重庆核桃种质资源表型性状多样性分析

Phenotypic traits diversity of walnut germplasm resources in Chongqing

  • 摘要: 【目的】 分析重庆核桃种质资源表型性状多样性,为重庆核桃种质资源客观评价及合理开发利用提供理论参考。【方法】 从重庆地区收集了16个实生居群(产区)的181份核桃种质资源,依据国家标准及行业标准对其植株和坚果的28个表型性状(17个质量性状和11个数量性状)进行测定,并分析其变异系数、遗传多样性及各表型性状间的相关性,最后基于表型性状进行聚类分析。【结果】 181份核桃种质17个质量性状的Simpson指数和Shannon-Wiener指数分别为0~0.87和0~1.93,其中以小叶形状、树冠、核壳表面特征和核仁皮色的多样性较丰富;11个数量性状的变异系数介于8.70%~53.70%,其中单枝结果数变异系数最大,果形指数变异系数最小。16个实生居群181份核桃种质的28个表型性状变异系数为0~67.90%,平均为19.79%;各居群间表型性状变异系数为15.20%~26.38%。181份核桃种质的多样性来源于居群内变异和居群间变异,但居群内的变异起主要作用,且坚果表型性状的变异较其他性状更大。相关分析发现,11个数量性状间的相关系数有29对达到显著(P<0.05,下同)或极显著(P<0.01,下同)水平,核桃表型数量性状间存在丰富的相关,其中显著正相关的性状有24对,显著负相关的性状有5对。聚类分析结果显示,当遗传距离为22.5时,可将181份核桃种质分为三大类群,来自同一地区的材料分散于各类群中,聚类结果无明显地域性。【结论】 重庆具有丰富的核桃种质资源,核桃表型多样性高,其表型变异主要来源于居群内变异;重庆核桃种质资源的亲缘关系与地理来源无明显相关性。

     

    Abstract: 【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 correlations between phenotypic traits were analyzed. Finally, cluster analysis was conducted based on phenotypic traits. 【Result】 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 geographical 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.

     

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