中文摘要：

【目的】以国家西瓜甜瓜种质资源中期库中的1 200份甜瓜种质为材料,根据19个表型性状的遗传变异,构建甜瓜核心种质。【方法】原始种质按照地理来源分为22组,各组种质根据表型数据分别进行聚类,按照不同比例（10%、15%、20%、25%和30%）取样,构建候选核心种质。通过比较候选样本的遗传多样性指数、表型保留比例、表型频率方差、变异系数等4个检验指标,最终确定甜瓜核心种质,并对其代表性进行评价。【结果】通过比较不同的取样比例,初步获得5个候选样本,其中采用15%的取样比例构建的核心种质包含189份甜瓜种质,其4个检验指标均达到最佳水平,确定为最终的核心种质。此核心种质各性状的特征值和表型频率分布与原始种质基本一致。【结论】研究所构建的甜瓜核心种质具有较好的代表性和遗传多样性,可作为原始种质代表性样本。

英文摘要：

[Objective]Core collection, the enrichment of the primary germplasm resources, contributes to the promotion of the utility efficiency and innovation ability of germplasm resources. In present study, a total of 1 200 melon （Cucumis melo L.） germplasm resources in National Mid-term Genebank for Water- melon and Melon were used for establishment of a core collection based on the genetic variability of 19 phenotypic characters. [Method]The primary germplasms were divided into 22 groups on the basis of their geographical origins, and then the germplasms in each group were clustered using the phenotypic data. Sampling at various percentages （10%, 15%, 20%, 25%, and 30%） was performed with each of the groups ; at this time the actual sampling percentages were adjusted according to the germplasm amount and diversity level in each group. This resulted in five candidate core collections which corresponded to the five sampling percentages. The final core collection depended upon the comparison of four test indices, i. e., Shannon＇s index, ratio of phenotype retained, variance of phenotypic frequency, and coefficient of variation, between the candidate core collections and the primary germplasms. Also, the representative of the core collection was evaluated. [Result]Based on the various sampling percentages, five candidate core collections were obtained, of which the core collection with the sampling percentage of 15% （189 melon germplasms） gave the best result in which the four test indices reached their optimal levels and was chosen as the final core collection. The various characteristic parameters and phenotypie frequency distribution of the 19 phenotypic characters of the final core collection were basically consistent with those of the primary germplasms. [Conclusion]The core collection established in this study was proved to have good represen- tative and enough genetic diversity and could act as the representative sample of the primary germplasms.