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The
98th Conference of the American Society for Horticulture Science was held
in Sacrament, California 22-25 July 2001. As usual, there are too many
sessions of interest for any one person to attend, but there were a few
papers delivered that may be of interest to greenhouse growers. Listed
below are brief summaries of four papers that I attended that I found
of immediate use to greenhouse growers. If you have any questions or would
like additional information, I have included email links to one of the
authors from each summary. Full abstracts are published in HortScience
vol. 36, no. 3.
Canopy Management System Affects Quality of Cut
Stems of Rosa xhyrida L.
Ryan M. Warner and John E. Erwin; Department of Horticultural
Science, University of Minnesota, 1970 Folwell Ave., Saint Paul, MN
55108.
Warner and Erwin conducted an experiment to evaluate differences
in quality and postharvest life of cut roses grown using two different
production systems. They harvested Kardinal stems every two weeks from
16 June to 7 Sept. 2000. The roses were grown in rockwool media irrigated
with a hydroponic solution under the traditional upright hedge system
or under the bent-shoot canopy management system in a commercial greenhouse
in Plymouth, Minn. Stem length was 29.6 ± 2.75 in. (75.1 ±
7 cm) for bent-shoot stems compared to 19.5 ± 2 in (49.5 ±
5 cm) for traditional upright stems across all harvest dates. Flower
size declined for bent-shoot stems, but not traditional upright stems,
from June to September. However, across all harvest dates, flower diameter
was 14% greater on stems harvested from plants grown in the bent-shoot
system than on stems from plants grown in the traditional upright system.
Vase life of individual cut stems was 11 ±2 d. The canopy management
system or harvest date did not influence vase life.
For more information, contact Dr.
John E. Erwin
Injection of a Hydrophilic Polymer and Its Effectiveness in Postproduction
for Annual Plants Grown in Hanging Baskets
D. Brisson, J. Caron, P. Jobin, C. Menard, and B. Dansereau; Département
de Phytologie, Département des Sols et de Génie agroalimentaire
Centre de Recherche en Horticulture, Faculté des Sciences de
l'Agriculture et de l'Alimentation, Université Laval, Québec,
Québec, Canada, G 1 K 7P4
Adding a hydrophilic polymer into the growing mix of container
plants in theory can increase the water-holding capacity of a container,
minimize plant responses to water stress and facilitate water management.
However, little information is available concerning the incorporation
and the effectiveness of hydrophilic polymers for hanging baskets, especially
after production and in the retail environment. Two experiments, greenhouse
and out-of-doors, were completed during the summers of1999 and 2000.
A crosslinked polyacrylate-K polymer was incorporated into the growing
mix of hanging baskets at the beginning of production and injected immiediately
after production. Petunia xhybrida L. and Torenia
xhybrida L. plants were used for the experiments. Adding the
polymer at the beginning of production was inefficient to reduce irrigation
frequency, but the injection of 3 g/L of polymer immiediately after
production reduced irrigation needs and had no influence on Petunia's
growth. Three injection levels [0, 1.7, 5, and 8.4 pounds
per cubic yard (0, 1, 5, and 3 g/L)] and two application patterns (at
6 and 12 points) of the polymer after production were tested. Results
demonstrated that only the 5 pounds per cubic yard rate increased the
delay of wilting by one day for Petunia. However, the polymer
had no effect delaying wiliting of Torenia at any injection level.
Injection patterns did not influence on the effectiveness of the polymer,
which means that an application at 6 points is no different than application
at 12 points.
For more information, contact Dr.
Blanche
Dansereau
Productivity, Quality, and Value Estimation of Cut-flower Roses
Grown in Soilless Media in Response to Shoot bending
Soo-Hyung Kim and J. Heinrich Lieth; Dept. of Environmental Horticulture,
Univ. of California, Davis, CA 95616
Cut-flower production of Kardinal and Fire'N Ice roses grown with
shootbending and traditional canopy management regimines and grown in
either coir or the traditional UC Mix was studied for two years.Shoot-bending
increased the average shoot stem length and dry matter for both cultivars
while decreasing the number of harvestable shoots. Fire'N Ice plants
grown in coir produced more harvestable flowering shoots than plants
grown in UC Mix while Kardinal production was the same between the two
media. Neither cultivar showed differences in stem length and dry matter
production between the two media. Calculation of themarket value showed
that with Fire'N Ice the improvement in stem length achieved by shoot-bending
did not offset the economic loss due to the reduction in the number
of shoots per unit area. For Kardinal the increased quality as a result
of shoot-bending did offset the reduced production. The combination
of bending and coir, a common combination used by many rose growers,
did not generate significant improvements in value over the other treatment
combinations. However, under market conditions where short stems are
discounted significantly and extra-long stems garner a substantial bonus,
shoot-bending can result in greater economic gain.
For more information, contact Dr.
Heiner Lieth
Effects of Gibberellin Treatments on Leaf and Flower Quality of
Cut Oriental, Asiatic and LA-Hybrid Lilies
Anil P. Ranwala and William B. Miller, Dept of Horticulture, Cornell
Univ., Ithaca NY 14853
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effects of gibberellin treatments on vase life and quality of several
Oriental, Asiatic, and LA-hybrid lily cultivars were investigated. Stems
were harvested when the first flower bud of the inflorescence showed
full color, and held in a room maintained at 68 °F (20 °C),
with fluorescent lights for 12 hours per day. Another set of cut stems
was held in water at 2-3 °C for 2 weeks in darkness before transferring
to the room previously described. Cut stems were treated with gibberellins
(GA3, GA4+7, or a combination of GA4+7,
and BA) as a pulse treatment or a foliar spray before moving into the
cold storage or as a component in the vase solution during the evaluation
phase. All three means of gibberellin applications were effective in
increasing vase life. Gibberellin treatments also prolonged the inflorescence
life span by several days. Although both GA3 and GA4+7,
delayed leaf chlorosis, GA4+7 was effective at lower concentrations
compared to GA3. For example, 6-hour pre-treatment of cut
stems in a 100 ppm GA4+7 solution increased vase life up
to 3 weeks. As a component in the vase solution, GA4+7, concentrations
as low as 5 ppm increased vase life. Cold storage of cut stems after
harvest decreased the vase life; however, gibberellin treatments prevented
cold-induced leaf chlorosis in all the cultivars tested.
For more information, contact Dr.
Anil Ranwala
Steven
E. Newman, Ph.D.
Greenhouse Crops Extension Specialist
Horticulture and Landscape
Architecture
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