| Soybean as the major food and cash crops in the world has a long planting history in China. Cultivated soybeans are the most important germplasm resources in our country, which played a major role in Chinese soybean production. A total of 1300 soybean cultivars had been released in China from 1923 to 2005.Huang Huaihai China and Southern China are the two major places where the cultivated soybean produced. Studying on the genetic diversity and genetic structure of soybean cultivars has important implications for cultivars conservation, making breeding program and parent selection. 153 soybean cultivars from Huang Huaihai China and Southern China were conducted in the following research by coefficient of parents, including 91 from Huanghuai China, 62 from Southern China, to analyze the genetic diversity of the population and the genetic differentiation into geo-ecological subpopulations and released period subpopulations. The results are as follows:1 The analysis of parentage coefficient showed that the relationship exists among 54.59% combinations, the range of COP value of all varieties is 0.00-0.50 with the average value 0.03, 28.83% of pedigrees Relationship Coefficients(RC) are biger than the average. The COP of varieties from Huang Huaihai China is smallerr than soybean cultivars' from Southern China, 0.05, 0.06, separately. Soybean of He Nan Province has the smallest COP which is 0.04. The COP of varieties from Hu Nan province is the highest. And the cultivated soybean in the period of 2001-2005 has the lowest COP which is 0.02. The COP of cultivars in 1923-1970 is the highest. According to the Neighbor-Join clustering method, Soybean cultivars tested were classified into two subgroups which are cluster?and cluster?, there are only two varieties in cluster?, the remainder are all in cluster?.2 Twenty seven primers were selected from 80 SCoT primers and then used to detect genetic diversity of 153 soybean germplasm.The primers generated a total of 130 bands among which 110 bands were found to be polymorphic,with an average of 84.62%. The Nei's genetic diversity(H)value of these 153 accessions was 0.24 ~ 0.49, with an average of 0.37; the Shannon's Information Index(I) was 0.41 ~ 0.69, with an average of 0.54. The average value of locus polymorphism information contents(PIC) 0.27. From the year of 1923, genetic diversity of cultivated soybean accessions is increasing as time goes by, the period subpopulations of cultivated soybeans in the year of 1971~1990 reach the highest and unchanged in the next two periods. This indicated that the genetic diversity of cultivated soybean germplasm is increased from 70 s. The cluster analysis showed that cultivars tested tend to cluster together when they from the same place.3 There were 238 alleles of genetic richness, 8.81 alleles per locus, 0.61 of average PIC ranging from 0.15-0.87 inside of the released cultivar population detected by 26 EST-SSR markers. Average PIC and genetic richness of soybean cultivars from Huanghuai China are all larger than the varieties from Southern China. When evaluate genetic diversity of Chinese soybean cultivars by specifically existent specifically deficient alleles, the result shows: The cultivars of Jiangsu Province have the largest specifically existent alleles. There are 0 specifically existent alleles in Hebei and Zhejiang province. There are not specifically deficient alleles in any province except Shanghai. The cultivars of 1991-2000 have the largest specifically existent alleles. The smallest number of specifically existent alleles is in ancestor and 2001-2005. There are 24 specifically deficient alleles in 1923-1970, and other period subpopulations are all lower than that.According to the Neighbor-Join clustering method, the cultivars tested were divided into three subgroups including cluster?? cluster? and cluster?. And cluster? only has six soybean cultivars. There are 73 and 74 individuals in cluster?? cluster?, separately. |
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