基于表型性状的不同梨品种遗传多样性分析

Genetic Diversity Analysis of Different Pear Varieties Based on Phenotypic Traits

为选育适合内蒙古自治区种植的优良梨品种并开发新品种,本试验以保存于内蒙古巴彦淖尔市梨树资源圃的18个梨品种的140个单株为研究对象,基于表型性状中的9个质量性状和19个数量性状,利用Shannon-Weiner多样性指数、变异系数、主成分分析及Q型和R型聚类分析,对梨种质的遗传多样性进行研究。结果表明,所调查梨品种的质量性状与数量性状的变异系数分别在11.78%~64.72%和9.28~59.54%之间,多样性指数分别在0.22~1.33和0.35~1.53之间,表明梨种质资源具有极其丰富的表型多样性。利用主成分分析法从所调查的28个表型性状中提取出10个主成分,特征值均大于1,累积贡献率为74.26%,其中果实形态是导致梨品种差异的最重要指标。利用R型聚类对28个表型性状进行聚类分析,在遗传距离15处可将其分为19个类群,各类群之间距离较远,说明各性状分布较散,相关性较低,可以更好地反映不同品种的差异。利用筛选出的性状进行Q型聚类分析发现,品种间的表型差异与种源地有着一定关系,不同种源地的部分品种被聚为一类。本研究结果可为高效利用梨种质资源改良现有品种并选育新品种提供参考。

In order to select excellent pear varieties suitable for planting in Inner Mongolia Autonomous region and develop new varieties,140 individuals of 18 pear varieties planted in the resource nursery of Bayan nur,Inner Mongolia were taken as the research objects,and based on 9 qualitative traits and 19 quantitative traits of the phenotypic traits,their genetic diversity were studied using Shannon-Weiner diversity index,coefficient of variation,principal component analyses and Q-and R-type cluster analyses.The results showed that the variation coefficient of the qualitative and quantitative traits of the surveyed pear varieties were 11.78%~64.72% and 9.28%~59.54%,and the diversity index were 0.22~1.33 and 0.35~1.53,respectively,indicating that the pear germplasm resources had extremely rich phenotypic diversity.Using principal component analysis(PCA),10 principal components were extracted from the 28 phenotypic traits,and all of which had the eigenvalues greater than 1 and the cumulative contribution rate as 74.26%;among which,fruit morphology was the most important indicator leading to the differences of different pear varieties.The R-type clustering results showed that the 28 phenotypic traits could be divided into 19 groups,and the distance between the groups was far,indicating that the distribution of traits was scattered and the correlation of traits between groups was lower,so they could better reflect the differences of different varieties.The Q-type clustering analysis results showed that the phenotypic differences between varieties had a certain relationship with the provenance,and some varieties from different provenances were clustered into one category.The results of this study could provide a reference for the efficient use of pear germplasm resources to improve the existing cultivars and breed new varieties.