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Chyun-Chien Liang, Tzu-Yao Wei, and Der-Ming Yeh

length (1.9–2.0 cm). Thirty styles were measured from each cultivar to determine the average style length. An additional six reciprocal crosses were designed to determine whether the style length of the female parent could affect seed production. These

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S.C. Schank, D.A. Diz, and D.S. Wofford

1 Professor. 2 Geneticist, DeKalb Seed Co., Argentina. 3 Associate Professor, to whom reprint requests should be addressed. The research work reported in this paper was supported by the Institute of Food and Agricultural Sciences, Univ. of

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Nicole Smith and Prem L. Bhalla

Brassica oleracea is an important vegetable crop, which includes fully cross-fertile cultivars such as broccoli, Brussels sprouts, cabbage, cauliflower, collard, kohlrabi, and kale. F1 hybrids are desirable, as plants grown from hybrid seeds benefit from the heterotic effect of crossing genetically distinct pure lines. But, there is no practical and reliable method to create male sterility for hybrid seed production that is suitable for Brassica vegetables. We have been working to induce nuclear male sterility in cauliflower (Brassica oleracea var. botrytis) by antisense inhibition of Bcp1, a unique anther-specific gene of Brassica. The production of nuclear male-sterile lines will enable male lines with superior agronomic traits to be converted to female parents. Thus, vegetative propagation of parent plants for hybrid seed production by tissue culture is desirable. To achieve this objective, we compared various plant tissues, including stem, petiole, leaf, leaf rib, flower stem, pedicel, flower bud, and petal as explants for tissue culture propagation of an Australian cultivar (B-4) of cauliflower, Brassica oleracea var. botrytis. Four different MS based media containing different amounts of BAP, NAA, GA3, and silver nitrate were used. The cultures were incubated at 25°C with a 16-hr photoperiod. Initial response was visible within 10 days, but percentage callus, root, and shoot formation was scored after 3 weeks of culturing. Of all the explants tested, pedicel explants showed maximum shoot initiation and leaf explant did not respond to regeneration under the conditions tested. The results from these on going experiments will be presented and discussed.

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Edward C. Tigchelaar

The coupling phase linkages have been synthesized between the gene aw (without anthocyanin) and the male sterile gene ms15 (and its alleles ms26, ms47, and an Israeli source of male sterility). Less than 2 map units separate aw and ms15 on chromosome 2, providing a convenient seedling marker gene to rapidly identify male sterility for both inbred development and hybrid seed production. The seedling marker also provides a convenient marker to rapidly assess hybrid seed purity. Unique features of each of the alleles involved in male sterility and their use in inbred and hybrid development will be described.

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M. Aneja, T.J. Gianfagna, S.A. Garrison, and E.F. Durner

Precocious flowering can be induced in asparagus (Asparagus officinalis L.) seedlings with N-phenylcarbamate herbicides, such as n-propyl N-(3,4-dichlorophenyl) carbamate (NPC); however, only ≈50% of the treated seeds produce flowering plants because these compounds inhibit germination and seedling emergence. We have improved the treatment method by determining the environmental conditions, timing, dose, and duration needed to maximize the percentage of germination, emergence, and flowering. Imbibing seeds in water for 5 days, and then treating germinated seeds with 0.4 mm NPC for 5 days after radicle emergence, with seedling aeration in the light, resulted in the production of flowering seedlings from >90% of the treated seeds. For freshly harvested seeds, in which germination rates are more variable than aged seeds, individual seedlings must be transferred to NPC within 1 day after radicle emergence to produce a high percentage of flowering plants. For seven male asparagus cultivars, chemical induction of flowering in seedlings with NPC produced a sex ratio similar to that of field-grown plants, demonstrating that NPC induces flowering without altering floral differentiation or sex expression. This method can be used for rapidly and accurately identifying the percentage of females in “male” cultivars.

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Yim F. So, Martin M. Williams II, and Jerald K. Pataky

hybrids (e.g., two to four hybrids) and has produced limited information on crop growth responses to weed interference. Moreover, the seed industry would like to identify cultivars with high CT suitable for organic production systems. The goal of this

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John R. Stommel

the F 1 hybrid exceeded that of the high seed parent in this cross and reduced seed count progeny were over-represented in the F 2 generation. In related Solanaceous crops, production of seedless parthenocarpic fruit is heritable but does not fit a

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Sarah M. Smith and Zhanao Deng

bulked pollen from 35 COTI paternal plants, resulting in 35 COTI REF families. Assessing seed production and seedling emergence of interspecific F 1 hybrids grown in the greenhouse Assessment of seed production was conducted in conjunction with the

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Mary Lewis, Matthew Chappell, Paul A. Thomas, Rebekah C. Maynard, and Ockert Greyvenstein

our study. A. hirtella was documented to produce 51.2 ± 7.2 seeds per pod in the wild ( Betz and Lamp, 1992 ), which was similar to hybrid A. hirtella results observed in our study. However, wild seed production in A. purpurascens (180.7 ± 31

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Travis C. Teuton, John C. Sorochan, Christopher L. Main, and Thomas C. Mueller

·ha −1 , which produces three to eight seed per square centimeter ( Beard, 1973 ). However, many of the turfgrass breeders and developers have had problems with low seed yield, low germination rates, and poor seedling vigor in many of the new hybrid