Analysis Of Genetic Diversity And Establishment Of Core Collection Of Rice Germplasm In Ningxia And Xinjiang

This study used phenotypic trait analysis and SSR molecular marker technique to explore the genetic diversity of 193 Ningxia and Xinjiang rice germplasm resources based on the morphology and molecular biology.Then,the core collection was constructed,The aim of this study was to provide theoretical reference for broadening the genetic basic of rice germplasm resources in Ningxia.The main results of the study were following:1.The results of 6 quality traits analysis showed that most of these rice germplasm resources presented coated stem node,not premature leaf,smal sword leaf angle,strong lodging resistance,panicle shape bending and shattering resistance.The genetic variation of 14 quantitative traits all reached a very significant level,in which the variation coefficient of single plant yield was the largest(23.8%).The variation range of genetic diversity index was from 1.86 to 2.08 and the average index was 2.02.Cluster analysis showed that 193 rice germplasm resources were divided into 8 groups.Most of the germplasm resources were distributed in the first group,accounting for 65.3%.The second group was accounted for 9.3%and the third group was accounted for 20.7%.The rest of these groups contained 9 kinds of rice germplasm which was accounted for 4.7%.Through principal component analysis,14 quantitative traits were converted into 7 principal components,and the cumulative contribution rate was 90.7%.2.56 paris of polymorphic SSR primers were screened by SSR molecular marker and 242 alleles were detected.The number of alleles,effective number of alleles,Shannon information index and Nei's genetic diversity index were 4.3214,2.3536,0.9277,0.5046,respectively.it showed that genetic diversity was abundant.Through cluster analysis,193 rice germplasm resources were divided into 10 categories at the genetic similarity coefficient of 0.745.among them,the first,the third,the fifth,the seventh,and the tenth all contained 1 germplasm.The second group,the fourth group and the sixth group contained 6,3 and 4 kinds of rice germplasm,respectively.The eighth group contained 68 gersplasm,accounting for 35.23%of all gersplasm and and ninth group contained 107 germplasm,accounting for 55.99%of all gersplasm.Population structure analysis by Structure 2.3.4 showed that 193 rice germplasm resources were divided into 5 groups.It indicated that 94.30%rice germplasm had a relatively single genetic components,while the remaining 5.7%was a mixed genetic components with complex genetic background.3.Based on SSR molecular markers,the core germplasm of 193 rice germplasm resources was constructed by progressive random sampling method,and 20 core germplasm were obtained.The retention rate of the 20 core germplasms to the original germplasm was 10%.The numbers of polymorphic loci,the percentage of polymorphic loci,the observed allele polymorphism loci,effective number of alleles and the retention rate of Shannon information index were 95.39%?94.83%?101.53%?106.23%?101.39%?109.35%,respectively.It could represent the inheritance and variation of the original germplasm resourses,and could be used as core germplasm for Ningxia rice breeding.