COMBINING ABILITY IN MAIZE SINGLE CROSS HYBRIDS FOR GRAIN YIELD: A GRAPHICAL ANALYSIS

Combining ability estimates are important genetic attributes to maize breeders in anticipating improvement via hybridization and selection. This study sought single cross maize hybrids (SC) that could be used for the production of double cross maize hybrids (DC) for improved grain yield. Five commercial SC hybrids were crossed following a complete diallel fashion. All the DC hybrids along with self progenies were evaluated for combining abilities and to determine heterotic effects among the SC hybrids, using biplot diallel analysis at the KPK Agricultural University, Peshawar, Pakistan during 2007. General combining ability (GCA) and specific combining ability (SCA) effects were significant for the studied trait. Genotype hyb-4 was identified to be the best general combiner for grain yield, while high SCA effects were observed for crosses hyb-4 × HYB-3, hyb-4 × HYB-1 and hyb-5 × HYB-2. The graphical demonstration proposed by the biplot analysis provided an effective overview of GCA and SCA effects, mean performance in crosses, as well as grouping of similar genotypes on the basis of heterosis. Moreover, the biplot also provided an opportunity for assessing the interrelationship among the genotypes.