Analysis of Genetic Diversity of Some Introduced and Domestic Winter Wheat Cultivars

In order to gain knowledge of genetic diversity of winter wheat,21 varieties introduced from the USA and 19 varieties planted in North-west China were analyzed for polymorphism by some SSR markers developed in our laboratory.A set of 52 SSR markers were screened and a total of 175 allelic variants were detected in the 40 wheat varieties,with the range of 2 to 13 and the average of 6.73 alleles per marker.The genetic similarity coefficient(GS) among the cultivars was 0.339 on average,and varied from 0.118 to 0.894.Introduced cultivars were higher than the domestic ones in 'mean of genetic distance(GD)',but lower in GS,suggesting that introduced cultivars possessed broader genetic variation.Based on 0.69 of GS,the cultivars used in this study were clustered into five groups.Group I consisted of 7 USA cultivars and one domestic cultivar,group Ⅱ,group Ⅲ and groupⅣ consisted of 10 domestic cultivars.Group V consisted of 12 domestic cultivars,which could be clustered into two sub-groups.The sub-group V-1 included only domestic cultivars,and the sub-group V-2 contained both of introduced cultivars and domestic cultivars.