Genetic Differentiation of Non-Heading Chinese Cabbage(Brassica campestris ssp.chinensis Makino) Germplasm Based on SRAP Markers

The genetic diversity and differentiation were assessed in 64 accessions of non-heading Chinese cabbage from all the world by SRAP(Sequence-related amplified polymorphism) markers.Two hundred and fifteen loci were detected by 21 pairs of SRAP primers.Among them,112 were polymorphic,the polymorphic rate was 52.09%,and 10.24 loci and 5.33 polymorphic loci were amplified by each pair primer an average.The Nei's gene diversity index and Genetic richness of B.compestris var.communis were 0.1410 and(190) 88.37% respectively,the highest among different types of non-heading Chinese cabbage,and 0.1451 and(185) 86.05% respectively in Jianghuai Plain,the highest among all the regions ecological regions.These two indices were respectively 0.1293 and(188) 87.44% higher in domestic cabbage than in the foreign cabbage.The measurement of genetic variation showed that the coefficient of genetic differentiation was 58.22%.Most of the genetic variation existed among populations.The gene flow(0.4031) was less among populations,indicating that the degree of genetic differentiation was higher.Six groups were clustered according to genetic similarity coefficient of 0.872.