Genetic diversity analysis of Pinus kesiya var.langbianensis germplasm resources based on SSR molecular markers
[Objective]The aim of the study is to reveal the genetic diversity and genetic structure of Pinus kesiya var.langbianensis germ-plasm resources,providing a theoretical basis for constructing breeding populations and formulating strategies for genetic improvement.[Method]A total of 338 samples from 11 natural populations were analyzed using SSR molecular markers technology,with the employment of 18 SSR primers.The genetic diversity of the germplasm resources was assessed through PowerMarker v3.25,GenALEx v6.4.1 and Struc-ture 2.3.4.[Result]A total of 120 alleles were detected,with a mean value of 6.667 per locus.The average of expected heterozygosity(He)was 0.524,the average Shannon information index(Ⅰ)was 1.016,and the average of polymorphic information content(PIC)was 0.468.A large proportion of genetic variation came from within populations.The average coefficient of genetic differentiation(FST)for the germplasm was 0.091,indicating that only 9.1％of the variation existed among populations.This result was consistent with AMOVA analy-sis.The gene flow(Nm)was calculated as 4.627(Nm＞1),indicating that gene flow played a role in preventing differentiation among populations.STRUCTURE analysis divided the 338 individuals into 2 groups,while UPGMA clustering based on Nei's genetic distance grouped the 11 populations into 2 branches.Notably,six populations in Simao Prefecture formed a distinct branch,and two populations in Xishuangbanna,one in Lincang,and one in Baoshan clustered together,with another distinct branch formed by one population in Dehong.[Conclusion]A higher level of genetic diversity was detected in P.kesiya var.langbianensis germplasm resources,indicating a broad genet-ic basis for potential genetic improvement.The observed genetic variation was primarily originated from within populations.Therefore,in the process of resource selection and conservation,emphasis should not only be placed on selecting populations with rich genetic diversity but al-so on identifying superior individuals within those populations.
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