Drought tolerance indices and path-analysis in long staple cotton genotypes (G. barbadense)

Document Type : Original Article

Authors

1 Agronomy Department, Faculty of Agriculture Assiut University, Assiut Egypt

2 Cotton research institute, Agricultural Research Center, Egypt

Abstract

Drought stress is a serious abiotic factor 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 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 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 were 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, Pressely 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.

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