Sixteen parents (13 lines and 3 testers), their thirty-nine top-crosses and two check commercial hybrids were evaluated under two irrigation treatments, i.e., normal and water-stressed at Research Station of the Faculty of Agriculture, Al-Azhar University, Assiut, Egypt. during the two seasons of 2021 and 2022, some traits, i.e., days to 50% silking (DS), ear height (EH), ears /plant (E/P), kernels/ row (K/R), 100-kernel weight (KW) and grain yield /plant (GY/P) were studied. Analysis of variance showed significant (P≤ 0.05 to P≤ 0.01) differences of genotypes for all studied traits under both environments as well as combined. Mean squares due to GXE showed significant (P≤ 0.05 to P≤ 0.01) differences for all studied traits, except for DS. Mean squares due to lines and tester were significant or highly significant for all traits under both environments except for ears/plant for lines under normal environment and ears/plant, 100-K/w under normal environment and 100-K/w under drought stress for tester which were not significant. The inbred IL-16, IL-15 and IL-11 showed positive and highly significant GCA effects for ears/plant, kernels/row and 100-K/w under the normal environment. While IL-18, IL-16 and IL-7 showed positive and highly significant GCA effects for ears/plant, kernels/row and 100-K/W under the drought environment, inbred linens IL-18, IL-16 and IL-15 had positive and highly significant GCA effects for same traits in combined. Inbred L-5 exhibited positive and highly significant GCA effects for grain yield/plant at both condition and combined. The crosses IL-4 × CML-57, IL-5 × SC-128, IL-21 × CML-57 and IL-23 × CML-57, had the best among the hybrids having the highest desirable specific combining ability effect for grain yield at normal, drought stress and combined for grain yield/plant. The highest value of heterotic effects relative to better and mid-parents for grain yield per plant were obtained by IL-21 × CML-57 it gave 531.04% and 649.53% and 109.81% and 140.85% the cross had the highest positive significant heterotic under both environments. Heritability in broad sense values was higher than narrow sense values because non additive variance was larger than additive variance.