Abstract:

Eleven phenotypic characters related to flower traits were collected from 625 accessions of 13 Pyrus species preserved in National Germplasm Repository of Apple and Pear. Distribution frequency，coefficient of variation，Simpson index and Shannon index were analyzed. Comparative analysis of intraspecific and interspecific diversities of 4 phenotypic characters，i.e. number of flowers per inflorescence，number of stamen，number of stigma and corolla diameter was carried out in 5 cultivated Pyurs species. The crisp-fleshed and soft-fleshed pear accessions were clustered. It showed that the phenotypic diversity in pear flower organ was abundant. White unopened flower，fuchsia anther，position of stigma above stamen，absent pubescence on the base of stigma had more proportion than other corresponding descriptors，accounting for 50.56%，47.52%，63.20% and 80.96% respectively. Anther color was found to have the richest diversity with 0.719 of Simpson index and 2.351 of Shannon index，respectively，and deep red anther and deep purple anther were newly discovered. The average variation coefficient of flowers per inflorescence，number of stamen，corolla diameter and number of stigma was 19.50%，15.12%，13.74% and 8.50%，respectively，which showed that genetic stability of number of stigma was higher than the other three traits. Based on the statistical analysis of frequency distribution of corolla diameter，5 levels of numerical classification and reference cultivars were proposed. There were significant differences in 4 flower traits of pear among and within populations，and phenotypic differentiation coefficient（V_ST）of intraspecies and interspecies was 72.97% and 27.03%，respectively，which showed that the variation within populations was more abundant. Cluster analysis showed that 196 crisp-fleshed local pear cultivars could be divided into 5 categories and 72 soft-fleshed P. ussuriensis accessions into 4 categories.

Key words: pear, germplasm resource, flower, phenotypic character, diversity