Understanding genetic variability and combining ability is essential for improving maize programs. Inbred line Sd 7 and single cross SC. Sk 187 were used as testers in the top crossing of 15 different white maize inbred lines during 2021 season. The produced 30 crosses and four checks were assessed throughout 2022 season in Sakha, Sids, and Nubaria Agricultural Research Stations in Egypt. All traits except days to 50% silking of Cr x Loc, showed significant mean squares owing to locations, crosses, and their interaction. The majority of the qualities under study showed substantial to extremely significant mean squares resulting from lines (L), testers (T), and (L x T) and their interaction with locations. Although non-additive gene impact is more significant in grain production inheritance, additive genetic effects were more prominent in days to 50% silking, plant height, and ear height inheritance. Two single crossings (SC. Sk5003/11 x Sd7 and SC. Sk5004/19 x Sd7) and one three-way cross (TWC Sk5002/8 x SC Sk 187) showed considerably better grain yield performance and superiority compared to checks. The inbred lines Sk 5001/4 and Sk 5003/13 exhibited negative, favorable, significant GCA impacts for days to 50% silking, height of plant, and ear height. Sk 5002/8, Sk 5003/10, Sk 5003/11, and Sk 5004/19, four inbred lines, demonstrated considerable favorable GCA benefits for grain yield. For SCA effects, Sk 5003/11 x Sd 7 were the best crosses, Sk 5004/19 x Sd 7, Sk 5001/1 x SC Sk187 and Sk 5002/8 x SC Sk187 for grain yield.