Abstract: In order to scientifically preserve and study the germplasm of Medicago ruthenica L., 113 wild M. ruthenica germplasm resources in Inner Mongolia were used as materials in this study. Based on the data measurement of 20 phenotypic traits, two genetic distances, three sampling methods, eight systematic clustering methods and six sampling ratios were used to construct M. ruthenica core germplasm. By comparing the mean difference percentage, variance difference percentage, range coincidence rate and coefficient of variation change rate of the core germplasm, the best strategy was explored to construct the core germplasm of M. ruthenica. In addition, the representativeness of the constructed core germplasm was tested by comparing the coefficient of variation, variance, diversity index, coincidence rate and principal components of the core germplasm and the original germplasm. The results showed that “Euclidean distance+priority sampling method+unweighted class average method+25 % sampling ratio” was the best strategy for constructing the core germplasm of M. ruthenica. The average coincidence rate of the mean value, maximum value, minimum value and diversity index of the core germplasm reached more than 90%, and the cumulative contribution rate of the principal component was higher than that of the original population. Indicating that these 28 constructed core germplasms of M. ruthenica were evenly distributed in the original germplasm range, which could represent the original germplasm. This study provided the theoretical basis and high-quality resources for scientific utilization and in-depth excavation of M. ruthenica germplasm resources.

Key words: Medicago ruthenica L, Germplasm resources, Core collection, Phenotypic traits, Sampling strategy

摘要： 为了科学保存和研究花苜蓿（Medicago ruthenica L.）种质,本研究以113份野生花苜蓿种质资源为材料,基于测定的20个表型性状数据,采用 2 种遗传距离、3 种取样方法、8 种系统聚类方法和 6种取样比例构建花苜蓿核心种质,通过对比核心种质的均值差异百分率、方差差异百分率、极差符合率和变异系数变化率,探寻构建花苜蓿核心种质的最佳策略,并通过比较核心种质和原始种质的变异系数、方差、多样性指数和主成分,对构建的核心种质进行代表性检验。研究结果表明,“欧氏距离+优先取样法+不加权类平均法+25% 的取样比例”是构建花苜蓿核心种质的最佳策略。核心种质均值、最大值、最小值和多样性指数的符合率均达到90%以上,主成分累计贡献率高于原始种群,表明构建的28份苜蓿核心种质均匀分布在原始种质范围内,能够有效代表原始种质。本研究为科学利用和深入挖掘花苜蓿种质资源提供了理论依据和优质资源。

关键词: 花苜蓿, 种质资源, 核心种质, 表型性状, 取样策略