Determination of genetic heritability for some agronomic traits in corn by diallel analysis

ABSTRACT: Combining ability estimates are important genetic attributes to maize breeders in anticipating improvement via hybridization and selection. To determine the combining ability for yield and yield associated traits, 8 diverse corn inbred lines were used in a half diallel mating design. Twenty eight F1 progenies along with their parents were planted in randomized complete block design with four replications in two locations during two years. Combined analysis of variance showed significant mean squares of general combining ability (GCA) and specific combing ability (SCA) for kernel lengh ( KL) , ear lengh(EL), leaf area (LA), number of leaf (NL), cob to ear weight ratio(CR)and kernel yeild (KY)indicating that the importance of both additive and non additive genetic effects for these traits. However, high narrow-sense heritability estimates, low degree of dominance and the ratio of estimates of GCA to SCA effects for number of leaf (NL) and cob to ear weight ratio(CR) indicated that additive genetic effect was more important for these trait. Most of the crosses with significant SCA effects for KY had at least one parent with significant GCA effects for the same traits. Significant positive correlations were detected between KY and other yield components including KL, EL, LA and NL, therefore these traits can be used as indirect selection criteria for KY improvement. The cross MO17 x Line8 with highest values of KY is considered as best cross combinations for improving the trait.