Genetic Diversity Analysis of Hawthorn Germplasm Resources Based on Fruit Phenotypic Traits
In order to protect the genetic resources of Crataegus pinnatifida,evaluate and select superior genetic resources,the fruit traits of 234 accessions of C.pinnatifida preserved in the National Fruit Germplasm Resource Center of Shenyang were identified and evaluated.The distribution frequency,coefficient of variation and genetic diversity index of the 26 fruit traits were analyzed,and the accessions were classified by clustering analysis based on the fruit traits.Principal component analysis was conducted based on the fruit traits.The results showed that the fruit descriptive traits of C.pinnatifida germplasm were diverse,with significant fruit spots,red fruit skin,nearly square fruit shape,many fruit spots,glossy fruit skin,open and curled calyx,calyx with downy hair,calyx with sawtooth,triangular calyx,distinct calyx attachment,depressed seed,conical calyx,broad and shallow groove of peduncle and peduncle base being the most frequent,accounting for 97.86%,90.17%,66.67%,65.95%,97.44%,56.84%,96.58%,97.86%,98.72%,89.32%,86.32%,65.81% and 98.29%,respectively.The coefficient of variation of the quantitative trait seed kernel rate(43.88% )was the largest,followed by fruit weight(41.38% ).The Shannon-Wiener index ranged from 0.68 to 2.02.The Shannon-Wiener index of the descriptive traits ranged from 0.07 to 1.67,with the highest values in fruit texture and color,the most diverse traits,and the Shannon-Wiener index of the quantitative traits ranged from 0.68 to 2.02,also showing rich diversity.Cluster analysis grouped the tested germplasm resources into 4 clusters when the Euclidean distance was 7,GroupⅠand GroupⅡare both C.pinnatifida Bge.var.major,most of the resources of C.pinnatifida Bge.are in Group Ⅳ,and the other several species are mainly distributed in Group Ⅲ and Group Ⅳ,without forming a separate group,but these resources are clustered together in the cluster map.However,these resources were clustered together in the dendrogram.Principal component analysis reduced the 26 phenotypic traits to 9 principal components,including 17 phenotypic traits such as fruit shape.