Two sets of yellow maize crosses were constructed by crossing 18 new inbred lines with two testers for each set using line × tester method at Sakha Agricultural Research Station in 2017 growing season. The resulting 36 F1 crosses in addition to three commercial check hybrids for each set were evaluated in 2018 at two locations (Sakha and Ismailia) for set-1 and at two locations (Sakha and Sids) for set-2. Days to 50% silking (DS) and grain yield ard/fed (GY) were recorded. The three inbred lines L-7, L-10, L-13 in Set-1 and L-32 in Set-2 were the best combiners for earliness and yielding ability simultaneously. Therefore, these lines can be utilized as promising inbred lines in hybridization programs to develop high yielding and early maturing yellow maize hybrids in the same time.The best hybrid for specific combining ability was L-7×Sk-1 for days to 50% silking and L-10×Sk-2 for grain yield in Set-1 and L-27×Gz-658 for days to 50% silking and L-29×Gz-658 for grain yield in Set-2. Also hybrid L-13×Sk-1 in Set-1 and L-23×Sk-11 in Set-2 outyielded and matured earlier than the best check. Days to 50% silking in the two sets was controlled mainly by additive gene action. Meanwhile, grain yield was controlled by additive gene effects in set-1 and non-additive gene action in set-2. The inbred lines in each set, for grain yield, based on heterotic group specific and general combining ability (HSGCA) method, were classified into two heterotic groups as follows: set-1 group-1(Sk-1) included L-2, L-3, L-4, L-5, L-8, L-9, L-10, L-14 and L15. While, group2 (Sk-2) included L-1, L-11, L-16 and L-17. In set-2, group1 (Sk-11) included L-20, L-22, L-29, L-30 and L34. Meanwhile, in set-2, group-2 (Gz-658) included L-19, L-25, L-26, L-27, L28 and L-33. These groups could be used in breeding programs for selecting the best parents in developing new crosses.