Post-Greenhouse Evaluations of Forced Bulbous Plants Progress Reports — September 1991
Date 9/3/91
Title of Project Postproduction Longevity of Potted Bulbs
Institution where work is being conducted University of Florida and North Carolina State Univ.
Amount of Endowment Grant $ 11,000
Covering Period 01/01/91 to 12/31/91
Anticipated Date of Project Completion/Final Report December 1993
Individual(s) Conducting Project:
(List Project Leader First)
T.A. Nell - Title Professor
Telephone Number (904) 392-7933
A.A. DeHertogh - Title Professor
J.E. Barrett - Title Professor
Postproduction Longevity of Potted Bulbs
T. A. Nell, A. A. DeHertogh, and J. E. Barrett
University of Florida and North Carolina State University
- A. Project Objectives:
- 1. To determine the effective home-life of selected rooting room and non-rooting room forced bulbs
and tuberous flowering potted bulbs.
Asiatic Lilies.
repeat this work in October, November and December 1991.
and light levels.
Narcissus plants were shipped in the fall season. Caladiums,
Freesias and Lilies were sent in Spring, 1991. Calla lilies and
Astilbes were forced but could not be sent to the University of
Florida due to excessive disease problems.
result of the treatments, depending on time of production and variety.
a problem on darker leaf varieties but placement of plants into the interior at a more advanced
stage minimized this problem. Few new leaves were produced at any interior temperature or light
level, thus emphasizing the need to market the plants at a mature stage of development.
possible that earlier applications are needed to obtain positive results.
temperature was maintained at 35 - 45′F.
elongation.
1991 and winter-spring 1992.
illustrate the importance of proper handling and interior conditions. This information should be useful in
floral marketing programs.
POSTPRODUCTION EVALUATION OF POTTED BULBS
- Postproduction research on rooting and non-rooting room bulbs was continued during the
fall of 1990 and spring of 1991 at the University of Florida, Gainesville. Postproduction
evaluations during this period include astilbe, caladiums, growth regulators on amaryllis, silver
thiosulfate applications on freesia, and simulated shipping of lilies. Plants were grown at North
Carolina State University and shipped to the University of Florida at marketable stage. Plants were
boxed and shipped for 3-5 days at temperatures maintained at approximately 42′F.
Postproduction evaluation rooms were maintained at 65, 70 or 75′F at light levels of 50 and 100
ftc. (12 hr/day). Relative humidity was 50% +/- 5%. Results on the postproduction performance
is presented by crop.
I. ASTILBE
temperature increased from 65 to 75′F, longevity decreased 8 to 16 days for ‘Bumalda’
and 5 to 12 days for ‘Etna’, depending on production time.
increased from 50 to 100 ftc.
was restricting.
No significant change in stalk height was observed between cultivars or between
postproduction treatments.
environment. Both cultivars experienced this problem at all treatments, especially when
maintained at the lower temperature and light level.
attempt to maintain flower stem height control. Ethephon was applied at the following
stages of stem development: 1) stem height of 15 cm; 2) stem height of 25 cm; and 3)
stem height of 15 cm and repeated at 25 cm. Nontreated plants were also included.
Plants were placed into postproduction evaluation rooms maintained at 70′F at a light
intensity of 50 ftc. The experiment was repeated twice.
last open flower of each experiment is presented in Graphs 1 and 2. In each experiment, height was
slightly reduced at each Ethephon treatment compared to control plants. The greatest
height control was obtained when Ethephon was applied twice. ‘Cocktail’ appears to be
more responsive to the growth regulator in each experiment. Although height was reduced
using Ethephon, stems were still very tall and had a tendency to topple over in the
postproduction environment.
in Graph 3 and 4. Results were variable within and between experiments. For example,
Ethephon appeared to control leaf height in ‘Cocktail’ when applied twice in experiment 2,
but failed to control height in experiment 1. Inherent variability in leaf development
between plants may play a role in masking Ethephon affects.
control plants. Control plants of ‘Intokazi’ lasted 3 weeks while ‘Cocktail’ lasted 2 to 2
1/2 weeks. Longevity was reduced 1 to 7 days in experiment 1 and 3 to 11 days in
experiment 2 on plants treated with Ethephon.
an approximate 26% reduction in number of open flowers was observed in experiment 1
on ‘Cocktail’ when Ethephon was applied either at 15 cm once or twice (15 and 25 cm),
and on ‘Intokazi’ at the 15 cm stem height Ethephon treatment (Graph 7.). Flower size
was not affected by Ethephon.
good’(according to N.C. State rating system) for both cultivars. No differences were
observed between Ethephon treatments. As stems continued to elongate, however, stem
strength progressively became weak and many stems toppled over.
(N.C. State rating system) which was the least desirable rating, for all treatments of
‘Inkotazi’, including control plants. ‘Cocktail’ had a better rating, averaging between ‘2′
and ‘3′ for all treatments.
between ‘poor’ and ‘fair’ regardless of treatment. Plants were categorized as ‘poor’ if
plants had very short leaves, 1 stem or plants toppled over, while ‘fair’ plants were those
that had short leaves that were weak and had only 1 stem. Most plants developed 2
stems, therefore, the major factor that contributed to the low quality rating was the
occurrence of stem toppling.
and ‘Candidum Jr.’ were evaluated in postproduction conditions. Plants were kept
in interior conditions for 8 to 10 weeks after which an evaluation was conducted.
do best when maintained
at 65 to 70′F. Plants maintained at these lower temperatures were smaller, but
leaf color was better maintained and did not fade. Plants held at 75′F were taller,
and had greater leaf development, but the red color was faded on new leaves that
developed in rooms.
at 65 and 70′F. Although leaf color was better maintained at these lower
temperatures, plants were shorter with less leaf development under interior
conditions. As temperature increased plant height increased and leaf color faded.
were maintained at 70 and 75′F at a light level of 100 ftc. Plants maintained at
65′F were smaller and had a tendency of leaves to turn a greenish color.
well under interior conditions for a long period of time. A potential problem is the
fading of leaf color under high interior temperatures and the lack of growth and
development of new leaves under low interior temperatures. Results also indicate
that the stage of development when placed into interior conditions is important.
It is important that plants be of sufficient size when placed in interior conditions
since plant growth is reduced.
attempt to promote flowering. STS was applied at either 2.5 or 5.0 g/liter when
plants were at marketable stage. Nontreated control plants were also included.
A factorial experiment with two cultivars and three rates (0, 2.5, 5.0 g/liter) was
used with five replications of 2 plants each. Plants were placed in postproduction
evaluation rooms maintained at 70′F at a light level of 70 ftc.
The number of open flowers of each stem is presented in Graph 1. No
differences in the number of open flowers were observed between control and STS
treated plants. Statistical differences were observed between cultivars only in
stem 1 and stem 2, where ‘Blue Navy’ had a greater number of open flowers.
The total number of buds of each stem is presented in Graph 2. Differences in
bud number were found between cultivars on each stem. ‘Blue Navy’ averaged 6
to 8 buds per stem, while ‘Florida’ averaged 4 to 6. No differences in bud number
were observed between control plants and STS treated plants.
Percent flower opening of each stem is presented in Graph 3. No statistical
differences were found between cultivars or STS rates, including control plants.
Generally, both cultivars had between 75% to 80% of flowers open on each stem.
The percentage of stems that flowered is presented in Graph 4. The percentage
of stems that flowered in each cultivar averaged between 90 to nearly 100%. No
differences were found between cultivars or between STS treatments.
Individual stem longevity is presented in Graph 5. Differences in stem longevity
were observed between cultivars in stem 1, 2 and 3 only. ‘Blue Navy’ stems had
an increase in longevity of 1 to 3 days compared to ‘Florida’. No differences in
stem longevity were observed between the three STS rates. A slight decrease in
stem longevity from stem 1 to stem 8 is evident, especially in ‘Blue Navy’ freesia.
This could be related to the fact that fewer buds develop on stems which develop
under interior conditions.
Total plant longevity, which was determined from first flower opening until the
last flower died, is presented in Graph 6. No statistical differences were found
between cultivars or STS treatments. These freesia cultivars lasted between 16
to 20 days in interior conditions.
35, 45 or 55′F, for 3, 6 or 9 days. Plants were then placed in postproduction rooms
maintained at 70′F at an interior light intensity of 100 ftc.
Plant longevity was not significantly affected by shipping treatments. Plant longevity
averaged 12 days for control plants and 11 days for all shipping treatments, excluding
plants shipped at 55′F for 9 days, where longevity averaged 10 days.
Most treatments, including control plants, lasted 11 to 12 days. Longevity was
reduced to 8 days on plants shipped at 55′F for 9 days.
This cultivar lasted 6 to 8 days for both control plants and shipping treatments.
when shipped at 55′F for 3 days. The percentage of flowers that opened after shipping
at 55′F for 9 days averaged 24% for ‘Aristocrat’, 15 % for ‘Horizon’ and 10 % for ‘Polka’.
from their shipping treatment, was faster on plants shipped at 55′F.
affected by the shipping treatments.
85% for ‘Polka’ and only 54% for ‘Horizon’. These averages were similar within each
cultivar when shipped at 35 or 45′F, but were reduced to 63% for ‘Polka’ and 43% for
‘Horizon’ and were the same for ‘Aristocrat’ when shipped at 55′F.
Bud drop was 2% or less for treatments, including control.
Bud drop in ‘Polka’ increased as shipping duration and shipping temperature
increased. Bud drop averaged 11% when plants were shipped at 35′F or 45′F for
9 days, and increased up to 23% when shipped at 55′F for 9 days. These
percentages were much higher when compared to a 2% bud drop observed in
control plants.
Bud drop averaged 24% in control plants, which was the highest bud drop
observed. Bud drop averaged 4% at shipping temperatures of 35′F, 8% at 45′F
and 10% at 55′F.
