Combining Ability and Heterosis for Yield and Component Characters in Maize

Abstract

Abstract: 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 7 was the best general combiner showing significant positive GCA effect for grain yield 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 1, Q4 and Q 5 were found suitable for higher number of kernels and Q1 and Q 7 were desirable for bold kernels. The cross combinations those exhibited significant sca effects for yield involved average × average and average × high