重庆核桃种质资源表型性状多样性分析OA北大核心CSTPCD

[Objective]This study aimed to analyze phenotypic traits diversity of walnut germplasm resources in Chongqing,providing a theoretical reference for their objective evaluation and rational exploitation of these resources.[Method]A total of 181 walnut germplasm resources from 16 natural populations(production areas)in Chongqing were collected as research materials.Twenty-eight phenotypic traits(17 qualitative traits and 11 quantitative traits)of the plants and nuts were measured based on national and industrial standards.The variation coefficient,genetic diversity,and corre-lations between phenotypic traits were analyzed.Finally,cluster analysis was conducted based on phenotypic traits.[Re-sult]The Simpson index and Shannon-Wiener index of 17 phenotypic quality traits of 181 germplasms ranged from 0 to 0.87 and 0 to 1.93 respectively.Walnut leaflet shape,tree crown,nut shell surface features and kernel color exhibited rich diversity.The variation coefficients of the 11 phenotypic quantity traits ranged from 8.70％to 53.70％,with the highest for fruit number per branch and the lowest for nut shape index.The variation coefficients of the 28 phenotypic traits were from 0 to 67.90％,with an average of 19.79％.The variation coefficients among populations ranged from 15.20％to 26.38％.The diversity of the 181 walnut germplasm resources was attributed to both within-population variation and among-population variation,with the former having the main function.Notably,the variation of nut phenotypic traits was greater than that of other traits.Correlation analysis revealed that 29 pairs of correlation coefficients of 11 quantity traits reached significant(P＜0.05,the same below)or extremely significant(P＜0.01)levels,indicating a rich correlation among these traits.Among them,24 pairs showed significant positive correlation,and 5 pairs showed significant negative correlation.Cluster analysis showed that when the genetic distance was 22.5,the 181 walnut germplasms could be divided into three groups.Materials from the same region were scattered in different groups,and there was no obvious geographi-cal distribution in the clustering results.[Conclusion]Chongqing is rich in walnut germplasm resources characterized by high phenotypic diversity,with its phenotypic variation mainly from within-population variation.Moreover,no obvious correlation has been found between the genetic relationships among walnut germplasm resources and their geographical origins.