Isolated Microspore Culture and Plantlet Regeneration in Huangxinwu Brassica rapa L ssp chinensis

To improve the frequencies of microspore embrogenesis in Huangxinwu(Brassica rapa L ssp chinensis),seven varieties from Huainan area were employed to study the factors of enhancing the embrogenesis,including genotypes,culture season and pretreatment.In addition,the ploidy variation of regenerated plants were investigated by flow cytometry.The results showed that embrogenesis frequencies varied remarkably among varieties,and embryos were obtained only from three varieties,09-96(Huainantadiwu 1),09-97(Huainanhuangxinwu 4),and 09-98(Huainanhuangxinwu 14),with the frequency of 1.13,2.93 and 4.63 embryos/bud,respectively.33℃ heatshock treatment was vital to microspore embrogenesis.Moreover,the embryo frequency was improved by the pretreatment of 0.2% n-butanol.Ploidy identification of regenerated plants indicated that haploid,double haploid,triploid,and tetraploid were all existed,however the most of which were double haploid plants.The percent age of double haploid in 09-97 and 09-98 were 70% and 80%,respectively.