THE INFLUENCE or LOW TEMPERATURE TREATMENTS —
ON THE DEVELOPMENT OF TULIPA SP. ‘

Thesis for the Degree of M. S.

MICRIGAR STATE UNIVERSITY ‘

JOHN FREDERICK SCHWARTZ
1968 ' '

 

Michigan State
mm ‘ University

 

THE INFLUENCE OF LOW TEMPERATURE TREATMENTS

ON THE DEVELOPMENT OF TULIPA SP.

By

John Frederick Schwartz

A THESIS

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

MASTER OF SCIENCE

Department of Horticulture

1968

ACKNOWLEDGMENTS

The author would like to express his sincerest
appreciation to Dr“ August De Hertogh for his suggestion
of the problem and for his interest, able assistance and
constant encouragement during the course of this disser-
tationo Respect and appreciation is also eXpressed to his
Graduate Committee, consisting of Doctors Roy A° Mecklen-
burg and I, w, Knobloch of the Departments of Horticulture
and Botany and Plant Pathology respectively.

A special acknowledgement goes to Dr° Louis Aung and
Mr. George Staby for their encouragement and assistance
with the statistical analyseso

Appreciation is given to his wife, Lyn, for her
enduring patience and encouragement throughout this entire
program and to his parents who have provided encouragement
and support through the yearso

This work was supported in part by a grant from the
Netherlands Flower-Bulb Institute of New York and The

Ornamental Marketing Board of the Hagueo

ii

TABLE OF CONTENTS

ACKNOWLEDGMENTS . . . . . . . .

LIST OF TABLES . . . . o . . . . . . .
LIST OF APPENDIX TABLES . . . . . . .
INTRODUCTION . . . . . . . . . . . .

LITERATURE REVIEW . . . . . . . . . . .

Flower Formation . . . . . . . ., . .
Flower Disorders . . . . . . . . . .
Low Temperature Requirements . . . . . .

METHODS AND MATERIALS . . . . . . . . .

Inspection and Dry Storage of Bulbs Prior to
Low Temperature Treatments . . . . . .

Planting Procedures . . . . . . . .
Shifting to Greenhouse . . . . .
Data Recorded . . . . . . . .

Class I--Very Early Forcing
Class II--Early Forcing . .
Class III——Medium Forcing
Class IV-—Late Forcing

O O O O
O O O 0 O 0

RESULTS 0 0 O 0 O O O O 0 O 0 O 0

Class I-—Very Early Forcing . . . . . .
Class II--Early Forcing . . . . . o .
Class III--Medium Forcing . . . . . . .
Class IV--Late Forcing . . . .

DISCUSSION

Storage on Total Height . .
Storage Time on Sprout Heights
Storage Effect on Foot Length.
Total Height and Foot .
Sprout Height on Total Height.
Sprout Height on Foot Length
Flower Size and Storage.
General Discussion

iii

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SUMMARY . . . . . . . . . . . . . . . . 66
BIBLIOGRAPHY . . . . . . . . . . . . . . 68
APPENDIX . . . . . . . . . . . . . . . 72

GLOSSARY . . . . . . . . . . . . . . . 78

iv

LIST OF TABLES

Table Page
1‘ Very early forcing . . . . . . . . . . 17
2. Early forcing . . . . . . . . . . . . l8
3. Early forcing . . o o . . . . . . .- . 19
4. Medium forcing . . . . . . . . . . . 2O
5 Medium forcing . . . . . . . . . . . 21
6. Late forcing . . . . . o . . . . . o 22
7. Late forcing . . . .r . . . . . . . . 23

8, Experiment I: Length of sprouts, total plant
heights, flowers and first internodes . . . 36

9: Experiment I: Flowering dates . . . . . . 37

100 Experiment II: Length of sprouts, total plant
height, flowers, and first internode . o o 38

ll. Experiment II: Flowering dates . . . . . o 39

12. EXperiment III: Length of sprouts, total plant
height, flowers and first internodes . o . 40

13. EXperiment III: -Flowering dates . . . . . “1
IA. Experiment IV: Length of sprouts, total plant
heights, flowers and first internodes . . . 42
15. Experiment IV: Flowering dates . . . . . o A“
16, EXperiment V: Length of sprouts, total plant
heights, flowers and first internodes . . . “6
1?. Experiment V: Flowering dates . o . . . 0 A8
18. EXperiment VI: Length of sprouts, total plant
heights, flowers and first internodes . . . 50
19. EXperiment VI: Flowering dates . . . . . . 51

Table Page

20. Experiment VII: Length of sprouts, total plant
heights, flowers, and first internodes . . . 52

21, Experiment VII: Flowering dates . . . . . 53

22: Experiment VIII: Length of sprouts, total
plant heights, flowers and first internode . 5“

23. Experiment VIII: Flowering dates . . . . . 55

2A. Experiment IX: Length of sprouts, total plant
heights, flowers and first internodes . . . 56

25. Experiment IX: Flowering dates 0 . . . . . 57

vi

LIST OF APPENDIX TABLES

Table Page
1. Simple correlations--Dutch Princess . . . . 73
2. Simple correlations--Apeldoorn . . . . . . 73
3. Simple correlations--Gudoshnik . . . . . . 73
A. Simple correlations--Andes . . . . .I . . 7“
5. Simple correlations--Dreaming Maid . . . . . 7“
60 Storage on total height: Pertinent statistical

information relevant to the effect of days in
cold storage on total height with the five
cultivars . . . . . . . ._ . . . . 75

7. Storage on sprout length: Pertinent
statistical information relevant to the
effect of days of storage on sprout height -
With the five cultivars . . . . . . . . 75

8. Storage on foot length: Pertinent statistical
information relevant to the effect of days
in cold storage on foot length with the
five cultivars . . . . . . . . . . . 75

9. Total height on foot length: Pertinent
statistical information relevant to the
effect of total height on foot length with
the five cultivars . . . . . . . . .r 76

IO. Sprout height on total height: Pertinent
statistical information relevant to the
effect of sprout height on total height
with the five cultivars . . . . . . . o 77

ll. Sprout height on foot length: Pertinent
statistical information relevant to the
effect of sprout height on foot length with
the five cultivars . . . . . . . . . 77

vii

INTRODUCTION

The processcfl‘bringing spring flowering bulbs into
flower by use of controlled environmental conditions is
called forcing.

By use of the prOper sequences of high and low
temperatures, the seasons of fall, winter and spring can
be condensed into a shorter time period. As a result,
bulbs can be made to flower at specified times.

To force tulips effectively, four different envir-
onmental regimes must be employed (l2, 19). These are;
(a) high temperatures after the bulbs have been harvested,
(b) dry storage temperatures subsequent to flower forma-
tion, (c) low temperatures during the rooting and mobil-
ization phase of develOpment and (d) Optimal greenhouse
temperatures.

Much work has been done not only on the temperatures
which influence flower formation (A,5,l2,lS,l6,l7,22), but
also on the temperatures for storage after flower formation
and prior to shipping (2,23). The temperatures to which
the bulbs are eXposed after harvesting are very critiCal
since blind plants or blasted flowers may result if the

flower is not properly formed.

Tulips which are grown in The Netherlands and are
intended for use in the United States and Canada must be
shipped. When transported by ship this normally takes three
weeks. At the present time, temperatures during transport
are being controlled only within broad limits. However, as
modern transportation facilities become available this will
change rapidly. It was because of this and other problems
as well as the advent of many new cultivars of tulips that
the need for more information on the precooling and rooting
of tulips, as well as other techniques, became apparent.

For these investigations the flowering season was
arbitrarily divided into five periods. These are:

(1) Very early (December 15 through January l5)o

(2) Early (January 15 to February 5).

(3) Medium (February 5 to March 10).

(A) Late (March 10 to April 10).

(5) Very late (April 10 to May 15).

In this dissertation these periods are referred to
as Classes I through V, however, only Classes I to IV were
examined.

The experiments carried out for this dissertation
were designed to develop cultural techniques in order to
be able to program the forcing of tulips and improve
quality. To do this three types of eXperimental variables
were investigated utilizing several cultivars of tulips.

These were;

(I) The use of various precooling temperatures and
lengths of precooling to supplement the low
temperature treatment during rooting.

(2) The use of different planting dates to vary the
length of the low temperature treatment during
rooting.

(3) The use of several rooting room temperature
sequences to influence the development of the
bulbs.

Through the implementation of these variables it was
intended that information would become evident as to what
effect each might have on: (a) Sprout length, as an
indicator of time to and/or easiness to flower (b) flower
size (0) length of the first internode (d) total plant
height and (e) the days to flower and spread date of

flowering.

LITERATURE REVIEW

Much of the research which has been done on spring
flowering bulbs has been carried out in Europe (A, 10, 13).
Among the areas which have been studied are: flower
formation (4,5,12,15,16,l7), dry storage problems (2,23),
transportation (2), nutrition (26), and various flower
disorders, e.g. blindness (11).

In addition to problems mentiond above there are
other factors that play an important role in flower forcing.
Growing conditions in the field, such as temperature, water
and fertilization will be a determining factor in the quality
of the bulb as well as the resulting flower. Harvesting
conditions also play an effective part in greenhouse
forcing.

Much of the early work with Tulipa sp. and their
requirements for high and low temperatures, as well as
other works have been reviewed by Purvis (l8) and also by
Went (2A). A later review was published by Hartsema (9)
who reviewed her own work as well as that of Dr. Blaauw,

her co=worker. Of importance also is the review by

Rees (l9).

Flower Formation

Flower formation is of primary concern when forcing
the tulip. The flower must be at stage VII in the scheme
designed by Blaauw. He referred to the seven distinct
stages of development within the bulbs as the stages I
through VII, respectively. Stage VII is that stage which
must be reached prior to the application of low temperature
treatments

Beyer (l) reclassified the seven stages of develOp-
ment using alphabetical stages of development selected to
correspond to the morphological stages of development. His
‘seven stages are referred to as I, II, P1’ P2, Al, A2, G.
Beyer's"G" is comparable to Blaauw's stage VII.

Blaauw, Luyten and Hartsema (A) showed the effect of
different temperatures on flower formation. They demon-
strated that abnormally high temperatures as well as
abnormally low temperatures had a deleterious effect on
flower formation. The extreme result was no flowers formed.
Luyten, Joustra and Blaauw (l5) examined a wide range of
different temperatures and found that by altering these
temperatures that the speed of flower formation is affected.

Blaauw and Versluys (5) also showed the effect of
different temperatures on flower formation, but showed
further that even though certain temperatures resulted in
faster flower formation that those flowers which formed

first did not necessarily flower first under normal

conditions. The results cfi‘ these studies showed the

cptimal temperature for flower formation to be l7-20°C.

Flower Disorders

Some flower disorders were investigated by Hartsema
and Luyten (11). They further substantiated that high
temperatures can be used to destroy the flower before
planting.

Hartsema and Waterschoot (13) also showed that
extreme temperatures can be used to retard flowering of
bulbs destined for planting and flowering in other coun—
tries, particularly the Southern hemisphere. For practical
reasons the use of high temperatures to prevent flowering
is not recommended for tulips as certain uncontrollable
retardation can occur during shipping. This method has
been suggested, however, for use with hyacinths and

daffodils.

Low Temperature Requirements

It was evident, however, that very little work had

been done on Tulipa sp. when one considers temperature

 

sequences, e.g. precooling and rooting room temperatures,

and storage and planting dates, that relate to the prOper

forcing room temperatures, and storage and planting dates,
that relate to the prOper forcing of the many available

cultivars.

It is important to note that when reference is made
to various temperatures we are referring to temperatures
in a controlled growth room and not those which are dependent
on the severity or mildness of a particular fall or winter.

Attempts have been made through the years to deter-
mine Optimum temperatures to be used for rooting and
satisfying the cold requirement for early forcing periods
(10).

Experimental evidence has shown that there was little
effect of different curing temperatures on forcing per-
formance of bulbs in lots precooled and rooted at 50°F.

It was shown, however, that a curing temperature of 100°F
delayed flower differentiation to the point that most

bulbs were killed (20). It was also shown that various
precooling temperatures produced plants of varying heights.

Stuart et a1. (21) showed that precooling of bulbs
at 40°F resulted in the production of longer stems and
earlier flowering than the same length of storage at 50°F.
‘They also showed that bulbs which were precooled at 50°F
then planted or held dry at 60°F, resulted in flowering
in the greenhouse which was not inhibited. The stems,
however, were greatly shortened. They concluded that cool
storage has more influence on factors which are responsible
.for stem elongation than on actual rooting. It is thought
that these changes are enzymatic in nature, but there is

little work at the present time which would verify this.

 

8
Rees (19), using the summary of Wood (25) says that,
In general all cooling to promote early growth and
flowering is detrimental to vegetative reproduction
and flower quality. The two objectives, flower
production and bulb increase are competitive and
the storage temperatures adopted practically are
those which are not optimal, but adjustments which
give a greater margin of safety for flower quality.
Stuart and Gould (20) and Gill EE.§l: (8) have
carried out investigations in the United States and showed
that precooling of tulip bulbs at A°C followed by planting
and a period of 6 weeks at 10°C gave longer stemmed plants
than when a 9-10°C treatment employed for the same period
of time. The A° treatment was started at a later stage
of development than is usually employed in normal precooling
procedures. It might be worthy to note at this time that
this 4°C treatment or 5°C bulbs as they are referred to
today, is essential for normal blooming in southern climates
where a gardener would encounter warmer soil temperatures.
Dickey (7), in Florida, has confirmed these obser—
vations of Stuart and his co—workers. He used storage
sequences at A0°F for 60, 90, and 120 days and also 50°F
for 90 and 120 days. He also stored bulbs for 90 days at
36°F. This particular treatment was reported as severely
depressing flowering. He found that storage for 30 days
was unsatisfactory at all temperatures. The bulbs stored
as long as 120 days at 60°F also did not produce satis-

.factory growth and flowering. Toyoda and Nishii (22) also

sfliowed detrimental effects from such storage treatments.

Stuart 32 al. (21) showed that the rooting period at
10°C carIbe eliminated.immediately after a precooling treat—
ment. This was done using a precooling treatment of 4°C
for 6 weeks. They further demonstrated that using the
precooling method for 12 weeks at A°C gave a reduced size
and a greater percentage of "blasted" flowers. They showed
that when bulbs were precooled at A°C for 6 weeks followed
by 3-6 weeks at 10°C, and then planted and forced at
a temperature of 15.5°C good results could be obtained.

The only objection to this method was that there was a
slight reduction in overall plant size. They concluded
that, "too short a period of cooling, or cooling at too
high a temperature, results in short stems or in delayed
blooming."

Hartsema, Luyten and Blaauw (l2) determined what they
considered a progressive stepping up of temperatures from
planting to anthesis. They advocate 9°C until the sprouts
are out of the bulbs. This is followed by an increase in
temperature to 13°C for approximately two weeks or until
the sprouts are 3 cm long, followed by 17°C for three weeks
until 6 cm of sprouts are apparent, then place in light at

23°C to continue forcing.

Crossley (6) from British Columbia further substan-
tiates the 9°C sequence but indicates better results are
obtainable if after the flower begins to color the temper-

ature is lowered.

 

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Blaauw (3) concluded that 9°C was the most Optimal
temperature for cold storage. Luyten (14) also had excel-
lent results using 9°C on the cultivar "Van der Neer."

Attempts have been made throughout the years to
determine Optimum temperatures to be used for rooting and
supplying the necessary cold for early forcing periods.

Prior to these investigations most experimentation
had been carried out on a limited number of cultivars.

Due to the lack of information pertaining to newer
cultivars, with reference to the correct procedures to be

used in rooting and forcing, this dissertation came about.

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METHODS AND MATERIALS

During the period of fall 1966 to spring 1967 nine
experiments were carried out.

For purposes Of clarification the information
necessary to explain each individual eXperiment and the
treatment that the bulbs received prior to precooling,
rooting and forcing were put in Tables 1 to 7.
Inspection and Dry Storage Of Bulbs

Prior to Low Temperature
Treatments

 

 

When each shipment Of bulbs was received the packing
crates were Opened and an inventory taken.

Bulbs which were diseased or mechanically injured
were discarded. The remaining bulbs were removed from the
containers and placed in hardware screen racks. All bulbs
were stored at 17°C prior to being placed in low temper-
ature rooms. All temperature control rooms were maintained
at the specified temperature i 1°C. A close check was
kept on the humidity to see that it did not get too high.
This was done to reduce the potential of infection by

disease.

Planting Procedures

 

A soil mix consisting Of sandy loam, peat and sand

(2:1:1) was used. The forcing flats measured 8" X 8" X A".

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Just prior to planting, the bulbs were removed from
storage and each individual bulb examined for mold and/or
mechanical injury especially to the basal plate. Each

bulb was mechanically peeled so as to expose the root

 

plate.

Sixteen bulbs were placed in each flat so that the ‘
"nose" Of the bulb was just even with or slightly above the 5?
top of the flat. Care was taken not to press the bulbs
into the rooting medium. The flat side Of the bulbs in
two front rows faced the front of the flat and the back .5

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two rows faced the back side of the flat. Each cultivar
within a treatment consisted Of three replications of
sixteen bulbs each.

After planting the flats were placed in the rooting
rooms and thoroughly watered to run-Off. This procedure
was repeated for three consecutive days. Additional
waterings were made as needed.

Light in the rooms was kept to a minimum. Once a
week the rooms were aired to allow a complete change of
air throughout the rooting room. Temperatures were observed

twice daily, with each observation being recorded.

Shifting to Greenhouse

On predetermined dates the flats were removed from
the rooting rooms and transported to the greenhouse for
:forcing. The treatments were placed in the greenhouse in

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The day temperature was maintained as close to
20°C as possible with the night temperature being held at
17°C.

The forcing flats were inspected each day and watered
as needed. All watering was done in the morning in order

to maintain a low humidity at night.

Data recorded

 

Sprout data were taken when the flats were removed
from the rooting rooms. When the floral buds were beginning
to show color, flowering data collection was started. Each
flower was measured from the tip Of the tepal to the base
of the receptacle. At the same time the overall height of
the plant to the nose Of the bulb, as well as the length of
the first internode (distance from nose of bulb to node of
first leaf) was recorded. All measurements were recorded

to the nearest 0.5 cm.
Class Im-Very Early Forcing

Experiment I.--This eXperiment was designed to eval—

 

uate various precooling and planting sequences of tulips

that were precooled at 9°C and forced for Christmas.

Christmas forcing is considered to be very early forcing.
As indicated earlier the treatments the bulbs

received is outlined in Table 1.

 

 

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Experiment II.—-This experiment dealt with various

 

precooling temperatures and their effect on overall plant
height, flower size,sprout size, length of the first
internode and time of flowering.

The information regarding treatments and other per—

tinent information is found in Table l.

EXperiment III.--This eXperiment was designed to

 

evaluate rooting room temperatures on the flowering of
tulips for Christmas. Consult Table l for technical infor-

mation.

Class Il--Early Forcing

 

Experiment IV.--This eXperiment utilized ten culti-

 

vars in order to investigate the optimum planting date in
conjunction with various rooting room temperature sequences
for tulips forced in mid-January.

Details are eXplained in Table 2.

Experiment V.——This eXperiment was designed with ten

 

different cultivars to study the effects of various rooting
room.temperatures on the flowering of tulips for Class II
or mid-January forcing.

The shipping information as well as other storage

temperatures and treatments can be observed in Table 3.

 

 

 

15
'Class III-—Medium Forcing

Experiment VI.-—This experiment was designed to

 

compare various rooting room temperatures. Information
concerning treatments prior to, and after planting, are

shown in Table 4.

Experiment VII.——This experiment was a planting date

 

experiment in which five cultivars were used in three

separate treatments.

 

The pertinent information is illustrated in Table 5.

Class IV--Late Forcing

The objectives were to try and determine which planting
dates and rooting room temperature sequences are satis—

factory to obtain properly timed plants.

Experiment VIII.--The first eXperiment used two

 

planting dates in combination with specific rooting room
temperature sequences to determine the best planting date
for a late March (early Easter) flowering. Eleven culti-

vars were used.

The cultivars and their respective treatments are

listed in Table 6.

Experiment IX.——The second eXperiment in this class

 

was designed to compare various rooting room temperatures

(M1 the flowering of tulips for late March.

16

Five cultivars were used in each of three treatments.

The initial rooting temperature, as in all experiments, was

at 9°C. The temperature treatments before planting as well

as those sequences given after are presented in Table 7.

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RESULTS

Class I--Very Early Forcipg

 

Experiment I.--This experiment was designed to

 

evaluate various precooling and planting sequences of
tulips forced for Christmas. The results of this exper-
iment are shown in Table 8.

The data show that there were significant differences
at the 5% level on sprout length when comparing treatments
within the cultivar. Treatment 3 produced larger sprouts
than treatments I and 2. There was little, or no signif-
icance, when comparing treatment 1 and treatment 2 in any
of the five cultivars. Although treatment 3 exhibited a
definite effect on sprout length none of the three treat—
ments affected the time to flower (Table 9). These data
suggest that sprout length, although affected by different
treatments is not an indicator of the resulting quality,
size of the flower, or ease of flowering.

No differences in flower size were apparent at the
5% level. No treatment effect was noted on flower color,
shape or size. In addition there were no significant
numbers of either "blind" or "blasted" flowers. This is
shown by the high percentage of plants that flowered

(Table 9).

'24

25

Differences in overall total plant height did occur.
Treatment 3, the longest time of precooling at 9°C, produced
the tallest plants. The differences between treatments 1
and 3 were significant. In addition, there were significant
differences when comparing cultivars within treatments.

Even though treatment 3 had less time at 9°C for
rooting this appears to be offset by the longer time
precooled at 9°C. It is apparent that increase in overall
height is partly reflected in the length of the first inter-
node or foot. This was observed in all cultivars with the
exception of Pax. It appears then that longer periods of
precooling at 9°C have affected the resulting overall
height.

The only significant differences in foot length
occurred between treatments 1 and 3 in the cultivars
Abodement and Christmas Marvel.

The spread dates in the flowering of the cultivars
can be attributed to a cultivar response and not the

result of any of the treatments (Table 9).

 

Experiment II.--This experiment evaluated various
precooling temperatures. The data from the four treatments
are shown in Tables 10 and ll.

When treatments are compared the data show that there
were no significant differences within cultivars in either
sprout length or flower size. There were significant
differences between cultivars within treatments. This is,

however, to be eXpected.

26

When comparing cultivars within treatments one finds
significant differences at the 5% level in all of the
investigated categories.

There were significant differences at the 5% level
when examining the total plant height as well as the length
of the first internode, in treatments within cultivars.

There was no significance between treatments 2 and
3 in any cultivars with reference to total height. Treat-
ment u is tall in each cultivar but significant only in the
cultivar Snowstar. This indicates that longer periods of
precooling at 5°C tends to give taller plants.

It is apparent that the treatments have had an
effect on the days of flowering (Table 11). Some treatments
promote earlier flowering while others delay flowering.

It should be pointed out that the only cultivars that
would be saleable cut tulips for Christmas are, Levant,
Preludium and Pink TrOphy (Table ll).

The results of the four treatments on the five culti-
vars can be summarized as follows: Those plants which are
designated for use as cut flowers should be precooled at
5°C for 6 weeks while those which are intended for use as

pot plants should be precooled at 9°C for 6 weeks.

Experiment III.--This eXperiment was designed to

 

evaluate various rooting room temperatures on the flowering
of tulips for Christmas.

Data recorded in this experiment are shown in Table 12.

27

With four of the five cultivars, treatment 1 resulted
in significantly longer sprout lengths than treatment 2.
Like other experiments carried out in Part I sprout lengths,
even though reduced in size, did not affect the resulting
plant height, flower size or length of first internode.
This coupled with other experiments is again suggestive
that sprout height is not indicative of the ease or readi-
ness to flower. Resulting flower sizes are also not indi-
cated by sprout length.

There was no significant difference between treat-
ments with reference to flower size.

No significant differences in total plant height
resulted from any of the three treatments.‘ There are
significant differences though when comparing cultivars
within treatments.

The shortest foot size in four out of five cultivars
resulted from treatment 1. In three out of five cultivars
treatment 2 produced the longest foot.

It should be noted that although three separate
treatments were employed using various combinations of 5°
and 9°C no one treatment was superior to the others.
Treatment 1, however, enhanced flowering in most cases
(Table 13). This seems to indicate that at some time during
rooting the bulbs should be subjected to a temperature of
9°C. This is an area that needs further investigation

because as indicated by the data in Table 13 one sees

28

the need to flower the plants 3 to U days earlier in order

to have the plants available for the Christmas market.

Class II--EarlyForcing

 

Experiment IV.--This experiment utilized ten cultivars

 

while investigating the Optimum planting date as well as
the Optimal rooting room sequence for tulips forced in
mid-January.

Sprout lengths, as seen in Tablelfl were significantly
shorter in treatment 5. Treatment 2, unlike treatment 5,
produced the tallest sprouts in all of the cultivars.

None of the treatments appeared to have any signif-
icant effect on flower size. Although differences occurred
there appeared to be no definite trend.

When the dates of flowering are compared it is seen
that treatments 5 and 6 flowered later than 3 and D which
were later than 1 and 2 (Table 15). This is attributed
to the fact that they were planted on later dates. Thus
the length of the low temperature treatment can influence
the days to flower. In addition it is seen that as the
length of low temperature treatment is shortened the total
plant height decreases. This could prove beneficial when
programing plants for use as pot plants.

To further substantiate this, it was found that in
the treatments which received 5°C for a longer duration of

time the overall height was increased. Thus, the plants

29

could be used as cut flowers. This is in agreement with the
work of Stuart 33 al. (21) where they found that storage

for longer periods does result in a much taller plant.
Genetically, however, there are limits as to the final
height of the plant. Perhaps this would be of use in
producing cut flowers from plants which are normally used

as pot plants.

It is felt that the amount of cold which tulips
required to perform satisfactorily as pot plants is
acquired within 14.5 weeks. An interesting comparison can
be seen with treatments 1 and 2 which were planted on
September 20 and initially rooted at 9°C for 5 weeks. Both
treatments were then stored at 5°C. Treatment 2 was sub—
sequently returned to 9°C. This resulted in longer sprouts
and taller plants. This difference was not however sig-
nificant at the 5% level.

A point of reference is the fact that changes in the
first internode length account for approximately 50% of the
height change (Table I“).

As in previous experiments the intended use of the
plants would delegate what treatment should be employed.
The results of this experiment indicate that there is a
definite relationship between planting time and rooting

room temperatures on the eventual height of the plants.

3O

EXperiment V.—-This experiment was designed to study

 

the effect of various rooting room temperatures on the
flowering of tulips for Class II or mid-January forcing.

This experiment consisted of eight rooting room
temperatures (Table 3). The most noticeable and statis-
tically significant results can be seen between treatments
7 and 8. These large differences are seen in the total
overall plant height. The results are shown in Table 16.
Treatment 7 consisted of 90 days of rooting at 9°C while
treatment 8 was rooted at 5°C for 90 days. In these two
treatments the extremes are eXperienced. Treatment 7
produced the longest sprouts while treatment A, which had
a return to 9°C after 28 days at 5°C, had second longest
sprouts. Treatments 5 and 6, which had decreasingly
shorter periods of 9°C at the end, gave shorter sprouts.

Treatments 1, 2 and 3 which rooted at 9°C and 5°C,
with no return to 9°C produced sprouts that were shorter
than treatments which were returned to 9°C. Some exposure
to 9°C after 5°C gave sprouts that were longer than those
that were not returned to 9°C. When the effect on the
total plant height is impaired the same treatment effects
are indicated.

These results are comparable to those of the previous
experiment on planting time and rooting room temperatures.
There is, however, an exception. With long periods of

low temperatures (Table l“) a return at the end of the

31

rooting period to 9°C gave longer sprouts and taller
plants. In this experiment treatment 8, which was rooted
continuously at 5°C, gave the tallest plants with 50% of
the difference again detected in the length of the first
internode.

In reference to time to flower (Table 17). None of
the treatments appeared to have any influence on the cul—

tivars.

Class III--Medium Forcing

 

Two separate experiments were conducted. One exper-
iment investigated the effect of planting dates while the
second dealt with a series of rooting room temperature

sequences.

Experiment VI.--This experiment compared various

 

rooting room temperature sequences. Five cultivars were
used in the four treatments.

In the majority of cases treatment A produced sprout
lengths that were significantly longer than the other three
treatments (Table 18). Here, as in the previous experiment
a return to 9°C after an initial rooting sequence of 9°C
and 5°C, produced sprout lengths longer than a rooting
period of only 9°C and 5°C. Some 9°C after 5°C appears to
have an accelerating effect.

Total plant height shows that treatment A, or

continuous 5°C produced significantly taller plants.

32

Treatment 1 produced the next tallest plants. In most cases,
treatments 2 and 3 produced shorter plants.

Flower size appeared to be affected by treatment A.
In all cases this treatment had flowers that were smaller
than the remaining three. Treatment 1 had slightly smaller
flowers than treatments 2 and 3, but were still larger than
treatment A. This indicates that even though storage at
5°C produced significantly taller plants flower size was
reduced. Some 9°C in the rooting sequence appears to be
beneficial for a well proportioned plant.

Treatment A produced the largest first internode.
Treatments 2 and 3 appear to have a direct affect on the
length of the first internode. They produced shorter
internodes.

Like earlier experiments, longer periods at 5°C
during the rooting phase produced plants which would be
more useful as cut flowers, while combinations of 9°C and
5°C gave plants that could be programed as pot plants.

In all cases treatment A accelerated flowering.

Here a return to 9°C appears to delay flowering by a day

(Table l9).

Experiment VII.-—This experiment was a planting date

 

experiment.
The sprout length of treatment 1 was significantly
taller than in the other two treatments (Table 20). There

appeared to be no significance between treatments 2 and 3.

33

Treatment effects were evident when examining flower
sizes. Treatment 3, which consisted of less time at 5°C,
gave the largest flowers. There was a significant differ-
ence between treatments 1 and 3. These results are in
agreement with other experiments. We see, therefore, that
a long period of time at 5°C gives smaller flowers.

The length of the first internode follows the
pattern set up by the total height. There is a significant
difference between each treatment. The treatment held
longest at 5°C produced tmelongest first internode and this
effect decreased as the length of time of rooting was

decreased.

Class IV--Late Forcing

Our objective was to determine by trying various
planting dates, as well as varying temperature sequences,
just what methods are most satisfactory to obtain prOperly
timed plants and yet maintain quality.

EXperiments for this period necessitate the use of
2°C. This lower temperature becomes an integral part of

the cold sequence because of the time of flowering.

Experiment VIII.——The first experiment was designed

 

using two dates.
The most noticeable effect is the speed of flowering
by the plants in treatment 1 (Table 23). This can be

attributed to the fact that they were planted two weeks

3H

earlier than those of treatment 2. The data in Table 22
show that treatment 1 was planted earlier and consequently
flowered quicker, flower size was reduced significantly
when compared with treatment 2. This was significant with
all eleven cultivars. This reduction in the size of the
flower in treatment 1 can be attributed to the extra time
they remained in cold storage.

There appeared to be no treatment effect on overall
plant height. The results tended to be erratic even though
treatment 1 exhibited consistently larger sprouts than
treatment 2. Again this is proof that sprout length is in
no way indicative of resulting height or flower size.

It appears that the later one gets in the forcing
season the less effect length of storage has on the

resulting plants.

Experiment IX.--The second experiment for this Class

 

IV period was designed to compare various rooting room
temperatures on the flowering of tulips for late March.

The data for this experiment are presented in
Tables 2“ and 25.

One could summarize the results of this experiment by
saying that there were not any differences that could be
described as being significant. All cultivars flowered in
a short period with three of the five flowering in the same

period of time.

35

It appears that in this class the bulbs respond to
varying treatments with similar results. This degree of
freedom is lacking in the earlier Classes indicating that
these early Classes are more responsive to low temperature
treatments. The responses are not completely independent,
however, but enough so that altering the length of storage
does not significantly effect the resulting time to flower
or quality of same. It is concluded that an alteration
of the size of the plants for this class of forcing cannot
be as easily accomplished as in earlier forcings due to

lack of treatment response by the various cultivars.

36

TABLE 8.--Experiment 1: Length of sprouts, total plant
heights, flowers and first internodes.

4

Length (cm)
Cultivar Trt.

 

 

 

Sprout Flower TOtal plant First
height Internode
Abodement 1 “.6 5.0 17.6 2.1
2 “.9 5.0 18.9 2.5
3 3.1 5.2 21.2 3.5
Christmas 1 5.0 “.9 27.8 7.2
Marvel 2 “.8 5.0 28.7 7.6
3 “.0 “.8 29.“ 8.2
Pax l 1.5 “.“ 28.9 5.1
2 1.6 “.5 30.6 5.6
3 0.8 “.3 30.7 5.5
Ralph l 3.2 5.2 23.3 5.7
2 3.0 5.2 23.6 5.5
3 42.5 5.0 25.3 6.2
Ruby Red 1 6.1 “.9 26.5 6.3
2- 6.3 “.8 25.“ 6.1
3 “.“ “.8 25.7 6.6
To compare treatments within cultivar
HSD 5% level 0.2 N.S. 1.1 0.5

 

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38

TABLE 10.--Experiment II: Length of sprouts, total plant
height, flowers, and first internodes.

 

Length (cm)

 

Cultivar Trt.

 

 

Sprout Flower Total plant First
height Internode
Levant 1 5.2 5.2 22.6 “.3
2 5.3 5.“ 2“.8 5.8
3 5.2 5.2 2“.2 5.2
“ 5.3 5.0 25.7 14.9
Pink Trophy 1 “.9 5.0 30.0 7.7
2 “.“ 5.1 30.6 7.“
3 “.5 5.2 32.6 8.3
“ 3.9 5.1 33.2 7.9
Preludium l 2.6 “.9 27.0 9.2
2 2.6 “.8 29.8 9.7
3 2.6 5.0 29.“ 9.7
“ 2.7 “.9 30.“ 9.9
Ranchi l 5.6 “.8 30.1 3.9
2 5.“ “.7 31.3 “.9
3 5.7 “.8 32.1 “.8
“ 5.9 “.7 32.2 “.7
Snowstar 1 3.8 5.2 26.2 7.2
2 3.6 5.2 29.“ 9.1
3 “.0 5.1 28.5 8.7
“ “.l 5.1 30.9 8.8
To compare treatments within cultivar
HSD 5% level N.S. N.S. 1.7 0.6

 

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HSD 5% level 0.“ 0.2 1.8 0.8

 

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TABLE l2.--Experiment III: Length Of sprouts, total plant
height, flowers and first internodes.

 

Length (cm)

 

Cultivar Trt.

 

 

Sprout Flower Total plant 3 First
height Internode
Dix's l “.l 5.1 31.3 9.2
Favourite 2 “.0 “.8 33.9 10.0
3 “.0 5.0 32.9 10.3
Emmy Peeck l “.9 “.7 33.0 6.“
2 “.0 4.8 35.6 7.6
3 “.3 “.9 3“.8 7.5
Gander 1 “.6 5.2 37.5 9.0
2 3.6 5.0 37.5 8.5
3 “.“ 5.1 38.3 8.0
Most Miles 1 5.3 5.1 “3.9 9.3
2 “.2 5.1 “1.0 9.8
3 5.7 5.2 “0.0 9.“
Victor Mundy l 6.2 5.1 31.6 5.3
2 “.6 “.9 32.6 6.0
3 5.5 5.0 32.6 5.6
To compare treatments within cultivars
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TABLE l“.—-Experiment IV: Length of sprouts, total plant
heights, flowers and first internodes.

 

Length (cm)

 

Cultivar Trt.

 

 

Sprout Flower Total plant First
height Internode
Cassini l 6.0 5.3 29.6 9.0
2 6.6 5.3 30.5 9.7
3 5.9 5.“ 29.7 9.2
“ 6.3 5.3 28.1 8.3
5 5.0 5.2 26.0 7.“
6 6.5 5.3 2“.1 6.6
Demeter l 6.3 “.8 “0.8 11.5
2 8.2 “.9 “1.1 10.0
3 5.“ 5.0 37.8 9.3
“ 6.8 5.0 36.1 8.7
5 3.8 5.0 33.“ 7.8
6 5.8 “.9 30.5 6.2
Dr. Plesman 1 5.2 5.0 29.3 5.3
2 6.2 5.2 28.7 5.“
3 “.7 5.2 28.0 “.8
“ 5.5 5.1 2“.6 3.9
5 “.2 5.2 25.2 “.0
6 5.1 5.3 22.9 3.2
Gander l 5.8 5.1 39.6 11.3
2 7.3 5.0 “0.2 11.7
3 5.5 5.1 39.0 11.0
“ 6.5 5.2 37.3 10.3
5 3.9 5.1 35.1 9.9
6 5.2 5.1 32.0 7.7
Madame Spoor l 3.8 5.5 32.“ 8.8
2 “.7 5.5 33.7 10.“
3 3.7 5.7 32.0 10.0
“ “.“ 5.7 26.“ 7.1
5 2.3 5.8 3“.9 9.3
6 3.2 5.3 28.1 7.9
To compare treatments within cultivar
HSD 5% level 1.2 0.3 3.7 1.9

 

To compare cultivars within treatment
HSD 5% level 1.3 0.5 8.3 3.1

 

“3

TABLE 1“.--Continued.

 

Length (cm)

 

Cultivar Trt.

 

 

Sprout Flower Total plant First
height Internode
Most Miles 1 7.0 5.2 35.1 10.0
2 8.“ 5.3 37.2 9.6
3 6.2 5.5 36.8 9.6
“ 6.5 5.3 35.“ 8.7
5 “.“ 5.2 35.8 10.0
6 7.2 5.6 3“.“ 8.7
Paul Richter l 5.5 “.6 27.8 6.0
2 6.7 “.6 27.“ 6.1
3 5.0 “.7 26.“ 5.6
“ 6.6 “.7 27.1 5.6
5 “.“ “.5 23.8 “.5
6 6.2 “.6 23.5 “.1
Prominence 1 2.6 “.8 23.1 8.1
2 3.0 “.9 2“.2 8.0
3 2.5 “-7 23.5 800
“ 2.9 “.8 21.3 6.7
5 2.1 “.8 20.“ 6.“
6 2.7 “.8 20.5 6.1
Ralph l “.0 “.9 2“.2 6.0
2 “.8 5.0 22.5 5.3
3 3.5 5.0 21.8 “.9
“ “.2 5.0 20.0 3.7
5 3.1 5.3 21.3 “.9
6 3.8 5.3 16.7 3.1
Snowstar 1 5.3 5.0 26.7 7.6
2 5.8 “.9 28.8 7.5
3 3.“ 5.0 2“.7 7.0
“ “.“ “.9 23.“ 6.“
5 3.“ “.9 22.7 6.1
6 “.0 5.0 23.6 6.1
To compare treatments within cultivar

HSD 5% level 1.2 0.3 3.7 1.9

 

To compare cultivars within treatment
HSD 5% level 1.3 0.5 8.3v 3.1

 

““

 

 

 

ON ON NO uu OH OO OO N uu uu O
ON ON OO uu OO OO O uu II II O
ON ON OO II II Nm OO mH uu uu O
NN ON OOH uu uu HN NN N uu uu O
mm mm mm II II mH mm II II II N
ON ON OO II II Om OO N II II H pooam OEOOOE
ON HN ON .. -u .. NO HO O N O
ON ON OOH uu uu uu NN OO OH uu O
OH OH OOH II II II II HN ON uu O
ON NH OOH uu uu II N OO OO O O
OH OH OOH II II II uu O ON OH N
ON NH OO uu uu uu uu OH OO O H NOOOOO
OH OH OO uu uu uu uu HN OO ON O
Hm ma mm II II II II mm mm m m
OH OH NO II II II II ON OO OH O
OH OH NN uu uu uu uu OH OO NH O
OH OH NO uu uu uu uu mH Om mO N
OH OH OOH II II II II OH OO Om H cmEmOHN .NQ
OH OH OOH uu II II uu uu OO NH O
ON NH OO II II II II NN HN uu O
NH OH OOH uu uu uu II II mN NN O
OH OH OO uu uu uu uu uu OO OH O
NH OH OOH II II II II II NH mO N
OH OH OO uu uu uu uu uu OO OO H NOpOsOO
NN OH OO uu uu uu ON OO OH uu O
NN OH OO -- u- .. OH OO OH -- O
ON NH OOH uu uu uu uu OO NO uu O
HN OH OOH II II II O HO Om uu m
ON NH OOH uu II II II OO NO II N
ON NH OOH II II uu uu NO OO uu H HchmmO
me O:
AOSOHM Ihmzowm Ihmzowm om ONINN ONION mmIHN ONIOH NHIOH OHINH .
Op mOmO mo Ome mpcmHO ANNOOOOOV One LO>HOHOO
Ommmm>¢ memm>< NO O mmpwo On wchmaon a

 

.mmme OOHNOOOHO ”>H OOOEHNOOxmuu.OH mHOOB

“5

 

 

 

NN OH OOH II II uu O OO O uu O
NN OH OOH uu uu uu OH NN OH uu O
OH OH OO uu ,uu uu uu OH OO HN O
ON NH OOH uu uu uu uu OO OO O O
OH OH OOH uu uu uu uu N OO OO N
OH OH OO II II II II II OO O H pmpmzocm
HN OH OO uu uu uu N OO ON uu O
ON NH OO uu uu uu uu OH OO uu O
OH OH OOH uu uu uu uu NH OO OH O
OH OH OO uu I: II uu ON HN N O
OH OH OOH uu uu II II O ON OH N
OH OH OO uu uu uu uu O OO N H OOHOO
ON HN OOH uu uu uu OO OO uu uu O
ON ON OOH uu uu uu OO OO uu uu O
HN OH OO II II II NH Om OO II O
HN OH OOH uu uu uu ON OO ON uu O
HN OH OO uu uu uu HH OO OO II N
ON NH OOH II II uu uu ON HN uu H OOcOcHEONN
NN OH OOH uu uu uu ON OO HN N O
ON ON NO uu uu uu OO OO OH uu O
HN OH OO uu uu uu O NO HO HH O
HN OH OOH uu uu uu ON OO NH OH O
HN OH OOH uu uu uu OH OO ON HN N
NN OH OOH II II II NH OO ON O H NOOOOHO HOON
HN OH OO uu uu uu uu NO NO N O
NN OH OO uu uu uu OH ON OH uu O
OH OH OO uu uu uu uu OH OO uu O
ON NH OO uu uu uu uu OO OO uu O
OH OH OOH uu II II uu uu OO O N
OH OH OO uu II II II uu OO O H OOHHz umoz
OOH OOH OO ONuNN ONuON ONuHN ONuOH NHuOH OHuNH
pmonm uamonm uamonN .
Op OOOO mo OOOO OOCOHQ HONOOGOOO nae NO>HOHOO
mepo>< Ommmm>< mo O Ompwo an OCHLOZOHO O

 

.UOSCH»QOOII.OH mqm<8

“6

TABLE l6.--Experiment V: Length of sprouts, total plant
heights, flowers and first internodes.

 

Length (cm),

 

Cultivar Trt. Sprout Flower Total plant First

 

height Internode

Apricot 1 6.2 5.8 31.8 6.3
Beauty 2 7.9 6.1 30.6 5.9

3 5.7 5.8 32.0 6.3

“ 9.5 5.7 30.0 5.7

5 8.2 5.8 30.1 5.6

6 6.8 5.8 31.3 6.“

7 9.3 5.8 27.“ “.6

8 8.3 5.7 33.1 6.9

Christmas 1 5.2 “.9 27.7 7.6
Marvel 2 6.8 “.9 28.6 8.0

3 5.5 “.8 27.5 7.“

“ 8.5 “.“ 29.0 7.“

5 7.9 “.9 28.3 7.8

6 7.1 “.8 29.2 8.2

7 8.“ “.8 25.“ 6.“

8 6.9 “.8 29.1 8.0

Diorama 1 3.0 “.8 32.1 7.0
2 3.0 5:1 35.2 7.“

3 2.9 5.2 3“.7 7.2

“ 3.9 5.1 33.1 6.2

5 3.“ 5.1 33.0 6.7

6 3.0 5.3 36.8 7.6

7 “.5 5.0 33.1 6.1

8 3.8 “.8 35.9 7.7

Merry Widow l 3.6 “.6 2“.5 8.1
2 3.8 “.6 25.8 7.8

3 3.2 “.8 23.9 7.3

“ 5.3 “.6 22.0 6.“

5 £1.“ “.7 23.2 7.3

6 3.9 “.6 23.8 7.“

7 “.6 “.7 21.7 5.8

8 “.1 “.5 26.8 8.2

Pax l 3.2 “.2 27.“. 7.3
2 3.5 “.3 28.1 7.5

3 2.5 “.2 26.5 6.8

“ 3.8 “.3 2“.5 5.7

5 2.7 “.3 25.3 5.6

6 3.2 “.3 27.7 7.0

7 3.“ “.2 26.1 5.8

8 3.2 “.1 3 7.“

28.

 

To compare treatments within cultivar
HSD 5% level 1.3 0.“ 3.3 l.“

 

'TO compare cultivars within treatment
HSD 5% level 1.2 0.7 7.9 “.6

 

“7

TABLE l6.--Continued.

 

Length (cm)

 

Cultivar Trt. Sprout Flower Total plant First
height Internode

Roland 1 3.1 “.6 22.2 7.7
2 3.6 “.5 21.0 7.1

3 3.5 “.8 21.7 8.2

“ “.2 “.7 20.0 6.0

5 3.7 “.6 20.“ 6.7

6 3.6 “.7 19.7 6.5

7 “.5 “.6 16.9 “.“

8 “.1 “.5 25.6 10.5

TOpscore 1 3.6 “.8 2“.0 8.2
2- “.1 “.9 25.8 8.9

3 “.0 “.9 25.2 8.7

“ 5.1 5.0 23.0 7.3

5 “.5 5.0 2“.6 8.1

6 3.9 5.2 25.9 9.5

7 5.6 5.0 2“.9 7.7

8 “.7 “.9 26.7 9.5

Trance 1 5.0 “.7 25.9 6.3
2 5.“ “.8 2“.8 5.8

3 “.6 - “.8 25.3 6.2

“ 8.0 5.1 23.9 5.3

5 6.6 “.8 23.2 “.9

6 6.5 5.0 26.2 6.2

7 6.9 5.0 2“.5 5.2

8 6.6 “.8 26.8 7.2

van der 1 “.“ “.9 32.6 9.7
Eerden 2 “.9 5.0 32.0 9.8

3 “.6 “.8 33.9 10.“

“ 5.“ 5.1 31.9 8.9

5 “.l 5.1 30.9 8.6

6 “.6 5.0 32.“ 10.1

7 5.7 “.9 27.3 7.0

8 5.7 5.0 36.8 11.“

Winter Queen 1 6.1 5.5 18.8 5.0
2 6.7 5.5 20.7 5.3

3 5.8 5.3 19.“ 5.1

“ 7.8 5.6 18.9 “.6

5 6.6 5.6 16.9 3.“

6 6.3 5.6 20.9 5.2

7 7.0 5.“ l“.9 2.7

8 6.3 5.5 19.7 5.1

 

To compare treatments within cultivar
HSD 5% level 1.3 0.“ 3.3 1.“

 

‘To compare cultivars within treatment
HSD 5% level 1.2 0.7 7.9 “.6

 

148

TABLE l7.-—Experiment V: Flowering Dates.

 

 

 

Z Flowering b Dates % of Average Average
January plants date of days to
Cultivar Trt. - flower— flower- flower
10-12 13-15 16—18 19-21 22-29 25 ing ing
Apricot l -- 39 55 -- -- -- 9“ lo 19
Beauty 2 -- 15 73 3 -- -- 91 16 19
3 -— -- 85 6 —- -- 91 18 2
u -- 67 3o —- -- -- 97 15 18
5 " 21 55 9 -- -- 85 17 2o
6 -- 15 71 5 -- -- 91 15 30
7 -- 9 73 15 -- -- 97 17 30
8 -_ 58 “2 -— -- i -- 100 15 18
Christmas 1 ‘—- 33 63 -- -- -— 96 15 18
Marvel 2 -— 6“ 31 3 -- -_ 98 5 18
3 -- 58 “2 -- -- —- 100 15 18
“ 7 89 “ -- —- -- 100 1“ 17
5 2 92 u -— _- -- 98 in 17
6 —_ 80 18 -- —- -- 98 15 18
7 ll 7 -- -- -- -- 98 1“ 17
8 —- 89 11 —— —- —- 100 15 18
Diorama 1 -— -- -— 38 56 —— 9“ 22 25
2 -- -- -- 2 8“ 2 88 23 26
3 -- -- -- 9 85 -- 9“ 33 89
“ -- -- —— 25 73 -- 98 22 25
5 -- -- -- 17 83 -- 100 93 36
6 —— -- -— 6 86 2 OH 23 95
7 -- -- -- 23 67 6 96 23 26
8 —- —- 2 63 29 -- 99 21 2a
Merry Widow 1 -- “ 73 21 -- -- 98 17 20
2 —- -— 21 77 -- -- 98 19 22
3 -- -- 25 I3 -- —— 98 19 22
“ —- 17 75 “ -- -- 96 16 19
5 -- “ 58 36 —- -- 98 16 21
6 —- 2 67 31 -— —- 100 18 21
7 -- -- 56 “2 -- -- 98 18 21
8 -_ 6 75 15 -- -— 9b 17 20
Fax 1 -- -- A“ “8 -- -- 92 1Q 22
2 —- -- - 23 77 -- -— 100 19 22
3 —- -- 10 9O -- -- 100 20 23
“ —- 2 25 73 -- -- 100 19 22
5 -- -- 6 79 13 -— 98 2o 23
6 -- -— 13 85 -- -- 98 20 2
7 -- -- 13 71 1“ -- 98 21 2
8 -- —- 50 5o -- —- 100 18 - 21

 

149

 

W r —r

 

 

S Flowering by Dates 1 of Average Average
January plants date of days to
Cultivar Trt. 1 flower- flower- flower
10-12 13-15 16-18 19-21 22-2“ 25 ing ing

Roland l -- 37 59 2 -- .- 98 16 19
2 -- 18 59 8 -- -- 85 16 19
3 -- 2 93 -- -- -- 95 17 20
“ 2 “6 39 -- -- -- 87 16 19
5 -- 39 61 -— -- -- 100 l6 l9
6 -- “ 79 -- -- I'- 83 17 20
7 -- 36 58 “ -- -- 98 16 19
8 -- 38 51 -— -- -- 89 16 19
Topscore 1 -- ' 25 75 -- -— -- 100 16 19
2 -- ' 6 88 6 -- —- 100 17 20
3 -- -- 96 2 —. -- 98 17 20
“ -- 33 65 -- -- -- 98 16 19
5 -- 13 83 2 -- -- 98 16 19
6 -0- —- 92 6 o.- .- 98 17 20
7 2 “6 “8 -- -- -— 96 16 19
8 -- 10 88 -. -- -- 98 16 19
Trance 1 -— “6 52 -- -- -- 98 16 19
2 -— 50 50 -- -- -- 100 15 18
3 2 33 63 -- -- —- 98 16 19
u -- 98 2 -- '-- -- 100 1“ 17
5 -- 83 15 -- -- -- 98 15 18
6 -- 71 29 -- —- —- 100 15 18
7 -- 60 “0 ~-- -- -- 100 15 18
8 -- 100 -- -- -- -- 100 1“ 17
van der 1 -- -- ““ 56 -- -- 100 19 22
Eerden 2 -- -- 17 73 2 -- 92 19 22
3 -- -- 17 73 2 -- 92 21 2“
u -- -- 5“ 38 -- -- 92 18 21
5 —- 2 35 um -- -- 81 2o 23
6 _— -- u“ 50 -- -- 9“ 2o 23
7 —- 2 31 63 2 -— 98 19 22
8 _- -- “6 an -- -- 9o 19 22
Winter 1 -- 92 “ -- -- -- 96 15 18
Queen 2 “ 9O -- -- -— -- 9“ 15 18
3 2 9“ » u -- -- -- 100 - 15 18
“ 8 88 -- -- -- -- 96 13 16
5 2 85 6 -- -- -- 93 15 18
5 u 9a 2 —- -- -- 100 1“ 17
g 21 65 a -- -- -- 9. 15 la

-- 9n -- -- -- -- 9n 1“ 17

50

TABLE 18.—-Experiment VI: Length of sprouts, total plant
heights, flowers and first internodes.

 

Length (cm)

 

Cultivar Trt.

 

 

Sprout Flower Total plant First
height Internode
Bellona 1 3.2 5.3 27.2 8.3
2 5.2 5.“ 23.8 6.2
3 “.8 505 2502 701
“ “.8 5.2 26.9 8.2
London» 1 2.8 5.2 30.8 5.“
2 3.8 5.6 26.0 3.3
3 309 5014 2905 “.2
“ “.5 “.8 28.1 6.0
Paris 1 3.“ “.“ 23.1 “.6
2 5.0 “.5 23.2 “.0
3 “.5 “.5 20.7 3.5
“ 5.1 “.3 22.1 “.0
Pax l 2.9 “.1 22.6 “.6
2 5.2 “.0 19.0 3.“
3 5.1 “}0 17.7 3.0
“ 5.5 “.1 26.1 6.1
Purple Star 1 “.1 “.6 33.9 11.1
2 5.7 “.“ 29.1 9.9
3 6.1 “.5 29.“ 10.0
“ 5.6 “.2 31.9 11.8
To compare treatments within cultivar
HSD 5% level 0.“ 0.2 1.7 1.1

 

To compare cultivars within treatment
HSD 5% level 0.3 0.2 2.5 0.7

 

51

 

 

 

om m mm In um mm m :
Hm m mm 1: mm Hm an m
mm OH mm 3 mm mw I: m
mm OH am m om m I- H “mum mHapsm
NH m OOH In In 3 mm a
pH m 00H 11 a mm mm m
NH m OOH I: II NH mm m
om m QOH I: OH mm m H xmm
mm HH 00H om o: z I: :
mm NH 00H mm mH 1| 11 m
mm MH 00H mm m I: I: m
mm MH mm am 3 II II H memm
mH m 00H I: m mu mH a
Hm m mm II 11 mm m m
mm 0H am mH mm m I: m
mm 0H om m mm I: II H copcoq
mH m 00H 1: In H» mm :
om m 00H 11 m mm 1| m
om m 00H In mm we I: m
cm m mm :1 mm. mu II H «COHHom
wcfi wcfi :Han HHum mum mum
pmsoHu Inmonm Inmonm .
on mama no muwv mucmHo Azpmsnnmmv nae nm>HpHso
mwmuo>¢ mwmpm>< no u mmpma an wanmZOHm a

 

.mopmc wcHumonm

uH> pcmsapmaxmuu.mH mamas

52

TABLE 20.--Experiment VII: Length of sprouts, total plant
heights, flowers and first internodes.

 

Length (cm)

 

Cultivar Trt.

 

 

Sprout Flower Total plant First
height Internode
Andes l 7.7 5.1 32.2 5.8
2 6.6 5.1' 27.7 “.5
3 7.“ 5.2 25.5 3.3
Apeldoorn l 3.9 5.2 31.“ “.1
2 3.0 5.5 26.“ 1.9
3 3.2 5.5 19.2 1.0
Dreaming 1 7.5 “.8 35.0 8.2
Maid 2 7.0 “.6 25.1 “.0
3 6.“ “.9 29.7 “.9
Dutch 1 6.3 5.0 35.“ 5.6
Princess 2 5.3 “.9 31.“ “.6
3 “.8 5.3 27.9 2.8
Gudoshnik l 1.9 5.0 “2.2 8.9
2 1.3 5.1 31.1 6.0
3 1.9 5.3 25.3 “.“
To compare treatments within cultivar
HSD 5% level 0.5 0.2 1.6 0.6

 

7*

To compare cultivars within treatment

HSD 5% level 0.6 0.1 2.3 1.3

 

53

 

 

 

mm ON :m H» mm II II II II m
mm NH mm am pm mm II II II N
am mH mm II mm a: pH II II H stmoosu
mm :H mm II II mm mm II II m
mm MH mm II II Hm 55 II II N mmmocHnm
mm OH OOH II II II NH mm II H Sousa
mm :H :m II II m: m: II II m
mm :H 3: II II Hm MH II II N on2
mm HH mm II II II we mH II H mCHEmme
mm OH OOH II mm OF N II II m
pm mH mm II mH an O II II N
mm HH OOH I- I- m ma mm I: H epooeHmaa
mm OH NO II II II mm mm mH m
mm OH HO II II II Hm ON II N
OH 5 mm II II II II :m mm H mmpc<
mcfi wsfi mmuom mHIaH mHusH mHIHH OHIw aum
pmSOHm IpoonM ImmSOHm .
on name no memo mpcmHQ Ampmsnommv nae pw>HpHso
mwmpm>¢ owwmm>< no a mmpmm an MGHpmonm N

 

.mmpmo wchmonm

"HH> pcmeHsmameI.Hm mamas

5“

TABLE 22.--Experiment VIII: Lengths of sprouts, total plant
heights, flowers and first internode

 

Length (cm)

 

Cultivar Trt.

 

 

Sprout Flower Total plant First
height Internode

Abe Lenstra l 6.6 “.8 36.2 5.9
2 5.5 5.2 33.9 6.“
Aristocrat 1 10.1 “.7 32.9 6.5
2 8.7 5.0 35.7 8.6
Blizzard l 8.2 “.9 18.5 2.1
2 6.9 5.3 23.7 3.7
Couleur 1 7.1 “.8 18.6 2.8
Cardinal 2 6.3 “.9 19.0 3.2
Diplomate 1 5.5 5.5 27.7 2.9
2 “.2 5.8 27.1 2.0
Edith Eddy 1 5.9 “.3 25.1 5.5
2 “.5 “.5 25.6 6.8
Makassar 1 6.7 “.6 33.1 5.0
2 5.“ 5.1 30.8 “.8
orange Sun 1 9.6 5.“ 29.2 5.6
2 7.7 5.6 27.8 5.2
Palestrina l 8.0 5.1 27.5 “.5
2 6.5 5.5 29.6 5.“
Peerless 1 7.6 6.1 27.3 2.8
Pink 2 6.1 6.2 28.1 “.3
Robinea 1 6.2 5.2 2“.“ 5.5
2 5.“ 5.“ 2“.7 6.“

To compare treatments within cultivar
HSD 5% level 0.2 0.1 0.7 0.“

To compare cultivars within treatment
HSD 5% level 0.8 0.6 3.8 1.8

55

 

 

HN HN NO II OO N II N
OH OH OO II NN NO N H OmcHOOO
ON ON OO NO Hm II II N OOHO
HN HN OO O ON OH II H mmmemmm
HN HN OOH II OOH II II N
ON ON OO II NO NO II H OOHOOOOHOO
OH OH OO II Hm NO II N
OH OH OOH II mm NO II H OOO mOcOtO
ON ON OO OO II II II N
NN NN OO O OO N II H pammmxmz
OH OH OO II II OO O N
OH OH OO . II II ON NN H NOOO BOHOO
OH OH OOH II mm NO II N
NH NH OOH II II OO N H OOOEOHOHO
OH OH OOH II O: OO II N HOOHOOOO
NH NH OOH II II mO NH H OOOHOOO
ON ON OOH II OO OH II N
OH OH OO II OH OO II H OpONNHHO
HN HN OO O OO II II N
ON ON om II as mm m H panooppme<
ON ON OOH HO Om II II N
ON ON OO II , OO II II H Oppmcmq 66¢
OOH OOH ONION NNION OHINH OHIOH
hmzodh I..H®3O._H.H ILGSOHM .
op mama mo mump mpcmHQ Anchmzv p69 pm>HuHso
mmmpm>< mwmpm>< mo m mmpmm_hn.wsapm¥on;R

 

.mmpwU wCHLmSOHm "HHH> meEHLquMII.MN mHm¢B

56

TABLE 2“.--Experiment IX: Length of sprouts, total plant
heights, flowers and first internodes.

h

Length (cm)
Cultivar Trt.

 

 

Sprout Flower Total plant First

height Internode
Dreaming 1 10.9 “.8 28.3 3.0
Maid 2 11.2 5.1 29.“ 3.8
3 10 3 5.0 28.7 3.7
Golden Eddy l 5.9 “.5 26.7 7.2
2 6.7 “.5 28.0 6.8
3 6.5 “.7 27.7 7.“
Ornament l 6.0 5.1 20.2 1.5
2 6.0 5.0 18.9 1.3
3 6.0 5.0 18.9 1.1
Paris 1 6.“ “.5 21.2 3.2
2 6.2 “.5 2“.6 “.5
3 6.“ “.7 25.6 5.2
Utopia l 7.2 “.7 30.8 6.7
2 7.6 5.0 31.8 6.9
3 7.2 “.9 30.9 6.6

 

To compare treatments within cultivar

HSD 5% level 0.3 0.2 0.9 0.“

 

To compare cultivars within treatment

HSD 5% level 0.5 0.“ l.“ 0.7

 

57

 

 

 

OH OH OO N OO II O
OH OH OO OH ON O N
OH OH OOH NH mO II H OHOOOO
ON ON OO ON OH II m
ON ON OO ON NH II N
ON ON OO HO Om N H OHOOO
OH OH OO II NO NO O
NH NH a OO II OO ON N
NH NH OO II NN OH H OOOOOOOO
NH NH OO II OO OO O
NH NH OO II OO OO N NOOO
OH OH OOH II OO OO H OOOHOO
NH NH OO N OO ON O
OH OH mO NH OO O N
OH OH NO O ON OH H OHOz OOHOOOOO
OOH OOH NNION OHINH OHIOH
eHmBOHM IcH®30HM IhmBOHh .
op OOOO mo mpmc OpCOHQ Aconmzv One O6O>HOHSO

mwmum>< mwmpm>< mo R mmpmo an wchmonm m

 

.mmumv wcHhmonm "xH unmEHthxMII.mm mHmOB

DISCUSSION

The effects<fl7various temperatures on the resulting
sprout heights, plant heights and length of the foot,
although significant at times, were variable from cultivar
to cultivar. That is to say that not all cultivars follow
the same pattern. The length of storage time did, however,
significantly affect the overall eventual height of the
plants, a phenomenon already noted by Stuart 32 a1. (21).
In their work it was determined that the longer the time in
cold storage the taller the plants. The data reported here
agree with this conclusion. This duration of cold had an
effect not only on plant height but also showed significant
correlations in some cases to foot length as well as
sprout height. Correlations existed also between length of
time in storage and flower size.

For dicsussion purposes the author has singled out
one experiment that contains the necessary variables.
Generally the other eXperiments reacted much the same as
the one to be described. This eXperiment was designed to
determine the Optimum planting date for rooting room
storage for a medium forcing period. This medium forcing
period includes Valentine's Day.

Five cultivars were used: Andes, Apeldoorn, Dreaming

Maid, Dutch Princess and Gudoshnik.

58

59

To determine their response to length of cold storage

the cultivars were evaluated separately.

Storage on Total Height

 

Pertinent statistical information relevant to the
effect of length of storage on total height on the cultivars
involved is shown in Appendix Table 6.

In the cultivars Dutch Princess, Apeldoorn, Gudoshnik
and Andes there is a highly significant correlation between
the total plant height and the length of time in storage
(Appendix Tables l,2,3,“). With Dreaming Maid there appears
to be no correlation (Appendix Table 5). Apparently there
is a direct cultivar response with Dreaming Maid.

These same results were experienced in preliminary
experiments where the majority of cultivars responded to a
treatment, while a small percentage did not.

There was a negative correlation to plant height as
storage times are altered or shortened. The less time in
storage the shorter the plants. These two extremes in
storage are beneficial when it is desirable to have either

a pot plant or a cut flower.

Storage Time on Sprout Height

 

Pertinent statistical data are shown in Table 7. In
the cultivars Dreaming Maid and Dutch Princess there is a
highly significant correlation between sprout height and the

length of time in storage. The longer the storage duration

60

the longer the sprouts (Appendix Tables 1,5). Because only
these two responded this way, with longer sprouts, and the
remaining three did not, it is possible to assume then that
this could be attributed to a cultivar reaction and not
a treatment effect. It is interesting to note that even
though these two responded with longer sprouts than did the
remaining three, this increase in height appeared to have
no effect on the resulting overall height. This is also
borne out when comparing Gudoshnik with a sprout length
of 1.9 Cm to the cultivar Andes that had 7.7 cm. The mean
total plant height for Andes three replications was 32.2
compared to Gudoshnik with the shorter sprout having a
total plant height of “2.2 cm. It is felt then that even
though longer times at cold storage may possibly affect
sprout height, in most instances they have no relationship
to the overall plant height.

In earlier years of bulb forcing many growers relied
strictly on sprout height as an indicator of "readiness to
force." It is shown in this dissertation that this is

not always the case.

Storage Effect on Foot Length

In four of the five cultivars there was a significant
correlation between the length of time in storage and the
foot length. These correlations are shown in the tables of
Simple Correlations (Appendix Tables 1-5). Pertinent

statistical data are shown in Appendix Table 8.

61

It appears that storage has an effect on foot length.
To further prove this it was observed by the author and
co-workers.that significant changes in total plant height
are actually reflected in the foot length and to a lesser
degree from the first node to the top of the flower. If
then storage times, and the temperatures, are altered enough
to seriously effect foot length one can assume that the
total plant height is also going to be directly affected.

The overall increase in total plant height which is
visible as an increase in foot length substantiates the
work of Stuart (21). He showed that longer storage time
is reflected in a taller plant. He does not indicate _
however whether the increase in height is principally in

the length of the foot.

Total Height and Foot

 

As discussed previously, increases in foot length
give an increase in total plant height. The actual increase
in total plant height is reflected in the plants as an
elongation of the foot itself and not so much an elongation
of the plant above the foot.

This phenomenon is proven by examining the five
cultivars under consideration as significance between total
plant height and foot with total height being the dependent
variable. The direct simple correlations are shown in

Appendix Tables 1-5.

62

With storage time being the independent variable, we
can see that total plant heights are also going to be altered
or determined by storage durations. Explanation of varia-
tions due to storage are shown in Appendix Table 9.

It can be hypothesized then by altering time of
storage we are altering resulting foot lengths which in turn
determine significant increases or decreases in total plant

height.

Sprout Height on Total Height

Only in the cultivar Dutch Princess is there a sig-
nificant correlation between sprout height and total plant
height (Appendix Table 1). This response is best explained
as a direct cultivar response and not one indicative of
any external treatment. This type of response should not
be a contributing factor in determining length of storage
for other bulbs in a forcing program. Pertinent statistical
information regarding this response is shown in Appendix

Table 10.

Sprout Height on Foot Length

 

Only with the cultivar Dutch Princess was there any
significance between foot length and sprout height (Appendix
Table 1). This also can be best explained as a direct
cultivar response and not one dependent on external factors.

Explanation of variations due to storage length are shown

63

in Appendix Table 11. This is further proven when remem-
bering that this cultivar was the only one that sprout

height and total height were correlated.

Flower Size and Storagg

Flower size is apparently genetically determined and
not readily altered by varying durations of storage. In
the cultivar Gudoshnik there was apparent the only signif-
icance and this was a negative one (Appendix Table 3). As
total height increased flower size had a tendency to
decrease. This decrease in size although related possibly
to total plant height is not as drastic as can be encoun-
tered when improper temperatures are given to the bulbs
either in dry or wet storage. In these cases complete

abortion or blindness occurs.

General Discussion

In a bulb forcing program the control of storage time
and temperature is a very useful tool. Through prOper
manipulation of length of time and temperatures the process
of forcing bulbs will involve less guesswork.

Stuart at al. (21) showed that storage time definitely
influenced the resulting height of the flowering plants.
This investigation not only confirms their findings but
also shows that many cultivars, can be quite precisely
regulated for use either as a pot plant or cut flower.

There are however cultivars that are genetically destined

6“

to be a certain size so that if alteration of this innate
trait is tried the plant will retort by either aborting the
flower or having some other undesirable characteristic.

In earlier work, by Hartsema, Luyten and Blaauw (l2)
much emphasis was placed on emerging sprouts. They advo-
cated moving the bulbs to another temperature when the
sprouts were of a certain size and then subsequently moving
them again when the sprouts were longer. However, from the
results of these present eXperiments, there was no statis-
tically significant correlation between sprout length and
total plant height, as was there no difference in foot or
flower size. Therefore these data are not in agreement
with the proposed scheme of Hartsema 33 a1. (12).

In the experiments that were described in the results
section much evidence was accumulated to add strength to
the preceding discussion. These results also show that it
was the treatment after planting that determines what the
resulting plant height will be. As indicated these exper-
iments deal not only with various planting dates but also
included different temperature schemes. Included in the
investigation were precooling and planting combinations.

These planting date experiments although having some
effect on foot heights, flower size, etc. exhibited exactly
what has been borne out in this latter work. That of course
is, for taller plants the length of storage time at 5°C

should be increased. This period should be at least 15

65

weeks for cut flowers and 13 weeks for pot plants. Therefore,
cut flowers need the longer time, while a shorter treatment
is satisfactory for pot plants.

By using the 13 week cold instead of the 15 week it
is eXpected then that varieties previously grown only as
cut flowers could be grown as pot plants. It is felt that
9°C in combination with 5°C is far superior as far as pot
plants are concerned.

It is concluded that by combining proper storage
temperatures with proper storage times the forcer can deter-
mine final plant size.

In addition to prOper storage temperatures and
durations there are many other conditions that can inter—
fere with forcing. These are imprOper dry storage times
and temperatures, disease infection, insect infestation, a
lack of moisture and/or poor temperature control during
rooting.

Important also are the temperatures in the green-
house during forcing. By controlling these variable
conditions, through programming and monitoring them
periodically, the use of storage durations and lower
temperatures (5°C) can be used as an effective means of

producing quality plants.

SUMMARY

The results of this investigation show that guidelines

can be developed to control with a great deal of accuracy

the performance of forced tulips.

Cultural techniques were investigated as well as

correct sequences of rooting room temperatures and precooling

treatments.

To illustrate, what each experiment clearly indicated

in the data, one experiment was chosen that contained all

the variables that the remaining eXperiments consisted of.

Each independent variable was analyzed. The results were:

(1)

(2)

(3)

In most cases sprout length was in no way an
indicator of the plants'final height or

readiness to be forced.

Flower size is not affected by varying durations
of storage and therefore appears to be genetically
determined.

Total plant height is directly affected by the
length of time in storage. This duration should
be 15 weeks for cut flowers and 13 weeks for pot
plants. The less time in storage the shorter the

plants.

66

67

(“) Storage duration has a direct effect on foot
length. Significant changes in total plant
height are reflected in changes in foot length.
At times this change can be 50% or better of the
overall change in total height.

(5) Days to flower and spread dates of flowering fiere
not seriously affected by treatments that closely
paralleled each other.

(6) By using a forcing scheme containing 13 weeks of
cold instead of 15 weeks, varieties previously
grown only as cut flowers could be grown as pot
plants. It is felt that 9° C in combination with
5°C is far superior when considering pot plants.

By the use of proper temperature sequences and

durations of temperatures not only overall plant heights are
controlled but other factors as well which contribute to the

final product, a quality plant.

BIBLIOGRAPHY

68

BIBLIOGRAPHY

Beyer, J. J. The terminology of the flower develOpment
in bulbous plants. [Dutch] Meded. Landbou—Hoogesch.
Wag. “6: l-l7. l9“2.

Beyer, J. J., and E. Van Slogteren. Early forcing
and transportation of bulbous plants. [Dutch] Comm.
Lab. Bulb Res. Lisse “2: l-35. 1931.

Blaauw, A. H. Rapid flowering of Darwin tulips.
I. Proc. Acad. Sci.Amst. 29: l3“3-l355. 1926.

Blaauw, A. H., I. Luyten, and A. M. Hartsema. Shifting
of the periodicity; adaptation and eXport to the southern
hemisphere. (Hyacinth and Tulip) [Dutch] Verh. kon.

ned. Akad. Wet., Sect. II 26: 7, 1-105. 1930.

Blaauw, A. H., and~M. C. Versluys. The results of
the temperature treatment in summer for the Darwin
tulip. 1. Proc. kon. ned. Akad. Wet. 28: 717-731.
1925.

Crossley, J. H. Tulip storage temperatures and flower
embryo develOpment in relation to forcing of British
Columbia bulbs. Proc. Bulb Growers Short Course
(1953). Tacoma, Wash., pp. 33-38. Hort. Abstracts
23: ““53.

Dickey, R. D. Growing tulips in northern Florida.
Proc. Flor. State Hort. Soc. 66: 331-333. 195“.

Gill, D. L., J. J. Beijer, N. W. Stuart, and C. J.
Gould. Some effects of bulb storage temperature and
planting conditions on production of tulip flowers in
the greenhouse and outside in Southern Georgia.

Proc. Amer. Soc. Hort. Sci. 70: “51—“60. 1957.

Hartsema, A. M. Influence of temperatures on flower
formation and flowering of bulbous and tuberous
plants. In: EncyclOpedia of Plant Physiology, Ed.
by W. Ruhland, Springer-Verlag, Berlin, Vol. 16,
pp. 123—167. 1961.

69

10.

11.

12.

13.

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15.

16.

17°

l8.

19.

20.

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Hartsema, A. M., and A. H. Blaauw. The shifting of
periodicity by means of high temperatures. Adaptation
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Proc. kon. ned. Akad. Wet. 38: 722—73“. 1935.

Hartsema, A. M. and I. Luyten. The so—called "stocking
blind" of tulip bulbs. [Dutch] Med. L.H.S. Wageningen
50: 6, 83-101. 1950.

Hartsema, A. M., I. Luyten and A. H. Blaauw. The
Optimal temperatures from flower formation to flowering
of Darwin tulips. II. [Dutch] Verh. kon. ned. Akad.
Wet., Natuurk., Sect. II 27: l, 1—“6. 1930.

Hartsema, A. M., and H. F. Waterschoot. The possi-
bility of making Hyacinths flower in the tropics,
and its limitations. [Dutch] Med. L.H.S. Wageningen
“3: 2, 1-27. 1939.

Luyten, I. Rapid flowering of early tulips "Van der
Neer." Proc. kon. ned. Akad. Wet. 30: 502-513.

1927.

Luyten, I., G. Joustra and A. H. Blaauw. The results
of temperature treatment in summer for the Darwin
tulip. II. Proc. kon° ned. Akad. Wet. 29: 113-126.
1925. '

Mulder, R., and A. H. Blaauw. The results of the
temperature treatment in summer for the Darwin tulip.
III. Proc. kon. ned. Akad. Wet. 29: 199-220. 1925.

Mulder, R., and I. Luyten. On the periodicity of the
Darwin tulip. [Dutch] Verh. kon. ned. Akad. Wet.,
Natuurk. Sect. II 26: 3, l—6“. 1928.

Purvis, O. N. Recent Dutch research on the growth
and flowering of bulbs. I. The temperature require-
ments of hyacinths. Scient. Hort. 5: 127—l“0. 1937.

. Recent Dutch research on the growth and
flowering of bulbs. II. The temperature requirements
of gulips and daffodils. Scient. Hort. 6: 160-177.
193 .

Rees, A. R. The Physiology of Ornamental Bulbous
Plants. Botanical Review Vol. 32, No. l,~l-23. 1966.

Stuart, N. W., and C. J. Gould. Storage and forcing
of tulips. Flor. Rev. 113: (2920): 31—32, 12“-l26.
1953.

21.

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25.

26.

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Stuart, N. W., C. J. Gould, and D. L. Gill. Effect

of temperature and other storage conditions on forcing
behavior of Easter lilies, bulbous iris and tulips.
Rep. XIV Int. Hort. Cong., The Hague, pp. 173-187.
1955. ‘

Toyoda, T., and K. Nishii. Studies on high temper-
ature treatments of tulip bulbs to prevent flowering.
I. Effects of date amilength of treatments on flowering
growth and bulb production. Jour. Hort. Assoc.

Japan 26: 2“3-250. Hort. Abstracts 28: 290“. 1957.

Van Slogteren, E. The influence of climate and
storing conditions on the flowering of flower bulbs.
Proc. 7th. intern. Cong. of Refrigeration “: 22-“2.
1936. .

Went, F. W. ThermOperiodicity. In: Vernalization
and photOperiodism, a symposium. Lotsya l: l“5—
157. l9“8.

Wood, J. Experiments on hot water treatment, 1937-
1939. Report on Bulb Experiments, The Agricultural
Institute and Experimental Station, Kirton, 7: 2“-
33. l9“0.

Zacharius, R. M., H. M. Cathey, and A. E. Steward.
Nitrogenous compounds and nitrogen metabolism in the
Liliaceae III. Changes in the soluble nitrogen
compounds of the tulip and their relation to flower
formation in the bulb. Ann. Bot. 21: 193-201.

1957.

APPENDIX

72

73

APPENDIX TABLE l.--Simple correlations--Dutch Princess.

 

 

 

 

 

 

 

 

Sprout Total Flower Foot Storage
Height Height Size

Sprout Height 1.000

Total Height 0.900 1.000

Flower Size -0.322 -0.“65 1.000

Foot 0 860 0.957 —0.555 1.000

Storage 0.886 0.935 —O.577 0.919 1.000

APPENDIX TABLE 2.--Simp1e correlations--Apeldoorn
Sprout Total Flower Foot Storage
Height Height Size

Sprout Height 1.000

Total Height 0.551 1.000

Flower Size —0.531 -0.“8l 1.000

Foot 0.650 0.912 -O.5“9 1.000

Storage 0.633 0.9“2 -0.617 0.910 1.000

APPENDIX TABLE 3.--Simple correlations--Gudoshnik.
Sprout Total Flower Foot Storage
Height Height Size

Sprout Height 1.000

Total Height 0.157 1.000

Flower Size 0.079 -O.731 1.000

Foot 0.1“1 0.973 -0.799 1.000

Storage -0.000 0.976 —o.757 0.966 1.000

 

7“

APPENDIX TABLE “.--Simp1e correlations--Andes.

 

 

Sprout Total Flower Foot Storage
Height Height Size

Sprout Height 1.000

Total Height 0.21“ 1.000

Flower Size 0.192 0.02“ 1.000

Foot 0.159 0.978 -0.l22 1.000

Storage 0.123 0.921 -0.235 0.961 1.000

 

APPENDIX TABLE 5.--Simp1e correlations--Dreaming Maid.

 

 

Sprout Total Flower Foot Storage
Height Height Size

Sprout Height 1.000

Total Height 0.“8“ 1.000

Flower Size -0.0“8 0.523 1.000

Foot 0.631 0.951 0.“39 1.000

Storage 0.816 0.“7“ -0.231 0.63“ 1.000

 

.666--5% level

.798--1% level

75

APPENDIX TABLE 6.--Storage on total height: Pertinent
statistical information relevant to the effect of days in
cold storage on total height with the five cultivars.

 

 

 

 

Regression Level of Error
Cultivar Equation coefficient signif- mean

squared (R2) icance square
Andes 2=6.59+0.2“x 0.8“9 <0.0005 1.718
Apeldoorn .§=—1“.07+0.““x 0.888 0.0005 “.032
Dutch Princess 7=6.98+0.27x 0.87“ 0.0005 1.767
Dreaming Maid 2=0.36+“.25x 0.235 0.186 20.22
Gudoshnik “=—22.03+0.60X 0.952 0.0005 3.0“0
APPENDIX TABLE 7.--Storage on sprout length: Pertinent

statistical information relevant to the effect of days of
storage on sprout height with the five cultivars.

 

 

 

Regression Level of Error
Cultivar Equation coefficient signif— mean

squared (R2) icance square
Andes 2=6.26+0.81x 0.023 0.69“ 0.803
Apeldoorn i=0.88+0.03x 0.“00 0.067 0.188
Dutch Princess 2:0.“9+0.05x 0.785 0.001 0.138
Dreaming Maid 2=3.60+0.0“x 0.667 0.007 0.11“
Gudoshnik §=1.71+—0.0x 0.000 1.000 0.10“

 

APPENDIX TABLE 8.--Storage on foot length:

76

Pertinent

statistical information relevant to the effect of days in
cold storage on foot length with the five cultivars.

 

 

 

 

Regression Level of Error
Cultivar Equation coefficien signif- mean

squared (R ) icance square
Andes Y=-6.37+0.12X 0.925 0.0005 0.208
Apeldoorn Y=-7.73+0.11X‘ 0.827 0.001 0.“30
Dutch Princess §=—“.56+0.09x 0.8“5 <0.0005 0.292
Dreaming Maid §=-5.03+0.11x 0.“03 0.066 3.“56
Gudoshnik §=—7.98+0.15x 0.93“ <0.0005 0.296
APPENDIX TABLE 9.--Total height on foot length: Pertinent

statistical information relevant to the effect of total
height on foot length with the five cultivars.

 

 

 

Regression Level of Error
Cultivar Equation coefficient signif- mean

squares (R2) icance square
Andes ?=-8.85+0.“8x 0.957 <0.0005 0.119
Apeldoorn ?=—3.80+0.2“x 0.832 0.001 0.“17
Dutch Princess ?=—6.78+0.35x 0.917 <0.0005 0.157
Dreaming Maid 2=-7.6“+0.““x 0.905 <0.0005 0.5u7
Gudoshnik Y=-2.05+0.26X <0.0005 0.238

0.9“7

 

77

APPENDIX TABLE 10.——Sprout height on total height: Pertinent
statistical information relevant to the effect of sprout
height on total height with the five cultivars.

 

 

Regression Level of Error
Cultivars Equation coefficient signif— mean

squared (R2) icance square
Andes 7=22.69+0.79x 0.0“6 0.579 10.90
Apeldoorn “=5.80+5.90x 0.303 0.12“ 25.13
Dutch Princess 7=8.50+“.21X 0.811 0.001 2.6“2
Dreaming Maid 9=0.36+“.25x 0.23“ 0.186 20.225
Gudoshnik Y=26.20+3.91X 0.02“ 0.686 62.650

 

APPENDIX TABLE ll.—-Sprout height on foot length: Pertinent
statistical information relevant to the effect of sprout
height on foot length with the five cultivars.

 

 

Regression Level of -Error
Cultivars Equation coefficient signif- mean

squared (R2) icance square
Andes i=2.76+0.29x 0.025 0.681 2.713
Apeldoorn A=-3.81+1.82x 0.“22 0.058 1.“37
Dutch Princess Y=-3.77+1.“7X 0.7“09 0.003 0.“90
Dreaming Maid ?=—12.36+2.59X 0.399 0.068 3.“77
.Gudoshnik . ‘2=“.8“+0.92x 0.019 0.717 “.“18

 

GLOSSARY

78

Basal Plate:

Blasting:

Blindness:

Bulb Cellar:

Cool Room:

Cultivar:

Dry Storage:

Flat:

Forcing:

GLOSSARY

The raised basal portion of the bulb from

which the roots emerge.

Failure of the bulb to produce a marketable
flower after the flower has been formed.
There are several stages of blasting. It
may occur as early as immediately after
flower formation or as late as the day the

flower colors in the greenhouse.

Failure of the bulb to form a flower.

See rooting room.

Controlled temperature room used for storage.

A variety or race that has originated and
persisted under cultivation. Usually prOpo-

gated asexually.

The storage of bulbs before planting. Some-
times used to refer to the storage of flowers

after cutting.

Wooden container used to grow bulbs for out

flower production.

The flowering of a bulb or plant using other

than naturally occurring climatic conditions.

79

Precooling:

Rogueing:

Root Plate:

Rooting Room:

Shoot:

Sprout:

Uncooled
Bulbs:

80

Dry storage of bulbs at “8°F or lower prior

to planting.

Selective removal of diseased plants to

prevent the Spread of pathogens.

See basal plate.

Controlled temperature facility used to
satisfy the rooting and cold requirement

of bulbs.

An organ bearing both vegetative and

floral parts.

See shoot.

Bulbs which have received no precooling.