基于SSR荧光标记的杧果核心种质构建OA

Germplasm resources are the key material support for the breeding of new mango varieties and the sustainable development of the industry,and the efficient conservation and utilization are of great significance for mango research.In the study,431 mango germplasm accessions were used.Combining different sampling strategies and genetic distances,the optimal sampling strategy combination for constructing the mango core collection was screened by the UPGMA clustering method,and the core collection was subsequently established.The results showed that the average effective number of alleles(Ne),average Shannon's information index(I),and average Nei's diversity index(H)of 12 pairs of primers was 4.0993,1.534 and 0.7361,respectively,indicating that the mango germplasm possessed rich genetic diversity.The t-test results of genetic diversity parameters revealed that the core collection constructed by the combination of the locus priority sampling strategy and Nei&Li genetic distance had the highest Ne,H and I among all tested groups,with value of 4.2603,0.7486 and 1.5855,respectively,demonstrating that the combination was the optimal method for constructing the mango core collection.The established core collection comprised 85 accessions,accounting for 19.72％of the original germplasm.The retention rate of Ne,I and H in the core collection reached 103.93％,103.35％and 101.45％,respectively,indicating that although the core collection was much smaller in quantity than the original germplasm,it exhibited superior performance in genetic diversity-related indicators.Principal coordinate analysis(PCoA)showed that the distribution of the core collection uniformly covered the distribution range of the original germplasm in the principal coordinate space,suggesting that the core collection could comprehensively retain the genetic diversity characteristics of the original germplasm and had good representativeness.