Abstract
Drought stress is a serious abiotic factor that adversely affects cotton yield and fiber properties. The objectives of this study were to screen several genotypes of cotton belong to Gossypium barbadense L. for drought tolerance, study drought indices, correlations, and path-coefficient analysis. Fourteen long- staple kinds of cottons cultivated, and obsolete cultivars were screened for drought tolerance at normal irrigation and drought- stressed experiments for two years. Mean squares indicated significant (p ≤ 0.01) differences among genotypes in the separate and combined analysis. The effect of years showed significant (p≤ 0.05 to p≤ 0.01) differences in most cases. The interaction of genotypes by years was significant for all traits except few cases. The reduction % caused by drought stress in SCY/P ranged from 31.44 to 39.39 with an average of 33.93. Among ten tolerant indices STI, MP, GMP, HM and DI could be considered the best tolerant indices to detect both of tolerant and susceptible genotypes. The correlation of SCY/P under normal irrigation was high with LY/P, Lint %, NB/P, LI and BW, moderate with NS/B and upper half mean length, and low with DFF, Pressley index and negative with Micronaire reading. However, the picture was different under drought stress, in which drought affected lint rather than seeds. The direct and indirect effects of SCY/P components varied greatly under both environments, and LY/P, NB/P and NS/B should be considered as selection indices under normal irrigation, NB/P and NS/B under stress when selection practiced for SCY/P.

Keywords: Correlation; Drought indices; Drought tolerance; G. barbadense; Path-analysis