基于SSR标记的海南54份榴莲种质资源遗传多样性和群体结构分析

Analysis of genetic diversity and population structure of 54 durian germplasm resources in Hainan based on SSR markers

对海南省引种种植的54份榴莲种质资源采用荧光SSR分子标记技术,进行SSR多态性分析、聚类分析、群体结构分析、遗传多样性分析。结果表明,筛选获得19对多态性较高的SSR引物,通过DNA扩增共检测出117个多态性等位基因,平均多态性等位基因数为6.158个,平均有效等位基因数为3.398个,香农指数平均值为1.372,观察杂合度和期望杂合度的平均值均为0.689,多态信息指数平均值为0.643,表明具有一定的遗传多样性。基于UPGMA方法进行聚类分析,在遗传距离0.6处54份榴莲种质资源可以分成3个类群,第一类群共45份种质资源,包括引种于不同国家的不同榴莲品种;第二类群共8份种质资源,均为引种于不同国家的猫山王榴莲;第三类群共1份种质资源,是引种于泰国的红榴莲。以遗传距离0.3为阈值,第一类群又可以分为9个亚群。基于Structure可以将54份榴莲种质资源划分为5个亚群。综合聚类和群体结构分析,明确了部分未知种质资源的品种所属,对不同亚群的遗传变异、遗传距离和遗传分化分析发现,个体的变异是总变异的主要来源,亚群5与其他亚群的遗传距离和遗传分化程度最大,不同亚群整体基因流较大,遗传分化程度较低。

The 54 durian germplasm resources planted in Hainan were analyzed by fluorescent SSR molecular marker technology to analyze SSR polymorphism,clustering,population structure and genetic diversity.The result show that 19 pairs of SSR primers with high polymorphism were screened.A total of 117 polymorphisms alleles were detected by DNA amplification,with an average number of 6.158,an average effective allele of 3.398,an average Shannon index of 1.372,an average of 0.689 for observed heterozygosity and expected heterozygosity,and an average of 0.643 for polymorphic information content,which has certain genetic diversity.Based on the cluster analysis of UPGMA genetic distance,at the genetic distance of 0.6,54 germplasms can be divided into 3 groups,the first group has a total of 45 germplasm resources,including different durian varieties introduced in different countries.The second group has a total of 8 resources,all of which are introduced to different countries‘Musang King’durian.The third group has a total of 1 resource,which is a kind of red durian introduced to Thailand.Taking the genetic distance of 0.3 as the threshold,the first group can be divided into 9 subgroups.Based on Structure,54 samples can be divided into 5 subgroups.Comprehensive cluster and population structure analysis identified some varieties of unknown germplasm resources.The analysis of genetic variation,genetic distance and genetic differentiation of different subpopulations showed that individual variation was the main source of total variation,subgroup 5 had the greatest genetic distance and genetic differentiation degree with other subpopulations,and the overall gene flow of different subpopulations was large and the degree of genetic differentiation was low.