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

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.