Comparison between Germinated Seed and Isolated Microspore EMS Mutagenesis in Chinese Cabbage (Brassica rapa L. ssp. pekinensis).

Mutagenesis is an important tool for breeding and genomic research. In this study, the germinated seeds and isolated microspores of a double haploid line 'FT' were treated with EMS, respectively, with the aim of comparing the effects of the two approaches on generating mutants in Chinese cabbage. For microspore EMS mutagenesis, the isolated microspores were treated with 0.12% EMS for 20 min, a total of 1268 plantlets were obtained, and 15 M₁ mutants were screened with a mutation frequency of 1.2%. For seed EMS mutagenesis, 7800 germinated seeds were treated with 0.8% EMS for 12 h, and a total of 701 M₂ mutants were screened, with a mutation frequency of 18.78%. In total, 716 mutants with heritable morphological variation including leaf color, leaf shape, leafy head, bolting, and fertility, were obtained from the EMS mutagenesis experiments. Homozygous mutant plants could be screened from M₁ lines by microspore mutagenesis, and M₂ lines by seed mutagenesis. The mutation frequency was higher in seed mutagenesis than in microspore mutagenesis. Based on these results, we propose that seed EMS mutagenesis is more suitable to generate a large-scale mutant library, and the microspore EMS mutagenesis is conducive to rapidly obtaining homozygous mutants. [ABSTRACT FROM AUTHOR]