Combining ability and heterosis for grain yield and growth characters were studied in maize through line x tester
mating design using twenty-six lines and two testers along with three checks. The variance due to SCA was higher than GCA
indicating the predominance of non-additive type of gene action for most of the yield attributing traits except days to 50 per
cent tasseling, days to 50 per cent silking, cob length and brown husk maturity. The lines viz., CIMMYT10, CIMMYT16
and CIMMYT23 and the tester KDMI6 were found to be the best general combiners with better performance for most of
the yield attributing traits. Among the hybrids, GH1628 and GH1630 were identified as superior as they recorded high
magnitude of per se performance along with significant positive sca effects and standard heterosis for grain yield.The
hybrids, GH1628 and GH1630 involving parents of positive and significant gca effects and high heterosis for grain yield
could be exploited further after testing across locations and environments to ascertain their yield stability. From the study
it was evident that the single cross hybrids synthesised by using exotic (CIMMYT) lines as females will improve cob and
grain traits in domestic maize hybrids.