Heterosis and Combining Ability Analysis for Yield and its Contributing Traits in Early Maturing Maize (Zea mays L.) Genotypes

In the present study heterosis and combining ability were estimated for 36 hybrids developed by diallel mating between 9 early maturing maize inbred lines. The analysis of variance indicated significant difference between genotypes for all the 16 traits studied except number of cobs per plant. The economic heterosis was significant for number of primary branches per tassel, cob leaf area, ear length and protein content characters. For protein content economic heterosis was significant in six crosses. None of the cross exhibited significant economic heterosis for grain yield per plant. However, maximum heterobeltiosis for grain yield per plant was in cross EI-720 x EI-670. The GCA mean square was significant for 9 and SCA for 15 characters. “² SCA washigher than “²GCA for all the characters. Parent JCY2-4 was good general combiner for days to 50 per cent tasselling, number of primary branches per tassel, number of grain rows per ear and shelling percentage. The parent EI-718 and CLQ-RCYQ40-3 were good general combiner for grain yield per plant andall the yield components. Crosses EI-720 x EI-670, EI-720 x EI-586, EI-586 x EI-670, EI-561 x EI-670, EI-561 x EI-586 and EI-720 x NP-06-07-R-76-11-3 had significant positive SCA effects but economic heterosis for grain yield was not there therefore, has no practical utility.