Abstract

Field experiments were conducted at the University of Ilorin Teaching and Research Farm in 2005 and 2006 cropping seasons with the objective to evaluate the combining ability for maize grain yield and other agronomic characters in 10 open pollinated maize varieties, which have been selected for high yield and stress tolerance. General combining ability (gca) and year (y) effects were significant for all the parameters except plant height, while specific combining ability (sca) and gca x year effects were significant only for grain yield. However, Tze Comp4 Dmr Srbc2, Tze Comp4 C2 and Acr 94 Tze Comp5 which are good general combiners for maize grain yield, also showed positive significant gca x year effects for flowering traits. Significant sca x year interaction effects were recorded for maize grain yield and days to flowering, with Hei 97 Tze Comp3 C4 combining very well with 3 parents (Acr 90 Pool 16-Dt, Tze Comp4-Dmr Srbc2 and Tze Comp4 C2). These parents and their hybrids probably have genes that can be introgressed into other promising lines in developing early maturing and high yielding varieties for cultivation in the Nigeria savannas.

Key words: Zea mays L., general combining ability, specific combining ability, grain yield, Nigeria savannas.