Evaluation of Drought Stress Tolerance in Some Faba Bean Genotypes Using Drought Tolerance Indices and Biochemical Compounds

In this study, different genotypes of faba bean were evaluated for Tolerance index and biochemical compounds under drought stress. 21 Genotypes of faba bean were studied based on RCBD design with three replications in two irrigation treatments (including normal irrigation and drought stress) during two cropping years (2018-2019) at Gorgan Agricultural Research Station. Based on the potential (Yp) and stress (Ys) yields, drought tolerance including Stress Tolerance Index (STI), Tolerance Index (TOL), Stress Susceptibility index (SSI), Mean Productivity (MP), Geometric Mean Productivity (GMP), Yield Index (YI) and Yield Stability Index (YSI), stress Susceptibility Percentage Index (SSPI) were calculated for each genotype. According to data combined analysis, drought stress has significant effect on all studied traits. In drought stress, seed hull tannin, Endosperm tannin, and starch were 31.5, 19.7 and 1.96% more than normal conditions, respectively. Genotype×drought interaction showed the G-faba-66, G-faba-65, G-faba-62, G-faba-294, G-faba-292, G-faba-523, G-faba-525, and G-faba-20 genotypes in normal irrigation and the G-faba-67, G-faba-66, G-faba-75, G-faba-72, G-faba-65, and G-faba-62 genotypes in drought stress had the highest seed yield. G-faba-65 genotype showed the highest resistance to drought stress based on Tolerance index and biochemical compounds content.