Assessment of genetic variability, heritability and genetic parameters for agronomic traits in maize (Zea mays L.) genotypes

Abstract

Understanding genetic variability and its heritable components is crucial for developing high yielding, stable maize genotypes. In this study, nine maize genotypes were evaluated during Kharif 2024 under a randomized complete block design to assess genetic parameters across ten agronomic traits. Analysis of variance revealed highly significant differences (p < 0.01) for most traits, confirming substantial genetic variability, while anthesis-silking interval was significant only at the (p < 0.05) level, indicating moderate genetic control and greater environmental influence. Traits like days to 50% tasseling, days to 50% silking, plant height, and grain yield per plot exhibited high genotypic and phenotypic coefficients of variation with narrow differences between phenotypic and genotypic coefficients of variation, suggesting strong genetic control. Heritability estimates were high (>89%) for most traits, and when coupled with high genetic advance as percent of mean, traits such as ear length, number of kernel rows per ear, and grain yield per plot were identified as ideal for selection under additive gene action. Conversely, anthesis-silking interval recorded moderate heritability and low genetic advance, making it a poor selection index in the current environment. While the study confirms the effectiveness of phenotypic selection for key yield traits, its limitation lies in being location and season specific. Future studies should employ multilocation and multi-season trials, integrate genotype × environment interaction models, and utilize genomic selection tools such as marker-assisted selection and genotype plus genotype-by-environment biplot analysis to validate stability and selection response across environments. This investigation reinforces the utility of biometric tools in guiding maize improvement and highlights critical traits and methodologies for future breeding strategies focused on genetic gain, adaptability, and climate resilience.