Drought stress is a major abiotic stress factor, constraining wheat production and quality
worldwide. Several drought indices were used to identify drought-tolerant lines among 49 wheat lines. These lines were grown in three locations in Egypt, under rainfed (Barrani and Matrouh) and irrigated (Assiut) conditions. Results showed that grain yield under stress and
non-stress environments were highly correlated with the mean productivity (MP), the geometric mean productivity (GMP), stress tolerance index (STI), yield index (YI), harmonic mean (HM), drought resistance index (DRI), and modified stress tolerance index (STI). We found that MP, GMP and STI were considered the best indices for the selection of the relatively tolerant lines. Principal component analysis indicated that the first two components accounted for more than 98% of the total variations for drought tolerant indices.