Abstract

Maize plays a great role for human food in Ethiopia. Even if it is cultivated for food, most improved varieties released were normal maize which are devoid of lysine and tryptophan. Combining ability analysis is one of the commanding means in identifying the best combiners that may be used in crosses either to exploit heterosis or to accrue productive genes. The objectives of this study were to examine combining ability of quality protein maize inbred lines, estimate the extent of heterosis and determine the nature of gene action. Six inbred lines were crossed with two testers (CML144 and CML159) to produce 12 F₁ hybrids. Twelve F₁ hybrids and two standard checks viz., BHQP542 and a normal maize hybrid, Jibat, were evaluated in a randomized complete block design with two replications in 2010/2011 at Ambo Agricultural Research Centre. Genetic differences were observed from mean squares of treatments for all traits except days to maturity, ear diameter, number of kernel rows per cob, protein content (%) and oil content (%). LN1 was good general combiner for grain yield. Hybrid HN7 (89.56%) and HN8 (85.63%) revealed significant positive standard heterosis and superior in mean performance for grain yield compared to check BHQP54. Therefore; even though it is a one year trial HN7 and HN8 could be exploited for commercial use.

Key words: Specific combining ability, general combining ability, gene action.