西瓜核心种质遗传多样性分析及指纹图谱构建

Analysis of Genetic Diversity and Construction of DNA Fingerprints for Watermelon Core Germplasms

深入了解西瓜核心种质资源的群体结构及遗传多样性,可以准确指导亲本间杂交组合的有效配置,避免具有相似遗传背景材料的组合,以便提高育种效率。据此,本研究通过采用45对具有多态性的SSR标记对不同来源的78份西瓜核心种质进行了多元统计分析。结果表明,45个SSR标记共检测出175个位点,其中具有多态性位点数为165个,多态性比率达95.41%,且每对引物平均检测到等位基因位点3.67个,PIC大小范围在0.049~0.781之间,平均值为0.415,其有效等位基因数(Ne)、期望杂合度(He)、观测杂合度(Ho)、多样性指数(I)及Nei's基因多样性指数(H)在该群体水平上分别为2.258、0.479、0.521、0.850和0.476,同时筛选出了28对多态性高、带型稳定、易于统计的核心引物,构建了78份西瓜核心种质的SSR指纹图谱。群体结构分析表明,78份西瓜核心种质资源划分为2大类群和4个亚群,其中来自不同地域的美国材料和日本材料分别独立趋于2大类群中,而中国种质材料普遍交叉分布于2大类群中,且各亚群之间存在着明显的基因交流,分子方差分析表明种质间遗传多样性主要存在于品种间和居群间。

Understanding the population structure and genetic diversity of watermelon core germplasm resources can guide the effective allocation of parental hybrid combinations,and avoid the combination of similar genetic background materials to improve breeding efficiency.In this study,multivariate statistical analysis was performed on 78 core germplasms of watermelons from different sources using 45 polymorphic SSR primer pairs.The results indicated that 175 loci were detected by the 45 SRR markers,including 165 polymorphic loci.On average,each pair of primers was capable of detecting 3.67 alleles and with a polymorphism ratio of 95.41%.The polymorphic information content values(PIC)ranged from 0.049 to 0.781,with a mean of 0.415.The effective number of alleles(Ne),expect heterozygosity(He),observed heterozygosity(Ho),aromatic information index(I)and Nei’s genetic identity(H)were 2.258,0.479,0.521,0.850,and 0.476 at the species levels,respectively.A total of 28 core primer pairs with high polymorphism,stable band and easy statistics were selected to construct SSR fingerprints of watermelon core germplasms.The 78 core watermelon germplasm resources were divided into two groups and four subgroups.American materials and Japanese materials were distributed in two different major groups,while Chinese germplasm materials were widely distributed in the two groups.There is obvious genetic communication between the groups.Molecular analysis of variance shows that genetic diversity among germplasm mainly exists between varieties and populations.