Abstract:

Given the unclear objectives of coordinated improvement for early maturity, high yield and superior quality, and the absence of quantitative standards for elite parent selection in the Hubei cotton industry, this study aims to systematically analyze the variation characteristics and evolutionary trends of major phenotypic traits in upland cotton varieties from Hubei Province, and to screen germplasm resources with superior comprehensive performance, thereby supporting breeding innovation in the Yangtze river region. A total of 114 upland cotton varieties approved for release in Hubei Province from 2001 to 2023 were used as experimental materials. Eleven phenotypic traits, including plant height, number of fruiting branches, boll number, boll weight, lint yield, and fiber quality traits, were measured. Descriptive statistics, correlation analysis, cluster analysis, and principal component analysis were employed for comprehensive evaluation. The results showed that yield-related traits exhibited large variation ranges, with coefficients of variation for boll number, boll weight, and lint yield ranging from 7.25% to 23.98%, indicating high potential for breeding improvement. In contrast, fiber quality traits, such as fiber length and fiber strength, showed relatively low coefficients of variation (4.21%-8.02%), reflecting high genetic stability. With the advancement of breeding periods, phenotypic traits exhibited clear evolutionary trends, characterized by increased lint yield, reduced plant height and number of fruiting branches, shortened growth period, and gradual improvement in fiber quality. Based on cluster analysis, the 114 varieties were classified into three groups, among which Group III showed the best overall performance in both yield and quality. Principal component analysis extracted three principal components with a cumulative contribution rate of 67.44%. Based on the comprehensive evaluation model, 10 superior germplasm lines were selected from mid- and late-maturing varieties, and 5 superior germplasm lines were identified from early-maturing varieties. This study demonstrated that upland cotton varieties in Hubei Province exhibited continuous improvement potential in yield-related traits while maintaining stable fiber quality, and that comprehensive phenotypic evaluation was effective for identifying elite parental lines. The research findings provided a theoretical basis and elite germplasm resources for the synergistic breeding of early-maturing, high-yield and high-quality cotton varieties in the Yangtze river region.

Key words: upland cotton, phenotypic diversity, genetic diversity, varietal evolution, principal component analysis, cluster analysis, breeding utilization