Genetic Diversity And Population Genetic Structure Analysis In Psathyrostachys Germplasm Using SSR Markers

In order to enrich the molecular genetic information of Russian wildrye(Psathyrostachys juncea)germplasm resources,improve their utilization efficiency,extract their excellent alleles and rare genes,also find out genetic characters and components of Russian wildrye parents.This research collected 28 Russian wildrye germplasm resources from different regions at home and abroad,which were given full consideration to their breeding characteristics of cross-pollination.171 individuals of 28 Psathyrostachys accessions were analyzed by simple sequence repeat(SSR)technology to show the genetic diversity and population genetic structure,as well analysis their genetic relationship,genetic variation and differentiation and other aspects.The main results show as follow:1.A total of 261 alleles and 253 polymorphic locus were identified with 16 pairs of SSR markers in Psathyrostachys accessions.The average number of primers amplified 15.81;38 pairs of SSR primers with good polymorphism were selected to find 308 alleles and 275 polymorphic locus among Psathyrostachys individuals with an average of 8.11 alleles per primer pair.The genetic diversity of individuals is higher than that of the accessions.2.The genetic similarity coefficient(GS)of most Russian wildrye materials varied from 0.7 to 0.8,indicating that the genetic relationship between the individuals and accessions of Russian wildrye was closer and the distribution was more concentrated.3.Different classification methods(UPGMA clustering,NJ clustering,and principal component analysis)divided Russian wildrye materials into three groups.The results showed that the distribution of most Russian wildrye materials within the groups had certain regional characteristics,and the remaining groups had no obvious geographical distribution characteristics,but the main part is obvious.4.Population genetic structure analyses were conducted on the accessions and individuals of Russian wildrye.When K(best group number)=3,the accessions and individuals were divided into three groups respectively.(1)By the dividing principle of Q value greater than 0.5,the accessions of group1,2 and 3 accounted for 57.14%,10.71% and 28.57%,respectively.The other two materials with more complicated genetic parts were divided into mixed groups.The result of population structure was consistent with it of principle component analysis.The inbreeding coefficient(Fst)of three groups was Group3(0.4008)>Group 2(0.3702)>Group 1(0.2339).The genetic diversity was Group 1(0.2973)> Group 3(0.2790)> Group 2(0.2085).The differentiation level of group 3 is higher,and the genetic diversity of group 1 is higher.(2)With the Q value greater than or equal to 0.6 as the dividing principle,the individuals of group1,2 and 3 accounted for 52.05%,36.84% and 4.09%,respectively.12 individuals were classified into mixed groups.The results of classification showed that the genetic structure was more consistent than the single plant material.The results of the division of individuals with complex genetic structure were slightly different.