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- Author or Editor: Brent Pemberton x
Cut flower production in a low-input greenhouse for winter and spring holiday sales was evaluated. Low-input structure was a plastic covered Quonset greenhouse modified with sides that could be manually raised or lowered. Sides were raised on mild days for ventilation and remained closed for minimum heating for the few brief periods of sub-freezing temperatures characteristic of the local winter climate. Bulbs of tulip (Tulipa sp L.) cultivars `Maureen', `Negrita', and `Oxford' were dry cooled for 12 weeks and planted in December for Valentine's Day forcing. 30% shading did not significantly increase stem length in `Maureen' and `Oxford' but did increase stem length in `Negrita'. `Oxford' was at a harvestable stage for the. Valentine's Day market, but not `Maureen' or `Negrita'. All cultivars were of an acceptable quality. Plugs of snapdragon (Antirrhinum majus) cultivars `Appleblossom', `Potomac white', and `Rocket Rose' were planted in late winter at 4 and 6 inch spacing and were either pinched or not pinched. For all cultivars, pinching resulted in higher yield but lower grade. Four inch spacing had a slightly larger number of higher grade stems possibly due to stretching. `Appleblossom' and `Potomac White' were florist grade, whereas `Rocket Rose' was more appropriate for mass marker For both tulip and snapdragon, cultivar evaluation is necessary to determine suitable market strategy.
Rooted liners of Rosa cvs. Meijikatar and Meirutral were potted into 11 cm pots and placed into growth chambers. One chamber provided 14 hours of light with 30C/21C (day/night) air temperature (HTLD) and another chamber provided 8 hours of light with 21C/17C (day/night) air temperature (LTSD). PPF was 725 μmoles m-2 s-1 in both chambers. When plants were established, they were pinched and forced to flower. Simulated shipping for 4 days at 16C in darkness resulted in a shorter shelf-life when placed in an interior environment at 21C with a continuous PPF of 30 μmoles m-2 s-1 and compared to non-shipped plants. In addition, LTSD grown plants exhibited a shorter shelf-life than HTLD grown plants. When Meirutral plants were sprayed to runoff 24 hours prior to shipping, 2 mmolar (aminooxy)acetic acid (AOA) increased the shelf-life to the same length as the non-shipped plants and 2 mmolar silver thiosulphate (STS) increased the shelf-life to longer than the non-shipped plants. However, AOA did not increase shelf-life over that of shipped plants for Meijikatar whereas STS increased the shelf-life to that of the non-shipped plants.
Field grown `Mr. Lincoln' rose plants were dug and wrapped in plastic to reduce moisture loss during transport to the lab. Plants were then pruned, weighed, and returned to the plastic cover. After recording initial weights, plants were allowed to dry for 0, 1, 4, 7, or 24 hours at 16°C. Plants were then oven dried, potted, or soaked in water for 20 hours before potting for each drying time treatment. The potted plants were forced to first flower in a glasshouse at which time growth measurements were made. Undried plants had a moisture content of 48%. Seven hours drying reduced moisture content to 41%, but had no effect on growth or flowering. The 24 hour drying time resulted in a plant moisture content of 33%, a plant loss of 44%, and delayed growth initiation and flowering by up to 15 days compared to undried controls. Soaking after 24 hours drying increased plant survival from 38 to 75%. Plants that survived the excessive drying produced flowering growth comparable to plants with a moisture content of > 40%. A critical moisture level for rose plant survival was found to be between 33 and 41%.
Long days are known to hasten flowering of Petunia hybrida. However, breeding of modern standard-type petunia cultivars has reduced this response. With the introduction of new genetics involved in the creation of trailing-type petunias, many cultivars have been observed to have a strong photoperiodic response to the point that it is an issue for late winter or early spring flowering cropping cycles. In order to characterize this photoperiodic response in modern seed-grown trailing-type petunia cultivars, seed of 51 cultivars of trailing petunias (Petunia hybrida) were sown in November in 288 plug trays. When established about 4 weeks later, uniform plants were selected and transplanted individually to 15-cm pots. Plants were exposed to either natural days or a 4-hour night interruption using incandescent light from 2200 to 0200 HR each day until flowering. A minimum night temperature of 17 °C was maintained. Days to first flower from sowing ranged from 72 to 117 days. Generally, the night interruption treatment hastened flowering. However, the degree of hastening ranged from 4 and 5 days for `Ramblin' Burgundy Chrome' and `Ramblin' Lilac Glo', respectively, to 27 and 32 days for `Tidal Wave Cherry' and `Tidal Wave Hot Pink', respectively. Effects of night interruption treatment on plant architecture will also be presented.
The East Texas Bedding Plant Pack and Garden Performance Trials began several years ago at the Texas A&M University Agricultural Research and Extension Center at Overton (Overton Center) with the goal of providing information on greenhouse and field performance of bedding plant varieties to the local bedding plant industry and consumers of these products. The program began with local trials that have now expanded in scope with the Smith County Master Gardeners Association playing an integral role in performing the trials. Entries are received from most of the major ornamental seed companies doing business in the United States giving the regional industry access to the only comprehensive greenhouse performance trials in this part of the country. Performance evaluation data is important to this industry since it has a wholesale value of over $500 million in the northeast Texas region, of which over $100 million is bedding plant production. The field performance trials are now replicated at the Overton Center, the Dallas Arboretum and Botanical Garden (Dallas Arboretum) and the Texas A&M University Agricultural Research and Extension Center at Dallas (Dallas Center), giving over 5 million consumers in the northeast Texas region the opportunity to see how promising new plants from all over the world perform in the local climate. Plants that grow well in this climate have the potential to reduce inputs needed for production and use in the home or commercial landscape. Many of the top performing varieties from the bedding plant trials are also chosen to be part of the Coordinated Education and Marketing Assistance Program (CEMAP), a statewide testing program headquartered at the Dallas Center in which entries vie for designation as Texas Superstar plants. The comprehensive benefit of the East Texas Bedding Plant Pack and Garden Performance Trials is the link between the rural bedding plant producers and the urban consumers which serves as a basis for improving the quality of life for the citizens of Texas.
The East Texas Bedding Plant Pack and Garden Performance Trials are performed as an interaction between the plant material source companies, the plant producer companies, volunteers, and retail consumers. The Overton Trial Site is located near a concentration of bedding plant growers ($80 million annual wholesale value) which is part of the close to $500 million in ornamental plant production in northeast and north central Texas, about half of the state industry value. The spring and fall trials consist of two phases. The greenhouse phase consists of assessing production performance for use by the crop production industry. Crops are usually finished in packs (36 cells per flat), but larger size containers are used as needed according to species. Height control is a major issue and specific issues have been addressed. This is one way that publishable data can be generated by these trials. The garden phase consists of assessing garden performance in a replicated field setting at the Overton site. Garden performance is also assessed for many of the entries at sites at the Dallas Arboretum and Botanical Garden and the Texas A&M Univ. Agricultural Research and Extension Center at Dallas. An integral part of the trials are the volunteers who, as members of the Smith County Master Gardener Association, donate hundreds of hours of labor to the seeding, transplanting, and garden establishment phases of the trials. In addition, a web site has been initiated as the only practical way to share the data and hundreds of images that are generated each trial season.
Rose (Rosa sp.) cultivars Blue Girl and Mister Lincoln were harvested bare-root on 1 Nov. 2001 and 22 Nov. 2002 from a commercial nursery in Arizona. Grade 1 plants were then potted and forced to flowering in either Tucson, Ariz., or Tyler, Texas. Total chilling hours were calculated as the number of hours that the plants were exposed to a temperature below 7 °C in the field and during shipping and cold storage. Data were recorded when the petals on the first flower beg an to reflex. Overall, the number of flowering shoots and plant performance was positively correlated to digging date, weeks of cold and total chilling hours received. Days from potting to flower were negatively correlated to weeks of cold storage and chilling hours. However, when the data were separated by location, the number of flowering shoots, the percentage flowering shoots, and plant performance was positively correlated to weeks of cold and chilling hours in Arizona, but was positively correlated to digging date in Texas. Days from potting to first leaf unfolding were recorded in Arizona only and were negatively correlated to weeks of cold storage and chilling hours. Days from potting to flower were negatively correlated to chilling hours at both locations and also to weeks of cold storage in Texas. The increase in chilling from two or four weeks of cold storage increased the number of flowering shoots and performance rating of plants forced in Arizona during both seasons, but only for the 2001 season in Texas. During the 2002 season in Texas, these responses were not influenced by cold storage, but were greater than those seen during the 2001 season. In Arizona, days from potting to flower were greater in 2001 than 2002, and decreased in response to cold storage in 2001, but not in 2002.
Florida-produced ‘Prize’ azalea plants were shipped to Minnesota with apical floral buds whose individual flowers had styles which had commenced elongating. These plants were ready for rapid forcing if given the traditional 6 weeks at 9°C. However, a single 2000 ppm GA (Pro Gibb3) spray treatment resulted in plants which flowered more rapidly without a traditional cold treatment when forced in a glasshouse under natural daylength (ND) in Minnesota during the spring and summer. Length of the ND in these experiments was considered critical, as plants forced in the spring and summer under an 8-hr short day (SD) treatment did not flower in a uniform manner, or floral abortion occurred in GA treated, uncooled plants forced during the autumn. Under ND conditions, extended to 20-hr by high pressure sodium, cool-white fluorescent or incandescent lamps, plants flowered more rapidly than those plants cooled at 9° for 6 weeks and forced under ND. Uniformity of flowering was enhanced and GA treatment had no effect when 3 weeks of 9° cooling preceded supplemental lighting treatments during autumn forcing. During winter, 20-hr of high pressure sodium + GA treatment or a SD treatment of noncooled plants resulted in more rapid, but similarly uniform flowering, when compared to plants with 6 weeks of cold treatment. These data provide evidence indicating that ‘Prize’ azalea floral buds may not exhibit a physiological dormancy.
Case-cooled bulbs of Lilium longiflorum `Nellie White' were potted on 4 Dec. 1995 and forced to flowering using standard growing procedures. Plants were illuminated from shoot emergence to visible bud with supplemental high-intensity-discharge sodium vapor light at 70 μmol·m–2·s–1 from 1700 to 2200 HR each day. When the first primary flower bud (first initiated flower bud most proximal on the shoot) was 5 to 7 cm long, each plant was treated with 3 ml of either de-ionized water or 500 mg·liter–1 6-(benzylamino)-9-(2-tetrahydropyranyl)-9H-purine (PBA). Sprays were directed at the flower buds and associated bracts. When the tepals on the first primary flower bud split, plants were placed at 2°C in the dark for 0, 4, or 21 days. After storage, plants were placed in a postharvest evaluation room with constant 21°C temperature and 18 μmol·m–2·s–1 cool-white fluorescent light. The first three primary flowers on PBA-treated plants lasted significantly longer than corresponding flowers on control plants, but there was no difference between flowers at the fourth and fifth positions. Also, the total postharvest life of the five primary flowers on PBA treated plants was 3 days longer than those on control plants. Storage time inversely affected the postharvest longevity of the first three primary flowers, but had no effect on the longevity of the fourth or fifth primary flowers or total postharvest life of the five primary flowers. There were no significant interaction effects between PBA treatment and storage duration on primary flower longevity.
Five cultivars of bare-root rose plants were exposed to increasing periods of drying and after rehydration were grown in containers until flowering in a plastic-covered greenhouse. At the start of the experiment, moisture content of well-hydrated roses was between 51% and 56%. Five or 7 h of drying resulted in moisture contents below 43% for four of the cultivars and caused up to 80% mortality, increased time to flower, and decreased the number of flowering shoots. ‘First Prize’ was most tolerant of drying conditions and all plants survived, whereas ‘Mister Lincoln’ plants were most susceptible and had poor regrowth performance. Whole-plant moisture of ‘Mister Lincoln’ was similar to that in the stem or shank, which means that aboveground components instead of the entire plant can be used for moisture determination.