IDENTIFICATION OF DROUGHT TOLERANT INDICES AND PHENOTYPIC TRAITS IN SPRING WHEAT GENOTYPES FOR EFFECTIVE WATER MANAGEMENT UNDER TERMINAL WATER STRESS CONDITIONS

Water stress reduces grain yield of wheat genotypes. Yet, drought stress at anthesis is the most crucial stage affecting wheat production. The objectives of present research were to evaluate the relationship and reliability of drought tolerance indices and phenotypic traits for effective irrigation water management under terminal water stress conditions. The trial was laid-out in split plot design with four repeats under water stress imposed at anthesis stage. Twelve wheat genotypes with diverse traits were evaluated. The combined analysis revealed that years, treatments, genotypes and treatments x genotypes interactions were significant. The correlation between grain yield in non-stress (Yp) and in water stress (Ys) was very high indicating that genotypes performed similar in both the environments. Grain yield in Yp or in Ys was positively associated with eight drought tolerance indices MP, STI, GMP, YI, YSI, HM, DI and RDI. Such results indicated that these indices are capable to discriminate group-A genotypes with superiority in both Yp and Ys conditions. The cumulative drought tolerance index ranked the genotypes similar to other indices. Generally, MP, STI, GMP, YI and YSI with higher values ranked genotypes 8, 9, and 5 as drought tolerant while 3, 4, 6, and 7 moderately tolerant and 1,2, 10 and 11 as the susceptible ones. Phenotypic traits like smaller leaf area, smaller stomatal dimensions, shorter period from anthesis to grain filling and stay green phenotype are the typical traits for better irrigation management at terminal stress.