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Gibberellic Acid and 2,4-D Treatments for Wheat × Barley Hybridization Using Detached Spikes

Riera-Lizarazu, Oscar, Dewey, Wade G., Carman, John G.
Crop science 1992 v.32 no.1 pp. 108-114
maternal effect, inflorescences, plant breeding, intergeneric hybridization, Hordeum vulgare, wide hybridization, embryo (plant), gibberellic acid, Triticum aestivum, seed set, 2,4-D, culture media, tissue culture
Wide hybridization is a complementary alternative for transferring desirable traits between wheat (Triticum aestivum L.) and barley (Hordeum vulgare Lo). Direct hybridization procedures have proven ineffectual because of genetic dissimilarities between diverse gene pools. Progress has been made by applying growth hormones prior to and after pollination. Using crossable lines has also contributed to successful hybridization. Detached spikes were used to evaluate the effect of 2,4-dichlorophenoxyacetic acid (2,4-D) and gibberellic acid (GA₃) on crossing success between ‘Fukuhokomugi’ (Fukuho) wheat and ‘Luther’ barley. Seed set was best when Fukuho was the maternal parent. More embryos were obtained by adding high concentrations of 2,4-D to the detached-spike culture medium (up to 225 μmol kg⁻ˡ). This synthetic hormone had no effect on embryo formation when barley was used as the female parent. Gibberellic acid (8.3 to 29.8 μmol kg⁻¹) did not affect embryo formation, regardless of the cross direction. The 2,4-D-induced increase in embryo set is presumably attributed to enhanced embryo survivability. Contribution of the Utah Agric. Exp. Stn., Journal Paper no. 4031. Partially supported by a USDA CSRS grant to W.G. Dewey, Agreement no. 88-34134-3396.