In 2012, six maize inbred lines were crossed in all possible combinations without reciprocals by using a half diallel cross mating design to obtain 15 single crosses. 15 F₁ single crosses were evaluated through 2013 season under 2 irrigation treatments, every 12 day (Normal irrigation) and every 18 days (stress), to assess the role of general and specific combining ability of inbreds in hybrid behavior under recommended irrigation and water stress conditions. Results showed that mean squares due to crosses, general (GCA) and specific (SCA) combining abilities were significant or highly significant for all studied traits under both non-stressed and water stressed conditions, except of SCA for plant height under both conditions, which was insignificant. This result indicated that both additive and non-additive gene effects are very important in the inheritance of these traits. The ratio of GCA/SCA were less than unity for anthesis date  under both conditions, silking date under normal irrigation, ear leaf area at stress condition, ear length under both conditions, and ears yield per plant at stress condition, indicating that  the non- additive genetic effects were more important and played the major role in the inheritance of these traits under these conditions. On the other hand, GCA/SCA ratios were more than unity for silking date under stress condition, ear leaf area at normal irrigation, plant height under both normal and stress conditions, and ears yield per plant at normal condition, indicating that the additive genetic effects were more important and played the major role in the inheritance of these traits under these conditions. The best general combiners were: P₂(Rg5) and P6(B 73) under both conditions, and P4 (R39) under normal for earliness;P1(Inb. 209),P5(Sids7) under normal, and P2 (Rg5) under both conditions for ear leaf area; P5(sids7) under normal, and  P6(B73) under both conditions for plant height(shortness);P1(Inb.209) and P3(sids34) under both conditions for ear length; and P1 (Inb.209) under normal, and P2 (Rg 5) under both conditions and P4 (R39) under stress for ears yield per plant. The best cross combinations were: eight crosses (No. 3, 4, 5, 6 , 9, 10, 12 and 13) under normal, and five crosses (No. 2, 3, 6, 9 and 13) under stress for earliness; two crosses No. 2 and No. 12 under normal, and three crosses No. 6, 13 and 15 under stress for ear leaf area; crosses No. 5 and 6 under  normal  and cross No.5 under  water stress for plant height (shortness);four crosses i.e. No.4, 8,10and 12 under normal, and four crosses No. 2, 12,13 and 15 under stress for ear length; and three crosses i.e. No. 1, 12 and 13 under normal, and six crosses  No. 2, 4, 6, 12, 13 and 15 under stress for ears yield per plant.