Analysis of the main effect clustering and decision-making coefficients for F2 generation of upland cotton in Southern Xinjiang

Abstract Yield and fibre quality traits respectively accounting for 4 and 5 of their 278 varieties (lines) and their 784 F2 crosses of upland cotton were for their additive and dominance effects by a genetic model comprising additive, dominance and their interaction effects with the environment in two years of Alar, South Xinjiang, People’s Republic of China. Based on the additive and dominance effects, all varieties were clustered using cluster analysis of the R software package.Then, the decision-making coefficient of F2 was analyzed. Results indicated that under the high-density planting mode of "low plant growth (plant height: 0.8–1.0m), high density(225,000–300,000 /hm-2), early ripe and film cover" in Southern Xinjiang Province, the additive effects of 278 parents were divided into fourteen groups. The average additive effects of yield and fibre quality traits of 21 varieties (lines) in the fourth group were at a good level. Obtain offspring was easy with both yield(except Lint percentage) and fibre quality traits by crossing between these varieties (lines). The fifth group had a better average additive effect on fibre quality traits, whilst the tenth group had a higher average additive effect on yield traits. The progeny with complementary yield and fibre quality traits could be obtained by crossing these two kinds of varieties. The dominance effects of 278 parents were divided into thirteen groups. The fourth group included 33 varieties (lines) that yield traits, and fibre quality traits (except lint percentage )were all at a better average level in dominance effect, which could be used as parents for hybrid utilisation of both yield traits and fibre quality traits. The average dominance effect of yield traits was higher in the first group, and the average value of dominance effect of fibre quality traits in the twelfth group was high. Results indicated the order of significant relationships of dominance effect, the decision-making traits of lint percentage to lint yield, length and micronaire. The decision-making traits of strength was length. The main decisive traits and restricted traits for improving the yield and fibre quality of upland cotton were also determined.