THE COMBINING ABILITY OF MAIZE (ZEA MAYS L.) INBRED LINES FOR GRAIN YIELD AND YIELD COMPONENTS

A full diallel cross comprising ten (10) inbred lines was studied for different characters to determine the nature of gene action in parents and hybrid genotypes.The analysis of variance revealed significant differences for general combining ability (GCA) and specific combining ability (SCA) indicated the presence of additive as well as non-additive gene effects for controlling the traits.However, relative magnitude of these variances indicated that additive gene effects were more prominent for all the characters studied except grain yield/plant.The ratio of the components revealed that the magnitudes of SCA components were much higher than that of GCA in all crosses except number of kernel row per ear.A wide range of variability of GCA effects was observed among the parents.For grain yield (GY) parents L2, L5, L6, L7 and L9, showed significant positive GCA effect.Thirteen five crosses exhibited significant positive SCA effects for grain yield (GY).These crosses involved high× high, high× low and low × low general combining parents (GCA).Although the cross L6 × L10 involved low × high general combiners, exhibited the highest significant positive of SCA effect (14.14 tha -1 ).The cross L1×L10 involved the two inbreed lines with lower general combiners and also showed the lower SCA effects (7.61tha -1 ).