Screening and Identification of Cotton Germplasm with Verticillium Wilt Resistance, High Yield, and High Seed Index in Kuitun, Xinjiang

Xinjiang is the major cotton-producing region in China, and identifying core germplasm with disease resistance, high yield, and high seed index is of great significance for guiding local cotton production and breeding practices. Using 182 upland cotton germplasm accessions, we systematically investigated Verticillium wilt (caused by Verticillium dahliae) disease index, yield, and seed index in Kuitun, Xinjiang, during 2018–2019. Comparative analysis revealed that the germplasm from the Yellow River Ecological Region (YER) exhibited the strongest disease resistance but ranked second in yield, while the germplasm from the Northwest Inland Ecological Region (NWC) was susceptible to disease, yet had the highest yield, indicating great potential for further improving cotton yield in Kuitun. The Verticillium wilt index decreased, and yield increased with breeding periods. PCA and K-Means clustering divided germplasm into three clusters, with Cluster 0 being disease-resistant, high-yielding, and having a high seed index. Using the 20th percentile method, 20 core germplasm (11.0% of total) were selected, including disease-resistant and high-yield accessions, 3 disease-susceptible and high-yield accessions, and 6 disease-resistant and high seed index accessions. The results of this study provide important material support and a theoretical basis for the synergistic breeding of cotton with disease resistance, high yield, and high seed index in Xinjiang.