STUDY ON COMBINING ABILITY AND HETEROSIS IN MAIZE (Zea mays L.)

Abstract

In rabi season 2016, six diversed maize inbred lines were crossed in all possible combinations without reciprocals using a half diallel mating design to obtain 15 single cross. Inbred parents and their F1 single crosses with a check were evaluated in rabi season 2017 to evaluate the role of general and specific combining ability and heterosis for some quantitative traits. Significant general combining ability variances were observed only for cob height and number of kernel per row and specific combining ability variances were observed for plant height, cob length, Number of kernel rows per cob , number of kernels per row, number of kernels per cob, cob weight, hundred grain weight and grain yield per plant. The GCA/SCA ratio was less than unity for all studied traits. Based on GCA estimates, it could be concluded that the best combiners were ML10, ML14 and ML15 inbred lines for most of the studied traits. This result indicated that these inbred lines could be considered as good combiners for improving these traits. Significant positive SCA effects were found for all studied traits. Based on SCA effects, it could be concluded that the crosses, ML06×ML10, ML10×ML15, and ML15×ML17 could be exploited by the maize breeders to increase maize yield. Three F1 hybrids such as ML06×ML10, ML10×ML15, and ML15×ML17 proved to be the outstanding hybrids to immediate further steps for commercial cultivation. In a conclusive decision the F1 hybrid, ML15×ML17 was the best combination as evaluated through combining ability and standard heterosis.