【目的】研究北美海棠品种资源果实表型的多样性和变异特点,为合理利用北美海棠品种资源、定向培育观赏海棠新品种提供理论参考。【方法】对78个北美海棠品种果实的7个数量性状和16个质量性状进行采集和整理,并进行多样性、相关性、主成分和聚类等分析。【结果】7个数量性状中单果质量变异系数最大,为105.34%;果形指数变异系数最小,为9.65%。16个质量性状共检测到64个变异类型,其中果实形状、成熟果色、果肉颜色变异范围较大。Shannon-Wiener信息指数(H)和Simpson多样性指数(D)变化范围分别是0.363~2.002和0.167~0.842。相关性分析结果表明,果实多数性状之间存在显著或极显著相关。主成分分析将23个果实性状转化为7个主成分,累计贡献率达71.756%,基本上可以反映北美海棠果实表型性状的绝大部分特征信息。基于果实表型性状聚类分析,在欧氏距离为21.5时,可将78个北美海棠品种分为3个类群。其中,第I类群可用于选育果大,果实整齐度好的品种;第Ⅱ类群可用于选育果色艳丽,观赏价值较高的观果品种;第Ⅲ类群可选育小果、果量多的品种。【结论】北美海棠品种资源果实表型存在丰富的多样性,果实大小、果色等性状是区分北美海棠品种的重要性状。研究结果可为海棠果实的观赏性状育种提供一定科学参考。

【Objective】The study aimes to investigate the diversity and variation in fruit phenotypic traits among North American crabapple cultivars, and provide theoretical support for the rational use of existing crabapple cultivar resources and the breeding of new cultivars. 【Method】A total of 78 North American crabapple cultivars were investigated for seven quantitative traits and 16 qualitative traits related to fruit characteristics. Data collected were subjected to diversity analysis, correlation analysis, principal component analysis, and cluster analysis. 【Result】Among the seven quantitative traits, the variation coefficient of fruit weight was the largest, being 105.34%, and which of the fruit shape index was the smallest, being 9.65%. A total of 64 variant types were detected for the 16 qualitative traits, among which fruit shape, fruit color and flesh color had a wider range of variation. The Shannon-Wiener index (H) ranged from 0.363 to 2.002, and the Simpson index (D) varied between 0.167 and 0.842, further confirming high phenotypic diversity. Correlation analysis revealed significant or highly significant relationships among most fruit traits. The principal component analysis found seven principal components with a cumulative contribution rate of 71.756%, reflecting most of the information on the phenotypic traits of crabapples. The 78 cultivars were divided into three groups at the Euclidean distance of 21.5. The first group comprises cultivars suitable for breeding large-fruited types with high uniformity; the second group includes accessions with brightly colored fruits and high ornamental value, ideal for ornamental fruit breeding; and the third group consists of genotypes bearing small but abundant fruits, useful for developing prolific small-fruited varieties. 【Conclusion】North American crabapple cultivars showed rich fruit phenotypic diversity; fruit size and color were important traits to distinguish cultivars. These findings offer practical insights and scientific support for ornamental trait-oriented breeding in crabapple, facilitating the efficient selection and utilization of germplasm for developing new varieties with desired fruit characteristics.