Evaluation of end season drought stress tolerance indices to identify tolerant genotypes offaba bean (Vicia faba L.)

Drought stress has reduced the yield and cultivated area of faba bean in many regions of Iran. So,in order to identify the best drought stress tolerance indices and select drought tolerant genotypes,24 genotypes of faba bean from ICARDA (International Center for Agricultural Research in DryAreas) drought resistance nursery and control cultivar (Barekat) were planted in two separateexperiments at Gorgan and Gonbad agricultural and natural resources research stations (GolestanAgricultural and Natural Resources Research and Education Center). Faba bean genotypes wereevaluated in a simple lattice design with two replications in 2015-2016. To determine droughttolerant genotypes, it is necessary to grow them under both stress and non-stress condition. To thisend, various stress tolerance indices such as tolerance (TOL), Stress Sensitivity Index (SSI), MeanProductivity (MP), Stress Tolerance Idex (STI), Geometric Man Poductivity (GMP), Yield Index(YI), Modified Stress Tolerance Index (K1STI) were calculated based on the genotypes in stressedyield in stress and non-stressed conditions. Multiple variance analysis of data showed that therewas a significant difference between the genotypes. In medium stress conditions (SI = 0.46), therewas a correlation between bean pod yield in stress and non-stress conditions, which indicates theability to generalize the yield results in non-stress to moderate drought stress conditions. MP,GMP, STI, HM, YI and K1STI indices can be used to identify tolerant genotypes due to theirpositive and significant correlation with yield in both stress and non-stress conditions. Therefore,1, 3, 12, 19, 20, 21, 22, 23 and 24 genotypes were selected for further investigations in thecrossbreeding program of drought resistance.