Genetic variances, heritability, and correlation studies on selected phenotypic traits in a backcross breeding program involving normal and opaque-2 maize

A study was undertaken to study the gene action, broad and narrow sense heritabilities, and interrelationships among five selected traits of maize including, plant height (PHT), ear height (EHT), cob length (COL), cob diameter (COD), and number of rows per cob (ROC). The obtained results indicated that all estimates of additive (VA) and dominance (VD) variances were positive for all characteristics with the exception of additive variance for cob diameter (COD), dominance variance (VD) being highly significant. The magnitude of VD was consistently larger than that of VA for all characteristics. High broad sense heritability estimates were detected for plant height (95%), ear height (81%), Cob length (75%), number of rows per cob (50%), emphasizing that the dominance genetic variance was the major component of genetic variation in the inheritance of these traits and the effectiveness of selection for improving these traits. However, moderate to low narrow sense heritability estimates were obtained for plant height (24%), ear height (34%) and cob length (4%). These results indicated the importance of choosing suitable segregating generations for exhibiting the best expression of genes of the different traits studied. Correlations among traits indicated that plant height was positively and significantly associated with ear height (0.82) in the recurrent parent population, (0.77) in the donor parent, and (0.73%) in the F1 generation. The F2 generation as well as the BC1 and BC2 generations recorded some levels of negative correlations among the traits studied.