Анотация: The major objectives of the study were to (1) evaluate genotypic yield performances of eighteen durum wheat genotypes, (2) determine their reliability and stability parameters and (3) estimate variance components and heritability of yield and yield-related traits. Eighteen durum wheat genotypes were evaluated in two conditions (rainfed and well watered) in Ilam and Gachsaran agricultural research stations of Iran during from 2009 to 2011 to identify patterns of genotype by environment interactions and their stabilities in terms of seed yield and yield-related components. Seed yield and its components are affected by plant genotype and environmental conditions. There were significant differences between genotypes of one or two years at each location for all the traits. Significant differences among years or between conditions were obtained in terms of all traits. Genotypes x environment interactions at all the traits were highly significant