :om66> 502m
FN mw 9. NF m w m o
r L _ L r _ L L _ L L _ L L — L L _ L L _ L L 0
w: I CC . I 7
n H
,rm
Nd
I? ..l
L a
mm H
, 8
pm a
, d
H a
”IO—.IAI
T N
mehm
. w
1 V
. hcx
,rE.
m2
,2

 

 

 

 

MODMI I w_._._mm._. .33.... III ..OmPZOO III

 

CHAPTER III

THE USE OF CARBOHYDRATE SINK COMPETITION TO REDUCE FRUIT SET
AND BOTR YTIS ROT IN SEYVAL GRAPEVINES

Abstract

Three pruning severities and two times of thinning were applied to Seyval
grapevines to vary the amount of fruiting and vegetative sinks at fruit set. Vines were
balanced pruned to either 10, 30, or 60 nodes per 454 g. of cane prunings. Half were
flower cluster thinned and half post-set thinned to 15 clusters per 454 g. of cane prunings.
In 1993, a third factor of cropping level was imposed across each treatment. Post-set
thinning decreased fruit set, yield, and Botrytis bunch rot while increasing berry weight
and soluble solids. Losses in yield could be overcome by decreasing thinning severity.
Increased sink competition created by greater numbers of apical meristems, had no effect
on fruit set or Botrytis infection, and decreased cane cold hardiness. Post-set thinning to
increase sink competition and reduce fruit set appears to be a viable cultural practice to

reduce Botrytis cluster rot.

Introduction

Botrytis bunch rot is a severe disease in Michigan’s cool, wet climate. Its control
to prevent the loss of yield and fruit quality can be a costly endeavor for the vineyard
manager. Chemical control and sanitation are successful approaches to minimizing Botrytis
infection. However, chemical control is expensive in Michigan’s climate and control
products are becoming more limited. Botrytis cinerea lives most of its life as a saprophyte,
getting nutrients from dead or dying plant parts (12). Sanitation practices reduce the
amount of inoculum in the vineyard before each growing season by removing old clusters,
dead wood, and debris from the vineyard. This can be costly and does not completely

relieve the problem.

89

Selecting for cultivar resistance and canopy management are also methods to control
bunch rot infection. Unfortunately, some cultivars used in wine production are susceptible
to infection. The cultivar Seyval (S.V. 5276) was chosen for this study because of its
importance in Michigan’s wine industry and serious cluster rot problems. Seyval vines are
susceptible to Botrytis infection because they form large, compact clusters. It is for this
mason that they are also easily overcropped. Seyval is managed using severe balanced
pruning and flower cluster thinning. It is recommended that a 15+10 balance pruning
formula with thinning to 17 clusters per 500 grams of cane prunings be employed to

Control crop level (17). The potential for yield increase is great if canopy management
PTaCtices are developed to control overcropping and help inhibit the infection of Botrytis
blmCh rot of Seyval in Michigan.
Botrytis cinerea may infect grape ﬂowers and it can remain latent in these tissues
Until the clusters begin to mature (13). The spores require prolonged periods of free water
and nutrients on the berry surface for germination (12,14). The fungus produces enzymes
that can destroy the integrity of the berry in less than 24 hours (12). The main protection
for the grape berry to infection is its skin. The cuticle membrane and the epicuticular wax
1)th ide the primary physical barriers to pathogen invasion (1). For beny infection to
(bent, the pathogen must find a weakness on the berry surface where it can bypass the
shtick membrane, or directly penetrate the surface (3). The epicuticular wax layer
1‘11 uences the retention of pesticides, the water retention of the berry surface, and the
E‘CIII‘ésive ability of plant pathogens (1). Percival et al. (15) found that exposed clusters and
be having little berry contact, produced more epicuticular wax and cuticle. Clusters with
g berry contact may be achieved by reducing the number of berries set per cluster.
6i The competition for carbohydrates and growth hormones between sources and
“ks to influence fruit set has been well documented. Intra-vine competition for

Nbohydrates and growth hormones by vegetative (22) and fruiting sinks (7) inﬂuences

 

\ 9o

fruit set. Decreasing the competition between sinks by shoot tipping at bloom (5,6,18),
girdling (2,5), or ﬂower-cluster thinning (23,24,225) increase fruit set. Heavy pruning
‘2 (23), leaf removal during bloom (4), and within-cluster competition decrease fruit set (11).
) Flower clusters compete for carbohydrates during bloom (l6) and after anthesis when the
shoot apex and the developing clusters become the strongest sinks (6,9,16). Flower-

cluster thinning increases pollen genninability (25) and shoot growth (8,11). Post-set

thinning can decrease fruit set by increasing the fruiting and vegetative sink competition for

assimilate and growth hormone (7,22), thus loosening cluster compactness. Post-set

thinning reduces berries per cluster in Seyval, and a compensatory increase in berry size

and fruit quality results (10). Vegetative vigor and the development of laterals decreased

When thinning was delayed until after fruit set (10). Potentially the number of benies per

CIUSter can be reduced, resulting in less berry contact and thus less Botrytis infection.

E . 1:]. .
1

To explore the effect of reducing pruning severity and/or post—set cluster thinning to
increase competition between sinks through anthesis in Seyval.

2-
TO determine if increasing the amount of fruiting sinks at fruit set will decrease the
3 number of berries set per cluster in Seyval.
I T6 determine if increasing the amount of vegetative sinks at fruit set will decrease the
4 number of berries set per cluster in Seyval.
- ’1‘

Q investigate if decreasing the number of berries set per cluster by post-set cluster
3 thinning will decreases the amount of Botrytis rot in Seyval.
\ .1‘
Q determine if the loss in yield in Seyval due to the decrease in fruit set can be
overcome by retaining more clusters per vine during thinning.

   

k

Materials and Methods

ElantLMaten'al

The experiment was established in March of 1991, 4.5 miles East of Lake Michigan
(42- 15’ latitude) at Fenn Valley vineyards in Fennville Mich. Mature, bearing Seyval
grapevines planted in 1975 on an Oshtemo sandy-loarn soil were used in the experiment.
Rows were spaced 3.0 meters apart with vines 2.4 meters apart within rows. The vines
were trained to a bilateral cordon on the top wire, 1.8 meters high (Hudson River Umbrella

training system).

We

By leaving three levels of nodes retained, three levels of sinks (vegetative and
fruitf‘ul) were established for each vine during the dormant season pruning in an effort to
i“Crease competition among sinks during bloom. This was accomplished by retaining 10,
30» (Dr 60 nodes (N, 3N, 6N) for every 454 grams of dormant one year cane prunings
respectively. The most severely pruned treatment (N), retained nodes on short spurs along
the Cordon. The (3N) treatment kept five node canes; and the lightly pruned (6N) treatment

retai lied canes of ten to ﬁfteen nodes in length along the cordon.
The (N) vines were pruned to 45-nodes and the live one-year cane prunings
ei ghed to estimate the previous year’s vine size. The node number for the (N) vines was
““311 set for the duration of the growing season following the procedures stated above.
EQQ~Eause of the number of nodes needed to obtain the (3N) and (6N) levels were much
gr'éaser than 45 nodes, a method was devised to estimate the weight of retained wood.

‘\ f‘ .
l ‘ {Qt pruning the (3N) and (6N) treatments to 90 and 180 nodes per Vine respectively, the

l \r
'5 canes were weighed. The remaining live nodes of canes on the vine were counted. A

91

 

92

weight was assigned to the number of nodes over 45 retained on the vine, based on a node
weight calculated in 1992 (113 gm per 52 nodes) and 1993 (113 gm per 50 nodes). This
weight and the weight of cane prunings were added, producing the vine size for each (3N)
and (6N) vine.

Crop thinning is also required in Seyval for optimal crop control. Flower-cluster

thinning (PCT) and post-set thinning (PST) were imposed to compare the influence of
increased cluster numbers per vine during fruit-set. Cluster thinning was conducted just
prior to bloom in the (FCT) vines, and when the berries were 3-5 mm in diameter (23
Weeks post-bloom) in the (PST) vines. The number of clusters per vine were proportioned
by using the weight of live one-year-old canes at pruning (vine size). Thus, crop level was
balanced among vines based on their vegetative production of the previous year.

In 1992, the treatment vines were cluster thinned to 15 clusters per 454 grams of
domlant one-year cane prunings. In 1993, three cropping levels were employed in an
ﬁtterIlpt to offset any loss in yield due to a decrease in fruit set The (C15) treatment
maj litained the cropping level imposed the previous year (15 clusters per 454 grams of
dotTrh'c‘tnt one-year cane prunings). Higher crop levels, (C18) and (C21), increased the

nu“) ber of clusters per vine after thinning to 18 and 21 per 454 grams of dormant one-year

e prunings respectively.

§ The effect of increased sink competition during bloom on vegetative growth was
beined. A consistent determination of vine size was measured as described above. At

‘1
q burst, nodes that did not produce a shoot (shootless nodes) were counted. Percent

Shsg . . . .
tless nodes, vegetativeness (vrne srze (gm) per shoot), count shoots (nodes retained at

\3 .
17hr“ ng minus blind nodes), and non-count shoots (total shoots minus count shoots) were

 

 

93

Calculated for each vine. Treatment comparisons and interactions of pruning data were

analyzed each year and over both years.

E . : l l ' .
Point quadrat assessments were taken at three times during the growing season each

year. A thin metal rod was inserted into the canopy to determine the number of leaves
above the fruiting zone (19). Five insertions along the cordon were made on each treatment
Vine at bloom, veraison, and harvest. Insertions were always made from the West side of
the canopy. A frequency distribution of the number of contacts and a seasonal history of

leaf layer formation were developed.

WW

During the 1993 growing season, detailed shoot and leaf measurements were taken
on e\’ery (C 15) vine of the sub-sub—plots in each replication. Within each sample vine, ﬁve
Shoots were randomly flagged along the cordon for vegetative measurements during the
grovVing season. These includect 1) primary shoot length (PSL); 2) primary shoot leaf
number (p315); 3) lateral number (L); 4) lateral length (LL); and 5) lateral leaf number

12.51% ; measured on May 26 (WK3 weeks after bud burst), June 2 (WK4), June 9 (WKS)'

e 16 (WK6), June 30 (WK8), July 29 (WK12), and September 23 (WK21) one week
mgr
9%

to harvest. Additional calculated data included total leaves per shoot (T SLF=
“I L’RrLLF) and total vegetative shoot length (PSL+LL). Treatment comparisons were
m at appropriate dates and over dates on those variables measured or calculated.
Vv‘ At thinning, none of the sample shoots were defruited so that shoot development
lth a fruiting sink could be studied for the remainder of the growing season. A count of

“a
QQ‘s (CS) longer than 10 cm and bearing three or more leaves was taken two weeks prior

 

 

94

to harvest. Primary leaves per vine (PSLF*SC), lateral leaves per vine (LLP"SC), and

total leaves per vine (TSLP‘SC) were then calculated and compared between treatments.

COldHardinessﬁxaluations
Prior to pruning in 1993-1994, a cold hardiness evaluation was taken of the
previous season’s vegetative growth. Previous work with Seyval (21) and a re-evaluation
Of that work (Appendix 1) has led to a definition of Seyval cane characteristics closely
associated with cold hardiness. Classifications were created from hardiness analyses done
on Dec 19, 1991 and Jan 22, 1992 on Seyval canes (Appendix 1). Periderm and primary
bUd 'TSO’s were determined for variations within four cane characteristics, and over node
POSitions along the cane. Canes having a medium diameter (7-10 mm), medium intemode
fen 8th (6—8 cm), and dark brown periderm were found to have superior cane and primary
bud Cold hardiness. Persistent laterals and node position (2-9) did not have any influence
on <=<>1<l hardiness. Total one-year-old canes were counted on each treatment vine and each
Cat-1e given a excellent, acceptable, or poor classification. Excellent wanes consisted of ten
or r11()re live nodes with the optimal characteristics stated above. Acceptable canes had five
or l’1'1Ore living nodes but failed in one of the optimal characteristics. Canes with less than
live live nodes or failing at least two optimal characteristics were plawd in the poor cold
infrqi hess category. Samples of Seyval cranes within the three classifications were collected
Si beeember, January, and March. Periderm and primary bud cold hardiness were
g1‘1if‘1eantly different among the treatments at the 0.01 level over the three dates. Excellent
$3 were superior while poor canes were inferior to acceptable canes. Using the three

Q‘ag -
h 3! ﬁcations was a rapid and effective way to evaluate the relative cold hardiness of each
atl‘nent vine.

 

 

95

Emit-Setandﬂatgztisﬁotﬁxaluations
A standard curve was developed to allow rapid determination of flower number per
cluster based on rachis length for both years. Thirty clusters were randomly sampled from
guard vines just prior to bloom. Cluster length was calculated by adding the length of
rachis from the lowest basal arm to the tip and the length of the lowest basal arm. Flowers
of each sample cluster were counted and a strong correlation was found each year (Figs. 1
and 2). The rachis length of clusters on sample shoots of (C 15) vines were measured and
their estimated ﬂower number calculated. At harvest, berry pedicles of sample shoot
clusters were counted and the percentage of benies set analyzed. The number of whole
berries showing no incidence of Botrytis rot infection were counted for rot calculations.
Subtracting these quality berries from the number of pedicles per cluster provides a number
or the berries infected with rot. Fruit-set and Borrytis rot comparisons were made each

y ear and over both years.

Ham . .

Treatment vines were harvested each year within ten days of October 1. Each vine

w

as hand harvested with the cluster number noted and the fruit placed into an individual
bi

n ‘ Each bin was then weighed in the field and a cluster weight calculated. Clusters from

filth D113 shoots of (C15) vines were harvested separately, weighed, and placed into
liq i" idual bags for berry counts and fruit quality determination. Berries were randomly

eh from these sample clusters to create a 100 berry sample for every (C15) treatment in
each replication. From these samples pH, titratable acidity, soluble solids, and berry
Qi ght were determined and the number of benies per cluster calculated. The number of

“Q“

‘Qount clusters per vine was calculated from the number of clusters harvested minus the
\\

umber retained after cluster thinning. Treatment comparisons of harvest data were

nyzed for each year and over both years. Using the harvest and pruning data, shoots per

96

cluster (total shoots/ harvest cluster number), productivity (yield per previous year’s vine
size), fruitfulness (yield (gm) per shoot), and crop load (yield per current season’s vine

size) were calculated for every sample vine and analyzed for each year and over both years.

E'IE‘II'

A split-plot design was used with the main-plot consisting of three treatments (N,
3N , 6N) of six vines each, replicated six times. Three rows, containing two blocks each
Were utilized. A guard vine separated each main-plot treatment. Each main-plot was divided

into two sub-plots, (FCI‘) and (PST), consisting of three vines. The three vines of the sub-
Plots were further divided into single vine treatments (C15, C18, C21) as sub-sub—
plc3‘28 in 1993. Comparisons and interactions between treatments were made each year and
over both years using the MST AT-C statistical computer package. Analysis was by
ANOVA, with mean separations calculated using Duncan’s Multiple Range Test (20). The
flIliteset standards and fruit-set vs. rot regressions were calculated using the Delta Graph

“1 Duter package. Point quadrat frequency distributions were calculated using the
MSTAT-C computer package. The experiment was terminated after pruning in March of

1 99.4

Results and Discussion

Decreasing pruning severity while maintaining a balanced crop inﬂuenced canopy
“e
Velopment, morphology, and maturity with little effect on total vegetative growth.

\
t\Ql‘easing the number of clusters per vine through anthesis showed no inﬂuence on

V . . . . .
egﬁttative growth. Vine size was never srgmflcantly different among treatments of either

97

the main-plots or sub-plots, averaging 0.55 kg of cane prunings per vine (Table 1).
Reduced pruning severity accelerated filling of the trellis area with foliage, but caused more

shading within the canopy by verasion (Figs. 3 and 4). Increasing the number of nodes

per vine three fold (3N) from the standard pruning severity (N), redistributed shoot growth

from non-count to count positions (Table 1). Over 65 percent of (N) canopies were
comprised of non-count shoots, while count shoots made up 75 percent of (3N) canopies.
Shoot numbers were similar; and thus, the number of vegetative apices remained
consistent. Increasing the number of nodes per vine six-fold (6N) from the standard
Pruning severity (N), produced 70 percent more shoots per vine and no growth from non-
COunt positions. As node number per vine was increased, vegetativeness decreased (Table

1 ) along with total shoot length, total leaf number, and lateral number per shoot (Figs. 5, 6,
and 7). Post-set thinning appeared to reduce the rate of growth of every vegetative
pa‘t‘a-tneter mcasured per shoot between bloom and verasion, although no signiﬁcant
differences were observed. The (FCT) and (PST) shoots had neariy identical rates of
glWOVVth from verasion to harvest. The (N) and (3N) treatments produced 70 percent of
”lei 1‘ total leaf number before veraison, while (6N) vines produced 80 percent by veraison
and half as many lcaves as the other two treatments between then and harvest (Fig. 6). The
lan of new leaf production after veraison in (6N) vines suggests older leaves were
rﬁshcnsible for photosynthate production during fruit and wood ripening in (6N) vines.
:hﬁding, caused by dense canopies, also contributed to poor wood maturity of (6N) vines.
hﬁ (6N) canopies produced significantly less excellent, and more poor cold hardy canes
(Table 1). No differences in cane cold hardiness were observed between thinning times.

at31mg the number of nodes retained at pruning inﬂuences vegetative growth more than
g1Weéater numbers of clusters per vine during f ruit-set.

 

 

 

98

Inﬂuence of Nodes Retained and Thinning Ireatment orLXield,.CemmnentsLolL;ieldLand
E . : . .

Increasing the number of clusters during f ruit-set by post-set thinning reduced fruit-
Set, concurring with work previously done (7,21). Post-set thinning increased the level of
Competition between fruitful sinks, resulting in fewer berries set within the cluster (Table
2). As the level of fruitful sinks retained through anthesis was augmented across pruning
sever-i ties, the level of competition increased and berry-set further declined. This additional
loss of berries reduced yield and vine productivity (Table 3). The (6NFCI‘) treatment was
Superior to the other treatments yielding 4.4 tons per acre. However, raising the number of
clusters per vine 20 and 40 percent at post-set thinning made yields at each pruning severity
comparable to that of ﬂower cluster thinning to 15 clusters per pound of cane prunings
(Table 4). Post-set thinning controlled unwanted crop (non-count clusters) better than

(PCT) (Table 5).

Post-set thinning increased berry weight, soluble solids, and pH with no variance
in titratable acidity (Table 5). The greatest variance was observed in the (6N) treatments
Where the competition was the highest between sinks during fruit-set. Post-set thinning
i“creased the percent soluble solids two brix greater than (FCI’). Larger berry weights and
iImproV'ed percent soluble solids agrees with Hunter et al. (10) findings on post-set
thinning. Post-set cluster thinning reduced berry-set within the cluster and improved fruit

compoSi tion.

Decreasing the number of benies set per cluster inﬂuenced the incidence of Botrytis
bunch rot infection in Seyval. A count of infected berries was performed on clusters from
sample Shoots of (C 15) vines at every level of pruning severity and time of thinning. Over

40 Percent of the berries from (FCT) clusters showed signs of rot infection at each pruning

 

 

99

severity over years, while post-set thinning averaged 16 percent (Table 2). As the number

of clusters increased during fruit-set between the (N), (3N), and (6N) treatments, the
Percent of berry rot infection decreased. The (NPST), (3NPST), and (6NPST) treatments
CXhibited an average of 29, 13, and 7 percent berry infection respectively over years. Each
year, the percentage of berry rot decreased linearly with decreasing berries per cluster
(Figs- 8 and 9). Thus, as the competition between fruitful sinks became greater and fruit-
set decreased, the percentage of berries infected declined. As the number of benies set per
cluster ranged from 100 to over 300 among treatments, Botrytis berry rot increased linearly
from 5 to 50 percent. Thus, the number of quality berries per cluster decreased only 25
Percent in the (PST) treatments, although the reductions in the number of berries set per
CluSter were much more severe (Table 3). The reduction of benies within the cluster
pr ovided a loose cluster architecture non-conducive to Botrytis cluster rot infection. This
agrees with Percival et al. (15) ﬁndings with clusters having little berry contact producing
more epicuticular wax and cuticle, the main protection against rot infection (1). Post-set

CIUSteI‘ thinning reduced Botrytis bunch rot in Seyval grapevines.
Conclusions

The relationship between sources and sinks competing for photoassimilate played a

major role in Seyval grapevine development throughout the growing season. Increasing
the “urn her of vegetative apices created greater distribution of vegetative growth within the
Canopy, resulting in earlier ﬁlling of the trellis area with foliage and optimal potential light
absorption. However, shading and reductions in leaf production after veraison become a

Concem‘ for fruit and wood ripening. Increasing the number of vegetative sinks during

amheSis had no affect on fruit-set The increase in competition caused by additional fruitful

sinks reduced berry-set and, thus, Botrytis bunch rot It appears that competition among

 

 

 

100

fruitful sinks is the determining factor in fruit-set and that this competition has little affect
on vegetative growth or maturity when maintained only through anthesis. Reductions in
yield caused by decreased f ruit-set were overcome by decreasing the number of clusters
thinned after anthesis. Once the crop level was established, fruitful sinks gained
sUpcr'iority in competing for carbohydrates and/or growth hormones. This occurred at the
expense of vegetative growth if insufficient supplies were available. Post-set cluster
tbinning appears to be a viable cultural method for reducing Botrytis bunch rot, and the
level of sink competition during bloom can be manipulated by pruning severity.

The 30+30 pruning severity adequately spaced shoots within the canopy to ﬁll the
trellis area with vegetative growth earlier than the 10+10 severity. The occurrence of some
non-count shoots suggests that the pruning severity could even be lower to better distribute
Vegetative growth. The 30+3O pruning severity provided adequate photoassimilate
competition between fruitful sinks to reduce fruit-set sufﬁciently to deter Botrytis bunch rot
i“faction. It also afforded superior cane and ﬂower bud maturity for growth the following
yw- A pruning severity slightly greater than 30+30 with post-set cluster thinning to a
level Of crop that maximizes yield and allows for adequate vine maturity, would be

recommended for management of Seyval grapevines.

 

 

 

 

Literature Cited

1. Baker, EL. 1982. Chemistry and morphology of plant epicuticular waxes. In:
Cutler, D.F., Alvin K.L., Price, C.E. (Eds): The Plant Cuticle, 139-161.

Academic Press, Toronto.

2. Brown, K., D.I. Jackson, and GP. Steans. 1988. Effects of Chlormequat, girdling,
and tipping on berry set in Vitis vineifera L. Am. J. Enol. Vitic. 39(1):91-94.

3. Bulit, J., and D. Dubos. 1988. Botrytis bunch rot and blight. In: Pearson, R.C.,
Goheen, A.C. (Eds): Compendium of grape diseases, 13-15.
APS Press, St. Paul.

4. Candolfi-Vasconcelos, MC. and W. Koblet. 1990. Yield, fruit quality, bud fertility

and starch reserves of the wood as a function of leaf removal in Vitis vinifera -
Evidence of compensation and stress recovering. Vitis. 29:199-221.

5. Coombe, B.G. 1959. Fruit set and development in seeded grape varieties as affected
by defoliation, topping, girdling, and other treatments. Am. J. Enol. Vitic.

10:85-100.

6- Coombe, B.G. 1962. The effect of removing leaves, ﬂowers and shoot tips on fruit
set of Vitis vinifera L. J. Hort. Sci. 3721-15.

7' COombe, B.G. 1973. Regulation of set and the development of the grape beny.
Acta. Horticulture 34:261-273.

8' pi Sher, K.H., O.A. Bradt, J. Wiebe and V.A. Dirks. 1977. Cluster thinning ‘de
Chaunac’ French hybrid grapes improves vine vigor and fruit quality in Ontario.

J. Amer. Soc. Hort. Sci. 102(2):l62-165.

9' Hal e, CR, and P.J. Weaver. 1962. The effect of developmental stage on direction of
translocation of photosynthate in Vitis vinifera . Hilgardia 33:89-131.

10. Hunter, D.M. and J.T.A. Proctor. 1985. Effects of timing of thinning inﬂuence on
Seyval blanc fruit yields and quality. Presented at 10th Annual meeting of the
American Society for Enology and Viticulture/Eastern section, Mississauga, Ont.

(August 1985).

11. Looney, NE. 1981. Some growth regulator and cluster thinning effects on beny set
and size, beny quality, and annual productivity of ‘De Chaunac’ grapes. Vitis
20:22-35.

12' Manes, J.J. 1987. Botrytis bunch rot of grapes. Oregon Dpt of Agr.: The Wine
Advisory Board Research Report June ($116

13. McClellan, W.D. and W.B. Hewitt. 1973. Early Botrytis rot of grapes: Time of
Infection and latency of Barrytis cinerea Pers. in Vitis vinifera L. Phytopathology.

63:1151-1157.

 

101

 

102

14. Nelson, KB. 1951. Factors inﬂuencing the infection of table grapes by Botrytis

cinerea (Pers). Phytopathology. 41:319-326.

15. Percival, D.C., J.A. Sullivan, and K.H. Fisher. 1993. Effect of cluster exposure,

beny contact and cultivar on cuticle membrane formation and occurrence of bunch
rot (Botrytis cinerea Pers.:Fr.) with 3 Vitis vinifera L. cultivars. Vitis 32:87-97.

16. Quinlan, J.D. and R.J. Weaver. 1970. Modiﬁcation of pattern of the photosynthate

17.

I8.

19.

20.

21.

25.

movement within and between shoots of Vitis vinifera L. Plant Physiol.
46: 527-530. .

Reynolds, A.G., R.M. Pool and LR. Mattick. 1986a Effect of shoot density and
crop control on growth, yield, fruit composition and wine quality of ‘Seyval blanc’
grapevines. J. Amer. Soc. Hort. Sci. 111(1):55-63.

Skene, K.G.M. 1969. A comparison of the effects of “Cycocel” and tipping on fruit
set in Vitis vinifera . Austr. J. Biol. Sci. 22:1305—1311.

Smart, R.E., C.M. Seaver. 1988. Handbook for Canopy Management Workshop.
Pesented at 2nd International Cool climate Viticulture and Oenology Symposium,
Matua Valley Vineyard Kumeu, New Zealand. (Jan. 1988). pg. 1-20.

Stee], R.G.D. and J.H. Torrie. 1980. Principles and Procedures of Statistics:
A Biometric Approach. McGraw-Hill Book Company, New York, NY.

Striegler, R.K., and GS. Howell. 1991. The inﬂuence of rootstock on the cold
hardiness of Seyval grapevines: 1. Primary and secondary effects on growth,
canopy development, yield, fruit quality and cold hardiness. Vitis. 3021-10.

' Weaver, R.J. and RM. Pool. 1968. Effect of various levels of cropping on Vitis

vinifera grapevines. Am. J. Enol. Vitic. 19:185-193.

Weaver, R.J. and RM. Pool. 1971b. Chemical thinning of grape clusters
(Vitis vinifera L.). Vitis. 10:201-209.

Winkler, A.J. 1929. The effect of dormant pruning on the carbohydrate metabolism
of the vine. Hilgardia. 4:153-173.

Wi nkler, A.J. 1958. The relation of leaf area and climate to vine performance and
grape quality. Amer. J. Enol. 9: 10-23.

103

.66... 605m 6.65.35. :62 9:60:00 0560 0:558 55.... 6.66666 6:665.

.35 Engage Lo: Lo 5:. a... .... an a E8_L_eo.n 662% n.

65:06 6:60 06660.0 6? 2 6665665 66.60... 65 5 66 663 060. 00:0 ~

65:06 6:60 0.6.6650 mp 2 6665665 5006 65 5 60 663 060. 00.0 >

60.666666 666506: 0.00 6005 0550.56 coon. L0 .6.066600< 66:60me 300660 65 55.3 65> .66 66:60 6 60:6: 65. x

 

 

 

 

 

6: 0: m: 0: 0: 6: 6: 6: 6: 6:
mm an w? m 0 mo mr adv Fm mmd «omﬁom
mm mm ml 5 0 mm 0? . 6.: on nmd 5.005 26
we 6* or 0.. ..w mm or 5.6? 06 mmd ~6m60n.
60 6.. mw m 0.. an 2. mm? on omd £006 20
IV 3 t or 06 we mL 6.6? 3 66.0 66600
mm mw m_. m mm : 0r New VF ..md Eoo.m Z
65.... 65:55 x
065666 66002
m: m: . . m: 6: 0: m: 6: 6: 6:
on mm or o : mm 6.. 50.. we mmd ~ Swamoa
6.. em 3 6 I 6 3 6.6. no 66.0 L. E026
m:.::.._F x
.6650 6 655
. . . . 6: . . . . . . . . . . . m:
6 mm 6 60 hr am 00 6 mo 66 3 n «.3 600 mmd 20
0 we n 9 t. 6m n C n vo n or n6 6.9 0 mm vmd Zn
n 06 n m_. we 6 m 6 mm 0 C. 6 or 6 new; 0 6.. mmd Z
.0L+0Luz.
6.056... 65:05
6 06:66.". 66002
06:60 x 06:60 x 66:60 x 66:60 060:6 060:6 66002 900:6. Em 065661 5652me 66566....
.665 3:600 5:600 3:600 6:00:02 6:00 0:..m ox. 6~.6 6:.3 66002 3% 65>
.006 6.066600< 5:6..60xm 60265660;

 

.66.... 6...... .5“. .5 5.6.53 .55 ... we. 6%. ...e. 866

«8...... ON.m 2.... 0... :0 8.5.... 6.3.0 .0 65. 0:6 5.2.3 0555. .o 862.... .L 6.65

 

104

.566... 66:66 6.05.0.2 362 6.:60:0o 6560 6500.00 55.3 606.6066 6:665.
.65 58:00.6 .0: .0 .... 0... .... 006 .6 58.....06 6626., H.
.:0.666. 6. 6:50.58 660.0 60 66:60 6 666660.60 65. N
.:0.66.:. 6. 0: 6:50.56 6060.0 .60 66:60 6 .6080: 65. ..
0.00.: o. .0.... .60. :66. 6.6.60.0 .6266 06 6 6665666660.. 0:6 66000 .00.. 606.: 0606.6 6 :0 06660 6.6050: 630.“. 066.503 x

 

 

 

 

 

 

6: . . . 2 .. 6: 6:
06.6 0 s 0 600 6 ..N 0 v: 666 6.6 .66 606.
66.6 6 66 6 060 6 6m 6 6'6 666 6.00 E85 :6
66.6 0 65 0:6 66w 0 ...N n 66.. 606 0.0.. «66 60a.
60.6 6 :V :6 66w 0 nv 6 606 006 0.: 500.0 26
06.6 0 6m 00 66.. 0 66 a 66.. 606 6.00 .66 «won.
669 6 ..v :6 63 0666 6 066 606 6.60 802m 2
6.5... 65:55: x
06566.". 66002
. . . . . . . . . . 6: 6:
00.6 60 me mm 060 606 6.00 06m «606.
60.0 0.. 06. 06 600 600 0.: 506.6
65:55.
660.0 6 65.5
. . . . 6: . . 6: . 6:
6 66.6 0 mm 660 n 06 696 n 606 6.05 26
6 06.6 0 06 060 n 06 666 6 666 6.: 26
n 60.6 6 66 060 6 3 066 a 606 6.00 2
.0F+0.uz.
6.056“. 05:26
>0 065666 66002
.50. ~ 6.60.0 > 6060.0 660.0 66:566....
.53 ....66 .66 2.66 66:66 66 ....66 .66 66:66 x 600.02 ...:0. 56:60
66066 .5600 0:60.66 .66 ... 630.". .66 6560.0
00...... ...... ...... 0 0......5 ...... .. 60......
0.0.. 0000.06 .00 ...... ..0 00.00.... 6.00.... .0 0..... 06 5.0.00 00.0.00 .0 00:02.... N 36.:

 

.52. oucam 03:32 302 $59.30 9.8: 255.8 55.3 5:233 mama—2

.35 235:9” .2 6 EL .x; ”C .xb 8 E825» 829 n.

.3555 2.3 938520 9 2 2:95am: 6w Eon 05 E .3 an; .80. no.6 N
.mmEcEa 980 233520 92 2:953: 802m 9.: 5 «cm was too. no.6 >

 

 

105

 

 

 

 

m: w: I . . we we
8.3 m6» 0 Dim 0 EN 0 ova. Pm and 8m Eon
no.3 v.03 a 3.2. a one a ops an 3.0 £02m cm
no.3 ad: a 9.3 on 8N. on go ov amd “ow 50m
v0.3 mdow m N92. nu «Na an 56 mm omd Eoo_m 2m
of? ﬁn? on RN; on Ed on 51m er and «cm Eon
053 «$2 n «0.3 on vow. on cam «F 5.0 6006 z
2:; SEE x
8522". «302
. . . . . . . . . . w: m:
3.: “mow 3.: and owe me mmd N «om Eon
3.9 02: 2.9 New Ed 3. $6 > 585
$3:th
5.3.0 .o E?
mc I m: we m: .. w:
3.9 a 0m? 3.? med mob m cm omd 20
m9? a No? 5.9 and mm.m n mm 3.0 Zn
8.9 a 0.09 3.3 3.0 mm.m o 3 mmd z
Aow+owuzv
Sacco”. @555
3 conﬂom 882
35m 9.3 ; 9025 85m 05> S AS .5 35%me uoESom 35>axv EoEEcC.
225322: >53 22: 529.223 22> 22> 8.82 £5 25
33 no.0 30:322.... 33:03.35
as gig; g; g: a “2.30% 3% s 2% .§ 5 bag:
as so: as 0% 8.; 2. S Page .230 3 as... can €28 Bean 3 8:255 .m 39:

.mULm>®C_> >m.:G.> CCGU on. l1!" ‘Iilf-
Amxv Em!) C0 0C.CC.£u «w 00...:Qu0L m_0>0_ QOLO msmwmgoc. .LO 00:01.1“:le

106

.89 .m >3... no 355: 5620 925 85> 2.an on... N
.89 .3 0:2, co 8:55 .236 So; moo; 2.0“: on... >

.mmcEEn 9.8 .o 2:90. Qmmv .on

 

992:0 E no .9 .3 2 can: «omnmon .6 Con: 88.2 556 an $58.23 _m>o_ no.0 x

 

 

 

Kim mmk Fm
mo.m mmd m?
vm.m 56 9 2m
vmh Sim Fm
5+ mvé mp
36 3h 9 2m
mm.m wm.m Pm
mfm 0N6 m—
mmd mvé m_. z
N x x .05.. mEmmoG
5n .5“. >2 >Eo>mm mcEEn

 

.wEgocS >o=m> econ .m 855nt .mgow no mm? s

as 2m; 8 9:22. a 8:52 «Eon use 8332 3 Eggs .V «BE

 

O UGO—-NQGF E0: UGOGNO)!

,OUNG>0C.> >0:G> CCOK .5 QQCQIQQQNU .I))°m x
>2L0)00 UC‘CULQ ‘0 00:03:93 m WdexF

loony—Ur: )a._vu3nv :3: RUE-w UnCUCOQEOU U.c.> ﬁr: CO UC.CC.C~ L0~ﬁ3~0 no AVE: DEG

 

0th 35¢ 29:22 302 95250 053 2.628 55? cozaanom 2.3.2

.65 anzegm .8 .o 5.0 x; .8 gm 8 Eagzcoa 83.9 ...

.3555 050 ...—3.23.0 m? 2 2:25am: «om Eon 9: c_ «om was too. no.0 N
.oucEEn ocmo 0.6.23.0 m? 2 2:958: £020 05 5 wow mm; 32 no.0 >

 

 

 

 

 

m: .. m: we we a: . o... .
N.m a 0.0? 05.0 0N0 0 omN n ﬁNwN NN o ové “ow «won
vN o 0.: who 0N0 N NN.N a 0.000 0N o ohm E86 20
N.N 0 0.9 050 N0 F mvN n meN 0N on 00.0 now «won
0.N on 0.: ~50 :0 N 00.N . a 0.m0N 0N an 50.0 8005 20
we n «.3 N50 0N0 N NNN n 0.NNN VN on No «00 «won
0... n 0.0? 2.0 NM 0 00.? n 0.0VN VN on 004m 6005 2
25.. 355 x
02.38... moooz
. .2. w: .. S. .. .. mc ..
m vN 0.2. 05.0 mN.m F 3N méNN MN 006 N wow Son
1 rm 0: to a; w 8N PEN mm (no > Emgm
9.2.5:»
.0520 .o oE:.
.. m: w: m: wc .. . m: m:
m 0N ...mw 05.0 0N0 m a omN no ¢.0mN mN 00.0 20
o ..N 0.: 050 3.0 N o NNN m 0.00N 0N 00.0 20
n 09 N0? v50 0N0 N 0 SN 0 EmoN VN 00.0 2
3:3qu
235.0“. ascan
B 8:32“. 882
.236 mozom €23. In 223.0 3.9 2:9 .3532 $529: E953;
\Boocm o_o:_ow 235:: Ezooéoz ..3 >..om .E .6620 .0520 En;

 

.mo.m>oc_> >o=a> :5... 6 3553.0 i>>om .o 000..-ng 89: 300.05

3205 3:95 :2. oco 2coconEoo 29> 9.: co 05:55 5820 .o 0:.: 0:0 3:93 chEn .o 8:255 .m m...m<h

 

108

ON

:m
«93. + 3 «Sam u 3. 82.0 u «E
€315sz $530
9 2 m

 

 

 

 

 

 

 

 

 

 

 

 

 

.mo.m>oc_> >m=m> econ
E «83890 513 E $5893me .296 .on 2950.. .o. Emocﬂw Nmmp .P .9".

H 00N
, 00¢
H 08
M a.
H as

com?

HEGWHN HEMO‘L-J

 

109

##m
Emotéo 33% "3. 886 u «E

Ea 1525 $530
mm om m. 2 m . o

 

 

 

 

 

O
O \ 1
000

 

 

 

 

 

 

 

 

 

.mo.m>oc_> >o=m> econ
E «83390 _m>>om 5 25893988 .938 .on 22.6.. .2 059.30 80. .N .9...

HBQWDN HBMOWd

110

$95: com_m.m> Eoo_m

 

 

 

20

 

 

ll

20"

2|

 

 

JeqwnN JSAB'I JBG‘I

 

 

.882. .99 32 mm Emmenxm .wo.m>oc_> >o..m> econ. E «83890

aimm .0 593292. .8058 .888 Nmmw 9.. co 3:98 0555 .o 82m .0 .9”.

111

59.9..

com_m.m>

Eoo_m

 

 

 

 

20]
20'
2|

 

 

 

 

 

.ﬁimm .o .882. .98. .mm. mm commenxm 3.98:3 >o=m> cam“. um moc_>onm.m

3280 .0 2.952920 >nocmo 83$ mm? 9.. :0 3:93 mEcEn .0 Spam .v .9”.

, no

m...

mN

JaqwnN JaAe'] men

:8000 05.590 000? 0:. 05.30 00.30:; 0.3) ::0u. .0 023890 .0100 .o
20.0.0. + :0E_.nv 62.0 .0n 50:0. 02.0.00? .08. 0:. :o 3:050 0:.:=.n .o 00:02.2. .0 .0.".

...mmDm 03m mwnhz mxmmg

 

 

 

 

«00201 :om_0.0> E005
NN ON 9 0r 3 NF 0? 0 0 v N 0
. _ _ _ . . _ . . _ r n L _ . _ . _ _ _ .
0
CC a. .
100 I.
, m
V
D ..l
r w
loop
m W...
20 o N
2..
, .I
row; m
T 9
18N(
.
z m T
omN

113

:8000 05.590 80. 0:. 0:..30 mo.0>0:.> 0:0) ::0... .0 00:.>0n0.0 .0100
.o 20.0.0. + 00.5.3 .85 .0n 0900. .06. 0:. :o 3.050 0:.:=.n .o 00:02.:. .0 .0.“.

...mmDm 03m th< wxmmg

 

.00>.0I 50.0.0) 836
NN ON 0 w 0 w E. N _. 0 _._ 0 0 V N 0
p . . b r _ . P F _ . p » — . P p _ p _ .
ﬁﬁ 1.“
.
20 o m
T
20 0 ,
W
Z 0 n

 

 

 

114

NN

.:o0000 0:590 000. 0:. 05.20 00.00:; >0._0> ::0u.

.0 033800 .0260 .o 69.0 .0n .0052: 0.0.0. :o >._.0>00 0555 .o 00:02.:. N .0....

 

 

 

 

meDm ODm EMF”? mxwm>>
.0020: :o0_0.0> Eoo.m
ON 0.. 0.. 3. N _. or 0 N 0

. L _ p p . p . p . p, . _ b O
IN
I V
10
I m
I or
2
f

 

 

HSGWON 'IVHSLV'I

115

.m
08.0. - 3 .03 n8. 000.00 "NE

0.3.0340 mun. kmm memwm
00N 00..
_ g _ L _ .

0

0mm 00m 0mm 00.. cm
_._,...+___ ..F....__r+

— ~ _ -

 

ITfTYf
l0 0

O
,_

to
f.

IO
N
.LOH SLLAHiOB lNEOHSd

O
(‘0

ID
(0

 

ITTTIIiTiTIIIIIIIYTYYTrrTTﬁIYYITTijTII

 

 

 

ID
V’

.00:.>0n0.0 _0>>0w
:. .0.020 .0n .00 00:00 .0 .0063: 0:. .o 5:05. 0 00 .o. 0...»..om 000.:00.0n N00. .0 0.....

116

......
000. I - 3 00 ..o no... 0.00.0 "mm

mwkmzqo awn. ._.mw mmEmmm

omm 000 omN 00N om? .oow cm 0
...... .. ........ ..........

L p

 

I ﬁr l T Y Y
O
P

,..
8

Y f T T

O

. , -. . . ,

8 8
103 SLLAELLOQ maouad

O
,,.
8

 

 

 

00
08380.0 .900
:_ .0.020 .0n .00 02:00 .0 .0062: 0:. .o 5.8:... 0 00 .0. 0.5.3 000.:00.0n 000. .0 .0....

CHAPTER IV

THE USE OF CARBOHYDRATE SINK COMPETITION TO REDUCE FRUIT SET
AND BOT RYTIS ROT IN VIGNOLES GRAPEVINES

117

Abstract

Three dormant season pruning seventies and an unpruned (UP) treatment were
imposed on Vignoles grapevines to vary fruiting and vegetative sinks during fruit set.
Vines were balanced pruned to either 15, 30, or 60 nodes per 454 g. of cane prunings.
The treatments leaving additional nodes per vine during the dormant season, were balanced
pruned after anthesis. Five and ten node canes were compared at each pruning severity.
Increasing the competition for carbohydrates between fruitful and vegetative sinks during
anthesis by decreasing pruning severity during the dormant season had little affect on f ruit-
set. The (UP) treatment decreased yield, due to reduced cluster formation per shoot. The
clusters that did develop had fewer flowers each year and thus, fewer berries set.
Reductions in Botrytis infection were observed only in 1993 in the (UP) treatment Cane
length had no affect on fruit-set or Botrytis infection. Competition induced by fruitful
sinks was limited because of the small size of Vignoles clusters. However, increasing
carbohydrate competition between fruitful and vegetative sinks through anthesis was
detrimental to fruit and vine maturity. Post-set pruning does not appear to be a viable

cultural practice for management of Vignoles grapevines in Michigan’s climate.

Introduction

Vignoles is an important cultivar in Michigan’s wine industry. It bears small,
compact clusters that are susceptible to harvest season Botrytis bunch rot infection.
Because of the smaller clusters, balance pruning alone is sufficient for crop control. A
15+15 pruning formula on a High Cordon training system is recommended (11). Botrytis
bunch rot is a severe disease in Michigan’s cool, wet climate. Its prevention or control can

be expensive, and if not sufficient, produce losses of yield and fruit quality. Chemical

118

119

control, sanitation, and canopy management are all successful approaches to minimizing
Botrytis infection (14). However, chemical control is extensive in Michigan’s climate and
control products are becoming more limited. Botrytis cinerea lives most of its life as a
saprophyte, getting nutrients from dead or dying plant parts (14). Sanitation practices
reduce the amount of inoculum in the vineyard before each growing season by removing
old clusters, dead wood, and debris from the vineyard (14). This can be costly and will
not completely relieve the problem. Canopy management practices for Vignoles grapevines
need to be developed to help inhibit the infection of Botrytis bunch rot in Michigan.

Botrytis cinerea may infect grape flowers and remain latent in these tissues until the
clusters begin to mature (15). The spores require prolonged periods of free water and
nutrients on the berry surface for germination (14,16). The fungus produces enzymes that
can destroy the integrity of the ben'y in less than 24 hours (14). The main protection for
the grape berry to infection is its skin. The cuticle membrane and the epicuticular wax
provide the primary physical barriers to pathogen invasion (1). For berry infection to
occur, the pathogen must find a weakness on the berry surface where it can bypass the
cuticle membrane, or directly penetrate the surface (4). The epicuticular wax layer
influences the retention of pesticides, the water retention of the berry surface, and the
adhesive ability of plant pathogens (1). Percival et al. (17) found that exposed clusters and
those having little berry contact, produced more epicuticular wax and cuticle. Clusters with
less beny contact may be achieved by reducing the number of berries set per cluster.

The competition for carbohydrates and growth hormones between sources and
sinks to influence fruit set has been well documented. lntra-vine competition for
carbohydrates and growth hormones by vegetative (25) and fruiting sinks (8) int] uences
fruit set. Decreasing the competition between sinks by shoot tipping at bloom (6,7,22),
girdling (3,6), or flower-cluster thinning (26,27) increases fruit set. Within-cluster

competition decreases fruit set (13), while severe pruning (26), or leaf removal during

 

120
bloom decreases fruit set (5). Flower clusters compete for carbohydrates during bloom
(18) and after anthesis when the shoot apex and the developing clusters become the
strongest sinks (7,9,18). By increasing the competition for carbohydrates during bloom,
potentially the number of berries per cluster can be reduced, resulting in less berry contact
and thus less Borrytis infection. The following eXperiment was designed to test this

hypothesis and to answer several other questions:

E . l :1 . .

1. Does reduced pruning severity and post-set pruning increase competition among
sinks through anthesis in Vi gnoles?

2. Do the number of vegetative and fruiting sinks at fruit set reduce the number of

berries set per cluster in Vi gnoles?

3. Does reduction in number of berries set per cluster also reduce Botrytis rot in
Vi gnoles? *
4. Do these pruning strategies influence shoot development or bud and cane cold

hardiness of Vignoles?

Materials and Methods

HamMaten'al

The experiment was established in March of 1991, 4.5 miles East of Lake Michigan
(42-15’ latitude) at Fenn Valley vineyards in Fennville Mi. Mature, bearing Vignoles
grapevines planted in 1976 on an Oshtemo sandy-loam soil were used in the experiment.
Rows were spaced 3.0 meters apart with vines 3.7 meters apart within rows. The vines
were trained to a bilateral cordon on the top wire, 1.8 meters high (Hudson River Umbrella

training system).

121

Experimentall'reatmems

The experimental treatments compared four levels of pruning severity in an effort to
increase competition between sinks (vegetative and fruitful) during bloom. This was
accomplished by retaining 15, 30, or 60 nodes retained (N, 2N, 4N) for every 454 grams
of dormant one year cane prunings respectively, and an unpruned treatment (UP). The
(2N), (4N), and (UP) treatments were pruned to the (N) level of nodes when the berries
were 3-5 cm in diameter (23 weeks post-bloom). Two cane lengths (5 or 10 nodes) were
compared to study the inﬂuence of node position within the canopy. One treatment retained
short (5 nodes), while the other retained long (10 nodes) canes, after dormant season and
post-set prunings. The unpruned treatments were pruned to either short or long canes after
fruit-set. The treatments provided increasing levels of vegetative and fruitful sinks during
anthesis.

The (N) vines were pruned to 65-nodes and the live one-year cane prunings
weighed to estimate the previous year’s vine size. The node number for the (N) vines was
then set for the duration of the growing season following the procedures stated above.
Because of the number of nodes needed to obtain the (2N) and (4N) levels were much
greater than 65-nodes, a method was devised to estimate the weight of retained wood.
After pruning the (2N) and (4N) treatments to 90 and 180 nodes per vine respectively, the
live canes were weighed. The remaining live nodes of canes on the vine were counted A
weight was assigned to the number of nodes over 65 retained on the vine, based on a node
weight calculated in 1992 (113 gm per 41 nodes) and 1993 (113 gm per 43 nodes). This
weight and the weight of cane prunings were added producing the vine size estimate for
each (2N) and (4N) vine. The total number of live nodes above 65 were counted on each

(UP) vine, and a vine size calculated using the average node weight of that year.

 

122

iegetatixeMeasuremems

The effect of increased sink competition during bloom on vegetative growth was
examined. A consistent determination of vine size was measured as described above.
Vegetativeness (vine size (gm) per shoot and node) was calculated for each vine and a
shoot number taken at verasion in 1993. Treatment comparisons and interactions of
pruning data were analyzed each year. During the 1993 growing season, detailed shoot
and leaf measurements were taken on one vine in each treatment replication. Within these
sample vines, frve shoots were randomly flagged along the cordon for vegetative
measurements during the growing season. These include: 1) primary shoot length (PSL);
2) primary shoot leaf number (PSLF); 3) lateral number (L); 4) lateral length (LL); and 5)
lateral leaf number (LLF); measured on May 26 (WK3 weeks after bud burst), June 2
(WK4), June 9 (WK5), June 16 (WK6), June 30 (WK8), July 29 (WK12), and
September 23 (WK21) one week prior to harvest. Additional calculated data included total
leaves per shoot (TSLFzPSLF+LLF) and total vegetative shoot length (PSL+LL). A count
of shoots (CS) longer than 10 cm and bearing three or more leaves was taken on WK19.
Treatment comparisons were made at appropriate dates and over dates on those variables

measured or calculated.

ColdﬂardinessEvaluations

Prior to pruning in 1993—1994, a cold hardiness evaluation was taken of the
previous season’s vegetative growth. Total one year old canes were counted and each cane
given an excellent, acceptable, or poor classification. This approach has been used
previously by Streigler and Howell (24). Excellent eanes consisted of ten or more live
nodes with the optimal characteristics of medium diameter (7- 10 mm), medium intemode
length (6—8 cm), and dark periderm. Acceptable eanes had five or more living nodes but

failed in one of the optimal characteristics. Canes with less than five live nodes or failing at

123

least two optimal characteristics were placed in the poor cold hardiness category. Samples
of Vi gnoles canes within the three classifications were collected in December, January, and
March after the 1991 and 1992 growing seasons. Using the three classifications was a

rapid and effective way to evaluate the relative cold hardiness of each treatment vine.

E'-S IE ‘EEI'

A standard curve was developed to allow rapid determination of ﬂower number per
cluster based on rachis length for both years. Thirty clusters were randomly sampled from
guard vines just prior to bloom. Cluster length was calculated by adding the length of
rachis from the lowest basal arm to the tip and the length of the lowest basal arm. Flowers
of each sample cluster were counted and a strong correlation was found each year (Figs. 1
and 2). The rachis length of clusters on sample shoots within the sub-plots were measured
and their estimated flower number calculated. At harvest, berry pedicles of sample shoot
clusters were counted and the percentage of berries set analyzed The number of whole
berries showing no incidence of Botrytis rot infection were counted for rot calculations.
Subtracting these quality benies from the number of pedicles per cluster provided a number
of the benies infected with rot. Fruit-set and Botrytis rot comparisons were made each

year.

11 El lE':l'!

Treatment vines were harvested each year within ten days of October 1. Each vine
was hand harvested with the cluster number noted and the fruit placed into an individual
bin. Each bin was then weighed in the field and a cluster weight calculated. Clusters from
sample shoots of sub-plot vines were harvested separately, weighed, and placed into
individual bags for berry counts and fruit quality determination. Berries were randomly

taken from these sample clusters to create a 100 beny sample for every sub-plot treatment

124
in each replication. From these samples pH, titratable acidity, soluble solids, and beny
weights were determined and the number of berries per cluster calculated. Treatment
comparisons of harvest data were analyzed for each year. Using the harvest and pruning
data, shoots per cluster (total shoots/ harvest cluster number), productivity (yield per
previous year’s vine size), f mitfulness (yield (gm) per shoot), and crop load (yield per
current season’s vine size) were calculated for every treatment vine and analyzed for each

year.

E' IE' 11'

The plots were established in March of 1991 at Penn Valley vineyards in Fennville
Mi. A split-plot design was used with the main-plot consisting of four treatments (N, 2N,
4N, and UP) of four vines each, replicated five times. One guard vine separated each main-
plot treatment. Each main-plot was divided into two sub-plots (Short and Long canes)
consisting of two vines. Comparisons and interactions between treatments were made each
year using the MSTAT-C statistical computer package. Analysis was by ANOVA, with
mean separations calculated using Dunean’s Multiple Range Test (23). The f ruit-set
standards were calculated using the Delta Graph computer package. The experiment was
terminated after pruning in March of 1994.

Results and Discussion

If S' E

Decreasing pruning severity increased the number of nodes retained, and increased
the amount of vegetation removed at post-set pruning. No significant differences were
found in vine size from 1991 among the treatments (Table 1). In 1992, vine size in the

(UP) treatment decreased dramatieally to 180 grams per vine compared to the other

125
treatments of 760 grams or more (Table 1). The (UP) vines averaged over 400 nodes
retained through anthesis. The (4N), (2N), and (N) treatments were significantly lower at
130, 56, 32 nodes retained, respectively. Thus, increasing amounts of vegetation (vine
size) was pruned away at post-set as pruning severity decreased. Nearly all of shoot
production arose from count positions in each of the treatments. Shoot numbers per vine
were similar to the number of nodes retained at post-set pruning (Table 1). In 1993, the
(4N) and (UP) vine sizes were significantly different from (N) (Table 2). The (UP) vines
improved their vine size to nearly equal that of (2N) and (4N), due to many of the shoots
being non-fruitful. The (4N) and (UP) vines had the same number of nodes retained
(103), 2-3 times more than (N) and (2N) (31 and 59 nodes retained respectively). Shoot
numbers decreased with the reduced pruning severity, and each treatment averaged 12-14
adventitious (arising from non-count positions) shoots (Table 2). Vine size decreased in all
of the treatments from 1991, however, decreasing pruning severity through anthesis

increased the rate of vine size reduction.

(hueMatnrity

Cane maturity was examined by calculating vegetativeness per node and shoot, and
by cold hardiness evaluations. Since nodes retained after post-set pruning and shoot
numbers among treatments in 1992, the vegetative response per node and shoot followed
the vine size response (Table 1). Because of the low vine size of the (UP) vines in 1992,
less nodes were retained during the post-set pruning in 1993. As a result, vegetativeness
per node was significantly greater (Table 2). However, no variance was observed in
vegetativeness per shoot although, shoot number decreased with decreasing pruning
severity (Table 2).

Samples of Vignoles eanes within the three classifieations (excellent, acceptable,

and poor) were collected in December, January, and March after the 1991 and 1992

126

growing seasons. Periderm and primary bud cold hardiness were significantly different
among treatments at the 0.01 level (Figs. 3 and 4). Excellent canes were superior while
poor canes were inferior to acceptable canes over years and at each date evaluated. Using
these classifications, each treatment vine cane was evaluated. In 1992, decreasing pruning
severity reduced the number of excellent quality eanes, while increasing poor quality eanes
per vine (Table 1). Decreasing pruning severity to the (4N) or (UP) level, reduced the
number of excellent quality cold hardy canes by 50 percent in 1993, but was found not to
be significant (Table 2). However, (4N) and (UP) vines matured signifieantly less
acceptable quality canes, and (4N) vines produced more poor quality eanes than the other
treatments. No significant differences were found in any of the vegetative indices
measured for either year between cane lengths. Reducing the severity of dormant season
pruning and increasing the amount of post-set pruning, decreased the amount of vegetation

the vine was able to utilize and mature after anthesis.

ShQQtAssessmems

Detailed shoot measurements were taken during the 1993 growing season from five
sample shoots on one vine of each treatment replication. Treatments did not vary in
primary shoot length or leaf number until after bloom, when (N) shoots were significantly
longer and had more leaves than (UP) shoots (Figs. 5 and 6). At harvest (4N) and (UP)
shoots were shorter than (N) shoots, and (UP) shoots still had fewer leaves. No
differences were seen in lateral number, lateral leaf number, and lateral length until after
bloom (Fig. 7, 8, and 9). Lateral growth decreased as pruning severity was reduced. The
(N) shoots produced superior numbers of laterals with more leaves and length than any
other treatment. The (2N) shoots produced greater numbers of laterals with more leaves
and length than (4N) and (UP) shoots. Lateral growth contributed to the separation of

treatments in total shoot length and leaf number. Again, (N) shoots were superior to the

Ill .IIIIII'I‘IIII

 

 

 

127

other treatments and the (2N) shoots produced more than (4N) and (UP) shoots (Figs. 10
and 11). No differences in shoot growth were observed among cane lengths for any of the
variables measured. Overall, decreasing pruning severity and increasing sink competition,
reduced the vegetative production per shoot. This agrees with previous work on increased

competition resulting from greater crop levels (2,23).

”“11. ”3.: l' :
Lower yields and fruit quality resulted from decreased pruning severities. In 1992,

the (UP) vines yielded less than half the crop per vine (more than 1.5 tons per acre) than
the other treatments (Table 3). This was the result of reduced berry and cluster weights.
Titratable acidity and soluble solids were significantly lower and pH was higher in berries
of (UP) vines. The (UP) vines produced 70 to 80 percent less crop than the other
treatments in 1993 (Table 4). They managed a crop of only a third of a ton per acre,
compared to yields of 1.25 to 1.90 tons per acre in the other treatments. This was a result
of non-fruitful shoots, resulting in a f our-fold increase in the number of shoots per cluster.
The (4N) vines produced 80 percent less crop than (N) vines. All of the treatments
subjected to post-set pruning had a decrease in berry weight each year, and the (UP)
treatment had a reduction in berries per cluster in 1993 (Tables 3 and 4). However, only
the cluster weight of the (UP) treatment was affected. This coincides with previous work
with increasing sink competition (10,19). Berries in the (UP) treatment were significantly
lower in titratable acidin with a higher pH than the other treatments in 1992 (Table 5). In
1993, the (4N) and (UP) vines produced berries with the highest pH and lowest titratable
acidity (Table 6); again, the result of a decreased crop load. However, the (4N) and (UP)
benies had the lowest soluble solids each year. This contradicts previous work (20,21)
suggesting canopy reductions improve eanopy microclimate. Post-set pruning reduced the

leaf area available for fruit and wood ripening in the (4N) and (UP) vines. Increasing sink

128

competition through anthesis caused reductions in yield, as a function of poor berry
development, and fruit quality.

Due to the decrease in yield in 1992, productivity and fruitfulness declined in the
(UP) vines, but a severe reduction in vines size caused crop load to be over twice as high
as the other treatments (Table 3). Long canes increased fruitfulness and productivity in
1992. Fruitfulness was significantly lower again in the (UP) vines in 1993, and their crop
load averaged 75 percent less than the other treatments (Table. 4). Long canes were more
fruitful in 1993, due to a significant reduction in the number of shoots per cluster. Cane

length had no other influence on the yield indices of Vignoles.

Delaying pruning until after anthesis, reduced the number of flowers produced per

cluster in each year. The treatments did not influence berry-set or Botrytis infection in
1992 (Table 5), but fruit-set and bunch rot in (UP) vines Was lower in 1993 (Table 6).
Twenty to 30 fewer berries were set by the (UP) vines and half the rot of (N) was
observed. The (UP) vines still ripened 30 percent less quality berries in 1993. Long eanes
produced more ﬂowers per cluster in 1992 (Table 5), but no variance was seen between
eane lengths in any other fruit-set or bunch rot measurement in that year or the next.
Longer eanes were more productive and fruitful because they were better exposed and
produced more numbers of shoots per cluster. Only at the (UP) level of nodes retained
through anthesis, did increasing carbohydrate competition inﬂuence fruit-set or Botrytis
infection.

Conclusions

Increasing the competition for earbohydrates among fruitful and vegetative sinks
during anthesis by decreasing pruning severity during the dormant season, had little effect

on fruit-set in Vignoles. The (UP) treatment decreased yield, due to reduced cluster

129

formation per shoot. The clusters that did develop had fewer flowers each year and thus,
less berry set. This was caused by either poor bud maturity the previous year, or because
of slower shoot development early in the growing season. Reductions in Botrytis infection
were observed only in 1993 in the (UP) treatment. Cane length had no affect on fruit-set
orBotrytis infection. Competition induced by fruitful sinks was limited because of the
small size of Vi gnoles clusters. However, increasing sink competition among fruitful and
vegetative sinks through anthesis was detrimental to vine maturity.

Reducing dormant season pruning severity resulted in more vegetation pruned from
the vine after anthesis. This resulted in poor crop ripening and wood maturity as less
canopy was available for a source of photoassimilate after anthesis. The number of shoots
per vine of the (2N), (4N), and (UP) treatments were reduced to the (N) level based on
vine size after anthesis. The canopies of differing treatments with the same vine size
contained equal numbers of shoots from count positions after summer pruning. Individual
shoot growth decreased as the pruning severity was reduced. Thus, with decreasing
dormant season pruning severity and increased post-set pruning, the eanopies contained
smaller shoots with less leaf and lateral growth by verasion. The (UP) vines could not
replace the deficiency in vegetation caused by post-set pruning. Yield, fruit quality, vine
size at harvest, and cane cold hardiness, all decreased in the ﬁrst year. The (4N) vines
were affected in the second year showing the same characteristics as the (UP) vines. Cane
length had no affect on shoot development or maturity. Longer canes were more
productive and fruitful because they were better exposed and produced more numbers of
shoots per cluster. Post-set pruning does not appear to be a viable cultural practice for
management of Vignoles grapevines in Michigan’s climate. A method to increase
earbohydrate competition (through anthesis) to decrease f ruit-set and Botrytr‘s infection and
yet, allow for adequate vegetation for fruit and wood maturity for the rest of the growing

season, needs to be developed for Vi gnoles grapevines.

go

Literature Cited

. Baker, EL. 1982. Chemistry and morphology of plant epicuticular waxes. In:

Cutler, D.F., Alvin K.L., Price, C.E. (Eds): The Plant Cuticle, 139-161.
Acedemic Press, Toronto.

Bravdo, B., Y. Hepner, C. Loinger, S. Cohen, and H. Tabacman. 1984. Effect of
crop level in a high yielding Caragnane vineyard on growth, yield, and wine
quality. Am. J. Enol. Vitic. 352247-252.

Brown, K., D.I. Jackson, and GE Steans. 1988. Effects of Chlormequat, girdling,
and tipping on berry set in Vitis vineifera L. Am. J. Enol. Vitic. 39(1):91-94.

Bulit, J., and D. Dubos. 1988. Botrytis bunch rot and blight. In: Pearson, R.C.,
Goheen, A.C. (Eds): Compendium of grape diseases, 13-15.
APS Press, St. Paul.

Candolfi-Vasconcelos, M.C. and W. Koblet. 1990. Yield, fruit quality, bud fertility
and starch reserves of the wood as a function of leaf removal in Vitis vinifera -
Evidence of compensation and stress recovering. Vitis. 29:199-221.

Coombe, B.G. 1959. Fruit set and development in seeded grape varieties as affected
by defoliation, topping, girdling, and other treatments. Am. J. Errol. Vitic.
10:85- 100.

Coombe, B.G. 1962. The effect of removing leaves, flOwers and shoot tips on fruit
set of Vitis vinifera L. J. Hort. Sci. 3721-15.

Coombe, B.G. 1973. Regulation of set and the development of the grape berry.
Acta. Horticulture 34:261-273.

Hale, CR, and P.J. Weaver. 1962. The effect of developmental stage on direction of
translocation of photosynthate in Vitis vinifera . Hilgardia 33:89-131.

10. Howell, G.S., T.K. Mansfield and J.A. Wolpert. 1987. Inﬂuence of training

system, pruning severity, and thinning on yield, vine size and fruit quality of Vidal
blanc grapevines. Am. J. Enol. Vitic. 38(2):105-112.

11. Howell, 6.8. May 1992. Pruning and training Vignoles grapevines in Michigan.

Vintner & Vineyard. Coop. Ext. Serv. Pub. 6(1): 1-6.

12. Hunter, D.M. and J.T.A. Proctor. 1985. Effects of timing of thinning influence on

Seyval blanc fruit yields and quality. Presented at 10th Annual meeting of the
Ameriean Society for Enology and Viticulture/Eastern section, Mississauga, Ont.
(August 1985).

130

 

I)...»
.‘ "F—ﬁ. _ .
A. a

 

13.

14.

15.

16.

17.

18.

19.

20.

131

Looney, NE. 1981. Some growth regulator and cluster thinning effects on berry set
and size, beny quality, and annual productivity of ‘De Chaunac’ grapes. Vitis
20:22-35.

Marios, J.J. 1987. Botrytis bunch rot of grapes. Oregon Dpt. of Agr.: The Wine
Advisory Board Research Report. June (5)21—6.

McClellan, W.D. and W.B. Hewitt. 1973. Early Botrytis rot of grapes: Time of
infection and latency of Botrytis cinerea Pers. in Vitis vimfera L. Phytopathology.
63:1151-1157.

Nelson, KB. 1951. Factors influencing the infection of table grapes by Botrytis
cinerea (Pers). Phytopathology. 41:319-326.

Percival, D.C., J.A. Sullivan, and K.H. Fisher. 1993. Effect of cluster exposure,
beny contact and cultivar on cutical membrane formation and occurrence of
bunch rot (Botrytis cinerea Pers.:Fr.) with 3 Vitis vinifera L. cultivars. Vitis
32:87-97.

Quinlan, J.D. and R.J. Weaver. 1970. Modification of pattern of the photosynthate
movement within and between shoots of Vitis vinifera L. Plant Physiol.
46: 527-530.

Reynolds, A.G., R.M. Pool and LR. Mattick. 1986b. Influence of cluster exposure
on fruit composition and wine quality of ‘Seyval blanc’ grapes. Vitis 25:85-95.

Reynolds, A.G., and DA. Wardle. 1989a. Impact of various canopy management
techniques on growth, yield, fruit composition and wine quality of
Gewurtztraminer. Am. J. Enol. Vitic. 40:121-129.

. Reynolds, A.G. and DA. Wardle. 1989b. Effects of timing and severity of summer

hedging on growth, yield, fruit composition, and canopy characteristics of ‘De
Chaunac’ 1. Canopy characteristics and growth parameters. Am. J. Enol. Vitic.
40: 109- 120.

. Skene, KG.M. 1969. A comparison of the effects of “Cycocel” and tipping on fruit

set in Vitis vinifera. Austr. J. Biol. Sci. 22: 1305-131 1.

Steel,R.G.D. and J.H. Torrie. 1980. Principles and Procedures of Statistics: A
Biometric Approach. McGraw-Hill Book Company, New York, NY.

Striegler, R.K., and GS Howell. 1991. The influence of rootstock on the cold
hardiness of Seyval grapevines: 1. Primary and secondary effects on growth,
canopy development, yield, fruit quality and cold hardiness. Vitis. 30: 1—10.

Weaver, R.J. and RM. Pool. 1968. Effect of various levels of cropping on Vitis
vinifera grapevines. Am. J. Enol. Vitic. 19:185-193.

 

 

132

26. Weaver, R.J. and RM. Pool. 1971b. Chemical thinning of grape clusters
(Vitis vinifera L.). Vitis. 10:201-209.

27. Winkler, A.J. 1929. The effect of dormant pruning on the carbohydrate metabolism
of the vine. Hilgardia. 4:153-173.

 

133

 

 

 

..005 005:. 0.5.3.2 302 0:00:30 050: 0:50.00 55.... :o..0.0n00 0:00.).

.0... .5258.» .8 .o ...... 0... .... $0 a 28:00.0 03.2 n.

0000: 0. u0:0.. .0000: m u..o:0 ”N035" :0 05:0.n 0550 .00 50:0. 0:00 N
00.0 to :0 0:.:....n .0 0N.0 05> :0 0000: .2. 0050.0. 00002 ..

.NQn (N :0 05:0.n .00 .00n .050 0050.0. 00002 x

 

 

 

 

 

0: 0: 0: 0: 0: 0: 0: 0: 0: 0:
0N N 0 0 0 00 N0 0N0 N20 00.0 0:3 00:05::
0. I N 0 0 00 00 00.. 0.0 00.. :20 025.55
0N NV 0 FN 0N N0 F0 0N. 0N0 30 0:0.—
0. 0.. m .0N .N N0 00 00' .N0 00.? 20:0 20
0. F. N 0N 00 N0 0N 00 00.0 No.0 0:0.
0. 0.. N 0N N0 F0 00 00 00.0 00.0 00:0 ZN
0 0 I 00 ..0 N0 00 00 2.0 00.0 0:3
0 N. I .0 0N N0 00 00 00.0 NN.. 00:0 2
50:3 0:00 x
0050.00. 00002
0: 0: 0: 0.. 0: 0: 0: 0: 0: 0:
cw : 0 N 0N N0 0N 0.: 00.0 00.0 0:0..
0F N.. 0 .N MN 00 00 00. 00.0 00; 00:0
N 50:0.. 0:00
. . 0: . . . . . . 0: 0.. . . . . 0:
0 ON 0.. 0 N 0 0 0 0 ..0 00 0 000 0 2.0 No; 00:05::
0 0. 0. 0 m n .N 0 0N N0 00 n on. 0 0N.0 00.5 20
n 3 I :N 00N 0 00 ..0 0N 000 0 No.0 00.0 ZN
0 0 o. 0 Z 0 00 00 .0 00 N0 0 N0 0 00.0 v0.0 2
.0.+0.uz.
.. 0050.0: 00002
00:00 00:00 00:00 89.0250. 0002150. .00502 x .00..00n 0.555 .0 005300.. .0520... 205.00;
.....000 .....000 .....000 05.. 05> 00 050 05> 00 80:0 0050.0... 0050.0... 050 05> 0N.0 05>
.oon 0.:0.n000< .:0__00xm 000:0>..0.000> 000:0)..0.000> 00002 00002 N00 P F005

 

.000. .0. sea... 03:... .0222... ..o__0> Eon. .0

00:_>0n0.0 00.0:05 .0 05.000.00.05 0:00 0:0 .oo:0 0:0 0N.0 05> 0:. :0 50:0. 0:00 0:0 0050.0. 0000: .0 .0050: 0:. .0 00:02.5 .F 0400...

 

..00... 00:00 0.5.3.2 302 0:00:00 050: 0:50.00 55.! :0..0.0000 0:00....

.2. 202.000 .2 .0 .... 0.. .... $0 .0 200.200 822, n.

0000: o. «0:03 .0000: m u:0:0 ”00.0.0 :0 055:: 05.00 .00 :.0:0. 0:00 0
00.0.0 :0 05:20 .0 0~.0 05> :0 0000: .2. 0050.0. 00002 >

.00:0.N :0 05:0... .00 .000. .0..0 0050.0. 00002 x

 

 

134

 

 

 

0: 0: 0... 0.. 0: 0: 0: 0... 0... 0:
0. 0. N 0. 00 00 0. 00. 00.0 N..0 23 0222:
.. .. 0 N. 00 00 0. .0. 00.0 0.0 :20 0222:
0. .. 0 v. 0. 00 N0 N0. .00 0N.0 20..
00 0 0 0. 0. 00 00 00. .00 0N0 :20 20
.. 0. N. 0. N. 00 00 .0 .00 00.0 000..
.. 00 0 0. 0. 0.. 00 00 .00 00.0 :20 20
0. 0. 0. N. 00 ... 00 00 .00 0N.0 20..
0. 00 .. 0. 00 N0 00 00 N00 00.0 :20 2
...0:0.. 0:00 x
02.0.... 00002
0.. 0... 0... 0... 0... 0: 0... 0: 0c 0...
0. 0. .. 0. .0 00 00 0N 00.0 00.0 0:3
... 0. 0 ... 00 00 00 0N 00.0 00.0 :20
N 50:03 0:00
.. .. 2 2 . .. .. .. . ..
0 0. 0 .. N N. 4 0 00 0 00 0 0. 0 00. 0 00.0 0 0.0 020.23
0 .0 0 0. 0 0. 0 0. 00 00 a 00 0 00. 0 00.0 0 0N0 2..
0 .. 00 N. 0. 0. 0 0. 0 .0 0 00 0 00 00 .00 0 N00 20
0 .. 000 0. 0. 0 .0 0.... 0.0 0 .0 000.0 000.0 2
.0.+0.uz.
.. 02.200 8002
00:00 00:00 00:00 .00:0..50. 000550. .00502 x .00-.000 35:0 .0 .0523: .0033... 505.00.:
3:030 3:030 3:030 ONE 0:.) mm ON.0 o...) 8 .00:0 0050.00— UOESOC ONE 005 ONE 0....)
.OOn. 0.9030000. .co__00xm 00000>=20u0> 000.002.2000) 00002 00002 0 Q 0 w Na 0 _.

 

.000. .0 :20... 0200 00.2.2... 30> 2.0 ...
005.6050 00.0:05 .0 05.000.00.05 0:00 0:0 .00:0 0:0 00.0 05> 0:. :0 :.0:0. 0:00 0:0 0050.0. 0000: .0 .0050: 0:. .0 00:05.5 .0 030......

135

 

.60... 093.”. 0.95.2 302 95830 as»: 3528 55.3 5:833 53.).

.65 285cm.» .2 .0 .... x; .... «.m a 28:2? 329, ...

.33: or "93.. .33: m utozm “$329 :0 3.5:. 3.5.. .3 59.2 280 ~
No.65 co 33 was no woman .2. 3582 $8: .omﬁoa >

 

 

 

 

 

 

m: m: as m: m: m: . m: a...
«N4; om omd wad av mdv u B? NF... mmé 98.. 3.53::
n“: 5 rod voé ov 9; no mm mmé mfu :95 09.295
omK 5F mob mm; ov m.mm an no vmd mmé 95..
nub nmv Fwd mm; on ﬁne 3% mo cod vmé tozm zv
mws we. no.0 mm; —m 7mm can mm 05m 5... 9.3
mw.v 3.: Sb ...mé mv m.mm noon :N and team ZN
56 X... «r.» mm; mm ...vo non mo and mo... 98..
no...“ 9: 56 mmé on 060 a 5 owd mod :95 z

£ch 930 x
3533. 8.32
m: 2 . m: m: m: m: m: m:
2.0 a: 8m cm. 3. m5 3 3a «a.» 9.3
was s: :6 mmé xv mdm ow Fwd no... :95
~ 596.. 980
.. .. 2. .. mc .. .. .. ..
m Swe— n vm 9 Cd 9 No; 3 n odv a me n 5% n cod 09.5.95
3 mm.m a vi a mmé m omé mv a 0.00 a .R a and a mud 2v
9 ate a on; a and 0 mm: mv a m.mm am mm a mvd a mad ZN
a own a mm? a an m cm; rm 6 vdo a R a and a mod 2
Amw+mwuzv
> 3:33. $32
.38 we; .82.». .36 was .83 ..3 8520 2:9 3 89.5: 32.: 35>.me E253;
«3:223 :28 22>. 83.223 >:mm 325m .286 .236 22> 22>
28.. no.0 $2.352”. 33:032.”.
.39.? .60 3.8.5: $29.05., >23) :5“. a
«655%... 3.965 .0 22> .0 9:38:30 05 23 22> o5 :0 59.2 2.8 new 8582 mono: .o .383: o... .o 8:02.... .m m..m<...

136

.58. 093.... 295.2 :62 9:850 922. 2.528 55.3 5:933 522
..ms 282:2... .2 a ...... 2.. .... 2.... a 28:22» 322, u.
.33: or no.3. ”mane: m ntozw ”ween co 92:3... 92:6 .3 59.2 050 N
.025... cc o~.m 05> no 33.. .2. 3532 auto: .8232 >

 

 

 

 

 

m: .....c m: m: a: w: m: a: an 2.
ta 8; 58 one. mm; mv chm I 3.0 vmd 95.. 35:95
to «N. f3 86 0N; No 59. m ..m.o vmd :96 35:95
«A mwé 9mm o...m mvé mm Emu ..m Pm; oNN 9.0..
m4 omh mNm Chm :4 ..m v.2. mN or... moN tozw Z¢
v... we... mNo mad >04 mm mNo vn mm; 5N 9.6..
we :2 mSm we...” 9N2. 0.. 0.: mm on; SN :95 2N
...F no.5 ...S and 00% Pm m.vm v¢ moN and 9.0..
m4 31m va 0N.m vm... mm was cc 2.; no.0 :95 Z
£95.. 280 x
853mm 8qu
. m: . we we m: m: we m: me
N; 3.6 mdm um... mm; mm v.3. on Na; omN 9.0..
...m Nm.v NKV 55 Na; mm _..mm 5N mré SN 29%
N 26.5.. wcmo
.. .. .. m: .. .. .. 2. .. ..
m mm 9 av; a Q? moN n mNé 9 mm n 9% n or o .56 o and 35:95
a v9 aw mom. a New 3...” n mNé a mm a fmn m on n vNé 5 SN zv
n we a 86 a «.8 min a Re a mm a NE a an an mt. on and 2N
a me a mud n f: moé a N»... a mm a Vow u Nv a 54 a wad z
639%.
> 8:35.". $qu
.236 SE was 8 Sosa .26 25> .53 .5. .0620 .E9 ..2. .wnEsc .5... .0539: 2.253....
.285 22> ..EB 22> «8:22: 3.8 32:8 .236 .236 22> 22>
98.. no.0 32:32.2“. 3.28322

 

.nmmw... .50 US$33...
35.6%... «2955 .o 22> .0 3:32.88 ucm 22> o... co 59.6. 2.8 new 3582 mono: .o 898:: 05 .o 852...:

.mEgoc; >o__a> c5... 8
.v m..m<.r

137

..moh 8.3m 22.5.2 302 9:855 9...... 2.828 5...... 5.6.88 2.8.2

.8. 2.82:2» .8 .o 2... 2.. .... ....m .a 282:2... 822. u.
88.. o. n83 .88.. m ":96 N22... 8 22...... 8...... .8 59.2 2.8

N

Nam. .m. 2.... ..o 9.5.... .8 $0.. .23 3529. $202 >

2.0.6. 22.. 05> o... :0 20.8.0

.0 0.08783 2... ......omémuv .3893 ....oogmnm 383". 22.; 9.25.. m. a 2...... 8.2.38 222.83.... 22... .o. .22.... 2._> x
.28. 2o: .22.... 2.. 2...... «2...... .0 $8....on

...... ”9.08.83 ”2.8-9.3 .qoovéwum £86“. 22.; 9.25. m. a 2.2. 8.3.3.. 222.833 3... .o. .22.... 25.2. ...
.Nm.o..m ..o .52... 223.0 8.0.55 Na .0 2.8.5.38... £95. ...... 2.58 ES. ova... 2.3.38 a :0 8...... 28.5... .032”. uo§==wm >

 

 

 

 

 

m: w: w: m: m: m: w: w: m:
... .... a ...... o... om... .... ... 8m 2.2 85.95
m. .... .. a... w... t... ... om .mm .55 8:295
.... .... w 98 3.. 8... ... .m .3. 9.3
m. .... a. .28 8.. ...... ..m ow NS .85 2..
.... .... .. 0.8 ...... mo... ..m a. ...... 9.3
.... m... m. ..om ..m. ...m mm mm NS .36 2m
a. ma ... 98 on. B... .... m. 2.. 2.3
.... m... m. ..om 8.. co... .m m. man .35 2
59.3 2.8 x
822% 882
we. m: w: w: m: m: w... m: .
.... .... .. 0.8 mm. 0.... mm a. mam 9.3
.... mm m. ..om R. ...o om om m... .55
~ £95.. 950
.. . 2. .. . .. 2. 2. ..
a m. n .... o. .. ...... a 3.. a o... .1. a. a .8 8.5.9...
o w. a m... .. a com a mu. .... «.... mm om a .8 2..
a M... a m... m. a new a mu. .... 8... mm .m a 8... 2m
m .... a ...o ... a mom a mm. a 8.0 3. m. a 2... z
.m.+m.uz.
> 8222. 882
x “cm 3 “cm 292mm .0520 wb=om .92.; In 5520 2Qan 5w :2... > .8532 2.0539...
22> .2220 ES. .2. 2. 236m 2222.: 32:8 .....25 .32.... .23.”. ......m

 

Na? .o. .80 3.83m... Na. .9 9...... ..o :93. 9.82.22.on Eoo.m
$5.636 8.953 .0 >52... new .3 ...... ..o 59.... 9.3 new 3520. mono: .o .35.... m... .o 8.83:...

22.26:... 3...; econ. .a

.m m..m<...

138

......» macaw 0.9.52 :62 9:855 9...... «5.5.8 55.! 5.3.38 2.32

...... 285...... .9. .o x... .... x. ....m ... 9.8%.... 82....
3...... o. "9.0.. ”mono: m ":25 ”8.0.9 .... 8.5.... 952. .8 59.... 250
.08. ..m. 2.... ..o 95...... .8 88 .2... “.0522 882
...2.o. 2o... o...> m... ..o ﬂaws... ... ....oowéﬁm
...... ”$8.8". _$oo.o..nm .....o..-o~nu ”$83. 29.... 9......2 .... a 9...... 8.3.9.. 2389...... 8; .o. .22.... 2.5
62.... 2o... .83.". o... 5...... 3.8.. .0 ....oopéwum
...... gowéouv ”9.8-3.4. .....ovémuw ”$8-0". 96...... 9.2:... m; a 9...... 3.3.96 202.83.... mm... .... 5.8.0 .......>> ....

NH.

>

X

@285 ..o 5...... 229.6 $.95.) on .0 35.5582 595. ...... 2.58 ES. cum... 92.5.» a co com... 235.... 526E no.wE_.wm >

 

 

 

 

 

w: m: w: a: m: a: w:
a o..~ a... «No 3. i new 9.2 85.95
.. ...om .... mm... am I own ......m 8.5.9.:
m. ...om m... cm... .... ... ...m 9.3
m. ...om .... mm... mm om «on ......m 2..
u. ....N mm. C... S .m ....m 9.3
... ...Nm 8.. ...... ... 8 «3 ......w 2m
t «.mm 3.. ...... mm mm ....m 9.3
mm ...Nm ...... m... 3 ... com .85 2
59.3 2.8 x
852.... 882
m: w: m: w: m: m: w...
... «.3 a... ...... om om NR 9.3
i ....m ow. ...... ... ... EN :96
~ 59.... 980
a o. .... 3m .. o... a 8.0 a mm .. ... .. owm 8:295
.... m. .. ...om .. o... a a... a .m .... ... a mam 2..
.... t a ...m a ..m. .. ...... a 8 a mm a 8m z~
m cm ... ...mm a mm. .. ...... a .... a .m a Sm z
.m.+m.uz.
.. 852.... 882
2953 5.3.0 «2.8 3.20.. In .250 macaw .90. .....n. > .3632
E2“. .om .... masow 2222.... $2.5m 2.620 28.3. .632“. ..mm 2.2...me

 

dam. .. .00 8.823. .8... .8 0.5.. ..o :93. $5623on 585 $28.23 >o__a> :5”. .a
8:323... 8.0.55 .0 2:2... new .3 .....n. ..o 59.2 9.8 ....u 35...... 3...... .o .35.... o... .o 8:02....

.0 mame

3m

 

139

 

 

mmmdmw + co www.mw .... 09 3:6 u 9%.
3.3 1.52%.. mwkmao
NF or m o v m o
_ _ _ . F . _ b r bf _ p .

o
woo_
woom Mu
, H
1000 N
w n
r W
, a
woov U
moon
,oom

 

 

.mmcSmaSm 8.89) E wEmEmSmmmE .236 8a «526: .2 Ewncmﬁ «mm. .P .9".

I40

:m
mat + 3 Rmem u as 88.0 u «E

3.8 Ikozwq mwhmDJO
9 m? 3 N? 0.. m w v N o
b . _

— Ll _ ’ — _ _ _ b p _ F b _ h _ b . — _ h P — _ P w o

 

HBSWHN HSMO'H

I
O
O
V

Y 1'

I

 

‘f'fﬁ
O
8

 

 

 

com

.mmc_>mam.m mm_ocm_> :_ 3589888 .936 8a 2950: .2 2%:me mam. .m .9“.

I40

, aim
Raﬁ + S Raﬁ u es 886 u NE

@3533 $530
2 .8 3 NF 2 m m v N o
. L . h _

p p _ _ p. h _ p . . — _ h p — b h h o

 

l
O
O
N

T

I

1

l
O
O
CO

I l I I

HHBWHN HEMO'H

§

I

 

 

 

 

.mmcswaﬁm 3.955 E mucmEmSmmmE 8620 8a 9950: .2 2355 89 .N .9“.

14]

2mm macaw

 

 

 

 

gem—2 Egan... .mnEmomo
- o

it. is .3. W

o r
mm. H
H w.
n o , m
«.02 2 m
D.
a , I.
m m._m<Emoo< mm: m
, G
- .m
o m Wow w
._.zm._._moxw , s
v m
a wmm M
, Z
, m
m womm

mm

.cozmagm @8592 25 meE 8685 8:568 mam? new 82 .m .9“.

142

 

93 295mm

 

 

 

 

gem—2 b352, .3688
- 0
mm
- d
, m...
wop W
o m w
coca w E m.
a O
a loam
m._m<Emoo< m H w
m o m mam
Fzmjwoxm H M
mom 2
, m
, w
wmm
m 7
. 8

.cozmagm mmmsEmc 552.3 8655 3:358 «amp new 59 .v .9“.

 

, ..;

mm

 

...mem 03m mwt< mxmmg

 

143

 

 

 

 

om m; 2 m o
_ _ _ f p _ L _ . . _ L r r F _ h _ _ O
.. \ wow
....
H m
n8 H
IA
ﬂ mu
.lom w
a W i
.......\w.\ ﬂoor W
a 8 womrm
n H
, m.
gm m 63M.
m a: I... 2v ..I.. 2m ll 2 .II ..om:
f
02

 

.cOmmmm 9:266 mm? 9: mczau m2m>m£> >m=m> Emu

E $5536 $633 5 A88 £95. 505 meE :0 btm>mm @555 6 85.35 .m 9....

HmmDm 03m EMF”? wxmmg
mm ON 9 0.. m o
_ _

k . . _ — V L p _ _ — .— — _ _ _ .r P o

.— r _ _

 

low

.19.

 

 

m ZVI 2| .

 

 

 

 

 

 

 

mm
.533 @5265 mm? 9: mczau m9m>¢£> >m=m> Emu.

E $5535 $635 5 cozoznoa $2 80% meE :0 3:93 9:55 ho 852E. .m .9".

J.GOHS Had SSAV31

145

mm

...mmDm 03m mmt< mxmw>>

 

 

 

 

 

 

 

 

 

ON 9 o_. m o
_ p T _ _ _ _ . _ . p . _ . _ _ _ _ _

, o
wm
WV
.10

0.0 -
0.0 - -_ .. illiiik ...m
a wow

9 n5 II ZN I -

m m f
3

 

.:ommmm 0:566 83 9: acts: 3.96:3 >m=m> ::m....
E mm:_>mam:m mm_o:m_> :_ :ozosuoa Socw .993 :o 3:98 9:5 .0 853:. N .9".

HEQWHN 'IVHElV'I

...mmbm 03m mwt< mxmwg

 

146

 

 

 

 

 

om m. o. m o
L F p b . _ _ : _ _ _ . F _ _ _ r . _ _ _ _ +

.o
£11 #11 ﬁlm
I:

0.0 m
we

0 -\\-\\\\ ,..
. \ wow
0 9 Km
.8
n m .8
”.8
a — “5 fl 2v II. 2m I 2 II .9
,8

.:ommmw @5266 39 9: 9:3: «2:583 >m=m> :5”.
am 35585 mm_o:m_> :_ :ozozcoa Km. .92.“... :o 3:93 @555 :o 852E. .m .9”.

HBGWHN :IVE'] WVHELV'I

147

mm

HmmDm 03m IMF”? mxwm>>
ON 9 or m o
_ _

H _ h .

 

 

_ h b — p _ p L h p p h _ _ . _ p o

«i \ -

 

 

 

 

m fanizvllﬁllzI;

 

 

 

our
.:owmmm @5265 mm? 9: acts: «Eggs >m=m> ::mu_

um mm:_>wam:m mm_o:m_> :_ AEov 50:2 82w .895 :o 5.9% m:_::a .o 852E. .m .9“.

(UJO) H.LEDNE'I .LOOHS "IVHBLV'I

...mmDm 03m mmE< wxmmg

 

148

 

 

 

 

mm om m: o. m o
p _ _ _ _ p _ _ _ _ + _ r _ b _ h _ _ _ . _ L p O
- i
-8
. m
. V
3 .I
r m
:29
wow. u
o - M:
o H w
wooman
n . H
, .o.
- wommrw.
m mall2¢||z~|zll_w
8m

 

.533 @5265 mam. 9: acts: «298:3 >m=m> Emu um 3:30.36 «2035 .o
9999+me28 80% :8 :65. m2§mmm> .59 m5 :0 2:98 @555 .o 852:. .9 .9“.

149

mm

meDm 03m EMF"? wxmm>>
ON 9. 0% m
_

— h p p k _ b r b h b h b — b p r p

O

 

 

«a.

 

lellZleNIIIZI

 

lIIIIﬂITjTTIIITYITjIT'IIfYIITrTITTIT

 

 

.:ommmm 9.39m 89 9.. acts: «963:3 >m_.m> :5... am 35586

8 8 8 8 2 °
.I.OOHS Had saAva'I 1V.LO.L

O
(D

O
[\

wm_o:m_> .o aﬁmﬁibméav 60% :mn. 82$. .99 m5 :0 5:98 9.55. .0 853.2. .2 .9...

 

CONCLUSIONS

150

 

151

The data presented here leads to the conclusion that the competition among fruitful
sinks (clusters) during anthesis has a greater influence on reducing f ruit-set than vegetative
competition. Lower berry set provides a loose cluster architecture and thus reduced
Botrytis bunch rot. Reduced pruning severity and post-set thinning produces grcater
numbers of fruitful sinks during anthesis, resulting in a greater response in Seyval
grapevines. Reductions in yield due to decreased fruit-set can be overcome by increasing
the number of clusters thinned. Thus, the level of sink competition can be manipulated by
pruning severity without adversely affecting yield. However, the vine’s capacity limits the
level of vegetative sink (apical meristems) competition it can accommodate and mature both
fruit and wood. This is also evident in the Vignoles cultivar. However, because they bear
smaller clusters, the fruit-set response to greater fruitful sink competition is less notable. In
order to reduce berry-set sufficiently in Vignoles and improve cluster architecture, pruning
severity must be reduced to the point where vegetative sink competition adversely affects
vine health. The hypothesis discussed in the introduction concerning reductions in fruit-set
to reduce Botrytis infection may have some practical applications as to how large clustered
cultivars are managed, but appear to be impractical for smaller clustered cultivars.

Hedging Seyval grapevines increases the number of nodes within the canopy cach
year. Greater numbers of shoots increase early filling of the trellis area with foliage, but
little leaf area production occurs after veraison. Thus, older leaves are responsible for
photosynthate production during fruit and wood ripening. Due to the early leaf arca
production, hedged canopies become shaded by the time of veraison. The shoots are
considerably smaller and grow upright for much of the season. This contributes to leaf
layer formation which increases canopy density and shading, reducing cane cold hardiness.
Canopy density also promotes Botrytis infection. If hedging is the preferred pruning

method, then cordon renewal is recommended after four to five years.

 

152

A moderate pruning severity in Seyval grapevines (30r40 in Michigan) that
adequately spaces shoots along the cordon allows for early filling of the trellis area with
foliage. Shoots are more developed before bloom facilitating berry development, resulting
in greater yields. Shoots produce laterals after bloom that bear new leaves during fruit
ripening and wood maturity. The optimal shoot spacing inhibits leaf layer formation and
shading is rarely a problem. Thus, cold hardiness is improved and Botrytis infection
reduced. Optimal shoot spacing within the canopy should be the primary consideration
during pruning.

If mechanization is necessary to reduce labor costs, then mechanical fruit thinning
needs to be developed for highly fruitful cultivars such as Seyval and Vignoles. Hand
pruning to ensure proper shoot spacing and sink competition, along with mechanical fruit
thinning, would be a more cost effective method for controlling Botrytis infection and

maintaining vine health of these cultivars.

”(J

 

a“! ‘1.) ‘

APPENDIX I

INFLUENCE OF CANE CHARACTERISTICS ON PRIMARY BUD AND
PERIDERM COLD HARDINESS

 

153

 

Summary

Striegler and Howell (1991) demonstrated a clear response in cold hardiness to
varying cane characteristics in Seyval grapevines. Three classifications (excellent,
acceptable, and poor) were developed from this work and from hardiness evaluations made
in December of 1991 and January of 1992 on canes from Seyval grapevines. Primary bud
and periderm TSO’s were determined for variations within four cane characteristics, and
over node positions along the cane. Canes having a medium diameter (7-10 mm) (Figs. 1
and 2), medium intemode length (6-8 cm) (Figs. 3 and 4), and dark periderm (Figs. 5 and
6) were found to have superior primary bud and cane cold hardiness. Persistent laterals
(Figs. 7 and 8) and node position (Figs. 9 and 10) did not have any influence on cold
hardiness. Samples of canes within the three classifications were evaluated for cold
hardiness in December, January, and March following the 1992 growing season. Excellent
canes were superior and poor canes were inferior to acceptable canes in both primary bud
and periderm cold hardiness at each date and over dates (Figs. 11 and 12). These results
were similar to those found by Striegler and Howell (1991). Using the three classifications
was a rapid and effective way to evaluate the relative cold hardiness of each treatment vine

(see Chapters 1 and 3).

154

 

155

 

 

.m
um
E
30 m

:

m

0

 

 

 

 

 

o m
......
1 0000000000000
oooooooo
ﬂ ...........
..........
. .... r
ooooooooooo
..........
ooooooooooo
..........
-----------
..........
...........
..........
...........
..................... “v
n .................... _
..........
...........
..........
...........
..........
........... P
...........
.....................
..........
........... —
..........
...........
........... pm
........... E
—
t
...........
..........
......
D .................... b
nnnnnnnnnnnnnnnnnnnn
uuuuuuuuuuuuuuuuuuuu
.................... m
oooooooooooooooooooo
Wk
' O .
MI—
OOOOOOOOOOOOOOOOOO
o-o-u ooouuuoooconnuuco-no VUIHUHOHIHIHOHIHIHIHL —.
l
5.. n ....................
N u
m m
m e. 2
*
ooooooooooo
i OOOOOOOOOO
- ..........
v ..........
r
1 ..........
z a... f ................... 4
..........
j ........
nnnnnnn
00000000000
....UIH
.
O
.....
.........
.............
OOOOOOOOOOOOOOOOO
'
s
....
.. _ .w.. ......I......'.....- W
00000
....................... T
..
...................... Y
.................... Y
00000000000000000000
I I
000000000000000000
.............. .u
0000000000
I
......
.- ﬂ
I
I
I
1
PO -
m l
r
_. a -
.m
1|
F 1
m l
O .
r
r
1
VI
T
T
T

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

.m;
m
w
.o
m
mob.
: E
.U. o
m
.. FA
U Nm
.0 m
o .
3.3
a ”E
a E
m
E o
tQ—i
0““ “5E3.
OWN—”......
m E
.U n
o v
:
won—f
no E
mom
: .m
o o:
a
...: $8
.
.m

.n.

(o
‘a m
2 30'68
S5.
1690):,
J.

On 0

8'-

M

B
0.:

Ltd

8

8

 

EoEmE mcwo

. Ems. . _ .i DOE _

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

.D
(II

 

 

 

 

 

 

 

 

 

 

 

 

C

.2. Nam...NN Z<... 59. .9 Own.

8

 

ﬁWjI'll

 

mv
.88 9A $93 .EE 94. ”E232 .EE nv ”..mEm $83235
.mimm .o $3.2m: 28 552.3 9.. :o .2955 28 ..o 8:022. .m .9".

(0192 MOIGQ 3991690) 091 wrapped

157

 

 

590.. 80:52.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

95.. _ 8.2 _ :95 r t t .85. _ :Bm
........... o
...H...H..HH..HH...U. .... f
Whammy”... ...”...mwun ”...”...mmm. .
”....ﬁm.” .UH.HHH.HHH.HHH.H..H madman“... H
mime... WEE”. ”“wame ..m
.....H..H..H... ...”...mww H.....HH..HH..HH..HH . d
....................................................... r U.
H..H..H..H..H.. .......HH..HH..HH..HH H....H..HH..HH..H.. w
“mum“... .mwmmmm WWW.» ..op m
H....HHH.HH.HH._H ”.3.me ...“.Hunmmnvu. . 8
............................................. n
”......HH..H....H.. ...”...HH..HH..HH..HH HH...H..UH...H..H.. . D.
“.mmmnmwnww Hummumﬂmm.” ..H..HH..HU..H..H . I.
.....H..H..H..H. .....u..u..w.nu. III... ﬁmw W
unnamwmm HH......HH.HHH.HHH.HH m
...”...wam ”...”...H... nu ..HHMH n .
”...”.wmw.” Human.“ . PM
...”...Hmm.” m..u......u..w.u ION %
.H..HH..HH..H..HH. ..HH..HH..HH..HH..HH. . s
”.....me ”Hummuwww. . mm
“unsuswhn. ..HH..HH..HH..HH..HH. T m
...”..H..H..... -mm 2
. m
. o
(
am a a .
now
¢ . v
Nmmw .mm 25. 59 .2 Own. .
. T
mm

.20 R ”9:3 .20 mé ”22.8.2 .20 av ”:05 883285

22.9w 2 8862: 28 :3 2952 on. :o :58. 80:82. 2 8:8.2. .0 .9”.

50:0.. 80:52.

 

158

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

9.3 _ 8.). _ :20 _ t 08.. _ .85. r :20 0
En...” ......”un .....ww... ”Hyena”... 1..
.m.m.m.m.m. nymmwmmw.” ..HH.H.HH.N.HH .HHH.HHH.HH..HH.HH.. H
wuumumuﬂm mmmmmmmumu. Wmuhwnnmu. ”.HH..HH..HH..HH..HHU . d
............................................................................. . -
.......H..H..H..H H...H..HH..HH..HH..HH .....H...H...H...H..H ”...“...u..u..u... .I or m.
...”...Hﬁ. ...”..undm...“ ...”..H..H..H..HH .....H..HH..H..H. . P.
. H...H...H..HH...H.... H a
......”wa ”Humnunwﬁ mummy. mum»... ”.9 w
r .... . I.
.............................................................. - 9
...... ..... . .... . 0
.... . ................... l \I
wwwnumwn .HH.HHH.HHH.HHH.HHH.H ”hwuwwnwﬁ WHHHHHL . ON a
mﬁ.~.~.m Juana”... .....H..~..H..H.. ...”..unmuwmm. .m
............................... .
.............................................................. . . 8
.Hn.m.m.m._uu. .HH..HH.HHH..HH.HHH.. ...”.mmmmw. n. N %
H..H..H..H..H..H H.HHH.HH..HHH.HH..HHH ....lllIL . 8
”an...” ”Rum... .. P
..... rill .1 on m

, m

w mm m.

.. . 5.9.
mmmp .NN 23.. amp .2. Own. H
r
mt

.20 mA ”0:04 .20 0-0 ”2200.2 .20 ov ”:05 083805
31080 88.0.0: 0.00 2:00:00 05 :0 50:0. 80502. ..0 8:82. .v .0.".

159

 

 

5.00 2.02.9.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

:305 0:00 _ :306 Em... _ _ :305 0:00 _ £505 Em...
............................ . . III:
1 .................... A oooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooo
...H.”.......m.w.uwu ...HH....H.H...HHH.HHH.HHH.. .H...”......H..H..H..H.. ..HH......................H. .
mm“wmmuunwwm Hmmmummmmmum” nnHHHHHHNHHHHNHU HumHummuuuumuun .l
.
...an...”......H......, ......H..........H...”...HH. .”......H......H..H..H..U u..........H...........H.. .
............................ . ............................ v.........o...o.ooo...o...... .........o....oo.o..oo.a.... I
...H...H...H...”swamp”. ........................................ . ............................
..................... . .
.................................................................................................................. 1
mm...”.....H...H..H..H H......HH..H............H... ......H..H..”......Hm. ......”...”...u......u...U .
...“......wmmmmH” ”unuwwm”mi... .H”...”...”mummy.“ H.m.”WNW“... .
...HH.....H............ we.........0.” ..H”......“..H..H..H..H. ......HH...H...H.....H...H .
an...“......H..H.. ......H......HH.ﬁx”. .............H..H..H..u..u l.-- ..... ..
.... . .
..................... A ... u..- -.- .o. ... ... as. 1. on. no. you can an. on. n. T
...........H..”xv...” H......H.......HH.......H... ..HH......H..~..H..H..u. .
.. ..............._...p.. ..... . r
Wham.“”human” H”.mpummmuxman.” l
...H.........H...H...n.m ”...”...mm.........HHH. .
a...”......HHHHW. l- .
“......“”...”?me .
. .
W.M.”..wm.mums” a
.................... . ... .. ..u'

. ..
«mm. .mm 23. 59 9 Own .
.

8:32.05

.m>>0m .0 88.0.0: 0.00 000 20:20 05 :0 .0.00 2.00:8 .0 8:82. .m .0.“.

a a :2 2
(ciaz moles $891560) 09; png Mewud

O
(O

In
(0

160

 

:30.m 0:00 :30.m Em...

.

_

5.00 2.02.01

 

 

..............
..............
..............
..............
..............
...............
..............
..............
..............
...............
..............
..............

.......
nnnnnnnnnnnnnn

uuuuuuuuuuuuuu
..............
..............
...............
..............
..............
..............
...............
..............
..............
..............
...............
..............
..............
oooooooooooooo
..............
..............
..............
..............
..............
..............
..............
.......

ooooooo
00000000000000
.......

.......
oooooooooooooo
ooooooooooooooo
oooooooooooooo
..............
uuuuuuuuuuuuuu
uuuuuuuuuuuuuuu
oooooooooooooo
..............
..............
uuuuuuuuuuuuuuu
..............
..............
oooooooooooooo
000000000000000
nnnnnnnnnnnnnn
uuuuuuuuuuuuuu

..............
..............
uuuuuuuuuuuuuuu
..............
..............
oooooooooooooo

oooooooooooooo
ooooooooooooooo
00000000000000

.......
00000000000000

IIIIIII
oooooooooooooo
-------

0000000
oooooooooooooo

ccccccc
..............
..............
---------------
oooooooooooooo
oooooooooooooo
..............
ooooooooooooooo
cccccccccccccc
oooooooooooooo
00000000000000
...............
oooooooooooooo
00000000000000
nnnnnnnnnnnnnn
ooooooooooooooo
oooooooooooooo
..............
oooooooooooooo
ooooooooooooooo
oooooooooooooo
cccccccccccccc
--------------
000000000000000
..............
..............
.......
.......
oooooooooooooo
oooooooooooooo

 

 

00000000000000
.......

 

.......
........
.......
.......
.......

ooooooo
nnnnnnn

ooooooo
ccccccc
........
.......
.......

uuuuuuuu
.......
ooooooo
nnnnnnn
ooooooo
.......
.......

 

 

 

«i

Nmmw .NN Z<_.

 

 

 

 

£505 200 _ £505 Em...

.
. ........................... . ........................... L
. .................... . .....................
w 000000000000000000000000000 A 0000-00--coco-conconoQ-Hoocug
........................... .
1 ........................... . ........................... L
............................ . ...........................L
............................ . L
000000000000000000000 ‘ .0. on. can 000 000 no. 00-
.........................................................
v ..........................................
. ...... ..
..................... . zxaaaxx
............................ .
. ........................................................
. ........................... . ............................
oooooooooooooooooooo ‘ no. on. 000 In. no. no. on.
............................ . .
. ........................... . ............................
............................ .
.........................................................
...H...H...H...H...”...”...HJ ..”...“..ouo..Hc.-H...H.-.Ho
IIIIIIIIIIIIII A .0 O. I. II .0 I. O.

............................ .
............................ .
............................ .
............................. III

w:

52. .2 Own.

T] I T

III'TIII'W—ﬁr
IO 0
F P

(\I
(0va mouse 8661590) 091 weaned

7

I
O
(O

.--...”
8 8

I

I

 

 

.0>>0m .0 88.0.0: 0.00 2.02.00 0:. :0 8.00 2.02.00 .0 8:022. .0 mt

0830005

ID
v

I6]

0306 2.0.0.. 20.0.0.9".

 

OOOOOOOOOOOOOO
00000000000000

00000000000000

-------

.......
00000000000000
IIIIIIIIIIIIII
OOOOOOOOOOOOOOO
oooooooooooooo
..............
00000000000000
ooooooooooooooo
oooooooooooooo
00000000000000
oooooooooooooo
IIIIIIIIIIIIIII
00000000000000
oooooooooooooo
..............
OOOOOOOOOOOOOOO
00000000000000
00000000000000
0000000

.......
--------------
00000000000000
oooooooooooooo
oooooooooooooo
uuuuuuuuuuuuuu
..............
oooooooooooooo
oooooooooooooo
..............
00000000000000
---------------
--------------
oooooooooooooo
oooooooooooooo
---------------
oooooooooooooo
00000000000000
nnnnnnnnnnnnnn
...............
uuuuuuuuuuuuuu
oooooooooooooo
00000000000000
ooooooooooooooo
..............
uuuuuuuuuuuuuu
nnnnnnnnnnnnnn

.......
oooooooooooooo
oooooooooooooo
000000000000000
00000000000000
oooooooooooooo
eeeeeeeeeeeeee
ooooooooooooooo
oooooooooooooo

OOOOOOOOOOOOOO
.......

00000000000000

0000000
..............

.......
..............
00000000000000
ooooooooooooooo
oooooooooooooo
oooooooooooooo
--------------
ooooooooooooooo
oooooooooooooo
cccccccccccccc
..............
IIIIIIIIIIIIIII
..............
..............

......
oooooooooooooo
oooooooooooooo
IIIIIIIIIIIIIII
00000000000000
tttttttttttttt
oooooooooooooo

.......
cccccccccccccc
..............
ooooooooooooooo
oooooooooooooo
..............
oooooooooooooo
..............
..............
..............
..............
..............
..............

 

 

 

 

 

 

 

0: «mm. .NN Z<0

..............
OOOOOOOOOOOOOOO
..............
00000000000000
.......

.......
00000000000000
00000000000000

IIIIIIIIIIIIII
00000000000000
OOOOOOOOOOOOOO
OOOOOOOOOOOOOO
OOOOOOOOOOOOOO
00000000000000
00000000000000
.......

..............
000000000000000
00000000000000
00000000000000
ccccccc

.......
IIIIIIIIIIIIII
oooooooooooooo
OOOOOOOOOOOOOOO
OOOOOOOOOOOOOO
00000000000000
.......

IIIIIII
00000000000000
00000000000000
ooooooooooooooo
ssssssssssssss
..............
0000000

llllllllllllll
.......

ooooooo
OOOOOOOOOOOOOO
00000000000000

OOOOOOOOOOOOOOO
00000000000000
oooooooooooooo
OOOOOOOOOOOOOO
000000000000000
CCCCCCCCCCCCCC
IIIIIIIIIIIIII
.......

lllllll
OOOOOOOOOOOOOO
00000000000000
IIIIIIIIIIIIII
..............
OOOOOOOOOOOOO

 

 

 

.......
0000000
’l’ 8 D 8 8

 

 

 

m:
Pmmw .9 Own.

I ' I I
IO 0 ID
1- 1-

l
O
N
(0332 M038 8333930) 091 one AHVWIHd

I
In
N

I
O
(0

 

 

.0>>0w .0 88.0.0: 0.8 0:: 20:20 0:. :0 8.0.0 .0.0.0. .0 00:022. N .m.u.

8830005

ID
('0

I62

00.0.0 00.0.0. 20.0.0.00

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

00> _ 02 _ _ 00> _ 02
-i-lll-“ --. v ..... H ...“...H..M.|..H ..... . ............................ 1 o
............................ . . .
$TH$$E .Hﬁﬂﬁﬁm Vﬁﬁﬂ$ﬁ Wﬁﬁﬁmw .
mmwmmmmmm”mm ...mwmmﬁm .Hmmmwmmwmm Hm.wH00... .0
......“ananH... H”a...”W.M.”... ”...”...”Hmnuww. Hm.””W.M.“...mm H d
ﬂ...........ﬂH. ”......”...»... ......mmm”My”... H.H.”.....ummm... ”.0. w.
......................................................... . o.
aﬁﬂﬁﬁﬂ. mﬁﬁﬁﬁw $ﬁﬂ¢$y KﬁﬁEﬁm . m
.
“may......H..H..... ..........H......u.w.... .... . H. mp
“awn..HU..HH..H..HH..H. Erna“.”Havana” banana”.Haw.””w H.HH.HH..HH.HH..H.UHH.Hu r W.
n....””HE...H. ”......“”......“ ....wa”Hum”... Hmm.in... 0 I
R.E....“.... ”in.“Human n”HM...””mm...“H. ....mmmmn”.... H m
............................ .. ... ... ... ... ... ... .. ... ... ... ... ... ... ...
“Human...”....H. an...an”... --- .......0.........“ .1 mm %
uwmmﬁwwm“ mm...””mum... ....... ,. ..... .. H m
m.«H.200 H.H...WEE ,. 00 m
”my...“my... H.m.......ﬁw n a
- .. . . . .. mm m
. (
0: 0: .. ow
000. .00 23. .00. .0. 08 .
.
00
0830005

.0200 .0 88.0.0: 0.00 2.00000 0:. :0 020.0 .220. .0 8:022. .0 m...

 

:00.00 20.". .00.0< 80.000 000

 

163

......
I I I
......
......
I I I
oooooo
I I
nnnnnn

I I I
000000
I I
000000
I I I

I I I
......

I I 0
......

I I I
000000
I I
......
I I I
oooooo
I I
000000
I I I
nnnnnn
I I
nnnnnn
I I I
......
I I
nnnnnn
I I I
......
I I
......

cccccc
I I
oooooo
I I I
nnnnnn
I I
oooooo
I I I
......
I I
nnnnnn
I I I

I I I
oooooo
I I
oooooo
I I

. I
000000
I I
......
I I I
......
I I
tttttt
I I I
......
I I
......
I I I

I I I
......
V I I
......
I I I
......
I
oooooo
I I

 

 

 

 

......
I I I
uuuuuu

I .
------
I I I
aaaaaa
I I I
IIIIII
I I
......
I I I
nnnnnn
I I I

I I I
oooooo
I I I
------
I I
IIIIII
I

I I
nnnnnn
I I I
IIIIII
I I
IIIIII
I I I
......
I I
IIIIII

I
oooooo
I I I
IIIIII
I I I
......
I I I
IIIIII
I I
oooooo
I I I
nnnnnn
I I
IIIIII
I I I
IIIIII

I I I
IIIIII
I I I
IIIIII
I I I
IIIII
I I
IIIIII
I I I
IIIIII
I I I
IIIIII
I I I
IIIIII
I I

I I
IIIII
I I I
IIIIII

IIIIII
IIIIII

I
IIIIII
I
IIIIII
I I I
IIIIII
I I
IIIIII
I I I
IIIIII
I I
IIIIII
I I I
IIIII
I

 

 

IIIIII
I I I
IIIIII
I I
IIIIII
I I I
IIIIII

I I I
IIIIII

I I I
IIIIII
I I I

IIIIII

I I I
IIIIII
I I I

I I I
IIIIII
I I I

IIIIII
I I
IIIIII
I I I
IIIIII

I I I
IIIIII
I I I

I I I
IIIIII
I I I

I I I
IIIIII
I I I
IIIIII
I I I

IIIIII
I I I
IIIIII
I I
IIIIII
I I I
IIIIII
I I
IIIIII
I I I
IIIIII
I I
IIIIII
I I I
IIIIII

I I I
IIIIII

I I I

IIIIII
I I I

IIIIII
I I I
IIIIII
I I
IIIIII
I I I
IIIIII
I I
IIIIII
I I I
IIIIII
I I
IIIIII
I I I
IIIIII
I 9
IIIIII
I I I
IIIIII
I I
IIIIII
I I I
IIIIII
I I
IIIIII
I I I
IIIIII
I I
IIIIII
I I I
IIIIII
I I
IIIIII
I I I
IIIIII
I I
IIIIII
I I I
IIIIII
I I
IIIIII
I I I
IIIIII
IIIIII
I I I
IIIIII
I I
IIIIII
I I
IIIIII

I I
IIIIII
I I
IIIIII
I I I
IIIIII
I I
IIIIII
I I I
IIIIII
I I
IIIIII
I I I
IIIIII
I I
IIIIII
I I I
IIIIII

I I I
IIIIII
I I I
IIIIII

I I I
IIIIII
I I I
IIIIII
I I
IIIIII
I I I
IIIIII
I I
IIIIII
I I I
IIIIII

 

I I I
IIIIII

IIIIII
I a I
IIIIII

I
IIIIII
I I I
IIIIII
I I O
IIIIII
I I I
IIIIII
I I I
IIIIII
I I I
IIIIII
I I I
IIIIII
I I I
IIIIII
I I I
IIIIII
I I I
IIIIII
I I
IIIIII
I I I
IIIIII
I I
IIIIII
I I I
IIIIII
o I
IIIIII
I I I
IIIIII
I I
IIIIII
I I I
IIIIII
I I
IIIIII
I I o
IIIIII
I o
IIIIII
I I I
IIIIII
I I
IIIIII
I I I
IIIIII
I I

I I I
IIIIII
I I
IIIIII
I I I
IIIIII
I I O
IIIIII
I I I
IIIIII
I I
IIIIII
I I I
IIIIII
I I
IIIIII
I I I
IIIIII
I I I
IIIIII
I I I
IIIIII
I I I
IIIIII
I I I
IIIIII
I I I
IIIIII
I I I
IIIIII
I I
IIIIII
I I I
IIIIII
I I
IIIIII
I I I
IIIIII
I I
IIIIII
I I I
IIIIII
I I I
IIIIII
I I I
IIIIII
I I I
IIIIII
I I I
IIIIII
I I I
IIIIII
I I I
IIIIII
I I
IIIIII
I I

I I
IIIIII
I I
IIIIII

I I.
IIIIII
I I I
IIIIII

I I I
IIIIII
I I I
IIIIII

I I
IIIIII
Q I I
IIIIII
I
IIIIII
I
IIIIII
IIIIII
IIIIII
IIIIII
I

IIIIII
IIIIII
IIIIII
IIIIII

 

 

 

 

O o I
IIIII
O I I
IIIIII
I I I
IIIIII
I I I
IIIII
I I I
IIIIII
I I I
IIIIII
I I I
IIIIII
I I I
IIIIII
I I O

I I I
IIIII
I o I
IIIIII
I o I
IIIIII
I I I
IIIIII
I o I
IIIIII
I I I
IIIIII
I I I
IIIIII
I I I
IIIIII
I I I
IIIIII
I I I
IIIIII
I I I
IIIIII
I I I
IIIIII
I I I
IIIIII
I I I
IIIIII
I I I
IIIIII
I I
IIIIII
I I I
IIIIII
I I I
IIIIII
I I I
IIIIII
I I I
IIIIII
I I I
IIIIII
I I
IIIIII
I I I
IIIIII
I I I
IIIII
I o I
IIIIII
I o I
IIIIII
I I I
IIIIII
I I I
IIIIII
I I I
IIIIII
I I I
IIIIII
I I I
IIIIII
o I I
IIIIII
I I I
IIIIII
O I
IIIIII
I I I
IIIIII
I I I
IIIIII
I I I
IIIIII
o I
IIIIII
I I I
IIIIII
I I I
IIIIII
I I I
IIIIII
I I I
IIIIII
I I I
IIIIII
I I
IIIIII
I I
IIIIII
I
IIIIII

I
IIIII
I I
IIIIII
I I
IIIIII
I I I
IIIIII
I I I
IIIIII

0-0 _ .0

 

 

 

 

 

 
 

 

 

 

I I O
IIIIII
o

IIIIII

I O I
IIIIII
I I I

I a o
IIIIII

I O I
IIIIII
o I o

I I I
......
a I O

IIIIII
I O 0
IIIIII
O c
IIIIII
I o o
IIIIII
I I
IIIIII
I I o
IIIIII
I I
IIIIII
I I I
IIIIII
I I
IIIIII
I I I
IIIIII
I I
IIIIII
I I I
IIIIII
I I
IIIIII
I a I
IIIIII
I I
IIIIII
o I I
IIIIII
I I
IIIIII
I I I
IIIIII
I I
IIIIII
I I I
IIIIII
O I
IIIIII
I I
IIIIII
I
IIIIIII
IIIIII
IIIIII
IIIIII

 

 

 

 

I
C
,—

I
ID
F

l .
IO
N

' I ‘ I
8 8
(0192 Moles 8861590) 091 pna Mewud

f
In
G)

 

I m:
Nmmw .NN 25. .59. .2 Own.

 

0830005 .0200 .0 008.0.0:
0.00 0:: 202:0 0:. :0 0:00 0:. 80.0 82000 000: .0 8:022. .0 mt

 

 

000.00 .00.“. .029. 002000 03

 

164

 

IIIIIIIIIII
IIIIIIIIIIIIIIIIIIIIIIIIIIIIII
IIIIIIIIIIIIII
IIIIII
I I

I I I
IIIIII
IIIIII
IIIIIIIIIIII

IIIIII
IIIIIIIIIIII
IIIIII
IIIIII

IIIIIIIII
IIIIIIIIIIIIIIIIII
IIIIII
IIIIII
I I I
IIIIII
I I I
IIIIII
I I I
IIIIII

I I I
IIIIII
IIIII
IIIIIIIIIIIIIIIIII
IIIIIIIII
IIIIIIIIIIII
IIIIII
IIIIII
I I I

IIIIII
IIIIIIIIIIII

IIIIII
IIIIIIIIIIIIIIIIII
IIIIIIIIIIII
IIIIIIIIIIIIIIIIII
IIIIII
IIIIII
O I O
IIIIII
I I I

IIIII
IIIIIIIIIIII
I I I

I I I
IIIIII
IIIII
IIIIIIIIIIII
IIIIII
IIIIIIIIIIII

I I I
IIIIII
IIIIII
IIIIIIIIIIII
IIIIII

IIIIII
O O O
IIIIII
I I I
IIIIIIII
IIIIIIIIIIIIIIIIIIIIIIII
IIIIIIIIIIII
IIIIIIIIIIIIIIIIIIIIIIII
IIIIIIIIIIII
IIIIIIIIIIIIIIIIIIIIIIII
IIIIIIIIIIII
IIIIIIIIIIIIIIIIIIIIIIII
IIIIIIIIIIIII
IIIIII

IIIII

IIIIIIIIIIIIIIIIIIIIIIIIIIIIII

IIIIII
IIIIIII

IIIIIIIIIIIIIIIIIIIIIIIIIIIIII
IIIIIIIIIIIII
IIIIIIIIIIIIIIIIIIIIIIII

IIIIII
IIIIII
I I I
I I I
IIIIII
I I I
IIIIIIIIIIIIIIIIIIIIIIIIIIIIII
IIIIIIIIIIIIIIII
IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII
IIIIIIIIIIIIIIIIII
IIIIIIIIIIIIIIIIIIIIIIIIIIIIII
IIIIIIIIIIIIII
IIIIIIIIIIIIIIIIIIIIIIII
IIIIIIIIIIIII
IIIIII
I I I
IIIIII
I I I
IIIIII
IIIIII
IIIIIIIIIIII
I I I
IIIIII
I I
IIIIII

I I I
IIIIIIIIIIIIIIIIIIIIIIII
IIIIIIIIIIIIII
IIIIIIIIIIIIIIIIIIIIIIIIIIIIII
IIIIIIIIIIIIIII
IIIIIIIIIIIIIIIIIIIIIIIIIIIIII
IIIIIIIIIIIIIII
IIIIII
I I I

O
IIIIIII
I
IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII
IIIIIIIIIIIIII
IIIIIIIIIIIIIIIIIIIIIIII
IIIIIIIIIIIIIII
IIIIIIIIIIIIIIIIIIIIIIIIIIIIII

IIIIIIIIIIIIII

IIIIIIIII

IIIIIIIIIIIIIIIIIIIIIIIIIIIIII
IIIIII

IIIIIIIIIIII

I I

IIIIIIIIIIIIIIIIIIIIIIIIIIIIII

IIIIII
IIIIIIIIIIIII

IIIIIIIIIIIII
IIIIIIIIIIIIIIIIIIIIIIIIIIIIII
IIIIII
IIIIII
I I

 

 

 

 

 

 

 

 

I I
IIIIII
I I

 

 
 

 

 

 

IIIIIIIIIIII
IIIIIIIIIIIIIIIIIIIIIIII
IIIIIIIIIIIII
’ IIIIIIIIIIIIIIIIIIIIIIIIIII

IIIIIIIII

IIIIIIIIIIIIIIIIII
IIIIIIII

 

IIIIIIIIIIIIIIIIII

 

 

I
IIIII
I I I I
IIIIIIIIIIII
I I
IIIII
IIIIIIIIIIII
IIIIIII
IIIIIIIIIIIIIIIIII
I I I I
IIIIII
I I I

 

 

 

I I
IIIIII

 

 

I I I
IIIIII
I I

 

 

 

.i‘ C.

Nmop .NN 25.. 5m? .0. Omo

 

00030005 .0>>00 .0 00050.00
0.00 0000000 00. 00 0000 00. 0020 002000 0000 .0 00002.5 .0. .90

P

I

In
P

. I v .
no
N

(0192 MOPS 3991590) 09.L ”113de

O
CO

ATV
ID
1')

l
O
V

 

165

news.

—

 

28 anmm

banana

_

.3888

_

 

 

«g.

,3

«50¢

m.._m<._.n_m00<

n

hzw44m0xw

ﬁﬂl-
10

I
O
,-

Ytl1*
In
F

v Y i

' T 1
IO
N

g g
(0
(0192 MOISQ 9991690) 091 ssaugpmH uuapuad

I ‘
l0
(0

 

 

.mEgmcs >m=m>
Emu. 8 $55qu 326w .0 $8.22 28 589.8 :0 moumtmuoemzo menu B 85.55 .3 .9“.

9

166

 

mama macaw

 

 

 

.mEgmcS >m=m> cam“. um «9.3255
$13 .0 «8:65... 38 95 basin :0 85:93.20 memo .o 8522. .3 .9“.

2822 b352, 598800
_ _ L _ _ C
t .5 cc :10
..m
o moon. m.
n a m
A: H
, m
m .1 m.
52.58% ..mpm
a m
. 0
o a [cum
Fzmjmoxm , .m
n m.
[mm a
n ,. Q
m
m won
. w.
W
mm

 

      

   

HICH

 
 
  

IGRN

3‘12

 

 

 

5m: UNIV. LIBRnRIEs
IIHIIMWIWIIVWWW"WI
93014150837