RÉSUMÉ
Combining ability of inbred lines is the ultimate factor determining future usefulness of the lines for hybrid development while, an idea about the nature of gene action controlling the yield and yield contributing characters is important for development of fruitful breeding programme. Owing to this, the present study was carried out to investigate the General Combining Ability (GCA) and Specific Combining Ability (SCA) effect of parental lines and hybrids respectively, and to deduce the type of gene action regulating the grain yield and its components. The 30 single cross hybrids were generated by crossing 6 lines with 5 testers in line x tester mating system and evaluated along with four checks at three locations for the estimation of combining ability effects. Significant differences were observed among the inbred lines, testers, hybrids and parents vs. hybrids for most of the studied traits. The non-additive gene action was predominant for all studied traits except plant height. PFSR 145 found to be good general combiner for traits such days to 50% tasselling, days to 50% silking, days to maturity, plant height and ear height. GP 329 is best general combiner for ear girth, number of kernel per ear, number of kernels per row, 100 kernel weight and grain yield. These parents could be used in future breeding programme for the accumulation of favourable genes and thereby improve maize yield with desirable traits. Hybrid GP 82×GP 83 found to be the best specific combiner for days to 50% tasseling, days to 50% silking, days to maturity, number of kernels per ear and grain yield. The hybrid GP 82×GP 83 can be further tested extensively for the development of potential early maturing hybrids.