Response of Cotton Genotypes to Water-deficit Stress using Drought Tolerance Indices and Principal Component Analysis

Drought impacts on cotton cultivation and production are expected to worsen as a result of global warming and water-deficit stress. Drought tolerance indices and PCA analysis were used to evaluate drought stress responses in eleven cotton genotypes and fifteen indices' ability to identify drought-tolerant genotypes under normal and drought circumstances. Seed cotton yield (Kentar feddan-1) was significantly affected by genotypes, years, and their interaction (p ≤ 0.05 or 0.01) under normal and water-deficit stress conditions, according to a combined ANOVA. Except for error variance, all genetic parameters studied for seed cotton yield were higher in normal irrigation conditions than in water-deficit stress conditions. According to PCA analysis, The STI, MP, GMP, HM, ATI, SSPI, and TOL are suitable indicators and were similar in their ability to screen, rank and detect tolerant genotypes, due to positive correlations among each other and also the highest association with seed cotton yield in both irrigation conditions. The genotypes G4, G9, and G10 (Group A) seemed to be the most drought-tolerant and cotton productive based on mean performance, GxY heatmap analysis, drought tolerance indices, and PCA analysis. The results of our study's drought tolerance indices and PCA could be useful and appropriate for studying drought tolerance mechanisms and cotton yield improvement in Egypt.