Genetic contribution and decision-making coefficients analysis of agronomic components of upland cotton in Southern Xinjiang to yield traits

Abstract

This study investigates the genetic contribution and decision-making coefficients of agronomic traits of upland cotton parents, and their F₁ crosses to provide a scientific basis for breeders to select and improve certain traits. Therefore, Genetic contribution and decision-making coefficients analysis were conducted on 4 agronomic traits and 4 yield traits of 130 upland cotton varieties (lines) and their 206 F₁ crosses using the additive-dominance genetic model and its interaction effect with the environment. The results showed that these traits had rich genetic diversity, and the coefficient of variation (CV) for these eight traits in the parents ranged from 4.68 to 50.83%, while that of the F₁ crosses was between 3.96 and 55.87%. The contribution rate of the additive effects of agronomic traits to yield, except for the first fruiting branch position and the lint percentage, was highly significant, ranging from 4 to 100%. Moreover, the additive contribution rate of the five petal boll rate and plant height to boll number and boll weight and the contribution rate of the dominance × environment interaction reached a positive and extremely significant level of more than 0.01. The additive variance, dominance × environment interaction, and residual variance among different models of genetic variation, as well as generalized heritability, significantly contributed to the total phenotypic variation in traits. The contribution of the dominance effect to the total phenotypic variation was highly significant, except for the boll number, and the contribution of the additive × environment interaction effect to the total phenotypic variation was highly significant, except for the lint yield. The main decision-making traits and limiting traits responsible for improving the yield of upland cotton hybrids were identified. The dominance decision-making coefficients of the lint yield, the decision-making coefficients of the dominance × environment interaction, the phenotypic decision-making coefficients, and the genotypic decision-making coefficients played a major role in determining the boll number. The decisive factors influencing boll weight, controlled by the additive effect, were the first fruiting branch position, plant height, and the five petal boll rate. The boll number was the most limiting trait affecting boll weight by influencing dominance decision-making coefficients, decision-making coefficients of the additive × environment interaction, decision-making coefficients of the dominance × environment interaction, phenotypic decision-making coefficients, and genotypic decision-making coefficients. Plant height and five petal boll number were the decision-making traits of lint percentage controlled by additive effects, while lint yield and boll weight were the major limiting traits.