Heterosis and combining ability for grain yield and its components in selected maize inbred lines

Information on heterosis and combining ability of adapted maize (Zea mays L.) inbred lines is essential to maximize their use for variety development. This study was conducted to determine heterosis and combining ability of selected inbred lines for yield and yield components. Eight inbred lines were crossed in a diallel mating system. The crosses and parents were evaluated in a randomised complete block design with three replications at Bako Research Center, Ethiopia, in 2001 and 2002. There were significant differences between the entries for measured traits. Mean mid-parent heterosis (MPH) ranged from 2.9% for days to maturity to 89.2% for grain yield and high-parent heterosis from 0.65% for ear diameter to 64% for grain yield. All crosses exhibited positive MPH for ear and plant height, ear length, kernels per row and grain yield. General and specific combining ability effects were significant for most traits. Gutto LMS5, CML-202 and CML-387 were good general combiners for ear and plant height, and days to maturity. Line 143–5-i was the best general combiner for grain yield. This study identified inbred lines and hybrid combinations that had desirable expression of important traits. This will be useful for the development of high yielding hybrids.