Evaluation and Classification of Yellow Maize Inbred Lines Using Line X Tester Analysis Across Two Locations

Ten yellow maize inbred lines and three testers were top crossed in line × tester scheme in 2019 season. The resulted 30 top crosses with two check hybrids were evaluated at two locations in 2020 growing season to assess mean performance, general and specific combining ability and their interaction with locations as well as elucidate type of gene action. The recorded data were days to 50% silking, plant height, ear height, ear length, ear diameter, No. of rows/ear, No. of kernels/row and grain yield (ardab/fed). The results showed that, the mean squares due to locations (Loc), genotypes (G), crosses (Cr.), G × Loc and Cr. × Loc interactions were significant for all the studied traits. Highly significant differences were observed among the evaluated lines (L), testers (T) and its corresponding hybrids for all traits. non-additive gene action gave an important role in the inheritance of all the studied traits. The inbred lines L2, L4 and L6 showed the best desirable GCA effects for earliness, L6, L7 and L10 for shortness and L4, L5, L6, L7 and L9 for lower ear placement.  Whereas the inbreeds L3, L6 and L7 were the best general combiners for grain yield. The crosses L2×T1, L8×T1, L1×T2, L7×T2, L3×T3, L6×T3 and L10×T3 had the best SCA effects for grain yield. The ten inbred lines were classified into three different heterotic groups using HSGCA method. These groups could be used for selecting the best parents for making crosses in maize breeding programs.