Genetic variability, association, and path coefficient analysis for yield and yield‐related traits of quality protein maize genotypes

Abstract Maize ( Zea mays L.) is among the most importantcereal crops worldwide, serving as a major source of food, feed, and industrial raw material. Estimation of genetic parameters, trait associations, and the direct and indirect contributions of agronomic traits to grain yield is fundamental for effective quality protein maize improvement. This study aimed to quantify genetic variability, heritability, genetic advance, and the relationships among yield and related traits in quality protein maize genotypes. Sixty‐six genotypes were evaluated using an alpha‐lattice design with two replications across four environments during the 2022–2023 main cropping season in Ethiopia. Highly significant differences ( p ≤ 0.01) among genotypes were detected for all measured traits, indicating substantial genetic variability. Elevated phenotypic and genotypic coefficients of variation were recorded for grain yield, ear rot, husk cover, ear aspect, and ears per plant, suggesting ample scope for selection. Grain yield, plant height, ear height, ear aspect, and ears per plant exhibited high broad‐sense heritability coupled with moderate genetic advance as a percentage of the mean, reflecting the predominance of genetic factors and the feasibility of effective selection. In contrast, anthesis–silking interval, days to anthesis, ear rot, and ear position showed relatively lower heritability and genetic advance. Grain yield was positively and significantly correlated at both genotypic and phenotypic levels with plant height, ear height, and grain moisture content. Path coefficient analysis revealed that plant height and ears per plant exerted strong positive direct effects on grain yield at the genotypic level, whereas ear height and ear position had notable negative direct effects. The observed genetic relationships and path coefficients provide valuable guidance for trait prioritization in quality protein maize breeding. Overall, the findings highlight key traits that can be effectively exploited as selection criteria for improving grain yield and adaptation of quality protein maize to the highland agroecologies of Ethiopia.