Microspore culture of white cabbage, Brassica oleracea var. capitata L.: genetic improvement of non-responsive cultivars and effect of genome doubling agents
1999
Rudolf, K. | Bohanec, B. | Hansen, M.
For the efficient application of haploid induction procedures in cabbage breeding, a sufficient number of regenerants should be achieved in a broad spectrum of genotypes. However, the majority of genotypes are somewhat recalcitrant. The efficiency of microspore culture was tested by crossing a responsive (28.7 embryos per Petri dish) and a non-responsive (0.1 embryo) cabbage cultivar. The embryo yield of one progeny was intermediate (18.9) while two were superior to the best parent cultivar (52.9 and 64.0 embryos). Thus, genes for haploid embryogenesis, present in responsive lines, can be effectively transmitted to response x non-responsive hybrids. Abscisic acid-induced desiccation of embryos was used for the efficient regeneration of plants. High germination percentages (54.7-70.6%) followed by normal plantlet development were achieved. Spontaneous genome doubling measured at the plantlet stage differed markedly in untreated genotypes. The percentage of diploids ranged from 21 to 67%. The effects of two antimitotic drugs applied to freshly isolated microspores were determined in two experiments. In the first experiment, trifluralin (0.5 and 1.0 mg/l) had no effect on embryo induction while oryzalin partly (0.125-0.25 mg/l) or completely (0.5 mg/l) inhibited the formation of embryos. In the second experiment, higher concentrations of trifluralin increased the proportion of diploidized plants. Application of antimitotic drugs to microspores did generally not improve the overall production of haploid plants, which was higher in an untreated control.
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