Abstract

Combining ability variances were estimated for grain yield and its related traits in maize (Zea mays L.). Nine maize varieties consisted of five IITA open pollinated varieties (OPVs) and four local varieties were crossed in line x tester mating design. During the 2007 cropping season to determine the general combining ability (GCA), specific combining ability (SCA) effects and heterosis. Parents and hybrids were evaluated in Damboa during the cropping seasons of 2008/2009. Significant level of genetic variability among the parental lines and their hybrids for days to tasseling, days to silking, anthesis silking interval (ASI), plant height, ear height, weight of cobs, dehusked cobs and grain yield, thus suggesting the possibility for genetic improvement. The relatively smaller proportion of GCA to SCA ratio indicated that the predominance of non-additive genetic effects with respect to all the traits except number of cobs per plant and number of cobs per plot. This suggests that high performing hybrids such as EVDT-99WSTRC0 x EX-DAMBOA WHITE, EVDT-99WSTRC0 x EX-BIU WHITE, EVDT-99WSTRQPMC0 x EX-DAMBOA YELLOW and TZECOMP₃DTC₁ x EX-BIU YELLOW may be used to develop potential varieties. Grain yield superiority of some hybrids over the higher parents was recorded suggesting the possibility of their commercial exploitation. The parents: EVDT-99WSTRC0, TZE-WDTSTRQPMC0, and EX-DAMBOA WHITE were identified as the best combiners in terms of GCA for days to tasseling, days to silking, number of cobs/plant, number of cobs/plot, dehusked cobs and grain yield.

Key words: Combining ability, heterosis, Nigeria maize, drought.