The concept of heterotic groups is fundamental to hybrid breeding theory and practice. In this study, fifty six new white inbred lines of maize were divided into three sets, each set contained 17, 20 and 19 inbred lines, respectively. Inbred lines in each set were top crossed with two inbred lines as testers; Sk-12 and Sk-13 for set-1, Sk-12 and Sd-63 for set-2 and Sd-7 and Sd-63 for set-3. The resulting hybrids in each set plus the hybrid between the two testers and a check commercial hybrid were evaluated at two locations in 2019 season for grain yield. The mean squares due to locations, lines, testers and lines x testers interaction were highly significant for all sets except for testers and lines x testers in set-1. The results of set-1 showed that 14 crosses were not significantly out-yielded the check; three inbred lines were identified as good general combining ability (GCA) effects, three crosses were noted as the highest for specific combining ability (SCA) effects and the tester inbred lines were able to classify 13 of the 17 tested lines into heterotic groups based on SCA effects and test crosses grain yield. In set-2, 13 crosses had significantly higher grain yield than the check, four inbred lines were the best for GCA effects, three crosses were the best for SCA effects, and the tester inbred lines classified 10 of the 20 tested inbred lines into heterotic groups. In set-3, 13 crosses were not significantly out-yielded the check, three inbred lines were the best for GCA effects, three crosses were the best for SCA effects and the testers were able to classify 14 from 19 tested inbred lines into heterotic groups based on SCA effects and crosses mean yield.