基于农艺性状的榕江茶（Camellia yungkiangensis）核心种质构建

摘 要：为得出较为可靠的榕江茶初级核心种质群体，以加强榕江茶种质选育、开发利用和分子遗传学研究，解决其种质资源保存成本较高问题，促进榕江茶种质资源的鉴定和有效利用。以118份榕江茶种质资源为材料，对19个表型性状和4个基本品质成分共计23个农艺性状进行分析；基于2种遗传距离(标准化欧氏距离、马氏距离）、4种聚类方法（离差平方和法、非加权组平均法、最长距离法、最短距离法）和7种总体取样规模（10%、15%、20%、25%、30%、35%、40%）构建了56个候选榕江茶核心种质，利用筛选得到的最佳构建方案构建初级核心种质。通过对原种质、保留种质和核心种质的表型遗传多样性和变异程度，以及各种质不同数量性状间的t检验来评价核心种质的代表性，并用主成分分析法对核心种质进行确认。构建榕江茶核心种质时，2种遗传距离中，标准化欧氏距离优于马氏距离；4种聚类方法中，最短距离法优于另外3种；7种总体取样规模中，30%的取样比例较适宜榕江茶核心种质的构建。对构建的38份核心种质进行分析评价，结果表明，核心种质与原种质23个性状的6个特征值一致性较好，并且遗传多样性指数有一定程度的提升；t检验结果表明，核心种质平衡了稀有性状的分布，有效保留了原种质的遗传多样性；主成分分析结果表明，核心种质的主成分累计贡献率高于原种质；对核心种质进一步确认时，发现核心种质均匀分布在原始种质范围内，无重叠现象，有效的避免了核心种质的冗余。所构建的榕江茶核心种质资源可以很好地代表原种质，较好的保留了原种质的性状、遗传多样性和变异。标准化欧氏距离、最短距离法和30%总体取样规模的构建策略，是构建榕江茶核心种质的最佳方法。最终构建了38份榕江茶种质资源的初级核心种质，占原种质32.20%。核心种质评价表明初级核心种质构建有效且质量较高，能够在保证冗余较少的情况下充分代表原种质遗传多样性。

Construction of Core Germplasm of Camellia yungkianensis based on Agronomic Traits

Abstract: In order to obtain a more reliable primary core germplasm population of Camellia yungkiangensis, strengthen the breeding, development and utilization of Camellia yungkiangensis germplasm and molecular genetics research, solve the problem of high conservation cost of its germplasm resources, and promote the identification and effective utilization of Camellia yungkiangensis germplasm resources. Using 118 Camellia yungkiangensis germplasm resources as materials, a total of 23 agronomic traits including 19 phenotypic traits and 4 basic quality components were analyzed; Based on two Genetic distance (standardized Euclidean distance, Mahalanobis distance), four clustering methods (sum of squares of deviations, unweighted group average, longest distance, shortest distance) and seven overall sampling scales (10%, 15%, 20%, 25%, 30%, 35%, 40%), 56 candidate core collections of Camellia yungkiangensis were constructed, and the primary core collection was constructed using the best construction scheme selected. Evaluate the representativeness of core germplasm by analyzing the phenotypic genetic diversity and degree of variation of original germplasm, preserved germplasm, and core germplasm, as well as t-tests between various qualitative and quantitative traits, and confirm the core germplasm using principal component analysis. When constructing the core collection of Camellia yungkiangensis, the standardized Euclidean distance was better than Mahalanobis distance in the two Genetic distance; Among the four clustering methods, the shortest distance method is superior to the other three; Among the 7 overall sampling scales, a sampling ratio of 30% is more suitable for the construction of core germplasm of Camellia yungkiangensis. The analysis and evaluation of the 38 core germplasm constructed showed that the core germplasm had good consistency with the 6 characteristic values of the 23 traits of the original germplasm, and the genetic diversity index had a certain degree of improvement; The t-test results showed that the core germplasm balanced the distribution of rare traits and effectively preserved the genetic diversity of the original germplasm; The results of principal component analysis showed that the cumulative contribution rate of principal components in core germplasm was higher than that in original germplasm; When further confirming the core germplasm, it was found that the core germplasm was evenly distributed within the original germplasm range without overlap, effectively avoiding redundancy of the core germplasm. The core germplasm resources of Camellia yungkiangensis constructed can effectively represent the original germplasm, while preserving the traits, genetic diversity, and variation of the original germplasm. The construction strategies of standardized Euclidean distance, shortest distance method, and 30% overall sampling scale are the best methods for constructing core germplasm of Camellia yungkiangensis. Finally, 38 primary core germplasm resources of Camellia yungkiangensis were constructed, accounting for 32.20% of the original germplasm. The evaluation of core germplasm indicates that the construction of primary core germplasm is effective and of high quality, which can fully represent the genetic diversity of the original germplasm while ensuring minimal redundancy.