中文摘要：

【目的】以300份新疆野苹果实生株系为试验材料，根据叶片、花朵和果实等器官15个数量性状的遗传多样性，研究新疆野苹果核心种质构建的方法。【方法】采用逐步聚类法，以30％的取样比例，根据2种遗传距离（欧氏距离和马氏距离）、4种系统聚类方法（类平均法、离羞平方和法、最长距离法和最短距离法）和3种取样方法（随机取样法、偏离度取样法和优先取样法）构建24个核心种质，以筛选出的最佳构建策略进一步比较7种不同取样比例（10％、15％、20％、25％、30％、35％和40％）的构建效果以确定最适宜的取样比例。【结果】（1）在新疆野苹果构建中，采用欧氏距离聚类优于马氏距离。（2）4种系统聚类方法比较表明，最短距离法优于类平均法、离差平方和法和最长距离法。（3）3种取样方法比较表明，优先取样法和偏离度取样法都能明显提高核心种质的方差差异百分率、极差符合率和变异系数变化率，均适宜于新疆野苹果核心种质的构建，前者略优于后者。（4）20％是最适宜的取样比例。【结论】以20%的取样比例，采用欧氏距离，利用最短距离法进行逐步聚类，结合优先取样法构建的核心种质最有代表性，是构建新疆野苹果核心种质的最佳方法。

英文摘要：

[Objective] The genetic diversity of 15 quantitative traits from 300 Malus sieversii accessions was used to study the method of constructing Malus sieversii core collection. [Method] A total of 24 Malus sieversii core collections were constructed at 30% sampling proportion by two genetic distances, including Euclidean distance and Mahalanobis distance, combined with four cluster methods including UPGMA, Ward＇s method, Complete linkage and Single linkage, and with three sampling methods including random sampling, deviation sampling and preferred sampling, respectively, using stepwise clustering. Using the best constructing method, the optimum sampling proportion was filtrated under seven different sampling proportions （10%, 15%, 20%, 25%, 30%, 35%, and 40%）. [Result] In constructing Malus sieversii core collection, Euclidean distance was much better than Mahalanobis distance. Comparing the four cluster methods, the single linkage was better than UPGMA, Ward＇s method and Complete linkage for constructing core collection. The preferred sampling was more suitable than deviation sampling, although the deviation sampling could also significantly increase VD%, CR% and VR%. Twenty percent was the optimum sampling proportion. [Conclusion] At 20% sampling proportion, using stepwise clustering, Mahalanobis distance and Single linkage method combined with preferred sampling can construct the most reprehensive core collection and is the most suitable method for constructing Malus sieversii core collection.