Combining ability and heterosis for grain yield and its components in maize inbreds over environments (Zea mays L.)

Twelve inbred lines were crossed with each of five testers in a line × tester design to evaluate combining ability and heterosis to identify promising hybrids of maize for various characters like, 50% tasseling, 50% silking, 75% dry husk, ear length, ear diameter, kernels per ear, kernel rows per ear, 1000 kernel weight and grain yield. The resulting F1s along with three checks and the parents were evaluated in two environments duringkharif 2010 and rabi 2010 to 2011. Pooled analysis of variance revealed highly significant differences among the genotypes. Crosses excelled their perspective parents in performance for most of the traits studied. L9among the parental lines and T2 among the testers were identified as the best general combiner for grain yield. Whereas among the hybrids, (L6 × T5) was identified as a potential cross combination for grain yield while the cross (L9 × T2) recorded highest magnitude of economic heterosis of 84.60% over the best standard check (Vivek hybrid-9). So the crosses (L6 × T5) and (L9 × T2) can be utilized for developing high yielding hybrid varieties as well as for exploiting hybrid vigor.   Key words: Combining ability analysis, heterosis, line × tester, maize (Zea mays L.).