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thesis entitled

A STUDY OF THE ENVIRONMENTAL AND PHYSIOLOGICAL
FACTORS lNV‘OLVED lN PRODUCING HANGING BASKETS
OF FRUI‘TED GRAPEVI‘NES FOR

BEDDING PLANT MARKET SALES
presented by

CAROL LYNNE HILL CRANKSHAW

has been accepted towards fulfillment
of the requirements for

M . S . degree in H C“? fie " ("TV 8{

yt’ii’lfitww H< (at/CHIN

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A STUDY OF THE
ENVIRONMENTAL AND PHYSIOLOGICAL FACTORS
INVOLVED IN PRODUCING HANGING BASKETS OF

FRUITED GRAPEVINES FOR BEDDING PLANT MARKET SALES

BY

Carol Lynne Hill Crankshaw

A THESIS

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

MASTER OF SCIENCE

Department of Horticulture

1983

b/dobfig

ABSTRACT
A STUDY OF THE
ENVIRONMENTAL AND PHYSIOLOGICAL FACTORS

INVOLVED IN PRODUCING HANGING BASKETS OF
FRUITED GRAPEVINES FOR BEDDING PLANT MARKET SALES

BY

Carol Lynne Hill Crankshaw

A production schedule was determined whereby fruited grapevines
of yiti§_'8eyval' can be produced as hanging baskets for spring market
sales in 9% to 14 weeks at 25-300C. Hardwood cuttings, dipped in IBA,
rooted in 21 days at 280C with bottom heat and intermittent misting.
Twelve cultivars were evaluated; 'Seyval' and 'Chelois' produced clusters
on 91.7% and 87.5% of the vines, respectively. SADH, CCC, BA and GAB'
sprayed on inflorescence and/or fruit clusters increased the number of
fruit per cluster; GA3 increased individual berry weight, volume and
diameter. CCC produced the greatest number of berries. Three treatments
proved superior: SADH (5000 ppm) at full bloom, SADH (2500 ppm) at full

bloom plus GA or BA 21 days later. Three levels of nitrogen and three

3

levels of pH were tested. Plants produced using 300 ppm nitrogen had an
increased number of fruit, increased foliar fresh weight and branching;

but more necrotic lesions than at 100 ppm.

ACKNOWLEDGEMENTS

I wish to express sincere appreciation to Dr. William H. Carlson
for his guidance during the course of my research project and in the
preparation of this manuscript.

Appreciation is also given to the other members of my committee,
Dr. Norman Good and Dr. Gordon S. Howell for their valuable discussions
and considerable assistance with this project.

I would also like to thank others who were helpful in a number
of ways: Dr. Dean Krauskopf, Dr. Lowell Ewart, Jim Wolpert and Tim
Mansfield.

I would like to extend special thanks to friends who were
supportive and immensely helpful, Leslie Weston, Jim Oris and Paul
Weston.

Special appreciation, gratitude and love is expressed to my
supportive parents and to my husband, Owen, for his patience, strength,
understanding and encouragement through all our years together and

especially during my graduate studies.

ii

TABLE OF CONTENTS

LIST OF TABLES . . . . . . . . . .
INTRODUCTION . . . . . . . . . . .
LITERATURE REVIEW. . . . . . . . .
Rooting Experiments . . . . . .
Temperature . . . . . . .

Time of Collection/Dormancy
Cane Segment/Cutting Weight

Growth Regulators . . . . .
Budbreak. . . . . . . . . . . .
Growth Regulators . . . . .
Temperature . . . . . . . .
Flowering . . . . . . . . . . .
Fruit Set, size and Development
Pruning . . . . . . . .

Growth Regulators . . . . .
Photoperiod and Light . . .
Temperature . . . . . . . .

Greenhouse Container Viticulture.

THESIS OBJECTIVES. . . . . . . . .

SECTION ONE: THE EFFECT OF ENVIRONMENTAL CONDITIONS
GROWTH REGULATORS ON ROOTING TIME AND BUDBREAK OF

HYBRID 'SEYVAL'

Introduction. . . . . . . . .
Material and Methods
Experiment I. . . . . . . .
Experiment II . . . . . . .
Experiment III. . . . . . .
Results
Experiment I. . . . . . . .
Experiment II . . . . . . .
Experiment III. . . . . . .
Discussion
Experiment I. . . . . . . .
Experiment II . . . . . . .
Experiment III. . . . . . .
Summary . . . . . . . . . . . .

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21

22
23
24

25
32
32

35
37
38
38

 

SECTION TWO: THE EFFECT OF VARIOUS GROWTH REGULATORS ON FRUIT
SET, SIZE AND YIELD OF VITIS HYBRID 'SEYVAL' UNDER GREENHOUSE
CONDITIONS

Introduction . . . . . . . . . . . . . . . . . . . . . . . . .
Material and Methods . . . . . . . . . . . . . . . . . . . . .
Results. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Discussion . . . . . . . . . . . . . . . . . . . . . . . . . .
Summary. . . . . . . . . . . . . . . . . . . . . . . . . . . .

SECTION THREE: THE EFFECTS OF THREE LEVELS OF NITROGEN AND SOIL
PH ON GREENHOUSE CONTAINER-GROWN VITIS HYBRID 'SEYVAL'

Introduction 0 O O O O O O O O O O O O O O C O O O O O O O O 0
Material and Methods . . . . . . . . . . . . . . . . . . . .
Results 0 O O O O O O O O O O O O O O O I O O O O O O C O O O C

APPENDICES

Appendix A: A Study of Vitis Cultivars Suitable for Hanging
Basket Greenhouse Culture. . . . . . . . . . . . . . . . .

Appendix B: A Grower's Guide to the Production of Hanging
Baskets of Fruited Grapevines. . . . . . . . . . . . . .

BIBLIOGRAPHY. . . . . . . . . . . . . . . . . . . . . . . . . . .

iv

39
4O
42
46
50

51
51
58

59

62

65

Table

10.

11.

LIST OF TABLES

Page
Influence of cutting weight on rooting of Vitis
hybrid 'Seyval' . . . . . . . . . . . . . . . . . . . . . . 26
Influence of propagation method on rooting, budbreak and
inflorescence presence of dormant hardwood cuttings of
Vitis 'Seyval'. . . . . . . . . . . . . . . . . . . . . . . 27
Influence of NAA, IBA and Fe on rooting and budbreak of
dormant hardwood cuttings of Vitis hybrid 'Seyval'. . . . . 28
Influence of propagation method in combination with NAA,
IBA and Fe on rooting, budbreak and inflorescence presence
of dormant hardwood cuttings of Vitis hybrid 'Seyval' . . . 29
Influence of temperatures on rooting, bud push and
inflorescence retention of Vitis hybrid 'Seyval' hardwood
cuttings in the greenhouse. . . . . . . . . . . . . . . . . 33

Influence of various growth regulators on budbreak and
rooting of hardwood cuttings of Vitis hybrid 'Seyval' . . . 34

The influence of various growth regulators on fruit set
and size of greenhouse—grown Vitis hybrid 'Seyval'. . . . . 43

Influence of flowering time on fruit size and yield
of Vitis hybrid 'Seyval' grown in the greenhouse. . . . . . 44

Influence of flowering time on number of days to sale
and days from full bloom to sale of greenhouse-grown Vitis
hybrid 'Seyval' . . . . . . . . . . . . . . . . . . . . . . 44

Influence of various growth regulators on days to sale
and the number of days from full bloom to sale of
greenhouse-grown Vitis hybrid 'Seyval'. . . . . . . . . . . 47

The influence of three levels of nitrogen on flower and
fruiting of greenhouse container-grown Vitis hybrid
'Seyval'. . . . . . . . . . . . . . . . . . . . . . . . . . 54

Table Page

12. The influence of three levels of nitrogen on
foliage fresh weight and vine growth of greenhouse
container—grown Vitis hybrid 'Seyval' . . . . . . . . . . 54

13. The influence of three levels of nitrogen and three
levels of soil pH on foliar growth and appearance
and fruit number of greenhouse container-grown
Vitis hybrid 'Seyval' . . . . . . . . . . . . . . . . . . 56

14. The influence of three levels of soil pH on foliage
fresh weight and vine growth of greenhouse container-

grown Vitis hybrid 'Seyval' . . . . . . . . . . . . . . . 57

15. Rooting and fruiting percentages of twelve Vitis
cultivars grown in the greenhouse . . . . . . . . . . . . 61

vi

 

'INTRODUCTION

 

Hanging baskets of fruited grapevines are a potential addition
to the bedding plant market. Hanging baskets provide an attractive and
practical solution to people with limited gardening space. Since
strawberry baskets and cherry tomato baskets are already popular pro-
ducts at many garden and retail centers, it is feasible that more crops
could be adapted to hanging baskets in order to further broaden the
bedding plant market. These baskets are a possible novelty item, with
lush, green foliage and attractive clusters. Generally, a 10-inch
basket containing four cuttings will provide three to six fruit clus-

ters five to eight inches long.

LITERATURE REVIEW

 

Tendrils and inflorescences of grapevines both arise from the
same primordia (45). Whether a primordium develops into an inflores-
cence or not is dependent upon many factors; such as presence of cyto-
kinins, stage of root development, temperature and photoperiod.

The grape inflorescence arises from a compound bud. Each bud,
which is borne on last year's cane growth, contains three buds, but
usually only the primary and sometimes the secondary buds develop (75).
The shoot and leaves appear first, followed closely by the pink-tinted

flower bud in the case of 'Seyval.‘

Rooting

Extensive research has been conducted to increase, hasten and
improve rooting of grape cuttings. Various parameters have been inves-
tigated, including temperature, cutting size, storage and the effect of

growth regulators.

Temperature

 

Temperature is a very important factor in the rooting of hard-
wood grape cuttings. A variety of temperature combinations have been
investigated for rooting cuttings in the greenhouse; both air and soil
temperatures influence rooting.

Hosoi (29) found increased rooting percentage and root number
when cuttings were placed in soil heated to 25°C compared to either
higher (300 and 350C) or lower (150 and 200C) soil temperatures. This
experiment was conducted in an unheated greenhouse, so the air tempera-
ture was lower than the soil temperature; although, air temperature was
not specified.

Malizewski and colleagues (38) compared cuttings rooted under
mist with warm air temperature (21°C) and bottom heat to those rooted
using cool air temperature (10°C) and bottom heat. The latter method
was intended to retard budbreak which might result in delayed root
initiation. However, the warm air method produced rooted cuttings up to
two weeks earlier. Fujii and Nakano (24) reported that optimum rooting
(higher rooting percentages and greater fresh weight) occurred with
'Delaware' cuttings using 21°C and 25°C bottom heat. They added that

not only bottom heat, but also warm air temperature promoted budbreak.

They concluded that developing buds on the cuttings promoted rooting
and removing these buds markedly reduced the number and percentage of
roots.

Conversely, Mullins and Rajasekaran (41) describe a procedure
for "pre-rooting" grape cuttings to allow adventitious root formation
prior to budbreak. Cuttings were placed in heated perlite rooting med-
ium (260C) with cold (4°C) air temperature for three to six weeks. Buds
remain dormant at this temperature until the rooted cuttings are potted
up and moved to a 27°C (day temperature) greenhouse. "Pre—rooted" cut-
tings, combined with leaf removal, resulted in inflorescences at anthe—
sis in 40 to 50 percent of the cuttings. The advantage of "pre-rooting"
was attributed to the fact that leaf and shoot growth have an inhibi-
tory effect on fruit cluster formation at budbreak. Floral differentia-
tion, occurring at budbreak, requires cytokinins (54) which are synthe-
sized in the roots of established plants (68). However, since budbreak
precedes rooting, cytokinins become the limiting factor in floral dif-
ferentiation. Expanding leaves are stronger sinks for endogenous cyto-
kinins than new inflorescences (40); hence the atrophy and senescence of
the developing floral bud prior to good root formation. Removal of
these expanding leaves, therefore, increased the survival rate of newly-

developing inflorescences.

Time of Collection/Dormancy

 

Alley and Christensen (6,7) found that dormant 'Thompson Seed-
less' cuttings taken in February, March or April and placed immediately
in a rooting bed, rooted better than those refrigerated for more than

two months. They reported that rooting refrigerated cuttings requires

4

an additional one to two weeks and that fewer and smaller roots are pro-
duced. In fact, 'Thompson Seedless' cuttings stored upside down in
sand at 12 to 190C have larger roots than those stored under refrigera-
tion (0 to 30C) or right side up or horizontally in sand. Mullins and
Rajasekaran (41) stored cuttings for their fruited test-plants in sealed

plastic bags at 40C.

Cane Segment/Cutting Weight

 

Cane segment and cutting weight also determine how well rooting
occurs. Cuttings from the basal third of dormant canes root more rapid-
ly and higher percentage than either the middle or apical cuttings (65).
Perhaps basal cuttings root better because they are often thicker and
therefore contain more nutrient and carbohydrate reserves.

The number of roots per cutting increases with increasing ini-
tial cutting weight (29) regardless of temperature. When cuttings were
compared weighing three, five and seven grams, the five- and seven-gram
cuttings had the greatest number of roots. Also, heavier cuttings (sev-
en grams) resulted in greater shoot growth (measured as dry weight)

when compared to three— and five-gram cuttings.

Growth Regulators

 

The treatment of dormant, hardwood grape cuttings with growth
regulators varies considerably with cultivar. Many experiments have
been conducted using indole-3-butyric acid (IBA) to improve and/or has-
ten rooting. Hard-to-root cultivars such as 'Salt Creek' and 'Harmony'
(4) have long been shown to benefit from IBA treatment. Singh (50)

tested the effect of five concentrations of IBA on 'Perlette' (O, 500,

5

1000, 2000 and 4000 ppm). The 500 ppm dip gave over 10 percent more
rooted cuttings than the control (0 ppm) and increased the number of
roots.

This experiment was repeated (51) using 'Himrod' and 'Thompson
Seedless' cultivars; no significant difference was found between treat-
ments, although 500 ppm IBA did increase rooting by five percent. Ad-
ditionally, IBA reduced the number of days required for callus and root
formation of 'Dog Ridge,‘ 'Salt Creek' and 'Harmony'(8). In later ex—
periments, IBA (5000 ppm) improved rooting of hard-to-root cultivars
('Salt Creek' and 'Dog Ridge') when placed in a 29.50C callusing box (5).
The roots of 'Salt Creek' had smaller diameters, but the number of roots
increased. With easy-to-root cultivars ('Ganzin 1' and 'Zinfandel'),
IBA increased the number of roots as well as the size of ‘Ganzin l'
roots. Likewise, IBA (1500 and 2000 ppm) increased the number of roots
when applied as a quick dip to 'Cabernet Sauvignon' (41), but had no ef-
fect on 'Thompson Seedless,‘ which supports the results of Singh and
Singh (51).

Recently, 15 cultivars were tested by Ehrlinger and Howell (22)
to determine if IBA enhanced rooting. Rooting was graded on five levels
from unacceptable to excellent, based on the number of roots present
after six weeks in the mist bed. IBA (3000 ppm) was applied as a tal-
cum powder dip (using Hormodin 2). Their results showed enhanced root-
ing in six of the 15 cultivars; among these are 'Chelois' and 'Seyval.‘

Naphthaleneacetic acid (NAA) and abscisic acid (ABA) have also
been shown to improve rooting (24). ABA (200 and 500 ppm) and NAA (25
and 100 ppm) increased the number of roots on 'Delaware' hardwood cut-

tings.

6

Applications of N-6-benzyladenine (BA) also increased the per-
centage of cuttings to root, but did not increase the number of roots

per cutting.

Budbreak

Budbreak in dormant hardwood grape cuttings occurs up to 25 days
prior to root initiation (64). This presents a problem as the inflores-
cence usually dehydrates and senesces if roots have not already formed
prior to budbreak. Further, although budbreak is dependent upon date of
collection, rooting is not (65). For example, cuttings taken in Jan-
uary and February had earlier budbreak than those taken in October, No-
vember and December. They concluded that the later the canes were

taken from the vineyard, the more rapidly the buds broke.

Growth Regplators

 

One way to minimize inflorescence dehydration and abscission is
to inhibit budbreak until after adventitious root growth. This can be
accomplished with cold air temperatures or growth regulators. Several
growth regulators have been tested and their effect on budbreak assessed.
Two chemicals reportedly hasten budbreak, succinamic acid dimethyl
hydrazide (SADH) at 2000 ppm and BA at 1000 ppm (70,74). However,
others found that BA (500 ppm) did not affect budbreak (36). The dis-
crepancies in these findings on the effects of BA on budbreak may be
due to their methods of application as well as to the differing con-
centrations. The former investigators (70,74) applied BA to unrooted
hardwood cuttings and the latter applied the chemical to two-year old

potted vines.

7

Many other growth regulators, however, delay budbreak of hard-
wood grape cuttings. One of these is the auxin benzothiazole-Z—oxyace-
tic acid (BOA) which was found to delay budbreak at concentrations rang-
ing from 200 to 2000 ppm (70,74). NAA (68) and potassium gibberellate
(KGA3) (200 or 2000 ppm) (68,70) also delay budbreak, as does Ethephon
(2000 ppm) and ABA (1000 ppm) (70). Further, 2—chloroethyltrimethyl-
ammonium chloride (CCC) at 200 and 2000 ppm (70,74) delays budbreak in
hardwood grape cuttings.

Gibberellic acid (GAB) at 50 ppm not only delays budbreak, but
also decreases the number of buds which do break (9). However, GA3 does
not affect budbreak on grapevines that have received 21 days of chilling;
this indicates that chilling may counteract the retardation effect of
GA (36). However, the chilled plants in this case were two-year old

3

potted vines rather than unrooted cuttings.

Temperature

 

Temperature also affects budbreak as shown by Mullins and Raj-
asekaran (41) who reported that.bud opening and initial inflorescence
growth occurred more rapidly at higher temperatures (330C day tempera-
ture/28°C night). However, at this high temperature, continued bud
development was abnormal; the bud shriveled and aborted after anthesis.
Bud growth and development occurred normally at the temperature regimes
of 24°C day temperature/19°C night, 27°/22°c and 30°/25°c with little
difference between them. As expected, at lower temperatures, more days

were required to budbreak.

8

Flowering

Anlagen are undifferentiated primordia formed at terminal or
axillary apices during one season and differentiated into either ten-
drils or inflorescences prior to budburst the following season (55).
Inflorescences and tendrils have been shown to be homologous (45,52).
Anlagen that branch repeatedly develop into inflorescence primordia
whereas tendrils are produced from anlagen which branch only once or
twice (52). Grapevines produce numerous anlagen but few develop into
inflorescences; most grow into tendrils (56).

Additional experiments show that BA affects other species as
well. Treatments with BA promote inflorescence initiation and develop-

ment in Bougainvillea 'San Diego Red' (23,46).

 

One aspect that affects branching is the presence or absence of
kinins. The application of BA or 6-(benzylamino)-9-(2-tetrahydropyranyl)
—9H-purine (BTP) to isolated grape tendils i2_vi£52_resulted in inflor-
escence development by these tendrils (53). Later, cytokinins were ap-
plied to grapevines ip_xivg_to convert tendrils to inflorescences (54).
BTP was applied to shoot apices or to entire plants at various concen-
trations and lengths of time. BTP treatments to whole plants on alter-
nate days for three weeks failed to convert tendrils into inflorescences.
These inflorescences continued to develop into mature fruit. Srinivasan
and Mullins (54) concluded that a continuous supply of cytokinins at the
apex is necessary for flowering. Additionally, responsiveness to this
technique depends upon the cultivar (56). They found that tendrils

from male vines (Vitis rupestris) were more easily transformed than

 

those of female or hermaphrodite vines, and that y. vinifera,

9

y, rupestris and their hybrids were more responsive than others.
Srinivasan and Mullins (55) further explored the effects of cy-

tokinins, GA and CCC on inflorescence formation of greenhouse-grown

3
grapevines (y, vinifera). They found that all three compounds affect
anlagen formation and tendril growth at any temperature and that GA3 in—

hibited inflorescence production. They stated that GA3 is involved in
anlagen formation and elongation into tendrils. Exogenous application
of CCC resulted in inhibition of anlagen formation and the growth of

tendrils, yet promoted inflorescence formation from pre-formed anlagen
or tendrils. CCC is known to be an inhibitor of 6A3 synthesis and may
also act to enhance cytokinin production. Further, as expected, cyto-

kinins applied to plants which had been pre-treated with CCC caused ten-

drils to convert into inflorescences.

Fruit Set, Size and Development

 

Buttrose (18) and Pratt (45) provide synopses of current know—
ledge regarding the anatomical and physiological aspects of bud develop-
ment. The grape inflorescence is initiated in the summer preceding its
flowering. The inflorescence occurs opposite a leaf bud in the same
position as tendrils. Conditions dictate whether a tendril or flower
primordium is formed from the meristematic tissue. For any cultivar,
the number of fruiting primordia per bud can vary from season to season.
This variation is due to climatic factors (18), cultural practices and
disease.

The particulars of fruit set and development have not been

studied extensively under greenhouse situations, although much research

10

has been conducted on field-grown vines. Many environmental and hormon—
al factors influence fruitfulness or yield. Fruit set and development
are affected by pruning, nutrition, temperature, light, and the applica-

tion of growth regulators.

Pruning

Pruning and its effect on yield have been researched primarily
in the field (21, 32), so the information does not truly apply to green-
house-produced plants.

Peterson and Smart (44) reported the effects of pruning 'Shiraz'
grapevines at several stages of plant development. They reduced the
vines to six and two leaves above the grape cluster at five stages of
development. They found that the six-leaf pruning did not reduce yield
(actually increased yield by the third year) while the two-leaf pruning
was excessively harsh. Pruning at the time of inflorescence elongation
had little effect on yield, although pruning done after that time was
detrimental. This response was explained by the source-sink relationship
and the demand for photosynthetic products (26).

Similarly, Buttrose (14) studied the effect of leaf removal on
entire 'Gordo' grapevines. He reduced leaf area by removing the leaves
below and opposite the fruit cluster and pruning off the apical part of
the shoot until only one, three or six leaves remained. He maintained
a constant leaf area, allowing no new growth. Berries on the pruned
plants took longer to mature and had a lower fresh weight than berries
on unpruned plants.

Kliewer and Antcliff (33) concluded that eight to ten square

centimeters of leaf area is necessary to ripen and mature one gram of

 

ll

fruit without decreasing sugar concentration. In their experiment,
berry set occurred before defoliation. Pruning significantly reduced
yields, with earlier and more severe defoliation causing greater reduc-
tion in berry weight and sugar content.

To produce fruiting grapevines in the greenhouse, Mullins (30)
developed a technique whereby fruit set was improved through the removal
of leaves below and adjacent to developing inflorescences. Leaves pro-
duced distal to the inflorescence were allowed to develop. He later im-
proved on this method (41) by removing all leaves near the inflorescence
at bud burst, excising the shoot tip, disbudding and pruning developing

lateral shoots.

Growth Regulators

 

Gibberellins, cytokinins and auxins are involved with fruit set
and growth (72). Many experiments on various fruits, including grapes,
have shown that exogenous applications of auxins, cytokinins and gib-
berellins are quite effective in influencing fruit set, development and
size (69,72). Research on various growth regulators began in the late
1940's. At that time, two auxins, 4-chlorophenoxyacetic acid (4-CPA)
and BOA showed potential; and 4-CPA was used commercially (63). Apply-
ing 4-CPA to grape foliage increases cluster size, but results in very
tiqht clusters which rot easily (66). BOA acts to delay fruit matura—
tion (63) and has not been used commercially.

GA3 is currently used on most 'Thompson Seedless' crops grown as
dessert grapes to thin clusters, increase berry size, prevent berry

shrivel and loosen clusters (63). Weaver and McCune (66) tested the ef-

fect of GA3 sprayed onto grape foliage with the fruit clusters covered

12

which resulted in increased fruit size. Later, they dipped clusters
or sprayed entire vines and clusters with GAl' GA3 or KGA3 (5 to 500
pm) (67). All three chemicals resulted in increased berry size; and
the clusters formed were looser and more elongated. No significant
differences were observed between the effects of GAl, GA3 and KGA3.
This study also found that gibberellins applied at prebloom or full
bloom resulted in the development of small, seedless berries.

Researchers have reported that GA (5 and 10 ppm) applied during

3
bloom increased fresh berry weights, but had no effect on the number of
berries per cluster (31). Applying GA3 at 100 ppm 11 days after full
bloom to 'Concord' vines increased fruit set and the fresh weight of the
clusters (13).

In summary, prebloom sprays of GA loosen clusters by reducing

3
fruit set and elongating the central rachis (62). While GA applied at

3
bloom produces loose clusters by reducing the number of berries set, it
also causes increased berry size (19) and results in elongated berries
(62).

Currently, Weaver (63) notes that the recommended vineyard pro-
cedure involves two GA3 applications, one at full bloom (5 to 20 ppm) to
thin the clusters, and the second (20 to 40 ppm) at fruit set to in-
crease size of 'Thompson Seedless' (19). A third spray approximately
two weeks after fruit set will further increase berry size (62).

Cytokinins have also been shown to increase berry size (71) and
induce fruit set in y, vinifera (72). Experiments with BA and BTP ap-
plied either as a spray or dip to various y,'vinifera cultivars increas-

ed the number of fruit per cluster and, in some cases, fruit size (73).

Berries were progressively larger with increased cytokinin concentration

l3

(0 to 1000 ppm). For example, BTP applied to 'Black Corinth' clusters
increased berry size three- to four-fold. Since BTP is more soluble
and mobile than BA, it is more effective in influencing berry size and
set. Both BA and BTP applied at shatter (1000 ppm) resulted in an in-
crease in berry size and number of 'Thompson Seedless' grapes. A mix-
ture of BTP and GA3 applied at full bloom produced the largest berries
('Black Corinth' and 'Thompson Seedless') and greatly increased the per-
centage of 'Thompson Seedless' fruit set (73).

Additionally, cytokinins affect fruit retention. Clusters of
several cultivars were dipped in 1000 ppm BTP at full bloom. At shatter,
the BTP-treated clusters dropped far fewer ovaries or berries than con-
trol (73). Rao (47) found that 500 ppm of BA significantly reduced
post-harvest berry drop. Also, BA has reduced pre-harvest berry ab-
scission (38).

In summary, exogenous applications of gibberellins usually act
to induce fewer, but larger, elongated berries while cytokinins and
auxins produce many small, round berries. Therefore, gibberellins like-
ly affect fruit growth and development while auxins and kinins primarily
affect fruit set (73).

Two growth retardants, SADH and CCC, influence set and yield of
grape clusters. SADH increased 'Himrod' fruit set by 100% when sprayed
at 2000 ppm just prior to anthesis (cap fall) (58). Likewise, SADH
(500 to 1000 ppm) applied either at or before bloom to 'Concord' in-
creased fruit set and yield (59). Also, 2500 and 5000 ppm SADH applied
one to two weeks before anthesis increased the number of berries set

per cluster in greenhouse-grown y, labruscana vines (42). Coombe (21)

 

reported similar results with SADH on field-grown 23‘vinifera.

14

Another growth retardant, CCC, increases the number of flowers
per inflorescence whether applied repeatedly as a spray or soil drench
(43). Applications of CCC resulted in increased berry set, although
the berries were smaller than normal (21). Fruit set and cluster
weight increased in 'Himrod' using 750 to 1250 ppm CCC (12). CCC ap-
plied to field-grown vines 20 days before full bloom (1000 to 3000 ppm)
and again 10 days later (1000 to 2000 ppm) gave the best results by re—
ducing flower bud drop and increasing the total number of bunches per

vine (ll).

Photoperiod and Light

 

Light intensity and duration have various important effects on
bud initiation and flower and fruit development. Bud initiation, in
particular, has been the subject of extensive research and numerous
publications. In 1972, Jackson and Sweet (30) wrote a summary on the
general subject of flower bud initiation in temperate woody plants.
Also, Buttrose (18) described the climatic factors that affect fruitful-
ness in grapevines. Bud initiation can be affected by vigor, nutrition,
carbohydrate level, gravity, growth regulators, water stress, tempera-
ture, photoperiod and total light energy (18).

Fruit crops vary greatly in their response to daylength. Under
eight hour days, blueberries form flower buds, but no vegetative growth
occurs. Conversely, under 16 hours of light, vegetative growth takes
place, but no flower buds are formed (27). On the other hand, apple
flower bud initiation is stimulated by long days (25). In working with
the effect of daylength on grapevines, vines of the cultivar 'Muscat

Gordo Blanco' responded to daylength; vines grown under 16-hour days

15
were four times as fruitful as those grown under eight- or lZ-hour
days (15). A one-hour light interruption in a long night did not af-
fect fruitfulness. However, an acceptable substitute for 16-hour days
was 12 hours light/4 hours dark/4 hours light/4 hours dark. In 1970,
Buttrose expanded his work to include four additional cultivars: 'Rhine
Riesling,‘ 'Shiraz,‘ 'Ohanez' and 'Thompson Seedless.‘ Each cultivar
responded differently to the various conditions, although 'Thompson
Seedless' and 'Ohanez' were not fruitful under any of the experimental
conditions. Plants were treated with either eight hours at 3,600 ft—c
or 16 hours at 1,800 ft-c. 'Gordo' was one-third as fruitful and
'Rhine Riesling' was one-half as fruitful under eight hours of light
compared to 16 hours. 'Shiraz' was not affected by this change and
was found to be greatly dependent on light intensity for fruitfulness.
Buttrose (l7) concluded that grapevines likely do not respond strictly
to daylength, but to the increased quantity of light available under
long days.

Mullins and Rajasekaran (41) tested the effect of light on
'Cabernet Sauvignon' grape cuttings. There were five treatments: 1)
natural greenhouse illumination (spring and summer), 2) greenhouse,
with shade applied to inflorescences and leaves, 3) growth chamber
with continuous illumination, 4) growth chamber with eight hour days
(short days) and 5)‘ growth chamber with 16 hour days (long days). The
inflorescences of plants which were shaded or kept under continuous il-
lumination abscised. At least 70 percent of the inflorescences surviv—
ed to anthesis in all other treatments. However, fruit production (num-
ber of berries per cluster) was greater under a 16-hour photoperiod with

high light intensity.

16

Temperature

 

Temperature plays an important role in inflorescence and berry
development; although, the effects of temperature are closely inter—
related with light intensity. In an experiment in 1958, Tukey (57)
studied the effects of temperature on berry development. His tempera-
ture treatments began at bloom and continued for 10 or 13 days. The
berries grown at 260C and 280C exhibited fastest daily growth and maxi-
mum berry size. However, temperatures as high as 320C reduced berry
growth, perhaps as a result of another limiting factor such as water or
carbon dioxide. Further, he found that an optimum temperature regime
involved a 28°C night temperature for the first eight days and there-
after a night temperature of 220C. Maximum growth was achieved when the
average day temperature was 23.50C. In general, increased night temper—
atures for 10 to 13 days after flowering increased the rate of berry
enlargement.

Studies by Alexander (1) were designed to determine if high
temperatures were responsible for poor fruit set. He found that high
night temperatures (190 to 250C) favored rapid shoot growth; but had
little or no effect on fruit set. He suggested that a loss of fruit set
under high temperatures was due primarily to moisture stress. Woodham
and Alexander (2) kept the roots of 'Thompson Seedless' at 11°, 20°, or
30°C with a common air temperature. Increased root temperatures improv-
ed the growth of roots, inflorescences and shoots.

Grapevines grown in growth chambers remained barren after 13
weeks of temperatures under 20°C, but were fruitful at temperatures be—
tween 250 and 35°C (l6, l7). Buttrose concluded that temperature af-

fected rate of bud development as well as the actual number of bunch

l7

primordia differentiated. However, there was a light/temperature inter-
action. Below 1800 ft-c, temperature exhibited little effect on pri-
mordia weight; however, at higher intensities the effect was signifi-
cant. The optimum temperature for grape leaf photosynthesis has been
0 0
shown to be between 25 and 30 C (35, 37).
"Pre-rooted" cuttings of 'Cabernet Sauvignon' were grown under
. o o . o o o 0

four temperature regimes: 25 C day/19 C night, 27 /22 C, 30 /25 C, and

o o . . o o .
33 /28 C w1th natural greenhouse llght (41). At 33 /28 C, bud opening
was quicker than at lower temperatures, but the inflorescences grew ab-
normally and soon dehydrated and died. At the other three temperature
regimes, no real differences in inflorescence growth occurred. However,
plants grown at 270/220C produced the greatest number of berries per
cluster.

Using scanning electron microscopy, Srinivasan and Mullins (52)
showed that anlagen (undifferentiated primordia) on vines grown at high
temperatures (330C day/28°C night) formed inflorescence primordia.

. o o o o .
Vines grown at lower temperatures (21 /16 C and 18 /13 C) contained an—
lagen that grew into tendril, rather than inflorescence, primordia.
This leads to the conclusion that temperatures between 250 and 300C re-
sult in superior fruit set. Temperatures higher than 300C are detrimen—

tal and those under 20°C result in vegetative growth.

Greenhouse Container Viticulture

 

Grapevines are generally propagated from dormant, hardwood cut-
tings which, even under favorable growing conditions, may not produce

fruit the first year. In 1963, Alexander and Woodham (3) developed a

l8

procedure to produce, for experimental purposes, small plants which bear
fruit in their first year. They succeeded in producing mature fruit on
60 percent of the 'Thompson Seedless' vines propagated by air layering.
However, air layering proved too time consuming and costly when large
numbers of plants were desired.

By removing all leaves below the inflorescence, Mullins (39)
produced small experimental plants with fruit clusters from one-node
cuttings from one-year old vines in 12 weeks. Having determined that
the inflorescence frequently abscised if leaf removal did not occur, he
theorized that abscission may be due to the inability of the inflores-
cence to compete with adjacent leaves for nutrients. Leaf removal al-
lowed the inflorescence to develop normally, although the fruit clusters
were considerably smaller than vineyard-produced clusters.

Mullins published a revised method in 1981 (41) in which he
reported the effects of "pre-rooting," temperature and light on inflor-
escence growth and fruit set of many yiti§_cultivars. Cuttings were
rooted in a heated container (260C) in a 4°C room (buds remained dormanU.
In four weeks, the cuttings were potted and moved to a greenhouse (270C
day and 220C night temperature) with l6—hour photoperiod. Leaves below
and adjacent to the inflorescence were removed at budburst and the shoot
tip was excised. Consequently, ripe fruit (about half normal size) was
produced in 16 to 18 weeks on 30 to 50 percent of the vines.

Alexander (2) rooted softwood cuttings in a heated mist bench.
These cuttings were grown on in the greenhouse, and 25 percent produced
fruit which ripened two months earlier than field vines. In 1979,
RObitaille and Janick (48) reported rooting softwood cuttings of 'Seyval'

after fruit set had occurred. They describe a method for producing

l9

grapevines with small clusters in eight weeks by rooting softwood cut-
tings with developing fruit in a mist bench.

Malizewski EEHEi° (38) reported a preliminary study on producing
fruited grapevines in hanging baskets. They evaluated the performance
of three Vigig cultivars: 'Seyval,' 'Concord,’ and 'Vignoles' and com-
pared two rooting methods: 1) 21°C air temperature with bottom heat in
a mist bench, and 2) 10°C air temperature with bottom heat in a growth
chamber. The latter method was intended to reduce or prevent budbreak
and allow root initiation. IBA (Rootone) was applied to both treatments.
'Seyval' required three to seven weeks at 100C from stick to transplant
and three to five weeks at 210C. 'Vignoles' took five to ten weeks at
10°C, but only four to seven weeks at 210C. Overall, cuttings with warm
air in the mist bench rooted faster, leafed out more rapidly and were
considered "further along" when planted in the hanging baskets.

Of the three cultivars evaluated, 'Seyval' showed the best poten-
tial. 'Vignoles' failed to flower; and while 'Concord' produced a few
fruit clusters, its leaves and growth habit were too large for a lO-inch
basket. The time required for 'Seyval' from stick to pea-sized fruit
was 13 to 14 weeks.

Since berries on the 'Seyval' clusters oftened abscised prema-
turely, BA was applied to the young clusters to prevent abscission. Af-
ter pruning, secondary growth developed, containing new flower clusters.

This experiment raised many questions. Additional clusters need
to be investigated, particularly table grape and seedless cultivars with
compact growth, early fruiting and attractive foliage. Improving root-

ing uniformity and decreasing rooting time are also important.

20

'OBJECTIVES

 

The objective of this study is to develop the techniques neces-
sary to produce grape baskets for the spring bedding plant market. Ac-
cording to preliminary work at Michigan State University (38), the Vitis
hybrid 'Seyval' was the most promising cultivar tested for hanging bas—
ket culture. Thus, experiments were conducted to determine optimum prac-
tical greenhouse production techniques using 'Seyval.‘ Elements of pro-
duction tested include: determining proper rooting procedures, enhancing
fruit set and development, determining nutritional and environmental re—
quirements and pruning needs, as well as cultivar trials and production
time scheduling.

Specific objectives of this study are as follows:

1) To determine optimal rooting procedures and temperatures for
hardwood cuttings of 'Seyval' and to reduce the number of days required
for rooting.

2) To determine if inhibiting budbreak with various growth reg-
ulators will improve fruit set of 'Seyval.‘

3) To enhance cluster appearance by improving fruit set, size
and retention of 'Seyval’ by using various growth regulators.

4) To determine the correct fertilization and soil pH levels
necessary to produce healthy, fruit-bearing 'Seyval' grapevines.

5) To determine which cultivars can be easily adapted to this
technique.

6) To develop a step-by-step production schedule to enable
growers to produce fruited grapevines in hanging baskets for spring

marketing.

SECTION ONE:

 

THE EFFECT OF ENVIRONMENTAL CONDITIONS
AND GROWTH REGULATORS ON ROOTING
TIME AND BUDBREAK OF

VITIS HYBRID 'SEYVAL'

THE EFFECT OF ENVIRONMENTAL CONDITIONS AND GROWTH

REGULATORS ON ROOTING TIME AND BUDBREAK OF VITIS HYBRID 'SEYVAL'

Introduction

 

Production time can be minimized by reducing the time necessary
to root cuttings. Extensive research has been reported on all aspects
of rooting. Of interest in this trio of experiments are the effects of
temperature, growth regulators and cutting size on ease of rooting.

Warm temperatures hasten rooting (7), but temperatures above 35°C impair
rooting (29). Heavier cuttings produce an increased number of roots and
greater shoot growth (29).

The effect of growth regulators on root initiation varies widely
with cultivar. Dozens of experiments conducted using indolebutyric acid
(IBA) show excellent results with some cultivars and poor results with
others. Ehrlinger and Howell (22) tested the effect of IBA on rooting
of 15 cultivars. 'Seyval' was one of the six cultivars listed as bene-
fitting from IBA treatments. Additionally, naphaleneacetic acid (NAA)
improves rooting (24).

It has been reported that budbreak occurs up to 25 days prior to
root initiation (64) which encourages inflorescence dehydration and sen-
escence. Inflorescence survival might be enhanced if budbreak was delay-

ed until after root growth occurs.

21

22
Material and Methods

 

Three rooting experiments were conducted to determine the opti-
mum rooting procedures for 'Seyval' hardwood cuttings. Experiment I
was a factorial experiment, comparing various humidity conditions and
various growth regulators. Experiment II compared two different temper—
atures for rooting. Experiment III compared the effect of various
growth regulators on budbreak, and consequently rooting and fruit set.

In all three experiments, dormant hardwood cuttings (eight nodes)
of one-year old canes were collected from mature 'Seyval' vines at Tabor
Hill vineyards in southwest Michigan. Cuttings were taken on December
15, 1980 and placed in plastic bags containing moist paper towels under
1.50 to 20C refrigeration. The wood was prepared as two-node cuttings,
cut just below the basal node and two to three centimeters above the
upper node, in late January for Experiment I and early March for Experi-
ments II and III. Cuttings were chosen from wood free of visible di—

sease and injury.

Experiment I

 

These two-node cuttings were divided into three weight groups:
light (2.0-3.4 grams), medium (3.5-5.4 grams) and heavy (5.5-15.8 grams).
Immediately before planting the cuttings in sand, they were dipped into
one of the treatment solutions to a depth of three cm. for five seconds.
A total of 288 cuttings were used: one-third placed in each of the fol-
lowing conditions: under intermittent mist, covered with clear polyethy-
lene tents or in the greenhouse with no other environmental treatment.

Within each of these treatments, one-quarter (72) were dipped in 500 ppm

23

indolebutyric acid (IBA), one-quarter in 250 ppm naphthalene-acetic acid
(NAA), one-quarter in 500 ppm iron chelate (Sequestrene 330 Fe, Ciba
Geigy, 10% active ingredient) and the remainder in deionized water.
Cuttings were placed 6.5 centimeters deep in flats of moist sterilized
sand and placed on heating mats (25°C) in the greenhouse under their
respective environmental treatments. All flats were placed in the same
greenhouse at an air temperature of 220C. Soil thermometers were used
to monitor soil temperature in each flat. Misting occurred for six
seconds every 15 minutes during daylight hours using deflection nozzles.
All flats were watered as needed by drenching the soil with deionized
water.

Each cutting was checked daily for root formation and then care—
fully replaced. Cuttings were recorded as "rooted" when one millimeter
of root was visible. Days to various bud stages were also recorded.
After 48 days, data on leaf and root number and surface area were col-
lected. Roots were rinsed in a pail of tepid water before being run
through a leaf area meter. Leaves were removed from the vine and measur-

ed; no stems or flower clusters were included in leaf surface area.

Experiment II

 

Cuttings were prepared as in Experiment I, although only those
weighing between 5.0 and 10.0 grams were chosen. A11 cuttings were dip-
ped in a powder formulation of 3000 ppm indole-3-butyric acid (Hormodin
2) and placed five cm. deep in moist vermiculite—Sphagnum peat-perlite
mix (VSP). Half of the cuttings (30) were placed in an 21 : 2.50C air
temperature greenhouse with 26.5 : 2.50C bottom heat, while the remaind-

+
er were placed in a 30 - 3°C air temperature with 32 : 2.50C bottom heat.

24

All cuttings were misted (six seconds every 15 minutes).

All cuttings were checked daily for root initiation. After 40
days, roots on all were counted, the longest root measured, and all
rooted cuttings were transplanted to six—inch clay pots containing the
same vermiculite—peat-perlite medium and placed in a 24°C greenhouse.
They were fertilized with 200 ppm liquid 20-20—20 N-PZOS-KZO (Peter's
General Purpose soluble fertilizer; with analysis of 5.61% nitrate nitro-
gen, 3.96% ammonium nitrogen and 10.43% urea, 20% phosphoric acid, 20%

soluble potash) at every other watering and checked daily until the in-

florescence reached post-bloom stage or abscised.

Experiment III

 

Cuttings were prepared as in Experiment I and only those weigh-
ing between 4.5 and 10.0 grams were used. Growth regulators were appli-
ed by spraying the entire cutting just prior to placing it in the flat.
Treatments involved treating 15 cuttings (total of 105) with each of the
following chemicals: 2500 ppm N-dimethylamino—succinamic acid (SADH),
150 ppm 2-chloroethyltrimethylammonium chloride (CCC), 100 ppm6&-cyclo-
propyl-d--(p-methyoxyphenyl)—5-pyrimidinemethanol (A-Rest(R)), 100 ppm
gibberellic acid (GA3), 250 ppm naphthaleneacetic acid (NAA), 100 ppm
gibberellins A4/A7 (GA4’7) and deionized water. Flats were filled with
moist media containing a 1:1 ratio of peat and perlite; cuttings were
inserted to a depth of approximately six centimeters. All flats were
placed in a 30 : 3°C greenhouse with bottom heat (32 : 2.50C), without
mist. Data were collected each day by pulling up each cutting until

roots had formed. Data were taken on days to root, days to callus forma-

tion and days to various bud stages.

25

Results

Experiment I

 

+
Number of Days to Root: Large cuttings (5.5 grams) required

 

significantly more days to root than the medium or small cuttings, re—
gardless of environmental or chemical treatment, with no difference in
days to root between small and medium weight cuttings (Table l).

Cuttings placed under polyethylene tents also required signifi-
cantly more days to root than those under mist or greenhouse conditions
(Table 2).

Of the chemical treatments, control and NAA-treated cuttings
rooted significantly earlier than Fe- or IBA-treated ones. IBA-treated
cuttings took almost nine days longer than H20. There was no signifi-
cant difference in days to root between NAA and control or between Fe—
and IBA-treated cuttings (Table 3).

The interaction between environment and chemical was significant
at the 5% level using Duncan's Multiple Range test. NAA-treated cuttings
placed in the greenhouse (NAA/greenhouse) were earliest to root, though
not significantly earlier than HZO/greenhouse treatment. However, cut-
tings treated with Fe/greenhouse required over eight days longer than
NAA/greenhouse cuttings. The IBA/polyethylene treatment required the
greatest number of days to root, rooting 18 days after the NAA/green-

house treatment. All three Fe treatments were among the slowest to

root (Table 4).

Number of Days to 50 Percent Rooted: There was no significant

 

difference in days to 50 percent rooted based on cutting size or envir-

onment. However, the small cuttings did require an extra seven days

26

 

 

Table 1. Influence of cutting weight on rooting of Vitis hybrid
'Seyval.’z

x Percenty Totaly

Cutting Number ofy Rooted Percent
Size Days to Root in 29 days Rooted in 45 days

Small 24.2 a 93.9 c 95.9 b
Medium 24.7 a 77.3 b 91.8 b
Large 27.6 b 55.5 a 80.3 a

 

zCuttings planted in the greenhouse, 22°C air temperature with 25°C
bottom heat and misted six seconds every 15 minutes.

Y

Data is mean of 288 cuttings.

xSmall cuttings weighed 2.0 to 3.45 9; medium 3.5 to 5.4 g; and large,
5.5 to 15.8 9.

Mean separation in columns by Duncan's Multiple Range test at the 5%

level.

27

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28

 

 

Table 3. Influence of NAA, IBA and Fe on rooting and budbreak of dormant
hardwood cuttings of Vitis hybrid 'Seyval.‘
Chemicalz Days toy Number of y Percenty'X Numbery'x Days toy
Treatment 50% Root Days to Root _Rooted of Roots Budbreak
NAA 21.9 a 21.2 a 93.1 b 8.3 a 9.2
IBA 29.1 b 31.7 b 75.1 a 8.8 ab 9.9
Fe 27.2 b 26.9 ab 95.9 b 7.8 a 10.0
H20 23.8 a 22.8 a 93.1 b 10.2 b 10.0

 

zNaphthaleneacetic acid, indolebutyric acid, iron chelate applied as five

second dip in solution.

YData is mean of 72 plants from three environments: greenhouse + mist,
greenhouse, and greenhouse + polyethylene tents, all at 22°C air temp-
erature (25°C bottom heat).

xData was taken after 45 days.

Mean separation in columns by Duncan's multiple range test at the 5%

level.

29

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30

compared to large cuttings. Fifty percent of all cuttings treated with
NAA and H20 rooted significantly earlier than those treated with IBA
(Tables 1,2,3).

The IBA/polyethylene treated cuttings required significantly
more days to reach the 50 percent rooted stage than all other treatments.
NAA/greenhouse reached 50 percent in 18.7 days, but IBA/polyethylene

needed 47.3 days. There was no significant difference between the re-

maining treatments (Table 4).

Percent Rooted by Day 45: The experiment terminated after 45

 

days when data were taken on total percent rooted. There was a signifi-
cant difference in rooting percent based on cutting weight. Almost 95
percent of small cuttings rooted compared to 92 percent of medium and 80
percent of large. There was no significant difference between medium
and small cuttings (Table 1).

Only 80 percent of cuttings placed under polyethylene rooted,
compared to 90 percent of greenhouse and 98 percent of misted cuttings.
There was no significant difference between greenhouse and misted cut-
tings (Table 2).

Likewise, chemical treatments provided significant differences
at the 5% level using Duncan's Multiple Range test. A significantly
smaller percentage of IBA-treated cuttings rooted than any other treat-
ments; however, there was no significant difference between remaining
treatments (Table 3).

The interaction between environment and chemical treatments
was also highly significant. The IBA/polyethylene treatment gave the

lowest percentage (42 percent), whereas IBA/greenhouse and IBA/mist each

31

resulted in almost 92 percent rooted. Four treatments showed 100 per—

cent rooting: HZO/mist, NAA/mist, Fe/mist and Fe/polyethylene (Table 4).

Number of Roots: Chemical treatments affected the number of

 

roots present after 45 days. The H20 (control) treatment had a signifi-
cantly greater number of roots than Fe and NAA.

Cuttings under polyethylene produced less than half as many
roots as greenhouse cuttings regardless of chemical treatment. Poly-
ethylene cuttings bore significantly fewer roots than mist and green-
house cuttings. Additionally, greenhouse-treated cuttings contained
significantly more roots than either mist or polyethylene-treated cut-
tings (Table 2).

The environment and chemical interaction was highly signifi-
cant. IBA/greenhouse cuttings resulted in almost four times as many
roots as IBA/polyethylene or NAA/polyethylene. IBA/polyethylene and
NAA/polyethylene treatments had significantly fewer roots than all treat-
ment combinations except Fe/polyethylene and IBA/mist. NAA/greenhouse
cuttings had more roots than all treatments except IBA/greenhouse, H20/

mist and H20/greenhouse. IBA/greenhouse-treated cuttings produced sig-

nificantly more roots than any other treatment (Table 4).

Root Surface Area: Only environment analysis resulted in any

 

significant difference. The polyethylene and mist environment treat-
ments had significantly less surface area than the greenhouse cuttings

(Table 2).

Days to Budbreak: There was no difference in days to budbreak

 

based on chemical treatment and no significant interaction between

 

32
environment and chemical treatment. However, buds under polyethylene

took significantly longer to break than those under other treatments.

Percent Flower and Days to Flower: There was no significant

 

difference in the percentage of cuttings which had floral buds, ranging
from 71 to 88 percent, regardless of cutting size, chemical treatment
or environment. Likewise, there was no difference in days to flower

which ranged from 22.9 to 31.1 (Table 2, 3, 4).

EXperiment II (Table 5)

 

The number of days required to 50 and 90 percent rooted was
highly significant. Ninety percent rooted in less than 21 days at the
higher temperature. At the lower temperature, 90 percent rooting was
not achieved until 30 days. Less than 30 percent rooted by day 19 at
the lower temperature. Almost 97 percent rooted in 40 days under both
temperatures. Roots of the high temperature treatment were almost
twice as long and numerous as those formed under lower temperatures.
Budbreak occurred significantly earlier under high temperatures.

Fifty-two percent of the floral buds were retained at least
to post-bloom stage under low temperatures; 58 percent were retained at
high temperature, but the difference is not significant. Seventy-eight
percent of all cuttings stuck broke with a primary floral bud; 43 per-
cent of these developed to the post-bloom stage (fertilized ovaries

begin to swell).

Experiment III (Table 6)

 

None of the chemicals tested showed a significant effect on

days to budbreak; although, budbreak occurred three days earlier than

33

Table 5. Influence of temperatures on rooting, bud push and inflores-
cence retention of Vitis hybrid 'Seyval' hardwood cuttings
in the greenhouse.

 

Air/Soil Temperature

 

 

21°/27°cz 29°/32°cz
Days to 59% rooting 25.7 17.7**
Days to 90% rooting 30.0 21.0**
Total percent rooted (day 40) 96.7 96.7
Length of longest root (cm) 11.2 21.5**
Number of roots (day 40) 9.2 20.1**
Days to budbreak 19.9 16.6*
Percent fruitfuly 52.0 58.0

 

z , .
Figures are the means of 30 cuttings.

yPercent of all flowerheads which develop to post—bloom stage (when

fertilized ovary begins to swell).

*,**Significant at the 5 and 1% level, respectively.

34

Table 6. Influence of various growth regulators on budbreak and rooting
of hardwood cuttings of Vitis hybrid 'Seyval.‘z

 

 

w Days toy Percent Rootedy'x Days toy
Treatment Root by Day 14 Budbreak
SADH 14.1 53.0 17.9
CCC 12.9 73.3 17.5
A—Rest 13.1 66.7 15.7
GA3 16.2 40.0 18.3

7.3 .7 .
GA4'7 l 06 17 8
NAA 13.3 53.3 16.1
H20 15.5 33.3 18.9
18d.05 2.4 -- —-
18d.01 3.4 -- —-

 

z . . . . . + .
Cuttings planted in peatslite mix in 30—3OC air temperature greenhouse
with bottom heat (32*2.5 C) without mist.

yFigures are the means of 15 observations.
X100% rooting occurred by day 36 in all treatments.

wTreatments were applied as a spray to runoff just prior to sticking.

control on A-Rest-treated cuttings. In fact, the control treatment re-
quired the greatest number of days to budbreak, but not significantly
longer.

All cuttings rooted in an average of 18 days, with no signifi-
cant chemical effect on days to root. CCC, A-Rest, SADH and NAA-treated

cuttings rooted in fewer days than those treated with H 0, but the dif-

2

ference was not significant.

Discussion

 

Experiment I

 

Cutting weight affected number of days to root, total percent
rooted and percent rooted in 29 days. Smaller cuttings (2.0 to 3.45 g)
rooted earlier and a greater total percent rooted. Initial cutting
weight did not influence the number of roots present, root surface area,
days to budbreak, percent flower or days to flower. This information is
contradictory to that reported earlier (29, 65). Weaver §t_al, (65)
found basal cuttings, generally heavier, rooted more rapidly than apical
ones; however, a weight difference is not specified. Hosoi gt_al, (29)
reported that heavier cuttings (7 g) had a greater number of roots than
3 gram cuttings. Perhaps a wider weight variation would have allowed
these differences to appear.

Chemical treatments influenced the number of days to root,
days to 50 percent rooted, total percent rooted and number of roots with
no effect on days to budbreak, root surface area, percent flower or days
to flower. Treatments with IBA hasten and improve rooting of various

cultivars (4,28,41). In 1981, Ehrlinger and Howell (22) increased

36
rooting of 'Seyval' hardwood cuttings with 300 ppm IBA in talcum powder
dip. The unexpected results in Experiment I are likely due to the con-
centration of IBA used (500 ppm). Earlier literature reported this
concentration successful in enhancing rooting of various cultivars;
Singh'gt_al, (50) achieved a 10 percent increase in rooting of 'Perlette'
cuttings using 500 ppm IBA; and later a five percent increase in rooting
of 'Himrod' and 'Thompson Seedless' (51). Additionally, the IBA in this
experiment was in solution and may have been washed away before it could
affect root initiation, especially in the mist treatment.

However, IBA-treated cuttings placed under polyethylene tents
took much longer to root than any other treatment with only 42 percent
rooting. This one treatment combination adversely affected the data on
IBA effectiveness, allowing no definitive conclusions to be drawn.

Treatments with Fe generally required more days to root and
produced significantly fewer roots than control; however, a greater per-
centage of Fe-treated cuttings rooted than IBA. Therefore, only NAA did
not adversely affect rooting, but the results were not significant. NAA
has previously improved rooting in 'Delaware' cuttings at 25 and 100
ppm (24).

Cuttings under polyethylene took longer to root and reach bud-
break, had fewer roots and a smaller percentage rooted. This is likely
due to high soil temperatures reached under the covering. Even with
ventilation, soil temperatures occasionally reached 37°C, although the
temperature usually remained around 32.20C. Soil temperatures never
rose above 32.2OC under the other two treatments. It was thought that
the polyethylene covering would prevent dehydration of the newly emerg—

ing leaves, but not lower the surrounding air temperature as a cool mist

37
does. However, it has been shown that soil temperatures over 300C
decrease rooting percentage and root number (29). Also, high tempera-
tures (330C) caused newly expanding buds to shrivel and abort (41).
Therefore, it proved difficult to differentiate between the mist and
greenhouse treatments when determining which method was superior. A
larger percentage of cuttings under mist rooted, although the greenhouse
treatment produced cuttings with a greater number of roots and root sur-

face area.

Experiment II

 

Hardwood cuttings root best at higher temperatures (6,29), but
the effect of rooting temperatures upon flower bud retention in 'Seyval'
was unknown.

Mullins and Rajasekaran (41) "pre-rooted" hardwood cuttings by
keeping buds dormant in a cold air temperature and warming the soil for
root initiation. This technique greatly increased the percentage of
inflorescences at anthesis (40 to 50 percent survived). They attributed
this to the fact that developing inflorescences require cytokinins which
are synthesized in the roots (54).

Therefore, it was not unexpected that at warmer temperatures,
only 21 days were required to achieve 90 percent rooting, compared to 30
days at the lower temperature. However, there was no significant differ-
ence in the number of floral buds surviving to post-bloom stage at either
temperature. Warm air and soil temperature treatment can reduce produc-
tion time by 12 days and result in better, more uniform rooting, as well
as produce more numerous and longer roots, since they had extra days in

which root development was occurring. An equal number of cuttings had

38

rooted under both temperatures, indicating that if given sufficient
time, the percentage of cuttings rooting will not vary with tempera-

ture.

Experiment III

The use of CCC, A-Rest and NAA hastened rooting by as many as
2.7 days compared to control and 4.4 days earlier than GA4’7. There
was no significant effect on days to root.

CCC, gibberellins and NAA (70) delay budbreak in some cases.
However, Kliewer and Soleimani (36) concluded that GA did not affect

3

budbreak, although they applied GA to two-year old potted vines rather

3

than unrooted cuttings.
In Experiment III, there was no significant effect by any
chemical on budbreak. In fact, budbreak occurred only one to five days

prior to root initiation, although many inflorescences still abscised

before flowerhead separation.

Summary

Based on these experiments the best method for rooting
'Seyval' cuttings is to use a soil-less medium and dip cuttings in tal—
cum powder IBA (3000 ppm) before sticking. Air temperature should be
0 o . o o . . .
between 26 and 32 C With bottom heat (21 to 34 C) and high humidity
or intermittent mist for rapid, uniform rooting. Under these condi-
tions, 50 percent rooting will occur in approximately 18 days and 90

percent in 21 days.

SECTION TWO:

 

THE EFFECT OF VARIOUS GROWTH REGULATORS
ON FRUIT SET, SIZE AND YIELD OF

VITIS HYBRID 'SEYVAL' UNDER GREENHOUSE CONDITIONS

THE EFFECT OF VARIOUS GROWTH REGULATORS ON FRUIT SET, SIZE

AND YIELD OF VITIS HYBRID 'SEYVAL' UNDER GREENHOUSE CONDITIONS

Introduction

 

'Seyval' cuttings generally produce an inflorescence while in
the rooting bench or shortly thereafter. These young inflorescences
usually abscise either as an entire cluster prior to separation of the
flowerhead or as individual florets shortly after bloom, resulting in
many vines without fruit clusters or with poorly filled clusters contain—
ing only five or ten berries. In preliminary experiments, less than 50
percent of the first inflorescences reached the post-bloom stage. Fruit
produced on greenhouse-grown vines is considerably smaller than fruit
produced from the same cultivar grown in the vineyard.

Growth regulators can improve fruit set and size when applied
either at full bloom or to immature fruit clusters: benzyladenine (BA)
has been shown to increase the number of fruit per cluster (73). Succin-
amic acid dimethylhydrazide (SADH) increases fruit set and yield of field
(21,58,59) and greenhouse-grown vines (42). Also, 2-chloroethyltrimethyl-
ammonium chloride (CCC) increases the number of berries per cluster (12,
43) although the berries are smaller than normal (21). Gibberellic acid
(GA3) at 100 ppm applied 11 days after bloom.was shown to increase fruit
set as well as the fresh weight of the clusters (13).

GA also improves fruit size when applied either at bloom or to

3

immature fruit (62). Applied at bloom, GA increases berry size; but

3

39

4O

reportedly reduces the number of berries set per cluster (19). However,

others (31) found that GA applied during bloom had no effect on the

3
number of berries, but did increase fresh weight of the fruit. In some
cases, BA has been shown to increase fruit size (73).

In a preliminary experiment, Malizewski 23 31, (38) experienc-
ed problems with the clusters of 'Seyval' containerized vines dropping
berries. This was alleviated by spraying the very small clusters with
BA. It has also been shown that dipping clusters in BA results in fewer
dropped berries (47, 73).

The following experiment was designed to determine the effect

of growth regulators on 'Seyval' hanging baskets.

Material and Methods

 

Dormant hardwood cuttings of one-year old canes were collected
from mature 'Seyval' vines and prepared as two-node cuttings, out just
below the basal node and two to four cm above the upper node. Cuttings
were taken in late March 1982 and immediately prepared for propagation.
Only cuttings which weighed between five and ten grams and free of visi-
ble disease and injury were used.

All cuttings were dipped in a commercial powder mix of 3000
ppm indole-3-butyric acid (Hormodin 2) and placed five to six cm deep in
a peat-perlite-vermiculite media (VSP) and placed in a warm, humid (30:
3°C) greenhouse with bottom heat (32:2.50C). A total of 320 cuttings
were stuck in the propagating bench; 95 percent rooted sufficiently to
transplant, and 85 percent had visible inflorescences. Cuttings with

five or more roots and a visible floral bud were transplanted three

41

weeks after sticking, one cutting per six-inch clay pot containing VSP
and placed under long day conditions (days equaled or exceeded 13 hours
of light).

About half of the inflorescences abscised within one week of
transplanting; 128 plants maintained an original inflorescence. These
plants were placed in Block I, "first flower" (those at full bloom be-
tween 4/29 and 5/12). Block II, "second flower" consisted of vines
whose original inflorescence abscised but that had a second inflores-
cence produced apical to the original on a primary shoot in full bloom
between 5/20 and 6/4. From each block, 45 plants were chosen for uni-
formity of inflorescence size and stage of development; there were 10
replicates of each treatment in each block. Only one cluster was allow-
ed per plant.

Treatments of deionized water, SADH (2500 ppm and 5000 ppm),

BA (50 ppm), CCC (2500 ppm), GA (100 ppm) were sprayed directly upon

3
the inflorescence at full bloom. Two treatments were applied directly to
immature fruit. These had SADH (2500 ppm) at full bloom, then BA (50

ppm) or GA (100 ppm) sprayed onto immature fruit 21 days after full

3
bloom.

The experiment was designed as a completely randomized block
with pots set on lO-inch centers on greenhouse benches. After trans-
planting, plants were fertilized with 200 ppm 20-20-20 N-PZOS-KZO
(Peter's General Purpose soluble fertilizer as described in section one)
twice weekly. Plants were staked and pruned every two weeks after
reaching four feet in height.

Data were collected at veraison (color change) about 90 days

from full bloom; and included cluster weight, cluster volume, number of

42
fruit per cluster, individual berry diameter, length of cluster and days
to sale. Volume was measured by water displacement in a graduated
cylinder, while fruit diameter was measured using a plastic circle tem-

plate.

Results

 

Number of BerriesAper Cluster: All treatments, except H20, re-
sulted in significantly greater number of fruit than control clusters
(Table 7). The clusters sprayed with SADH (5000 ppm) contained more
berries than GAB' control or HZO-treated clusters with no difference
between the two levels of SADH. CCC-treated clusters contained the
largest number of fruit, more than all other treatments. In fact, CCC-
treated clusters bore 12.6 times as many berries as control and 3.7
times as many as HZO—treated clusters.

There was a significant difference in number of fruit between

blocks. First flower vines contained fewer fruit per cluster than did

second flower vines (Table 8).

Cluster Weight: All treatments, except H 0, resulted in a

 

2

highly significant increase in weight over control clusters (Table 7).
The heaviest clusters occurred on vines treated with CCC at full bloom.
Clusters from first flower vines weighed significantly less
than those from second flower vines due to the larger number of fruit
present on second flower vines rather than an increase in weight per

berry (Table 8).

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43

 

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44

 

Table 8. Influence of flowering time on fruit size and yield of Vitis
hybrid 'Seyval' grown in theygreenhouse.

 

 

 

**
Floweringz No.y Individualy Individualy'x Individualy'w
Period Fruit Berry Weight Berry Volume Berry Diameter
(9) (ml) (Hmu
First 22.4 1.30 1.1 5.0
Second 36.8 1.43 1.2 5.2

 

zFirst flower period, 4/29/82 through 5/12/82; second, 5/20/82 through
6/4/82. Original inflorescence abscised on second flower vines and a
second inflorescence was produced apical to the original on a primary
shoot.

Data are the mean of 45 vines each with one cluster.

Berry volume was measured by water displacement in a graduated cylin-
der.

Berry diameter was measured using a plastic circle template.
**
Significant at the 1% level.

 

 

Table 9. Influence of flowering time on number of days to sale and
days from full bloom to sale of greenhouse-grown Vitis hy-
brid 'Seyval.‘ '

 

 

 

Floweringz Days toy'x No. of Days fromx
Period Sale Full Bloom to Sale

First 70.8 34.7

Second 86.5 32.5

LSD.05 " '—

 

 

zFirst flower period, 4/29/82 through 5/12/82; second, 5/20/82 through
6/4/82. Original inflorescence abscised on second flower vines and a
second inflorescence was produced apical to the original on a primary
shoot.

Number of days from stick to "pea-sized" fruit (8-10 mm diameter).
Data are the mean of 45 vines each with one cluster.

 

 

 

 

45

Individual Berry Weight: The GA3 treatment produced the

heaviest berries of all treatments and was the only treatment that was
significantly greater than control (Table 7). However, the control
clusters bore berries significantly heavier than the H20 treatment
which resulted in the smallest individual berries. SADH plus GA3-
treated berries were not heavier than control and weighed less than
berries sprayed with GA3 at full bloom. No difference existed between

individual berry weight of first and second flower vines (Table 8).

Cluster Volume: The difference between the control clusters'

 

volume and all treatments, except H 0, was highly significant (Table

2
7). Similarly, all treatments, except control, had larger cluster
volumes than H20. There was no difference between remaining treat—
ments.

Clusters from first flower vines displaced less volume than

those from second flower vines due to a greater number of fruit present

on second flower vines rather than an increase in berry size (Table 8).

Individual Berry Volume: Only the clusters treated with GA

 

3

at full bloom resulted in berries of greater volume than control (Ta-
ble 7) or any other treatment. There was no difference between the
remaining treatments or between first and second flower vines (Table

8).

Individual Berry Diameter: Only GA sprayed at full bloom

 

3
produced highly significant differences over control (Table 7). How-

ever treatments using GA3, SADH plus GAB' and SADH plus BA gave larger
berries than CCC, SADH (2500) and SADH (5000) as well as H20. No dif-

ference in berry diameter existed between blocks (Table 8).

46

Length of Cluster: All treatments, except H 0, resulted in

2
significantly longer clusters than control (Table 7). SADH (5000),
CCC and SADH plus GA3 treatments produced clusters longer than H20-
treated ones. Applications of 5000 ppm SADH produced clusters longer

. Clusters treat—

than all treatments except BA, CCC and SADH plus GA3

ed with 5000 ppm SADH at full bloom were four times longer than control.

Days to Sale: The mean number of days from stick to sale for
first flower vines was 70.8; 86.5 days for second flower; however,
this was not significant. Marketable size fruit was defined as having
a diameter between eight and 10 millimeters (Tables 9, 10). There
also was no difference in days from full bloom to sale.

Although the difference was not statistically significant,
the second flower vines spent an average of 15.7 days longer in the
greenhouse because their original inflorescence abscised. Those extra

days were spent developing a second inflorescence.

Discussion

The successful production of greenhouse-grown fruited grape-
vines will involve the use of growth regulators to improve market
appearance.

The use of any spray at full bloom improves fruit set from
three times (deionized water) to 12.5 times (CCC). Therefore, any
spray increases cluster weight, volume and length. The goal of this
experiment is to produce clusters that are aesthetically pleasing on
grapevines in a hanging basket, not just clusters containing more or

larger berries.

47

Table 10. Influence of various growth regulators on days to sale and
the number of days from full bloom to sale of greenhouse-
grown Vitis hybrid 'Seyval.‘

 

 

x Days toz'y No. of Days from2
Treatment Sale Full Bloom to Sale
Control (no treatment) 75.4 33.3
Deionized H20 79.4 33.4
SADH (2500 ppm) 79.8 33.7
SADH (5000 ppm) 81.0 34.2
BA 78.2 33.0
CCC 78.6 33.6
GA3 79.8 33.5
SADH + GA3W 79.0 34.7
SADH + 13Aw 76.6 33.0
LSD.05 " '-

 

zData taken were the average of five vines per two replications.
yNumber of days from stick to "pea—sized" fruit (8-10 mm diameter).
Chemicals were combined with deionized water and sprayed to runoff
at full bloom.
SADH (2500 ppm) was applied as spray to runoff at full bloom, second
treatment was applied 21 days later to immature fruit.

48

Deionized Water and Control: Control vines had very poor

 

fruit set and consequently the clusters were unsaleable. Clusters

sprayed with deionized H 0 contained more fruit, but each individual

2
berry was smaller than the control and were considered unsaleable.

Cycocel: Clusters treated with CCC produced by far the
greatest number of fruit and the longest clusters. However, the fruit
were quite small and many were hard, tiny green berries.

That CCC increased the number of berries per cluster was not
unexpected (12, 43) nor was the observation that the berries were
small (21). However, an undesirable result of the use of CCC was the
production of uneven, unattractive clusters, with an unbalanced mix of
very tiny and average-size berries.

SADH: No difference was apparent between 2500 and 5000 ppm
SADH with regard to any of the measurements except cluster length;
5000 ppm produced longer clusters which resulted in more attractive
appearance. Generally, the 5000 ppm SADH clusters were the most at-
tractive of all treatments. The clusters sprayed with 2500 ppm SADH

were tight and clubby, often developing mold prior to harvest.

Benzyladenine: BA treatments at full bloom resulted in good—

 

sized berries in fair numbers on attractive clusters. They contained
more fruit than control, H20 and GA3-treated clusters; and the fruit
were larger than many treatments.

GA was also sprayed on the immature fruit to increase size
(73) and prevent fruit drop (38,47,73). These clusters were sprayed
at full bloom with 2500 ppm SADH to reduce floral abscission. There-

fore, the number of fruit does not vary from that produced using 2500

or 5000 ppm SADH only at full bloom. No fruit drop was experienced

49

after 14 days from full bloom, so this effect of BA could not be
evaluated. However, BA-treated fruit were heavier and larger than
those treated with H20, CCC or SADH alone and were slightly larger and
heavier than fruit sprayed with BA at full bloom.

Gibberellic Acid: GA3 sprayed at full bloom resulted in the

 

largest berries. As was expected, this treatment produced fewer
berries than any treatment except H20 and control. Each individual
berry was larger, but the cluster weighed less than all but control.
These clusters were generally too loose and much shorter than other
treatments.

GA3 was also applied to fruit 21 days after full bloom to in-
crease fruit size (13, 62) without reducing the number of fruit. SADH
(2500 ppm) was sprayed at full bloom prior to the GA3 treatment. This
combination gave more fruit and resulted in berries which weighed less
than the GA-treated at full bloom. The reduced weight was unexpected;
perhaps the treatment should have been made earlier or at higher con-
centrations.

Further, there was no difference between the diameter of
berries treated with GA3 at fruit or at bloom, although the latter were
slightly larger. The SADH + GA -treated berries had larger diameters

3
than many and were about the same size as those treated with BA and
control.
The only difference between first and second flower vines was
in the number of fruit per cluster. Second flower vines contained
larger numbers of fruit which resulted in larger cluster weights and

volumes. However, there was no difference between blocks in regard to

individual berry weight, volume, diameter and total cluster length.

50

Summary

The objective of this experiment was to produce good-sized,
attractive clusters in a short period of time. Three treatments stand
as superior to the others. SADH sprayed at 5000 ppm at full bloom re-
sulted in clusters that were aesthetically full, well-tapered and com-
posed of numerous fair-sized berries. An advantage of this treatment
was that only one application was required. SADH (2500 ppm) at full
bloom plus BA 21 days later, produced attractive clusters containing
slightly fewer fruit which were larger; therefore, an improved, al-
though tighter, cluster was produced. However, two applications and
chemicals are required and BA is not generally used by bedding plant

producers. The third possibility is SADH (2500 ppm) plus GA 21 days

3
later. These clusters were attractive and the fruit were slightly
larger than those formed using one spray of SADH at full bloom.

Using any of these three treatments produces attractive,
full clusters from hardwood 'Seyval' cuttings in 9% to 11 weeks for the
early flowering vines and 11 to 14 weeks for the later ones. The late
flowering vines bear larger clusters. This fact, combined with the

low percentage of vines which retain their initial clusters, makes two-

stage marketing and production desirable.

THE EFFECTS OF THREE LEVELS OF NITROGEN AND SOIL PH ON

GREENHOUSE CONTAINER-GROWN VITIS HYBRID 'SEYVAL'

Introduction

 

In preliminary experiments, many of the container-grown
grapevines developed circular necrotic lesions on the foliage, perhaps
due to a combination of high soluble salts and low pH. Little is
documented on pH and nitrogen preferences of grapevines grown in soil-
less media in the greenhouse, although general field recommendations
are available; so this experiment was conducted in order to make

recommendations regarding fertilizing procedures.

Material and Methods

 

Dormant hardwood cuttings (eight to 10 nodes) of one-year
old canes were collected at Tabor Hill vineyards in southwest Michi-
gan. Cuttings were taken in late March and immediately prepared as
two-node cuttings, out just below the basal node and two to three cm
above the upper node. Cuttings were selected from wood free of visi-
ble disease and injury and placed in six cm deep 1:1 ratio of peat and
perlite at 301 3°C under intermittent mist (six seconds every 15 min-
utes) with bottom heat (32*2.50C).

Cuttings rooted in three weeks; at that time, they were

selected for uniformity of root area, shoot growth and inflorescence

51

SECTION THREE:

 

THE EFFECTS OF THREE LEVELS OF NITROGEN
AND SOIL PH ON GREENHOUSE CONTAINER-GROWN

VITIS HYBRID 'SEYVAL'

52

size, then transplanted into six-inch clay pots. Only cuttings with
a visible inflorescence were chosen.

Three batches of soil were mixed prior to transplanting:
high pH (6.1 to 7.0), medium (5.1 to 6.0) and low (4.0 to 5.0). All

mixes were based on a 1:1 ratio of peat to vermiculate and included:

1362 g/cu yd magnesium sulfate

120 g/cu yd treble super phosphate
1589 g/cu yd trace elements (Esmigram)
3 oz/cu yd wetting agent

Additionally, the high pH mix contained calcium carbonate (2270 g/cu
yd), the medium pH mix contained calcium carbonate (1135 g/cu yd) and
calcium sulfate (1135 g/cu yd); while the low pH contained calcium
sulfate (2270 g/cu yd).

Twenty-seven cuttings were planted in the proper medium,
divided into three groups, and fertilized with O, 100 or 300 ppm
nitrOgen (N). All three nitrogen levels contained 90 ppm potassium
from K2804. Phosphoric acid was added to correct the solution pH to

6.0. Fertilizer solutions contained:

0 ppm N 100 ppm N 300 ppm N
0.23 g/l K2804 0.2 g/l NH4NO3 0.79 g/l CaNO3
0.23 g/l KNO3 0.4 g/l NH4NO3

0.23 g/l KNO3

All cuttings were watered as needed with the solution and leached with
deionized water (pH 6.0) once every two weeks. Soil pH was recorded
weekly. Flower clusters were sprayed with 5000 ppm SADH at full
bloom.

After 10 weeks, all plants were pruned back to seven nodes
(no flower clusters were removed). Measurements were made after 17

weeks including, the number of nodes below the inflorescence, total

53

vine length, new vine growth since pruning, number of fruit, fruit
weight, number of tendrils, number of branches, length of longest
branch, total number of nodes and the number of woody nodes. Plants
were also rated for foliage chlorosis (1 = deep green, no chlorosis;

2 = entire leaf slightly chlorotic; 3 = entire leaf severly chlorotic,
primarily yellow or white) and presence of necrotic spots (1 = no
spots, 2 = less than five spots per leaf, and 3 = more than five spots

or spots larger than 1.25 cm in diameter).

Results

Fruiting: The level of nitrogen significantly affected the
number of fruit clusters, the number of fruit per cluster and total
number of fruit. Vines fertilized with 300 ppm N had significantly
more clusters as well as a greater number of total fruit, using Dun—
can's multiple range test at 5% level. Vines treated with 300 ppm N
had over 2.5 times more fruit than 100 ppm N and over 14 times more
than 0 ppm. There was no difference between the number of fruit per
cluster of vines treated with 100 or 300 ppm N. Both treatments had
significantly more fruit per cluster than vines receiving 0 ppm N.
The 300 ppm N treatment averaged almost 44 berries per cluster; the
100 ppm treatment had over 30, compared to less than six berries per

cluster for 0 ppm N (Table 11).

Fresh Weight of Vines and Foliage: Vines fertilized with

 

increasing levels of nitrogen had increasing fresh weight. Also,
plants grown in low pH had significantly greater fresh weight than

those with high pH (Table 12).

54

 

 

 

Table 11. The influence of three levels of nitrogen on flower and
fruiting of greenhouse container-grown Vitis hybrid
'Seyval.‘
Z Z . z,
No. of Total No. No. Fruit
Nitrogen Level Fruit Clusters of Fruit per Cluster
0 ppm 0.7 a 6.7 a 6.7 a
100 ppm 1.2 a 37.4 a 30.3 a
300 ppm 2.1 b 94.0 b 44.0 b

 

z .
Data based on means of 27 Vines.
Mean separation in columns by Duncan's

multiple range at the 5%

level.

 

 

 

 

 

 

 

Table 12. The influence of three levels of nitrogen on foliage fresh
weight and vine growth of greenhouse container-grown Vitis
hybrid 'Seyval.‘

Foliagez z 2
Fresh Initial ,y New ,x z z w z
Nitrogen Weight Vine Length Growth No. of Foliar ' Foliar A}
Level (9) (cm) (cm) Branches Chlorosis Necrosis
0 ppm 31.20 a 30.7 a 16.9 a 0.3 a 2.5 b 1.8 b
100 ppm 122.28 b 94.7 b 84.9 b 4.1 b 1.0 a 1.1 a
300 ppm 138.73 c 88.4 b 78.7 b 4.9 c 1.0 a 1.8 b

 

zData based on means of 27 vines.

Vine length on 6/10/82 prior to pruning, cuttings were stuck on 4/2/
82.

xMeasurement of new growth which occurred between 6/10/82 and 7/22/82.
Rated on a scale from 1 to 3; l = no chlorosis; 2 entire leaf
slightly chlorotic; 3 = entire leaf severely chlorotic, primarily
ellow or white.

Rated on a scale from 1 to 3; l = no spots, 2 less than five spots
per leaf, 3 = more than five spots or spots larger than 1.25 cm in
diameter.

Mean separation in columns by Duncan's multiple range test at the 5%

level.

 

 

55

The interaction between nitrogen and pH also affected foli-
age fresh weight (Table 13). The combination of 100 ppm N/low pH and
300 ppm N/medium pH produced vines of highest fresh weight. The 100
ppm N/high pH combination had significantly less foliage than 100 ppm

N/low pH.

Vine Length: Nitrogen also affected initial vine length and

 

new growth after pruning (Table 12). Plants grown with 0 ppm N were
significantly shorter than those fertilized with 100 and 300 ppm N.
pH had no effect on initial vine length, but did affect new growth
(Table 14). The low pH vines were 1% times longer than the high pH

vines.

Foliar Chlorosis and Necrosis: Low levels of nitrogen (0

 

ppm) resulted in leaves that were severely chlorotic and contained
numerous necrotic lesions. High levels of nitrogen (300 ppm) also re-
sulted in significnatly more necrosis than was present on 100 ppm N-

treated foliage (Tables 12, 13).

Number of Branches: With increasing levels of nitrogen,

 

there were increasing number of branches per plant. Those treated
with 0 ppm N grew very few side branches (only one out of three plants
had even a single side branch). The 300 ppm N treatment averaged
five branches per plant, significantly more than the other two treat—

ments.

56

.nmon omCoH onHnHCE m.CooCCQ mCHmC Ho>oH mm onn no nCoOHwHCmHm COHnooHonCH
.%

.HonoEoHp CH Eo mN.H Conn nomnoH mnomm no mooH mom mnomm

m .mooH Mom mnomm o>Hm Conn mmoH u m .mnomm oHnonooC 0C n H "m on H Eonm oHoom o Co ponom
.oan3 no BOHHo> wHHnoEHnm .OHnOHOHno mHono>om

m «OHnOHOHno >HnanHm wooH oanCo n N umHmOHOHno 0C u H "m on H Bonn oHoom o Co ponom
.0.e-H.o u roHo u0.ouH.m u eonooe u0.9.0.0 u no son

.mm\Nm\H pCo Nm\OH\© Coo3non ponusooo COHns nn3onm 3oC mo mnCoEoHCmooz

.mm\m\¢ Co xoCnm onoB mmCHnnso .mCHCCHm on HOHHQ Nm\OH\m Co nnOCoH oCH>

o>HM Conn mHOE u

D

mooH oanCo n

X 3 >

 

 

 

 

 

.mCOHnooHHmon oonnn CH moCH> oonnn mo mCooE Co pomon onoow
t COHnooHonCH
m.oe H.mn m.H o.H mm.v o.Ho H.mm no m.HMH ann
H.me 0.m0H o.H o.H gm.m m.ee N.00 o m.ogH esHooe and oom
h.mw m.mm m.H o.H mm.¢ v.0m 0.0m no v.mMH 30H
m.mm 0.om N.H o.H ma.m o.He o.em n n.00H non;
e.tH e.Hm o.H o.H HH.e 0.eo m.00 on o.0HH genome and 00H
0.0m h.¢m o.H o.H om.¢ m.mm >.mOH p c.0vH 30H
0.m 0.0 o.H s.m mm.0 s.m g.om o m.mm Bonn
0.m 0.m o.H e.m 0H.0 e.mn 0.mm o e.mm ssHooe and 0
o.OH 0.0H h.H m.m mv.o «.mm o.Hm o H.mm 30H
HonmCHO nHCnm mHmonooz meonoHnU monoCon Afiov AEUV Amy mm Ho>oH
Mom no C.NnoHHom >.NHoHHom nmo .oz nn3onw nnmCoH oCH> .nB nmonm 3HHom ComonnHz
NnHCHm N.oz / x.n3oz %.NHoHnHCH NomoHHom
IIIIII /
..Ho>>om. pHnnan mHnH> CzonmlnoCHonCoo omsonCoonm no nonECC annn pCo ooCoHoommo
poo nnsonm noHHom Co mm HHom mo mHo>oH oonnn pCo ComonnHC no mHo>oH oonnn no ooCoCHMCH one .MH oHnoB

57

Table 14. The influence of three levels of soil pH on foliage fresh
weight and vine growth of greenhouse container-grown Vitis
hybrid 'Seyval.‘ ' ‘ " '

 

 

Soilz Foliagey Newy’x

pH Fresh Weight Growth,
Low 107.0 b 73.9 b
Medium 98.3 ab 59.4 ab
High 86.9 a 47.3 a

 

zLow pH = 4.0-5.0, medium = 5.1-6.0, high = 6.1—7.0.

yData based on means of 27 vines.

XMeasurement of new growth which occurred after pruning on 6/10/82 and
before 7/22/82.

Mean separation in columns by Duncan's multiple range test at the 5%
level.

58

Discussion

 

It appears that of the three levels of nitrogen tested, a
nitrogen concentration between 100 and 300 ppm is preferable. At 300.
ppm (during late spring) the plants bore more clusters and more fruit
per cluster; and the vines were more extensively branched, which is im-
portant for attractive hanging baskets. Plants grown using 100 ppm
were well-branched and bore an acceptable number of fruit clusters.

It was not known whether or not levels of nitrogen as high as
300 ppm would reduce fruit formation. An excess of nitrogen has been
shown to reduce crop yield (75). In experiments in perlite—vermiculite
media, one to four millimoles of NO3 produced superior vine growth and
fruitfulness than 0.5 millimoles. The researchers concluded that a
nitrogen supply that promotes good foliar color and growth will also
enhance fruit production (34). In this experiment, the levels of
nitrogen were 0.0 mM (low), 7.1 mM (medium), and 21.4 mM (high), con—
siderably higher than that reported by Kliewer and Cook (34).

However, the 300 ppm N treatment produced more fruit than other
levels, however, it also resulted in a greater number of necrotic

lesions. Therefore, a concentration between 100 and 300 ppm is recom-

mended. Further, pH had no effect upon plant growth.

APPENDICES

 

APPENDIX A

A Study of Vitis Cultivars Suitable for Hanging Basket

Greenhouse Culture

Malizewski epflal. (38) conducted a preliminary experiment on
three grape cultivars: 'Seyval,‘ 'Vignoles,' and 'Concord' to determine
their suitability for hanging basket culture. 'Seyval' showed the best
potential while 'Vignoles' failed to flower and was discarded. 'Con-
cord' flowered and set fruit, but was considered "too leggy" and
awkward-looking in a lO-inch basket due to its large leaves and long
internodes. 'Seyval' produced five to eight-inch pea-sized clusters in

13 to 14 233ks.

Material and Methods

 

Dormant hardwood cuttings were collected in January and Febru-
ary from various sources in Michigan, California and New York and plac-
ed in cold storage (20C). Cuttings were prepared as two-node cuttings,
out just below the basal node and two to three cm above the upper
node. Cuttings were chosen which weighed between 5.0 and 10.0 grams
and were free of visible disease and injury. All cuttings were dipped
in a powder formulation of 3000 ppm indole-3-butyric acid (IBA) and
bases placed in moist 1:1 ratio of peat and perlite medium. The flats

were placed under intermittent mist (6 seconds every 15 minutes) in a

59

6O

300C greenhouse and supplied with bottom heat (320C). There were
three replications of eight cuttings each.

All cuttings were checked for root formation every other day
and data were taken on days to root, days to flower, percent rooted and
percent fruited. Cultivars are shown in Table 15. A11 cultivar per-
formance was compared to 'Seyval.‘ Any flower clusters which develop-

ed were sprayed with 2500 ppm SADH at 50 percent bloom.

Results

Four of the tested cultivars produced fruit within sixteen
weeks (Table 15). 'Seyval' had fruit clusters on 91.7 percent of the
vines; almost 96 percent rooted in 35 days. 'Chelois' had clusters on
87.5 percent and 91.7 percent rooted. 'Alden' and 'Viblanc' bore
clusters on 20.8 percent and 12.5 percent respectively. None of the
others bore clusters.

Almost 100 percent of 'Ventura' and !Steuben' (Michigan) cut-
tings rooted in 35 days. These cultivars leafed out nicely, but no
flowers were ever formed. 'Queen,’ however, had almost 92 percent of
its primary buds develop an inflorescence, but no roots ever formed and
the inflorescence dehydrated and senesced. Of the four cultivars sent

from California, only 'Alden' rooted on 50 percent of the cuttings.

Discussion

 

Only 'Seyval' and 'Chelois' produced fruit clusters on a great
enough percentage of vines to merit growing them. Both cultivars have

attractive foliage and short internodes so they produce full baskets.

61
Both are wine grapes which are grown in Michigan. 'Seyval' is a white-
fruited cultivar and produces long, tapered clusters. 'Chelois' has
purple fruit; the fruit is fair-sized but the clusters are rounder than
'Seyval.‘ Both cultivars can be produced on the same time schedule,

using the same techniques.

 

Table 15. Rooting and fruiting percentages of twelve'Vitis cultivars
grown in the greenhouse. ...

 

 

% Rootedz Total %z'y %2 %z,x
Cultivar 21 Days Rooted Flower‘ 'Fruit
Michiganw
Seyval 91.7 95.8 87.5 91.7
Chelois 83.3 91.7 83.3 87.5
Ventura 83.3 100.0 0.0 0.0
Alden 79.2 87.5 62.5 20.8
Viblanc 83.3 95.8 75.0 12.5
Steuben 87.5 100.0 0.0 0.0
Interlaken 50.0 70.8 0.0 0.0
Californiaw
Alden 25.0 50.0 0.0 .
Ruby Seedless 0.0 0.0 0.0 0.0
Ribier 0.0 0.0 0.0 .0
Queen 0.0 0.0 91.7 0.0
New Yorkw
Himrod 25.0 50.0 10.7 0.0
Steuben 50.0 70.8 0.0 .
Suffolk Red 62.5 70.8 0.0 .

 

Data based on mean of 24 cuttings.

In 35 days.

Cuttings with fruit clusters present in 16 weeks.
Source of wood.

X"<:N

22

APPENDIX B

A Grower's Guide to the Production of Hanging Baskets of

Fruited Grapevines

Production time: Crop flowers in two stages. Vines retaining their

 

initial clusters will be ready for sale and have "pea-sized" (8-10 mm)
fruit in 9% to 11 weeks. The second half of the crop will be ready in

11% to 14 weeks.

Rooting: Root hardwood cuttings in sterilized sand or soil-less media,
burying only the lower node. Air temperature should be around 30°C
with bottom heat (320C) and high humidity or mist for fastest, most
uniform rooting. At this temperature, 50 percent will be rooted in 18
days and 90 percent in 21 days. Use a talcum powder dip of 3000 ppm

indole-3—butyric acid (IBA) before sticking.

Cultivars: 'Seyval' is a popular wine grape which produces white
clusters that are five to eight inches long. 'Chelois' is also a wine
grape which bears purple fruit in the same time period as 'Seyval,‘

although the fruit clusters are smaller.

Transplanting: Transplant before the roots become too long. Grape

 

roots are thick and brittle, easily broken during potting. Vines with

broken roots experience greater transplant shock.

62

63

. o .
GrOWing On Temperature: 25-30 C is recommended. Temperatures above

 

350C and those below 20°C result in tendril formation rather than

inflorescence formation.
Media: Any well-drained mix.

Spacing: Four two-node cuttings per 10-inch basket are recommended.
One cutting occasionally will not survive transplanting and three out-

tings make a full, attractive basket.

Fertilization: Apply between 100 and 300 ppm N at every other watering

 

along with potassium and phosphorus. A suitable pH is between 5.0 and
6.0; at higher pH, iron deficiency and necrotic lesions are more like-
ly to occur. A foliar spray or soil application of iron may be neces-

sary after transplanting.

Photoperiod: Vines produce greater numbers of berries when placed

 

under 16—hour days. Continuous lighting greatly reduces the number of

fruit.

Growth Regulators and Fruit Production: For improved fruit set apply

 

ppe of the following to flower clusters when at least 50 percent of the
inflorescences have opened:
1) SADH (5000 ppm) at 50 percent bloom.
2) SADH (2500 ppm) at 50 percent bloom plus GA3 (100 ppm)
21 days later to immature fruit.
3) SADH (2500 ppm) at 50 percent bloom plus BA (50 ppm) 21

days later to immature fruit.

Pests: Spider mite is the main pest in the greenhouse.

Sample Schedule:

 

February 6
February 27
March 8 - 20
March 28 - Apr 12
March 20 - Apr 10
Apr 18 - May 3
Apr 14 - 22

Apr 26 - May 12

Total Time:

64

Stick cuttings

Cuttings rooted; transplant

First full bloom - apply SADH to inflorescence
Second full bloom - apply SADH to inflorescence
Spray first fruit (optional) with GA or BA

3

Spray second fruit (optional) with GA3 or BA
First flowering baskets ready for sale

Second flowering baskets ready for sale

9% - 11 weeks for first flowering

115 - 14 weeks for second flowering

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10.

11.

12.

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