基于RAD-SNPs分析的四川核桃良种资源的遗传多样性研究

Studies on Genetic Diversity of Juglans Cultivar Germplasms in Sichuan Based on RAD-SNPs Analysis

摘要:

为了解四川核桃（Juglans）种质资源的遗传多样性，利用RAD二代测序技术对42份核桃良种资源进行测序，分析其遗传结构和遗传多样性。结果表明，共获得70G clean data，Q30平均为96.3%，并获得160 309个多态性SNPs。聚类、遗传结构和主成分分析结果高度一致，42份种质资源聚为两大类，基本反映了两个原始祖先血统，即普通核桃类（AJR，33份）和泡核桃类（AJS，9份），两类群具较高的遗传分化（F_ST=0.285），且分类与地理位置分布和种群相关；且修正了‘威薄01’、‘白龙1号’和‘石棉巨核’3个品种的类群认定。AJS和AJR类群中分别有9和14个良种为纯血统且亲缘关系较远，而其余的良种均为两个血统的混杂。42个核桃良种资源的核苷酸多样性[P_i（π）]和期望杂合度（He）分别为0.029和0.286，表明这些资源具有丰富的遗传多样性，相对于AJR类群，AJS类群的杂合率（He）与核苷酸多态性更大，而SNP数更少，AJS遗传多样性更丰富。这些为四川的核桃种质资源保存和杂交育种研究奠定了基础。

Abstract:

In order to understand the genetic diversity of walnut (Juglans) in Sichuan, the genetic diversity and genetic structure of 42 walnut germplasms were analyzed by RAD-SNPs method. The results showed that a total of 70G clean data and 160 309 high consistent SNPs were obtained, and the average Q30 was 96.3%. Forty-two walnut genotypes could be divided into two main groups, such as AJR (J. regia group, n=33) and AJS (J. sigillata group, n=9). The high genetic differentiation (F_ST=0.285) between two groups had correlation with their geographic distribution. Meanwhile, the groups of three varieties of ‘Weibo No.1’, ‘Bailong No.1’ and ‘Shimianjuhe’ were adjusted. There were 9 and 14 varieties in AJS and AJR groups with pure blood, respectively, while the rests in AJS and AJR groups were mixed blood. There were high genetic diversity among 42 walnut germplasms with nucleotide diversity[P_i(π)] of 0.029 and expected heterozygosity (He) of 0.286, and the J. sigillata group has higher genetic diversity than J. regia group. So, these would provide basis for the preservation and cross breeding of walnut germplasm resources in Sichuan.