湘西地区核桃坚果表型特征及多样性研究

Research on the nutphenotypic traits and diversities of walnut in western Hunan

【目的】了解湘西地区核桃(Juglans regia)资源表型特征和多样性状况,为湖南省核桃资源的开发和利用提供理论参考。【方法】以湖南省龙山县、泸溪县、靖州县、石门县采集的223份核桃资源为研究对象,测定了坚果表型的质量性状和数量性状,对其21个表型性状进行多样性和聚类分析。【结果】湘西地区核桃坚果质量性状的变异系数为20.62%~79.21%,Simpson指数为0.171~0.823,Shannon-Wiener指数0.450~2.760,数量性状的变异系数8.37%~27.49%。单果质量5.28~31.70 g,<7 g的小果资源和>22 g的大果资源各有4份。基于核桃属DUS测试指南描述的坚果表型性状,补充了3种种形、3种沿缝合线纵切面形状、1种横切面形状和1种核仁皮色等质量性状。表型性状分析表明,表型分化系数平均为64.03%,21个坚果表型性状的群体间变异大于群体内变异。聚类分析结果显示,在欧氏距离15处,可以将15个群体划分为4个类群。Mantel检验结果表明,群体间的欧氏距离与其地理距离存在显著正相关性(R=0.502,P=0.023)。【结论】湘西地区核桃坚果表型多样性丰富,特异性明显。

【Objective】 This study aimed to understand the phenotypic diversity of walnut resources in western Hunan, to provide a theoretical reference for the development and utilization of walnut resources. 【 Method 】 A total of 223 walnut resources from Longshan County, Luxi County, Jingzhou County, and Shimen County in Hunan were used to measure the phenotypic quality and quantitative characteristics of nuts. Diversity and cluster analyses of 21 phenotypic characteristics were conducted. 【Result】The coefficient of variation of walnut quality traits in western Hunan ranged from 18.71% to 79.21%, and the Simpson and Shannon Wiener indices ranged from 0.171 to 0.823, and 0.450 to 2.760, respectively. The coefficient of variation of quantitative traits ranged from 8.37% to 27.49%. The nut weight ranged between 5.28 and 31.70 g, and there were four small walnut resources that weighed less than 7 g, and four large walnut resources whose weight exceeded 22 g. In addition to the nut phenotypic traits described based on the “Guidelines for the conduct of tests for distinctness, uniformity, and stability-Juglans(Juglans)”, there were eight unreported nut traits in this study. Among them, three for nut shape, three for shape of longitudinal section perpendicular, one for shape of cross-section, and one for skin color of kernels. The average coefficient of phenotype differentiation was 64.03%, and the variation in the 21 phenotypic traits among populations was larger than that within populations in this area. The results of the cluster analysis showed that 15 populations could be divided into four groups at a Euclidean distance of 15. The Mantel test showed that there was a significant positive correlation between Euclidean distance and geographical distance(R=0.502, P= 0.023). 【Conclusion】The phenotypic diversity of walnuts in western Hunan was abundant, and this phenotypic diversity was manifested itself in the form of an array of phenotypic clusters.