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,coef-ficient 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,indica-ting that the pear germplasm resources had extremely rich phenotypic diversity.Using principal component a-nalysis(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 re-sults 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 pro-vide a reference for the efficient use of pear germplasm resources to improve the existing cultivars and breed new varieties.
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