Abstract

In order to study the response of twelve of Egyptian cotton genotypes to drought stress, a field experiment was conducted in a split plot design with randomized complete blocks (RCB) arrangement with three replications under irrigated and water stress conditions during a successive growing seasons 2018. The estimates of stress tolerance attributes indicated that the identification of drought-tolerant genotypes based on a single criterion was contradictory. Result of correlation analysis between yield and its component in both conditions and calculated drought resistance indices revealed that stress tolerance index (STI), mean productivity (MP), geometric mean productivity (GMP), harmonic mean (HM), yield index (YI), Yield stability index (YSI) and drought resistance index (DI) were the best indices for identifying high yielding genotypes for seed cotton yield and lint cotton yield in both conditions (drought tolerant genotypes). Therefore, these indices could be used successfully as selection criteria for the screening of genotypes for performance under various soil moisture levels. Screening drought tolerant genotypes using mean rank, standard deviation of ranks and rank sum (RS) distinguished G4 and G5 as the most drought tolerant genotypes. Cluster analysis showed that the genotypes, based on indices tended to group into three groups: tolerant, semi- tolerant and sensitive genotypes. Principal component analysis (PCA), indicated that first and second components justified 99.82% and 99.858% variations for seed cotton yield and lint cotton yield, respectively among drought tolerance indices

Keywords

Egyptian cotton (Gossipum barbadense L.), seed cotton yield, drought tolerance indices, ranking method, principal component analysis, clusters analysis