Assessment And Classification Of Genetic Diversity On Common Bean (Phaseolus Vulgaris L.)

Based on the date of agroecological, morphological evaluation, a core collection comprising of 400 samples selected from 4029 common bean accessions was developed with the strategy combining stratification, random sampling with cluster analysis by using Ward's method. The proportion of the core collection in the original collection was 9.93%. According to representative test, the primary core collection could well represent the original collection on the genetic diversity.The results of evaluation on the morphological characters showed that common bean was susceptible to photoperiod and temperature. The average diversity index of Chinese common bean was 1.632 while alien common's was 1.227. The first and second principal components totally represented 46% of morphological diversity. Based on morphological data, 324 accessions were clustered into 3 groups . Common bean was mainly distributed in the regions from northeastern China to southwestern China.36 paris of SSR informative primer combinations were employed to assess the genetic variation of 377 common bean accessions (332 Chinese common bean accessions, 16 alien common bean accessions and 29 wild bean accessions). The results were as follows:(1) Based on dates of alleles and Shannon-weaver index, The genetic diversity of Chinese common bean was higher than that of wild common bean and the genetic diversity of wild common bean was higher than that of alien common bean germplasm resources.(2) Among Chinese common bean accessions, the germplasm resources from Guizhou province had more alleles. The Shannon-Weaver index appeared the highest level in the accesses from Heilongjiang province and then Yunnan and Guizhou province.(3) Based on date of SSR, 377 accessions were clustered into 6 groups. 29 wild bean were clustered into the first group without other one. It were clustered into the sixth group that llof 16 alien common bean accessions and 25 Chinese common bean.All the results obtained in the present study confirmed that Yunnan and Guizhou province were secondary origin center of common bean-China center. It is suggested that ecotypes of common bean were classified, i.e. the Northeast ecotype, North China ecotype, the middle and lower reachers of the Yellow River ecotype and Southwest ecotype.