Source: CORNELL UNIVERSITY submitted to
CULTURAL PRACTICE AND ENVIRONMENTAL INFLUENCES ON GROWTH OF HERBACEOUS HORTICULTURAL CROPS
Sponsoring Institution
State Agricultural Experiment Station
Project Status
TERMINATED
Funding Source
Reporting Frequency
Annual
Accession No.
0202070
Grant No.
(N/A)
Project No.
NYC-145369
Proposal No.
(N/A)
Multistate No.
(N/A)
Program Code
(N/A)
Project Start Date
Oct 1, 2004
Project End Date
Sep 30, 2009
Grant Year
(N/A)
Project Director
Wien, H. C.
Recipient Organization
CORNELL UNIVERSITY
(N/A)
ITHACA,NY 14853
Performing Department
HORTICULTURE
Non Technical Summary
In recent years, use of unheated, plastic-covered tunnels has become popular for production of high value crops such as cut flowers and vegetables. The tunnels allow earlier planting, and also extended season production in the fall, but subject the crop to other stresses that may be detrimental to production, such as high temperatures, and buildup of pests not prevalent outdoors. The proposed work will determine optimum handling practices for these crops in tunnels. When vegetables and flower crops are exposed to adverse weather conditions, such as high temperatures and adverse moisture conditions they develop disorders that makes them unmarketable. We will use greenhouses and growth chambers to manipulate the environmental conditions to recreate the disorder that we observe in the field. Once the causal factors are identified, we can screen for varieties that are less susceptible, or search for other factors that may reduce the incidence of the disorder.
Animal Health Component
100%
Research Effort Categories
Basic
(N/A)
Applied
100%
Developmental
(N/A)
Classification

Knowledge Area (KA)Subject of Investigation (SOI)Field of Science (FOS)Percent
2041499102010%
2041499106015%
2042121102015%
2042121106015%
2042129102010%
2042129106015%
2042410106020%
Goals / Objectives
To determine the effect of planting date and other cultural practice manipulations on growth and quality of cut flower species grown in high tunnels and outdoors. To probe the influence the effect of environmental factors such as temperature, photoperiod and level and quality of light on physiological disorders of cut flower species and vegetables.
Project Methods
The cut flower cultural practice research will be conducted at the East Ithaca Gardens research facility, where a plastic-covered high tunnel is placed in the same field where outdoor production is also possible. We envision the conduct of variety trials, manipulations of plant spacing, planting dates, and various methods of extending the growing season at both ends using protective structures. Manipulation of environmental factors will be done in conventional greenhouses in which daylength can be changed by use of automatic black curtains. Light quality changes will involve use of colored screens and netting materials. For investigation of physiological disorders such as tipburn of lettuce, we will use controlled environment chambers in which humidity control is possible.

Progress 10/01/08 to 09/30/09

Outputs
OUTPUTS: The applied research program with cut flowers consisted of 17 variety trials of 10 cut flower species, comprising 99 cultivars. These trials were conducted in the field, and for 4 species, in an unheated high tunnel as well. Cultural practice trials probing such factors as date of planting, effect of plant apex removal were tested on Matthiola incana and Consolida (larkspur) in the high tunnel only. Experiments on the effect of transplant container size and plant age were tested on Godetia and Eustoma in field experiments, and we determined the light requirement for daylength sensing of the long-day plant Rudbeckia hirta in greenhouse and high tunnel experiments. Tests to determine the time that sunflowers are sensitive to daylength continued. We investigated ways of getting earlier flowering with early exposure to short days, without the formation of disfiguring excessive axillary buds. A high tunnel was erected at the Homer Thompson Vegetable Research Center dedicated to vegetable research using organic practices. In the 2009 growing season, a trial on trellising methods suitable for muskmelons was conducted in this structure, as well as a sweet pepper variety trial with 6 cultivars. In late summer, after the melon experiment was completed, a time of planting and cultivar trial with 14 varieties of leafy greens was begun, which will be carried out until spring 2010. Results of the cut flower cultivar and cultural practice trials were disseminated through the publications of the Association of Specialty Cut Flower Growers, and at the annual meetings of New York and Pennsylvania vegetable and cut flower growers. PARTICIPANTS: The high tunnel extension and applied research program was conducted in collaboration with 7 Cornell Cooperative Extension specialists located in all parts of New York. The expertise of Mr. Craig Cramer in the Dept. of Horticulture at Cornell was essential for the high tunnel website development. Dr. Michael Mazourek in the Dept. of Plant Breeding at Cornell collaborated on the organic vegetable high tunnel work. The Association of Specialty Cut Flower Growers provided funding and materials for some of the cut flower work. TARGET AUDIENCES: The primary target audience is the current and future producers of fresh market vegetables and cut flowers in New York State and surrounding states and provinces. These may farm conventionally or using organic practices, and could be small or large scale enterprises. An additional audience is the manufacturers of high tunnels and equipment used therein, since our work is testing ways of improving environmental conditions in high tunnels. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.

Impacts
The cut flower variety trials identified several promising cultivars that warrant further testing and wider use. Among sunflowers, Procut Brilliance is a sturdy yellow-flowered variety with little daylength sensitivity. Greenheart Orange shows promise as an unusual double calendula with long stems. Among new delphinium varieties, Centurion White seemed less subject to root disease and early death than most cultivars, and produced tall sturdy stems. Magic Fountain Cherry Blossom had similarly robust growth. Magic Deep Blue lisianthus was productive and attractive in both field and high tunnel. The Audray series of gomphrena stood out for high productivity and good stem length. Plant apex removal experiments with campanula indicated no advantage from that practice, with stem lengths and yields not improved. The common varieties of stock (Matthiola) do not branch if pinched, so apex removal is not recommended. Small transplant containers stunt godetia seedlings permanently, a finding confirming last year's results. Again, similar treatments of lisianthus seedlings were not detrimental. Studies with Rudbeckia hirta indicated that the daylength response requires about 3 micromoles of light for saturation. A fall trial in the high tunnel indicated that none of the solar cell-powered lights tested were powerful enough to provide that output, resulting in plants with short flower stems, typical of fall-grown plants of this species. Tests with excessive bud problem in short-day sunflowers indicated that if the 3-week short day treatment beginning at emergence is interrupted with one week of long days (16 hrs), Sunrich Orange responds by eliminating these buds. Premier Light Yellow and Premier Lemon did not respond, so bud elimination treatments need further study for wide applicability. The muskmelon trellis trial in the high tunnel showed no improvement in yield, quality or earliness with training of the plants either vertically or on a slant. Interest in building and use of high tunnels among growers continues to be high. The principal investigator presented the results of our research findings, and information on high tunnels generally, at 9 growers meetings and open houses, attended by 12 to 60 participants. The Cornell high tunnel web site and blog is continuing to add new content and to alert growers and extension staff to new information on high tunnels. A session on high tunnels at the Cornell Cooperative Extension In-service in late 2008 attracted 25 extension educators and ensured that they were informed on where information on this topic can be found. A short video clip was produced on high tunnels by the American Institute of Physics, for use in educational TV broadcasts. Our high tunnel work was the subject of one departmental seminar, and two presentations at scientific conferences.

Publications

  • Wien, H.C. 2009. Microenvironmental variations within the high tunnel. HortSci. 44:235-238.
  • Wien, H.C. and M.P. Pritts. 2009. Use of high tunnels in the Northeastern USA: Adaptation to cold climates. Acta Hort. 87:55-59.
  • Wien, H.C. 2009. Floral crop production in high tunnels. HortTechnol. 19:56-60.
  • Wien, HC. 2009. No more ugly buds! ASCFG Quarterly 21(1):56.
  • Tata, S.J. and H.C. Wien. 2009. Petal drop in sunflowers: Varietal differences. ASCFG Quarterly 21(2):18-19.
  • Nyankanga, R. O., M.O. Olanya,. H.C. Wien, R. El-Bedewy, J. Karinga and P.S. Ojiambo. 2008. Development of tuber blight (Phytophthora infestans) on potato cultivars based on in vitro assays and field evaluations. HortSci. 43:1501-1508.
  • Nyankanga, R.O., H. C. Wien and O.M. Olanya. 2008. Effects of mulch and potato hilling on development of foliar blight (Phytophthora infestans) and the control of tuber blight infection. Potato Res. 51:101-111.


Progress 10/01/07 to 09/30/08

Outputs
OUTPUTS: As part of applied research on cut flower crops, 15 cultivar trials were conducted on 9 cut flower species, determining yield of cut stems and stem length of the entries. Of the species tested, zinnia, lisianthus, statice, trachelium, campanula and nigella were grown in both a high tunnel and outdoors to compare performance. In general, species tend to flower earlier and produce greater stem length in the high tunnel, and that held true again this year. Cultural practice trials were also performed with cut flowers in both the high tunnel and the field, totaling 7 in all. Factors investigated included the effect of daylength on earliness and stem length in sunflower. Results confirmed that daylength sensitivity occurs in the first three weeks after plant emergence, and that treating seedlings with 16-hour daylength for one week during that period results in plants of intermediate height and flower size, without the undesirable excessive flower bud production. Apex removal of sunflowers increased stem yield by a factor of 3, but flower size of topped plants only remained adequate if plant spacing was increased to 12 x 12 in., rather than the 9 x 9 in. normally used. Studies of the influence of transplant cell size in lisianthus and godetia indicated that crowding of seedlings reduced yield and stem length of the crop, especially if the seedlings were delayed in transplanting to the field. Due to lack of funds, the high tunnel scheduled to be constructed at the experimental station was erected in fall 2008, and will now be functional in spring 2009. Cultural practice and cultivar trials with vegetables grown in high tunnels were conducted in growers' high tunnels around New York State, and have been reported in the Smith Lever annual report. PARTICIPANTS: The applied research on high tunnel-grown vegetables was conducted in collaboration with 7 vegetable specialists in the Cornell Cooperative Extension program throughout NY State. Details of this collaboration are given in the Smith Lever Annual Report. TARGET AUDIENCES: The target audience is the current and future producers of fresh market vegetables and cut flowers in New York and adjacent states and provinces. These producers farm either conventionally or by following organic guidelines. An additional audience is the manufacturers of high tunnels and equipment used therein, since our work is testing ways of improving environmental conditions in high tunnels. PROJECT MODIFICATIONS: Insufficient funding for construction of the proposed multibay tunnel required us to scale down the size of the high tunnel to a single bay structure, and to delay erection to the fall of 2008. It will be used for experimentation with organically-grown vegetables in 2009.

Impacts
Results of the cultivar and cultural practice trials on cut flowers were disseminated through the publications of the Association of Cut Flower Growers, at the annual growers meeting for New York State (Fruit and Vegetable Expo), and at annual meetings in other states. Additional information exchange occurs through participation in the ASCFG cut flower listserve, in which growers submit questions that are answered by other growers or researchers. This is a highly efficient way of providing cut flower information to the relatively small number of participants in New York State. Interest in high tunnels has increased steadily in the last year, with most wanting to learn about producing vegetables and small fruits in high tunnels. High tunnel field days were conducted on 6 growers tunnel farms in Northern NY in 2008, with attendance ranging from 12 to 35. In addition, a cut flower session and a high tunnel session at the NY Fruit and Vegetable Expo attracted about 40 participants, and the PI reported on his flower research at both the New Jersey and Pennsylvania grower conferences.

Publications

  • Nyankanga, R.O., Wien, H.C., Olanya, O.M. and Ojiambo, P.S. 2007. Relationship between late blight (Phytophthora infestans) of potato on tuber and foliage, as affected by the disease severity on foliage, cultivar resistance, and atmospheric and soil variables. Can. J. Plant Pathol. 29:372-387.
  • Wien, H.C. 2007. Day-neutral sunflowers: Do they exist, and what difference does it make Cut Flower Quarterly 19(1):48-49.
  • Wien, H.C. 2008. Cornell-copia: Sunflower daylength screening test. Cut Flower Quarterly 20(1):46-48.
  • Wien, H.C. 2008. Cornell-copia: Growing snaps in the field or a high tunnel Pinch them! Cut Flower Quarterly 20(2):16-17.
  • Wien, H.C. 2008. Cornell-copia: Pinching sunflowers. Cut Flower Quarterly 20(3):12-13
  • Wien, H.C. 2008. Cornell-copia: Pinching Lisianthus. Cut Flower Quarterly 20(4):12-13.


Progress 10/01/06 to 09/30/07

Outputs
OUTPUTS: During 2007, seven cultural practice experiments and ten variety trials with cut flowers were completed. The topping studies with snapdragons confirmed the 2006 results, showing that apex removal increased yield by 26 and 38 percent in spring field and fall tunnel experiments, respectively. Late flowering varieties were less responsive than early flowering lines. Topping experiments with lisianthus were also conducted in both field and high tunnel, and also increased yield if six nodes were left on the plants. In sunflower, topping produced multiple stems, each of which were much smaller than the plants that had not been topped. Spacing the plants farther apart (12 x 12 in. vs, 9 x 9 in.) counteracted this trend to some extent, and may be necessary to produce sunflowers with consumer appeal. Investigations of the daylength response of sunflowers were continued, with the screening of 16 cut flower varieties for sensitivity to 12 or 16 hours daylength in the first three weeks after emergence. Six varieties showed no response in flowering time or plant size, four had a slight short-day reaction, and five were classed as sensitive short day types. The latter flowered 18 days later in long-day conditions, and the plants were 45 in. tall, compared to 28 in. for the short-day plants. Two trials to pin down the exact time of daylength sensitivity in sunflower indicated that plants reacted most strongly when exposed to the critical daylength during week 2 after emergence, but this will need to be verified with additional work. Some sunflower varieties readily lose their petals if these are disturbed by brushing, even if the flower has just opened. This petal loss greatly detracts from flower appearance. An objective test was developed that measures the force required to pull a petal from the flower receptacle. Variety comparisons found clear differences, with Moulin Rouge, Strawberry Blonde and Procut Bicolor most susceptible to petal loss, and Sunrich Orange and Procut Lemon most resistant. In previous years, variety trials with delphinium have suffered from a heavy loss of plants due to a severe root disease. Neither straw mulch nor silver color plastic mulch improved plant stands over the standard black plastic, but the variety Aurora White was reduced to a 33 percent stand at the end of the season, compared to 50 and 59 percent for Guardian Blue and Candles White Shades, respectively. Cut flower variety trials were conducted with lisianthus, ageratum, dianthus, gomphrena, larkspur, salvia, scabiosa, statice, ornamental kale and ornamental peppers. Many of the entries were provided by the national cut flower trial of the Association of Specialty Cut Flower Growers, and the results will be reported in their quarterly publication. New lines of lisianthus were particularly interesting, with new flower colors, including light brown, and a much smaller flower size showing promise. A field trial designed to test the response of five major vegetables at 3 stages of growth was not successful, because the silt loam soil did not retain sufficient moisture to stress the plants. PARTICIPANTS: There was no change in the participants in the project. In early April 2007, Pritts and Wien provided training in high tunnel management to growers and extension staff in four locations in Northern New York. The presentations, and tours of growers' tunnels, were arranged by Ms. Anita Deming and Amy Ivins, Cornell Cooperative Extension, Essex County.

Impacts
The results of our sunflower daylength sensitivity work have been publicized through articles in trade journals and at extension conferences visited by cut flower growers in New England and the mid-Atlantic states. As a result, flower seed catalogs are slowly correcting their information on daylength response, although some have so far not done so. We now have sufficient information on our topping trials to publicize this work in trade journals and in conferences. The technique is simple, and gives important benefits of spreading the flower harvest and increasing yield. Now that a simple objective test for petal loss in sunflower has been developed, there is a big opportunity to test for ways of arresting petal loss in susceptible varieties. Additional research will also help to provide an understanding of the link of petal removal force and flower vase life. The results of the variety trials are also publicized at extension meetings, and acquaint growers and the public about the particular flower species, as much as the specific variety. There is considerable interest in the use of high tunnels to grow high value horticultural crops, and cut flower species are part of that interest. High tunnel construction and use for horticultural crops has been a popular topic at a number of extension meetings, and that interest is likely to continue. To pursue satisfactory outcomes in our research on the effects of flooding on vegetables, the 2007 experiment demonstrated that field trials will require more elaborate facilities, that permit water ponding around the plants for specific periods, followed by drainage. While this can be accomplished using small containers in a greenhouse, the results of such experiments are unlikely to have applicability to the field situation, in which one would expect interaction with plant pathogens.

Publications

  • Wien, H. C. 2007. Book review: Crops and Environmental Change: An Introduction to Effects of Global Warming, Increasing Atmospheric CO2 and O3 Concentrations, and Soil Salinization on Crop Physiology and Yield. HortScience 42(7):1749.
  • Wien, C. 2007. Floral crop production in high tunnels. Program and Abstracts, ASHS Annual Conference. HortScience 42(4):838.
  • Wien, H. C. 2007. Increasing snapdragon cut flower yields with early pinching. Program and Abstracts, Annual Conference. HortScience 42(4):1016.
  • Lubag-Arquiza, A. and Wien, H. C. 2007. Treatments for producing potted Paeonia Paula Fay for Mothers Day and Valentines Day. Program and Abstracts, ASHS Annual Conference. HortScience 42(4):974.
  • Wien, H. C. 2007. Effect of time, heat and light on sunflowers. Pages 101-102 in Proc. Mid-Atlantic Fruit and Vegetable Convention, Hershey PA.
  • Wien, C. 2007. Day-neutral sunflowers: Do they exist, and what difference does it make? The Cut Flower Quarterly 19(1):48-49.
  • Wien, C. 2006. Can we grow cut flowers with longer stems? The Cut Flower Quarterly 18(3):32-33.
  • Wien, C. 2006. Growing Black-eyed Susan and sunflower out of season. Growing for Market 15(6):17-18.


Progress 01/01/06 to 12/31/06

Outputs
Research continued on climate control in high tunnels (unheated polyethylene-covered greenhouses). In two tests within one high tunnel, we tested the effect of four low tunnel materials covering cut flower crops, on temperatures in spring and fall during periods of frost outside the high tunnel. Clear polyethylene, spunbonded nylon and greenhouse shading fabric all elevated minimum temperatures by 3 to 5 C when outside temperatures were -2 C, but if not removed on sunny days, clear plastic covers elevated temperatures around the plants to injurious levels. Variety trials of new cut flower cultivars were conducted on 10 species in the field, and 8 of these were also done in the high tunnel. Of the ornamental grasses tested, Feathertop Pennisetum was most productive and decorative, but produced a massive underground root. Lisianthus (Eustoma grandiflora) ABC 2-3 Green, and ABC White GX12444 were attractive and productive, Dianthus Sweet Scarlet had early stems with brilliant red flowers, and Celosia Temple Belle New Scarlet was a productive cockscomb type. Cultural practice trials with cut flowers tested the effect of daylength during the first three weeks after emergence on earliness in flowering and plant and flower size of 25 sunflower varieties. Of these, 10 were day-neutral, 11 flowered more than 2 weeks earlier after short day treatment (12 hrs.) than if exposed to 16 hrs. in the first three weeks, and two flowered later under short day pretreatment than under long days. Apex removal to stimulate early branching was tested on sunflower, lisianthus and snapdragon. With sunflower, we confirmed that although topping at nodes 4 or 6 increased stems per plant to 3 to 4, the flower diameter was reduced by 50 percent, and vase life was decreased. In Lisianthus, stem yield was not significantly affected by apex removal, but stem length was increased by 15 percent. Topping at node 3 and 6 successively delayed the bulk of the flower harvest, compared to the control, and may be a way of making flower harvest more uniform through the season. The greatest positive effect of apex removal was obtained with snapdragons. In 2 trials, one conducted in the high tunnel and one outside, stem number increased by 50 and 33 percent respectively when 6 nodes were left on the main stem. Stem length was unaffected or decreased by 10 percent by topping. Four cultivars were compared in the trial, and those in Flowering Groups 1, 2 and 3 gave higher yields, and responded to topping more than the Group 4 variety Rocket. The response of Rudbeckia hirta to time of planting was tested by sowing the seeds on four dates, and transplanting them either in the field or in a high tunnel (last two plantings). Sowing March 8 produced an average of 33 stems per plant over the season, about twice as many as the May 1 sowing. Planting a month later reduced yield to 7 stems per plant, and these were 17 percent shorter. A final planting in early July produced only sessile flowers. A test of the photoperiod response of the three varieties on a controlled daylength bench in the greenhouse confirmed that they are obligate long day plants that fail to flower at a 12-hour photoperiod.

Impacts
High tunnels have aroused much interest among growers wishing to extend the growing season on valuable horticultural crops in spring and fall. Work on low tunnels is showing that such secondary covers over the crop in the tunnel can increase night temperatures and reduce high temperature stress on sunny days. The spun-bonded materials are the most promising in this regard, and will be tested in growers tunnels in 2007, and publicized at winter extension meetings. The results of our sunflower photoperiod work has aroused considerable interest among seed companies and cut flower growers, for it helps in understanding growth responses of the crop when grown in high tunnels early in the growing season. The knowledge of the daylength response of specific cultivars will pressure seed companies to be more forthright about these characteristics to their customers. The work on topping of snapdragons confirms that productivity of this crop can be considerably increased by the simple practice of encouraging early branching. A normal harvest of the main stem, in contrast, removes many potential branches. Topping has the added benefit of stimulating simultaneous flowering of several stems on each plant, thereby reducing harvest costs. Because of its sensitivity to daylength, Rudbeckia hirta performs best when it is allowed to produce an adequate vegetative frame before initiating flowers. With later plantings, the vegetative period is shortened, and productivity declines.

Publications

  • Wien, H.C. 2006. Ethephon treatment may alleviate the suppression of female flowers of Cucurbita pepo under high temperatures. HortSci. 41:1421-1422.
  • Wien H.C. and T.A. Zitter. 2006. Initiating sudden wilt disorder in muskmelon with low light stress. Pages 60-64 in: Proceedings of Cucurbitaceae 2006. G.J. Holmes, ed. Universal Press, Raleigh, North Carolina.
  • Vanek, S., H.C. Wien and A. Rangarajan. 2005. Time of interseeding of lana vetch and winter rye cover strips determines competitive impact on pumpkins grown using organic practices. HortSci. 40:1716-1722.
  • Vidal, M. Das Gracas, D. DeJong, H.C. Wien and R.D. Morse. 2006. Nectar and pollen production in pumpkin (Cucurbita pepo L.). Revista Brasil. Bot. 29:267-273.


Progress 01/01/05 to 12/31/05

Outputs
During 2005, 4 species of flowers grown for use as cut flowers were grown in a high tunnel and in the open field, testing the performance of 29 varieties. Most noteworthy were ABC 2-3 Blue, ABC 3-4 Rose and Echo Champagne lisianthus, Summer Dafne and Summer Helios trachelium and Flamingo Salmon godetia. Subjecting Sunrich Orange sunflower to 12 instead of 16 hrs daylight during the first 3 wks of seedling growth advanced flowering by 3 wks, and resulted in 75 instead of 125 cm stem length. Since natural daylengths are short during early spring plantings, using photoperiod sensitive varieties could lead to earlier harvests. With many flower species, stem length at harvest is not sufficient to satisfy consumer expectations. In a field trial, we found that growing lisianthus, trachelium and Rudbeckia Prairie Sun in a 50 pct shade canopy increased stem length by 20 pct, but stems harvested reduced by 32 pct. Erecting a side curtain of the same material to protect against wind resulted in a 10 pct increase in stem length, without decreasing yield. Snapdragon varieties used as cut flowers are classified according to their adaptation to winter, summer or intermediate conditions. To determine which types are best suited to early or late high tunnel production in New York State, 5 varieties spanning these types were transplanted in mid-April, late July or mid-August in our high tunnel, and outdoors in mid-May. Winter types produced similar yields in the April and July plantings, while the summer types had significantly decreased yields in the later planting. Both types were inhibited from flowering during August and early September by high temperatures, but the winter types resumed production more quickly than the summer varieties. Rudbeckia hirta is a short-lived perennial that produces attractive, long-lived blooms in the first year. The varieties most valuable as cut flowers are obligate long-day plants. Removing the growing point of cut flower seedlings in the preflowering stage to force early branching is a common strategy to increase yield. When 2 sunflower varieties were topped to leave 4 or 6 nodes, there was an increase in stem numbers, but the results varied with the variety. In the earlier Procut Orange, many of the resulting flowers were small and misshapen. In Sunrich Orange, stem yield increased by 211 and 300 pct, and the size and attractiveness of the flowers was not adversely affected. A similar study with lisianthus increased stem yield by 36 pct in 2 varieties, without negatively affecting stem length or earliness. We continued work on sudden wilt of muskmelon. We tested the premise that this collapse at harvest is brought about by a carbohydrate stress, in which limited assimilates are translocated preferentially to the fruit rather than to the root system. By subjecting field plots of melons to 40 or 80 pct shade, beginning at the time the first fruit were just ripening, we found that we could cause the plants to collapse within 10 days, with severity of collapse correlated to the degree of shade. It is not known if the imposed stress worsened incidence of root pathogens, or acted directly on plant root function.

Impacts
The testing of new varieties of cut flowers is part of a national trials organized by the Association of Specialty Cut Flower Growers, and results are nationally publicized to members. In addition, the encouraging performance of relatively less known crops like Trachelium, publicized through ASCFG and locally will increase production of this crop. Our tests of the daylength response of sunflower contradict the claims of several seed companies, and will guide growers in more predictable ways of growing this crop. The use of 50 percent shade to increase stem length has been shown by our research to depress yield too much, but use of side curtains to reduce wind-induced plant movement is practical, and can be easily implemented. Extending the research on snapdragons from greenhouse to production in tunnel and field indicates that the earliness and productivity of the winter greenhouse types could be useful in summer planting for fall harvest. This may be even more important in milder climate zones. The simple process of plant topping appears to be a useful and simple way of increasing yield, but in sunflower, some varieties suffer adverse effects on flower appearance. With lisianthus, the results were encouraging and warrant additional work. This is the first time that we have been able to induce sudden wilt of muskmelons. If the result is confirmed in subsequent work, it will demonstrate to plant breeders and agronomists the importance of root health in the harvest period of the melon crop. It may also justify the use of disease-resistant rootstocks in melon production.

Publications

  • No publications reported this period