Trinity Road, Raleigh, NC 27607; U.S. Dept. of Agriculture Floral and Nursery Research Initiative, Beltsville, MD 20705-2350; and J. Frank Schmidt Family Charitable Foundation, Boring, OR 97009. Use of trade names in this publication does not imply
Richard T. Olsen, Thomas G. Ranney and Dennis J. Werner
Gilles Galopin, Laurent Crespel, Jean C. Mauget and Philippe Morel
flower bloom. The flowering axis develops over 2 years of growth ( Galopin, 1995 ). Continuous plant growth over the first year ensures the formation of the stem. It is followed by floral transformation that is morphologically identifiable by the
Yi-Lu Jiang, Tzong-Shyan Lin, Ching-Lung Lee, Chung-Ruey Yen and Wen-Ju Yang
). Strategies such as breeding for winter cultivars and developing methods to regulate flowering seasons are being implemented to produce winter crops. Theoretically, night breaking by using supplemental light might lead to winter fruit production ( Yen and
J.O. Payero, M.S. Bhangoo and J.J. Steiner
The effects of six applied N treatments differing by rates and frequencies of application on the yield and quality of pepper (Capsicum annuum var. annuum L. `Anaheim Chili') grown for seed was studied. The timing of N applications was based on crop phenology, leaf petiole nitrate-nitrogen concentrations (NO3-N) minimum thresholds, and scheduled calendar applications of fixed amounts of N. Solubilized NH4NO3 was applied through a trickle-irrigation system to ensure uniform and timely applications of N. Rate of mature (green and red) fruit production was unaffected by any treatment except weekly applications of 28 kg·ha-1 of N, which stopped production of mature fruit before all other treatments. Early season floral bud and flower production increased with increasing amounts of N. The two highest total N treatments produced more floral buds and flowers late in the season than the other treatments. Total fruit production was maximized at 240 kg N/ha. Differences in total fruit production due to frequency of N application resulted at the highest total N level. Red fruit production tended to be maximized with total seasonal applied N levels of 240 kg·ha-1 and below, although weekly applications of N reduced production. Total seed yield was a function of red fruit production. Pure-1ive seed (PLS) production was a function of total seed production. Nitrogen use efficiency (NUE) for red fruit production also decreased with N rates >240 kg·ha-1, but PLS yield and NUE decreased in a near-linear fashion as the amount of total seasonal applied N increased, regardless of application frequency. Season average NO3-N (AVE NO3-N) values >4500 mg·kg-1 had total seed and PLS yields less than those treatments <4000 mg·kg-1. Six-day germination percentage was reduced with weekly N applications of 14 kg·ha-1. Seed mass was reduced with weekly N applications of 28 kg·ha-1. Final germination percent, seedling root length and weight, and field emergence were unaffected by any of the N treatments. These findings indicate that different N management strategies are needed to maximize seed yield compared to fruit yield and, therefore, there may be an advantage to growing `Anaheim Chili' pepper specifically for seed.
Michele Renee Warmund, Patrick Guinan and Gina Fernandez
crop on ‘Kiowa’ was most likely the result of its growth in early spring (J.R. Clark, personal communication). Floral survival on the other blackberry cultivars may be attributed to subsequent or late growth from primary buds after the freeze event
Steven McArtney, Duane Greene, Tory Schmidt and Rongcai Yuan
sprays was low with fewer than 5% of spurs floral in the next year ( Tables 1 and 2 ). These responses illustrate the severity of biennial bearing in this cultivar. Although chemical thinning significantly reduced crop density and increased return bloom
Eduardo J. Chica and L. Gene Albrigo
, it activates the expression of floral identity genes that initiate floral organ morphogenesis ( Abe et al., 2005 ; An et al., 2004 ; Mathieu et al., 2007 ; Michaels et al., 2005 ; Wigge et al., 2005 ). Up-regulation of FT expression is key for
Yan Chen and Jayesh B. Samtani
Asia is a region rich in plant biodiversity with many centers of origin for numerous horticultural crops. Plant germplasm from Asia is thus important for new crop development in North America. Globalization and increased immigration have opened up
Daniel Warnock*, Megan Fifarek and Heather Lash
The development of the Renaissance series of cut poinsettias, Euphorbia pulcherrima, presents unique opportunities and challenges to cut flower producers. This series has curled bracts, long stem length, excellent vase life and is highly marketable. Literature indicates that this crop is suited for pot or bed production, but does not compare methods. This study assessed the impact of production system on final stem quality. Uniform rooted cuttings of `Renaissance Red' obtained from a commercial supplier were transplanted into 30.5-cm pots or a 1.2-× 2.4-m bed containing a soilless media to obtain 2 plants per 0.9 m2. A total of 56 cuttings were used for each production system and grown using standard production techniques. Transplanting occurred on 11 Aug. 11 2003 with plants reaching market stage, two cyathia shedding pollen, about 17 weeks later. To minimize border effects, plants in the outside rows of each production system were discarded. Thus, stem length, stem diameter, bract diameter, floral development, and number of axillary shoots were determined for 30 interior plants in each system. The production systems differentially impacted stem length and number of axillary shoots. Mean stem length in the bed system (89.7 cm) was greater than that observed in the pot system (71.4 cm). Plants in the bed system had significantly fewer axillary branches per plant (0.5) than plants in the pots (2.0). Stem diameters were similar for both systems (11.5 mm and 10.9 mm for bench and pot, respectively) as were bract diameters (14.3 cm and 13.4 cm for pot and bench, respectively). Both systems produced marketable stems; however, stems produced in the bed system had longer stems, fewer axillary branches, and were more uniform than those in the pot system.
Christopher L. Owens, J.F. Hancock and A.F. Iezzoni
Sour cherry and strawberry are examples of two Rosaceous species that often suffer crop reductions due to spring freezes. Breeding for improved floral freezing tolerance has the potential to mitigate the susceptibility of these plants to spring frosts. In model plant systems, researchers have been able to identify genes that play a role in freezing tolerance by initially searching for mRNAs regulated in response to cold temperatures. To search for cold-responsive freezing-tolerance genes in strawberry and sour cherry, it is necessary to first define their cold acclimation response. To test the hypothesis that sour cherry and strawberry flowers have the ability to cold acclimate, blooming plants were exposed to 4 °C and 16 h light for 14 days. Sour cherry styles and strawberry receptacles from open, fully developed flowers were excised, and electrolyte leakage curves were generated over a range of subzero temperatures. The temperature at which 50% electrolyte leakage (EL50) occurred was used to compare treatments. The flowers of two strawberry cultivars were tested for the ability to cold acclimate. Non-acclimated `Chandler' receptacles had an EL50 of -2.9 °C, while non-acclimated `Honeoye' had an EL50 of -3.4 °C. Conversely, acclimated `Chandler' receptacles had an EL50 of -7.7 and acclimated `Honeoye' receptacles had an EL50 of -8.7 °C, both are significantly different from non-acclimated values (P ≤ 0.01). Additionally, sour cherry styles were collected from the field at full bloom from a mapping population of 86 individuals from the cross `Rheinische Schattenmorelle' × `Erdi Botermo' and acclimated as previously described. The EL50 of the 86 progeny ranged from approximately -2.0 to -6.0 °C.