This study aimed to evaluate twenty elite yellow maize inbred lines as well as the suitable tester among threedifferent. The elite inbred lines were crossed as female parents with three testers as male parents, i.e.Gem.Pop.(Broad genetic base), Single cross 101(Narrow genetic base) and Inbred line 100 (Narrow genetic base) at theExperiment Research Station of Moshtohor, Benha University, Egypt during 2014 growing summer season. Theresulting 60 top crosses with three commercial check hybrids i.e. SC.155, SC. Pioneer 3080 and TWC.352 wereevaluated in a yield trail in two sowing dates during 2015 growing summer season. Each experiment was laid outin randomized complete block design with three replications. The recommended packages of agronomic practiceswere followed to achieve a good yield. The morphological and agronomical evaluated traits included eardiameter (ED), number of rows per ear (NRE), number of kernels per row (NKR), 100-kernel weight (100KW) andgrain yield per acre (1 hectare= 2.5 acre) (GYPA). The results showed significant mean square for sowing dates forall traits except for (NRE) and (NKR). The parental inbred lines (L-4, L-5, L-10, L-12, L-13, L-14 and L-19) possessedhigh GCA effects for grain yield. The inbred tester resulted the best combiner among the testers and expressedthe best SCA effect over all crosses. Therefore, inbred line or single cross tester is preferred as it may permit quickerutilization of new lines in commercial hybrids especially if the tester is already in commercial use
