Determination of Drought Tolerance for Some Cotton Genotypes (Gossypium hirsutum L.) under Deficit Irrigation Conditions

The aim of this study was to use water more efficiently and determine drought-tolerant cotton genotypes by reducing the irrigation water at certain rates. In this study, 7 different cotton genotypes (Aday 1, Aday 2, Aday 3, May 1. Aday 5. Aday 6, and Aday 7) and a control variety (Stonville 468) were used. In order to determine drought tolerance, parameters including, Stress Susceptibility Index (SSI), Yield Stability Index (YST), Yield Reduction Ratio (Yr), Yield Index (YD, Tolerance Index (TOL). Mean Productivity (MP), Harmonic Mean (HM), Geometric Mean Productivity, Modified Stress Tolerance (K1STI-index calculated from potential yields, K2STI- index calculated from yield values in stress conditions) Stress Tolerance Index (STI) and Yield Strength Index (YSI) were used. Stressed and non-stress conditions applicability of HM, MP, GMP, STE, K1STI indices has appeared in Aday 4 genotypes. The highest value of MP was found in Aday 6 genotype. The lowest SSI index was in genotype May 2. As a result. of the mean comparison (LSD), principal component analysis (PCA) and cluster analysis, the Aday 2 genotype was found highly tolerant to drought under non stress conditions.