关键词: 扁穗雀麦, 形态性状, 变异, 种质, 多样性

Abstract:

Detecting the diversity of germplasm collection is important to plant breeders for utilizing and management the collection efficiently and effectively. A total number of 87 prairie grass(Bromus catharticus) accessions with worldwide geographic origins were studied in field at the Yaan city of Sichuan province, and nine phenotypic characters were recorded. According to the coefficients of variation, all studied characteristics showed a high degree of variability, but it were highly pronounced for dry matter per plant, tiller number and leaf width. The majority of significant correlation coefficients were found in the traits representing plant size. Steam diameter and length of first internode had significantly positive correlations(P<0.01) with others, and the correlation coefficient between length of second upper leaf and breadth of flag leaf was the highest one(r=0.912,P<0.01). Principal component analysis(PCA) was performed for phenotypical diversity determination and grouping of germplasm collections. Two principal components were found to explain 74% of the total variation in the dependence structure. Plant size characters together with tiller number appeared to be the major sources of diversity among B. catharticus accessions. Based on the cluster analysis using UPGMA method, accessions included in three main clusters, first group had large plant size with broad leaves, wider stems and medium tillers number, second had medium plant size, and third had small size with narrow leaves and large tillers number. Scatter plot using two first principal component scores also confirmed the grouping by cluster analysis. Overall, the study demonstrates that B. catharticus is a highly versatile forage species and the quantitative trait diversity in the germplasm has significance for forage grass breeding programs and future collecting strategies.

Key words: Bromus catharticus, Morphological trait, Variability, Germplasm, Diversity