基于SSR荧光标记构建睡莲核心种质

Construction of Core Collection of Nymphaea Based on SSR Fluorescent Markers

采用SSR荧光标记技术对240份睡莲资源进行遗传多样性分析;利用Structure软件分析其群体结构,采用主成分分析和聚类分析进行验证;基于最小距离逐步取样法构建核心种质并进行t筛选验证。结果表明,16对SSR荧光引物共检测到205个等位基因,平均Shannon’s信息指数(I)为0.2036,Nei’s基因多样性指数(H)为0.1168,有效等位基因数(N_(e))为1.1697,表明睡莲的遗传多样性丰富。Structure软件分析结果显示最优的群体数K值为3,群体间有少量种质混杂;群体结构分析将240个睡莲品种(种)分为3个类群。采用最小距离逐步取样法,按70%、65%、60%、55%、50%、45%、40%、35%、30%、25%、20%、15%和10%的比例取样,各个核心子集遗传多样性指数总体上变化不明显;最终确立了15%的取样比例,包含36个睡莲品种(种)核心种质,其中Shannon’s信息指数(I)保留率为117%,Nei’基因多样性指数(H)保留率为118%,有效等位基因数(N_(e))保留率为102%。t检验结果表明,构建的包含36个睡莲品种(种)的核心种质与原始种质的遗传参数无显著差异,能充分代表原始种质的多样性。

The genetic diversity of 240 accessions of water lily germplasm resources was analyzed using fluorescent SSR marker;the population structure of water lily resources was analyzed using Structure software and validated by the principal component analysis and cluster analysis.The core germplasm of water lilies was constructed based on the minimum distance step-sampling method and validated by a t-screen.The results showed that a total of 205 alleles were detected in 16 pairs of fluorescent SSR primers,with an average Shannon information index(I)of 0.2036,an average Nei genetic diversity index(H)of 0.1168,and an average effective number of alleles(N_(e))of 1.1697,showing rich genetic diversity.The K-value of the optimal number of populations was three,with a small amount of germplasm mixing between populations;the population structure analysis divided the 240 accessions of water lily into three taxa.The method of LDSS was used to sample at percentage of 70%,65%,60%,55%,50%,45%,40%,35%,30%,25%,20%,15%,and 10%of the core subsets,with no significant overall variation in genetic diversity indices.Thirty-six accessions of core germplasm of Nymphaea were finally constructed,accounting for 15%of the initial collection,with the retention rates of I,H and Ne were 117%,118%and 102%,respectively.The t-test showed that the genetic parameters of the core germplasm containing 36 accessions of water lilies were not significantly different from the original germplasm and adequately represented the diversity of the original germplasm.