Improved production of doubled haploids in Brassica rapa through microspore culture

The current study aims at producing doubled haploid Brassica rapa plants through isolated microspore culture. Genotypic differences in embryogenic response and regenerative ability of microspore-derived embryos to plants were observed. Compared with the longer incubation period (72h), heat shock treatment at 33°C for 24 or 48h was more beneficial for microspore embryogenesis. Microspore embryogenesis was improved with the addition of 6-benzylaminopurine and naphthalene acetic acid to the NLN medium. The highest frequency of microspore embryogenesis was achieved in 'SH-8' (21.1embryos/bud), whereas 'SH-6' had the best regeneration ability (67.4%). In total, 1112 regenerated plants were produced from 2025 embryos in a series of experiments using different modifications of microspore culture technique. The average spontaneous doubling frequency of the different genotypes of B. rapa was 57.5%. © 2011 Blackwell Verlag GmbH.