Genetic diversity of 96 wheat breeding materials in the southwest wheat region based on important agronomic traits

【Objective】 The genetic diversity of wheat breeding materials in the southwest wheat area was analyzed to provide a theoretical reference for parent selection and improved mining of germplasm resources for wheat breeding in Yunnan.【Method】 Eleven quantitative traits and five qualitative traits of 96 excellent wheat breeding materials planted in Chuxiong,Yunnan were investigated and determined. The coefficient of variation and genetic diversity index of these traits were calculated. These quantitative traits were also subjected to correlation, principal component and cluster analysis.【Result】 The average coefficient of variation and average genetic diversity index of quantitative traits in 96 wheat breeding materials were higher than those of their qualitative traits. The average coefficient of variation of 11 quantitative traits was 33.83%, while the coefficient of variation of powdery mildew was the highest(70.28%)and that of seeding date was the lowest(4.35%). The average genetic diversity index of these quantitative traits was 1.6591, while the genetic diversity index of kernel number was the highest(2.0701)and that of kernel texture and leaf rust were the lowest(0.9461). The average coefficient of variation of five qualitative traits was 25.93%, while the coefficient of variation of kernel color was the highest(55.05%)and that of glume color was the lowest(0.00%). The average genetic diversity index of these qualitative traits was 0.6383, while the genetic diversity index of panicle type was the highest(1.1892)and that of glume color was the lowest(0.0000). The results of correlation analysis showed that there were complex correlations among 11 quantitative traits. The yield was very significantly correlated with the kernel number and 1000-kernel weight(r=0.452** and 0.479**,P<0.01), positively correlated with the tiller number and leaf rust(r=0.213* and 0.245*,P<0.05 the same below), and negatively correlated with powdery mildew (r=-0.233*). Some other correlations were observed between yield and further traits,but these were considered not significant(P>0.05). The results from principal component analysis showed that the main information was concentrated in the first four principal component factors with a cumulative contribution of 87.721%. PC1 was related to yield, PC2 and PC4 with disease resistance and PC3 with biomass. The results of cluster analysis showed that the tested materials were divided into six groups at the threshold of 0.785, and the phenotypic traits of these groups were different and presented unique characteristics.【Conclusion】 There are some differences in the characteristics of materials from different regions. However,the exchange of wheat breeding materials between regions leads to the development of the same characteristics in some varieties. For wheat breeding,breeders need to carry out identification locally and analyze the characteristics of the introduced materials. In addition, breeders should give priority to the complementary dominant traits of parents, followed by consideration of the geographical source.