Dissecting trait associations in maize (Zea mays L.) through phenotypic and genotypic correlation coefficient analysis

Abstract

The improvement of grain yield in maize (Zea mays L.) relies not only on direct selection but also on understanding the interrelationships among yield and its contributing traits. This study was undertaken to estimate phenotypic and genotypic correlation coefficients among ten agronomic traits in nine diverse maize genotypes using data analyzed through RStudio (v4.5.1) with the ‘variability’ package (v0.1.0). The analysis of variance confirmed significant genetic variability among genotypes for all studied traits. Phenotypic correlation analysis revealed a highly significant and positive association between days to 50% tasseling and silking, indicating synchronized flowering. Grain yield per plot exhibited strong negative correlations with flowering time traits, suggesting the advantage of early maturity. Yield contributing traits such as ear length, ear girth, number of kernel rows per ear, and number of kernels per row were positively and significantly correlated with grain yield at both phenotypic and genotypic levels, emphasizing their potential as reliable indirect selection criteria. Conversely, traits like anthesis silking interval and test weight exhibited higher phenotypic than genotypic correlations with yield, reflecting a greater influence of environmental factors. These findings highlight that traits with strong and consistent genetic associations should be prioritized in selection programs for improving maize yield potential, while traits with environmentally influenced correlations require cautious interpretation and advanced breeding strategies.