基于SSR标记的63份芥菜型油菜种质资源的遗传多样性和群体结构分析OA

[Objective]The present paper aimed to investigate the genetic diversity and population structure among 63 Brassica juncea germ-plasm resources,providing a theoretical basis for mining superior allelic variations,improving breeding efficiency,and accelerating the breed-ing process.[Method]63 B.juncea accessions from diverse origins were used as research materials,and genetic differentiation analysis,cluster analysis and population genetic structure analysis were conducted employing SSR molecular marker technology.[Result]54 SSR markers with good polymorphism and clear bands,uniformly distributed across the 18 chromosomes of B.juncea,were selected for genetic diversity analy-sis.A total of 204 allelic variations were detected,with an average of 3.7 alleles and 1.97 effective alleles per primer pair.The average Shan-non's genetic diversity index was 0.68,the average Nei's gene diversity index was 0.49,and the average observed heterozygosity(Ho)was 0.58.The PIC values ranged from 0.28 to 0.38,with an average of 0.36,indicating that all primers were moderately to highly polymorphic(PIC＞0.25).In summary,the 54 SSR markers exhibited moderate to high polymorphism and effectively detected the genetic diversity of the tested materials.Additionally,the 63 B.juncea accessions displayed rich genetic information,with uniform and abundant allelic variations.Furthermore,cluster analysis and population genetic structure analysis were performed based on the SSR marker results.The UPGMA method classified the 63 accessions into two major groups:Group Ⅰ comprised 9 accessions,while Group Ⅱ included 54 accessions.Population struc-ture analysis using the structure software revealed that the maximum ΔK occurred at K=2,indicating that the 63 B.juncea accessions could be divided into two subpopulations.The result was consistent with the two-dimensional principal coordinate analysis(PCoA).In Subpopula-tion Ⅰ,48 accessions(76.19％of the total)had Q-values greater than 0.6,and 29 accessions(46.03％of the total)hadQ-values greater than 0.9.These results demonstrated that the 63 B.juncea accessions exhibited diverse genetic backgrounds and a rich population structure.[Conclusion]54 SSR markers with clear bands,moderate to high polymorphism,and effective detection of genetic differences are selected.A-nalysis using these markers reveals that the 63 B.juncea accessions possess abundant genetic information and high genetic diversity.