Combining Ability and Heterosis for Yield and Component Characters in Maize

Heterosis and the nature and combining ability was studied in 7 × 7 diallel cross in maize for grain yield and yield contributing characters. The significant estimates of GCA and SCA variances suggested the importance of both additive and non-additive gene actions for the expression studied traits. Preponnderance of additive gene action was noticed for ear diameter and 1000-kernel weight and the other characters were preponderantly controlled by non-additive type of gene action. Standard heterosis ranged from -17.60 to 9.71%; -20.41 to 8.04%; -13.89 to 7.54% and -6.17 to 14.48% for yield per plant, number of kernels per ear, length of ear, ear diameter and 1000-kernel weight, respectively. Kernel weight showed maximum heterotic contribution to high yield. The parent Q was the best general combiner showing significant positive GCA effect for grain yield 7 and all the yield components and also simultaneously possessed high mean values indicating that per se performance of the parent could prove as an useful index for combining ability. Parents Q Q and Q were 1, 4 5 found suitable for higher number of kernels and Q and Q were desirable for bold kernels. The cross 1 7 combinations those exhibited significant sca effects for yield involved average × average and average × high GCA parents. Crosses Q × Q , Q × Q , Q × Q and Q × Q possessed significant high sca effects as well as 2 3 4 6 1 7 6 7 high heterosis for yield could be used in hybrid development.