Genetic and heritability studies of grain yield and other agronomic traits in low-N maize

Abstract

A research was conducted at the Biological Garden of Elizade University, Ilara-Mokin, Nigeria to investigate gene actions and heritability estimates for grain yield and other agronomic traits in low-N maize using North Carolina Mating Design III. Two maize inbred lines were crossed to get F1 and proceed to F2. Four randomly selected F2 segregants that serve as male were backcrossed with each of the two parents inbred lines (P1 and P2) that serve as female. The crosses generated were evaluated using a randomized complete block design with three replications in the late cropping seasons in 2019 and early cropping season in 2020 under two environments (low and high nitrogen conditions). General combining ability of females was significant for all study traits at P < 0.05 while general combining ability of males was significant for all study traits at different probability levels. Specific combining ability was significant for the traits studied (P < 0.05) except leaf blight. The environment was also significant for all traits at P < 0.05 excepted ear rot that was significant at P < 0.01. There was a preponderance of dominance genetic variance for ear height, days to 50% silking, and grain yield while additive genetic variance prevailed over other traits. However, the average dominance ratio was lesser than unity in most of the traits studied. The narrow-sense heritability estimates for study traits ranged from 1.25–79.08%. The results revealed that the additive and dominant gene actions were both important for agronomic traits in low-N maize. Hence, the adoption of reciprocal recurrent selection becomes necessary in incorporating low-N traits into selected elite maize cultivars