关键词: 板栗, 种质资源, 花序, 表型性状, 多样性, 聚类分析

Abstract:

【Objective】The study on the diversity and genetic rules of catkin phenotypic traits of 211 Chinese chestnut germplasms from 10 provinces was conducted, in order to provide valuable basic data and theory foundation for the protection, utilization, innovation and genetic improvement of existing germplasm resources. 【Method】According to the method described in Descriptors and Data Standard for chestnut(Castanea mollissima Bl.), the data were collected for 15 phenotypic parameters of catkin phenotypic traits from 211 Chinese chestnut germplasms from 10 provinces in Germplasm Repository of chestnut of Changli Institute of Pomology, Hebei Academy of Agricultural and Forestry Sciences. Then, the genetic variation analysis, Shannon-index, correlation andprincipal component analysis of chestnut flower phenotypic traits were carried out by using the SPSS20.0 software. The Chinese chestnut were clustered using MEGA 7.0 according to morphological data.【Result】phenotypic traits related catkin of Chinese chestnut were rich in phenotypic diversity, with mean variation coefficient (CV) of 28.23% and Shannon's diversity index(H') of 1.70. The mean variation coefficient (CV = 60.66) of female flower numbers/bearing shoot was the largest, the mean variation coefficient (CV = 7.37）of male catkin numbers/ catkin numbers was the smallest. The Shannon's diversity index (H'=1.99）of floral axis width/catkin width was the highest, The Shannon's diversity index (H'=1.41) of bisexual catkin numbers/bearing shoot and bisexual catkin numbers/catkin numbers were the lowest. Further analysis showed that the phenotypic diversity of Chinese chestnut existed differences among 10 populations, which was the highest in Hebei province. Catkin length, floral axis width, catkin density, female flower numbers/bearing shoot, bisexual catkin numbers/catkin numbers, male catkin numbers/catkin numbers, female flower numbers/bearing shoot were highly significant, which indicated that a wide range of variation existed in these two levels. The correlation analysis showed that: catkin morphology traits were highly significantly or extreme significantly related, catkin number traits were highly significantly or extreme significantly related, and the correlation between catkin morphology traits and catkin number traits were not highly significantly related. Principal component analysis showed that catkin traits in the first 5 principal components reflect the total information content 84.18%, catkin length, bisexual catkin numbers/bearing shoot, catkin width, catkin length/catkin width, female flower numbers/ bearing shoot, male catkin numbers/catkin numbers, bisexual catkin numbers/catkin numbers, stamen length height characters were the main factors causing variation in traits of Chinese chestnut. The 211 materials were divided into 8 kinds of cluster analysis. Catkin character same source with similar material part could get together, and the results were similar to principal component analysis.【Conclusion】There were abundant variation and high genetic diversity degree based on the phenotype of catkin phenotypic traits of Chinese chestnut. The degree of genetic variation and diversity was different between regions, for there were significant differences in traits between populations. The correlations between catkin morphology traits and catkin number traits were not highly significantly related. 8 traits were selected to be as the important comprehensive evaluation indexes used for Chinese chestnut germplasm. 9 chestnut germplasm with more female flowers was selected as parent materials to control sex and improve the yield.

Key words: chestnut, germplasms, phenotypic trait, catkin, diversity, cluster analysis