Forty F₁ grain sorghum crosses, their parents (eight CMS A-lines and five male R-lines) and one commercial hybrid (H-306) as check were evaluated for grain yield/plant and some other traits in 2011 and 2012 seasons at Shandaweel Agric. Res. Station, Sohag, Egypt under three irrigation levels (100, 70% and 40% from optimum water irrigation level). The combined analysis across the three levels of irrigation at each of the two years showed highly significant mean squares due to irrigation levels, and genotypes and their interaction for all studied traits, indicating genetic variability for all studied traits. In addition, highly significant mean squares were found due to interaction of genotype × irrigation, indicating differential response for different genotypes under different levels of irrigation for all studied traits except for days of 50% flowering. Also, high significant differences among genotypes, crosses, parents were found, for all studied traits in the two seasons. These results reflect the important roles of both additive and non-additive in the inheritance of number of days to 50% flowering, plant height, 1000-grain weight and grain yield/plant. Female lines (ASH-6, ASH-11, ICSA-37 and ICSA-88003) and the male lines (ICSR-92003 and ICSV-273) had positive and highly significant general combining ability effects for grain yield under the three irrigation levels over the two seasons. These lines had favorable genes and would be considered good combiners for high yielding ability. The crosses (ASH-8 × ICSR-89028) and (ICSA-37 × ICSR-92003) had positive and highly significant SCA effects under the three of irrigation treatments over the two seasons and would be considered the best combinations for grain yield.