Evaluation of Drought Tolerance in Durum Wheat Genotypes Using Drought Tolerance Indices

To evaluate drought tolerance in durum wheat, 49 lines along with one check cultivar Aria, were studied in an RCBD with two replications under drought stressed (rainfed) and non-stressed conditions at the Gonbad Agricultural Research Station, Golestan, Iran. Six drought tolerance indices, i.e. Stress Susceptibility Index (SSI), Tolerance Index (TOL), Mean Productivity (MP), Stress Tolerance Index (STI), Geometric Mean Productivity (GMP) and Harmonic Mean (HM) were calculated based on grain yield under stressed (Ys) and non-stressed (Yp) conditions. The analysis of variance of the data showed significant difference between genotypes. Lines SULA/AAZ-5//CHEN/ALTRA… and LIRO-3/LOTAIL-6 had the highest grain yield under stressed (447 gm-2) and non-stressed (529 gm-2) conditions, respectively. The highest MP, GMP, STI and HM were observed in line SULA/AAZ-5//CHEN/ALTRA…, but lines CNDO/PERIMADUR//HAI-OU17/3/SNITAN and R143/RUFF//STIL/3/YAV79/4/SHAWA/MALD/… had the greatest TOL and SSI, respectively. The correlation coefficients between tolerance indices and mean yield under stressed and non-stressed conditions revealed that the most effective indices for screening under these conditions were MP, STI, GMP and HM.