基于SSR分子标记的闽楠(Phoebe bournei)核心种质的构建

为更好地发掘和利用现有闽楠种质资源,本研究利用7个SSR位点对江西和福建16个闽楠群体的237份材料进行基因型分析,采用逐步聚类(随机取样策略,位点优先取样策略)和模拟退火算法(等位基因数目最大化策略,遗传距离最大化策略)4种取样方法构建闽楠核心种质,并将各遗传多样性指标进行分析。结果表明:7个SSR位点共检测到50个等位基因,平均为7.143,平均有效等位基因为2.115,Shannon信息指数为0.778,观测杂合度为0.302,期望杂合度为0.442。基于逐步聚类方法构建的核心种质相较于基于模拟退火算法构建的核心种质各遗传参数指标都相对较高。对其进行t检验后,选择以基于逐步聚类位点优先取样策略在25%的取样比例下选取的种质为核心种质,其等位基因数、平均有效等位基因数、多态性位点百分率、Shannon多样性指数的保留率分别为初始种质的98%、104.92%、90.09%、97.94%。筛选出的59份核心种质材料能够较好地代表闽楠种质资源的遗传多样性,为闽楠的种质资源保存提供科学依据。

Developing a Mini Core Germplasm of Phoebe bournei Based on SSR Molecular Marker

In order to make the best of germplasm resources of Phoebe bournei,7 SSR loci were used in this study to analyze the SSR genotyping of 237 accessions from 16 populations in Jiangxi and Fujian provinces,the central distribution areas of Phoebe bournei.The core germplasm of Phoebe bournei was constructed with stepwise clustering(random sampling strategy,site-first sampling strategy)and simulated annealing algorithm(allele number maximization strategy,genetic distance maximization strategy),and each genetic diversity index was analyzed.The results showed that a total of 50 alleles are detected by 7 pairs of primers,with an average of 7.143,the average effective allele is 2.115,the Shannon information index is 0.778,the observed heterozygosity is 0.302,and the expected heterozygosity is 0.442.The core germplasm constructed based on the stepwise clustering has higher genetic parameters than the core germplasm constructed based on the simulated annealing algorithm.After t-testing it,the germplasm selected with 25%sampling ratio based on the stepwise clustering site-first sampling strategy was selected as the core germplasm.Its allele number,average effective allele number,percentage of polymorphic loci,and Shannon diversity index retention rates were 98%,104.92%,90.09%,and 97.94%of the initial germplasm,respectively.The core germplasm of 59 collections has most of genetic diversity of the initial germplasm of Phoebe bournei,and provide scientific basis for conservation of germplasm resources of Phoebe bournei.