Post-Greenhouse Evaluations of Forced Bulbous Plants 1995 Proposal
II
During Phase I of this project, a comprehensive database was established
for 22 species of flower bulbs forced as potted plants. This information
has been released to the industry in various publications (see Literature
cited) and many lectures given by the project leaders. In addition, it
will be summarized in the fifth edition of the Holland Bulb Forcer’s Guide
to be released in Spring 1996.
In Phase II of the project, two areas will be investigated. The first
is related to the post- greenhouse longevity of potted Asiatic and Oriental
hybrid lilies. Previous studies have (Phase I of this program) shown that
some lily cultivars have little or no post-greenhouse life after cold storage,
while others are satisfactory for two to three weeks. Factors to be studied
are: (1) genetic variation amongst cultivars, (2) the influence of various
greenhouse factors, e.g., nutrition, and (3) post-storage handling systems.
The second area to be investigated will be the post-greenhouse requirements
and performance of: (1) Ornithogalum dubium, a potential new potted plant;
and (2) new clones of Paperwhite Narcissus that have been developed by
the Volcani Centre, Bet Dagan, Israel.
All plants in these studies will be forced at N.C. State University
and then transported to the University of Florida for subsequent evaluations
under controlled interior conditions.
These studies will provide the floral industry with information to properly
market flowering potted lilies. The result will be that consumers will
have a greater satisfaction with these floral products and return sales
will be enhanced. The studies on O. dubium and the new clones of Paperwhite
Narcissus are needed to ensure that when new plant products or cultivars
are released that they will perform satisfactorily not only under greenhouse
conditions but also under consumer conditions.
2. INTRODUCTION AND LITERATURE REVIEW
Studies conducted (Nell et al., 1991; Nell et al., 1992a., 1992b; Nell
et al., 1993; Nell et al., 1994) on the post-greenhouse requirements of
flowering bulbs as potted plants have demonstrated that the “Consumer Phase”
of forcing is highly dependent on the species and cultivar used. For example,
Anemone blanda plants were forced at N.C. State University. When they were
removed from the greenhouse, they appeared to be excellent quality potted
plants. However, after being sleeved, packed, and transported by a commercial
flower carrier, they had no useful potted life for the consumer. Thus,
it is essential that before “New” or “Improved” potted plants are introduced,
they are evaluated under simulated home conditions to determine their usefulness.
We have conducted limited greenhouse forcing trials on O. dubium. This
species needs to be evaluated prior to releasing a forcing program for
it.
In addition, our trials (Nell et al., 1993) showed that ‘Galil’ and
‘Ziva’, the two most widely forced Paperwhite Narcissus (De Hertogh, 1996),
has a potted life of 22 and 26 days, respectively. The plant breeders at
the Volcani Center in Bet Dagan, Israel are increasing four new clones
for potential release. We will evaluate their post-greenhouse longevity
to be certain that their consumer performance is at least equal to, and
preferably greater, than the currently forced cultivars.
The 1994 USDA Floriculture Crops Summary indicates that the forcing
of Asiatic and Oriental hybrid lilies as potted plants is increasing. A
total of 1,541,000 and 1,742,000 were forced in 1993 and 1994, respectively.
In Phase I of this program, Asiatic and Oriental hybrid lilies were evaluated.
In the initial experiments (Nell et al., 1995), simulated shipping and
post-greenhouse conditions were evaluated. Potted Asiatic Hybrid lilies
‘Aristocrat’, ‘Horizon’ and ‘Polka’ were boxed when the first flower was
fully colored but not open. They were maintained in darkness (simulated
shipping), at 2, 7 or 13 C for 3, 6 or 9 days and then placed at 21 +/-
2 C at an irradiance of 14 umol m-2*s-1 for postproduction evaluation.
Maximum plant longevity of 16 days was achieved at all temperatures when
plants were stored for only 3 days. At 7 C, they could be stored for up
to 6 days and for up to 9 days when maintained at 2 C. Plant longevity
was reduced by 5 days when transported for 9 days at 13 C. Due to the larger
number of floral buds that fully opened, ‘Aristocrat’ was superior in postproduction
performance when compared to ‘Horizon’ and ‘Polka’. Simulated transport
greater than 3 days decreased flower opening on ‘Horizon’ and ‘Polka’.
In the second experiment, ‘Aristocrat’ and the Oriental hybrid ‘Star Gazer’
were evaluated at postproduction temperatures of 18, 21 or 24 C at irradiance
levels of 7 or 14 umol m-2*s-1 after being commercially transported at
5 +/- 2 C for 4 days. Most floral buds of ‘Aristocrat’ opened under all
postproduction conditions. ‘Star Gazer’ had reduced flower opening due
to either floral bud abscission or abnormal bud development, which increased
as the postproduction temperature increased. Maximum flower longevity,
total plant longevity and quality was achieved with a postproduction temperature
of 18 C. Postproduction irradiance had no effects on the parameters evaluated.
In the 1994-95 trials, the effects of 0, 3, 6 and 9 days of 2 C storage
of marketable plants were evaluated. It was found that ‘Buff Pixie’ could
not be cold-stored, while ‘Sun Ray’ and ‘Miss Burma’ could be stored for
up to 6 days. Thus, with these genetic variations, it is obvious that expanded
studies are needed to provide a scientific base for not only the forcing
of Asiatic and Oriental Hybrid lilies as potted flowering plants but also
their ability to be stored and shipped.
3. OBJECTIVES AND ANTICIPATED BENEFITS
The overall objective and anticipated benefits to the floricultural
industry is to provide a scientific database on the post-greenhouse performance
of forced flower bulbs. Therefore, the consumer, who is the most important
person in the marketing chain, will be satisfied with the products purchased.
The specific objectives for Phase II of this project are: (1) To determine
the post-greenhouse performance and requirements for O. dubium. (2) To
determine the post-greenhouse performance of four new clones of Paperwhite
Narcissus. (3) To expand the database on the forcing and post-greenhouse
requirements for Asiatic and Oriental hybrid lilies as potted plants. We
will evaluate cultivars, greenhouse cultural factors, and post-greenhouse
storage conditions.
4. MATERIALS AND METHODS
A. O. dubium.
Plants will be forced using guidelines being developed at N.C. State
University. The key steps are as follows:
1. 5/6 up cm, in circumference, Israeli-grown bulbs will be
used.2. Bulbs will be stored at 77 F (25 C) until four weeks before planting,
then placed at 63 F (17 C).3 . The first planting will be on October 15th, then 4 week intervals
will be used.4. A sandy, very well drained, pH 6 to 7, sterilized planting medium
will be used.5. Plants will be forced in a medium light intensity (5,000 ft.c.)
greenhouse and at 72/65 F (22/18 C) Day/Night temperatures. 6. Plants will
not be fertilized until they begin to flower and then, very lightly.7. When 2 to 3 florets are fully colored, they will be removed from
the Greenhouse benches, packed and shipped to the University of Florida.
Plants will be placed into interior rooms providing temperatures of 65
(18 C), 70 (20 C) and 75 F (23 C) and light levels of 50 and 100 ft-c.
There will be a total of 6 treatments for each bulb species. Light will
be provided 12 hours daily from cool white fluorescent bulbs. Temperature
and humidity (50-55 %) will be constant during the day/night period. Data
to be recorded will include:
(1) Height at arrival
(2) Date of final flower opening
(3) Total number of flowers opening
(4) Total plant longevity
(5) Overall plant quality
B. Paperwhite Narcissus.
Clones 9, 10, 11 and 12 will be forced according to guidelines published
in the Holland Bulb Forcer’s Guide (De Hertogh, 1996). When they reach
the “Bud” stage of flower development, they will be packed and shipped
to the University of Florida. They will be placed at 100 ft.c. and 65 F
(18 C). Data to be recorded will include:
Height at arrival First Stem - first stem to flower
First open flower
Height at flower opening
Longevity of first open flower
Height at death of first flower
Last Stem - final stem to flower
First open flower
Height at flower opening
Longevity of first flower
Height at death of first flower
Total plant longevity
Total plant quality
C. Asiatic and Oriental hybrid lilies.
Twenty four of the most readily available cultivars will be forced
according to guidelines published in the Holland Bulb Forcer’s Guide. Groups
will be planted on separate planting dates so that one group can be packed
and stored at 2 C for 6 days, while a second group will not be stored prior
to shipping to the University of Florida. They will subsequently be placed
at 100 ft.c. and 65 F (18 C) to determine their post-greenhouse characteristics.
Data to be recorded include:
- Date of first flower opening
- Diameter of first open flower
- Longevity of first open flower
- Date of last flower opening
- Diameter of last open flower
- Longevity of last open flower
- Number of floral buds
- Number of floral buds that flowered
- Number and date of bud drop
- Total plant longevity
- Total leaf number and % of leaves browning
- Total plant quality
After the genetic characteristics of the cultivars have been established,
subsequent studies will be conducted on selected cultivars to determine
the effects of nutrition on their longevity. In addition, post-storage
handling procedures such as lukewarm water and intermediate temperature
acclimation will be conducted on selected cultivars.
5. LITERATURE CITED
De Hertogh, A.A. 1996. 5th Edition, Holland Bulb Forcer’s Guide. International
Flower-Bulb Centre, Hillegom, The Netherlands.
Nell, T.A., J.E. Barrett and A.A. De Hertogh. 1992a. Post-Greenbouse
(Consumer) Requirements for Rooting Room Bulbs Forced as Potted Plants.
Holland Flower Bulb Technical Service Bulletin No. 34. Netherlands Flower-Bulb
Institute. Hillegom, The Netherlands. 8 pp.
Nell, T.A., J.E. Barrett and A.A. De Hertogh. 1992b. Post-Greenhouse
Longevity of Rooting Room Bulbs as Flowering Potted Plants. Acta Hort.
325: 175-184.
Nell, T.A., J.E. Barrett and A.A. De Hertogh. 1993, Post-Greenhouse
(Consumer) Requirements for Non-Rooting Room Bulbs Forced as a Potted Plant.
Holland Flower Bulb Technical Service Bulletin No. 38. Netherlands Flower-Bulb
Institute. Hillegom, The Netherlands.
Nell, T., J.E. Barrett and A.A. De Hertogh. 1994. Increasing the Longevity
and Quality of Flowering Potted Bulb Plants. Ohio Florists’ Assoc. Bull.
782: 3-4.
Nell, T.A., A.A. De Hertogh and J.E. Barrett. 1991. Bulbs as Flowering
Potted Plants - Keys to Increased Longevity. Grower Talks 55(7): 57-60.
Nell, T.A., R.T. Leonard, A.A. De Hertogh and J.E. Barrett. 1995. Asiatic
and Oriental Hybrid Lilies as Flowering Potted Plants Influenced by Transport
and Postharvest Conditions. HortScience (In Press).
United States Department of Agriculture. 1995. Floriculture Crops 1994
Summary. National Agricultural Statistics Service. Agricultural Statistics
Board, Washington, D.C.
6. BUDGET
A. N.C. State University:
Labor and supplies for forcing the bulbs, packing and storing plants
. . . . S7,500.00 (Bulbs ($6,500) will be provided by AGREXCO of Israel
and United Bulb Co.)
B. University of Florida: Labor and supplies for the collection of data
for the postproduction . . . . $18,000.00 evaluations (Table 1) once plants
are received from N.C. State Univ.
TOTAL REQUEST . . . . . . $25,500.00
7. LEADERS QUALIFICATIONS
August A. (Gus) De Hertogh is a Professor of Horticultural Science
at N.C. State University. He has developed the procedures used by bulb
forcers throughout North America. His expertise is recognized world-wide.
Drs. Terril A. Nell and James E. Barrett are Professors of Environmental
Horticulture at the University of Florida. Dr. Terril A. Nell has established
the flowering potted plant post- production program at the University of
Florida, and Dr. James E. Barrett is highly recognized for his knowledge
of floriculture growth and development. The post-greenhouse evaluation
facilities at the University of Florida are the most up to date post-greenhouse
facilities in North America.
