Heterosis and combining ability for grain yield and its contributing characters in maize

Combining ability analysis for grain yield and its contributing characters in maize were carried out in 5A—5 diallel cross. The highest percentage of heterosis for grain per ear over mid parent and better parent were observed by the cross P2A—P3. Crosses P1A—P3 and P1A—P5 showed significant negative heterosis for days to maturity. Significant general and specific combining ability variances were observed for all the characters except ear height. Almost equal role of additive and non-additive gene actions was observed for days to maturity. Additive genetic variance was preponderant for grains per ear and 1000-grain weight and non-additive gene action was involved in plant height, ear height, days to silking, and days to maturity. The inbred lines P2 and P5 were found to be best general combiner for 1000-grain weight. Key Words: Heterosis, combining ability, grain yield, maize. doi:10.3329/bjar.v33i3.1596 Bangladesh J. Agril. Res. 33(3) : 375-379, September 2008