Post-Greenhouse Evaluations of Forced Bulbous Plants 1993 Proposal
The basic objective of these post-greenhouse experiments is to establish
a
comprehensive data base to determine the effective home-life of selected
non-rooting room forced
bulbous and tuberous flowering potted plants. Similar work has been
completed and published in trade
magazines on rooting room bulbs as part of this project. Amaryllis,
Astilbe, Caladium, Dahlia, Asiatic Lily,
Oriental Lily, and Paperwhite Narcissus will be forced to the optimal
marketing stage at N.C. State
University, transported to the University of Florida and subsequently
evaluated under controlled interior
conditions. Longevity of Astilbe, Caladium, Dahlia, and Paperwhite
Narcissus will be determined at interior
temperatures of 65, 70 and 75′F and 50 and 100 ft-c. of light, based
on specific quantitative criteria, such
as bud drop, flower longevity, stem elongation etc. Amaryllis will
be treated with Ethephon prior to
marketing stage to determine if stem elongation can be minimized without
a loss in interior longevity.
Benefits to the industry - This information is needed to provide the
floral industry with data to encourage
proper marketing and consumer utilization of these flowering potted
plants. The end result will be that
the consumer will enjoy a greater satisfaction with these floral products
and return sales will be enhanced.
Results of our previous studies on rooting room bulbs will be presented
in a technical bulletin and trade
journal article during the coming year lo provide the industry with
ready access to this information.
INTRODUCTION AND BACKGROUND INFORMATION
The United States floral industry has been forcing spring flowering
bulbs and non-rooting room
bulbs as either cut flowers or potted plants for a number of years.
DeHertogh has developed many of
the requirements for successful cooling and forcing of spring flowering
bulbs. Postharvest studies have
been conducted to extend cut floral life with floral preservatives
(Staby and Naegele, 1984) or to develop
the optimal storage conditions for cut bulb flowers (Hopper and Carlson,
1985), while this project
investigates potted flowering bulbous plant longevity. Vase-life studies
have also been conducted on
tuberous plants (De Hertogh, 1989). To the best of our knowledge, there
have been no studies reported
on the home-life of bulbs forced as potted plants prior to the commencement
of this research in 1988.
In our 1988-92 trials, we found significant effects of interior temperature
on the interior
performance and longevity of a number of rooting room and non-rooting
room bulbs (Nell et al., 1991,
1992). Interior light level did not have a major influence on longevity
but some effects on plant quality
were observed. The research proposed for 1991-92 will expand the results
obtained over the past two
years by evaluating additional species. Also, a number of handling/longevity
problems observed in
previous experiments will be addressed.
MATERIAL AND METHODS
A series of experiments will be conducted to identify the effects of
interior light, temperature and
transit conditions on forced flowering potted bulbous and tuberous
plants. All experiments will be
repeated (shipped) at 3 different times (Table 1).
A. Interior Light Level and Temperature.
Plants will be forced in Raleigh and shipped to Gainesville at time
of marketability. Bulbs
will be placed into interior rooms providing temperatures of 65, 70
and 75′F and light levels of 50
and 100 ft-c. In other words, 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.
Our efforts in 1992 - 1993 will concentrate on longevity of non-rooting
room bulbs (Table
2). Also, this table provides information on the bulb species completed
in 1988 - 1991 relative
to those being evaluated in the coming year. In each case, we feel
that at least two years of
evaluations are required for accurate development of the effects of
temperature and light level on
longevity. Data to be taken includes dates of opening and death for
first and last open flowers;
flower diameters, colorometric analysis of flower color, initial and
final plant height and number
of open flowers. Clearly, data will vary with plant species as outlined
in Table 3. All data will be
subjected to analysis of variance and regression analysis in order
to establish differences between
temperature and light levels.
B. Effect of Ethephon on Postproduction Performance of Potted Amaryllis
In the past two years, Amaryllis interior longevity has been excellent.
However, two
postproduction problems have been observed — poor root development
during production has
reduced interior longevity and excessive stem elongation indoors has
resulted in plants and pots
failing over after 5-7 days indoors. The root development problem was
solved by changing the
growing medium. In 1990-91 we evaluated the use of Ethephon to minimize
shoot elongation.
The preliminary results suggested that height could be reduced but
longevity was shortened
significantly in treated plants. These results must be confirmed in
the coming year to prevent
problems for the floriculture industry.
In this study, we will evaluate the use of Ethephon (this material reduces
stem topple in hyacinths)
during production as a means of improving the postproduction performance
of potted Amaryllis. Two
Amaryllis varieties will be treated with Ethephon at 2 concentrations
when the shoots are either 15 or 25
cm tall. Data will include:
Amaryllis Data
Initial stalk height
First and last stem:
First open flower
Height at first open flower
Diameter of first open flower
Longevity of first flower
Height at death of first flower
Last open flower
Height at last open flower
Diameter of last open flower
Longevity of last flower
Height at death of last flower
Total plant longevity
Total number of buds
Total number of open flowers
A 2 x 3 x 2 factorial experiment will be conducted and data will be
subjected to analysis of
variance and regression analysis.
FACILITIES AND EQUIPMENT AVAILABLE
A. N.C. State University- Coolers and greenhouses are available to
properly program, store and force
the bulbs used in these experiments.
B. University of Florida- We have 13 specially designed postharvest
rooms and 5 coolers to conduct
the post-greenhouse evaluations and shipping trials. Additional post-production
space is being
constructed by the University of Florida to meet the needs of this
program.
LITERATURE CITED
1. De Herlogh, A.A. 1989. 4th Edition, Holland Bulb Forcer’s Guide.
International Flower-Bulb
Centre, Hillegom, The Netherlands.
2. Hopper, D. and W. H. Carlson. 1985. The What, When and How of Flower
Storage. Mich. Florist,
Feb. pp 16-17.
3. 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.
4. Staby, G. and B. Naegele. 1984. The Effects of STS on Vase-Life
of Flowers. Florist’s Rev. Oct.
25, pp. 17-21.
BUDGET - 1992-93
Total requested is $12,000. This funding will cover the following costs:
A. N.C. State Univ. - Labor and supplies for growing and packing the
bulbs with be $3,500. Bulb
costs ($6,500) will be covered by a grant from the Dutch Bulb Exporters
Association and
Caladiums are being supplied by Bates and Sons Caladiums, Lake Placid,
Florida.
B. University of Florida - $8,500. This funding will provide labor
and supplies for the collection of
data for the postproduction evaluations (as shown in Table 1) once
plants are received from North
Carolina State University.
C. Transportation costs are included in the budget since we are having
to transport the plants by
rented van from Raleigh to Gainesville.
