Obtaining Doubled Haploid Plants of Loose-curd Cauliflowers(Brassica oleracea var. botrytis L.)by Microspore Culture

Five loose-curd-type cauliflower(Brassica oleracea var. botrytis L.) hybrids were applied to induce embryogenesis and plant regeneration via isolated microspore culture. The results indicated that the embryogenesis was mainly genotype-dependency. The highest embryo production was found in Chinglong 65, which produced an average yield of 15.5 embryos per flower bud. The germi-nated rate for microspore-derived embryos in loose-curd cauliflowers was normally at 30%, therefore a great number of doubled haploid plants were efficiently obtained. Cold pretreatment to flower buds had a significant influence upon microspore embryogenesis, but a great difference was found among tested genotypes. The growth duration and fertility for regenerated plants showed a big segregating at both heading stage and anthesis, finding above 50% plants giving normal seed set and fertile capacity, which implies unnecessary doubling treatment in cauliflower microspore culture.