This study was conducted in a rainforest ecology of Southwestern Nigeria during 2016 and 2017 cropping seasons under rainfed conditions to estimate character association and path coefficient of grain yield (t ha-1) and its component characters, to identify characters whose selection could be used in improving maize grain yield (t ha-1). Fourteen late-maturing pro-vitamin A maize (PVAM) synthetics were conducted in a randomized complete block design with three replications. The following agronomic characters were recorded: plant stands per plot, days to 50% tasselling, days to 50% silking, anthesis-silking interval, plant height (cm), ear height (cm), number of ears harvested, field weight (kg), and grain yield (t ha-1). In both 2016 and 2017, plant stands per plot, the number of ears harvested and field weight (kg) correlated positively and significantly with grain yield (t ha-1) at the phenotypic and genotypic levels. Also, in both years, positive and significant phenotypic and genotypic correlations were found for plant stands per plot with number of ears harvested and field weight (kg), days to 50% tasselling with days to 50% silking, plant height (cm) with ear height (cm) and number of ears harvested with field weight (kg). Path analysis for both years at the phenotypic and genotypic levels identified field weight (kg) and the number of ears harvested to have a positive direct effect on grain yield (t ha-1), an indication that optimum plant population per plot is paramount to increasing grain yield (t ha-1). Hence, the number of ears harvested and field weight (kg) are characters that could be considered in the improvement of maize grain yield (t ha-1).

In crop breeding, the selection for yield is made complex because of the quantitative and polygenic nature of the character. This study was undertaken to assess character association and show the contribution of various yield contributing characters in some maize varieties through the help of correlation and path coefficient analyses in order to identify appropriate plant characters for selection to improve maize grain yield. Seventeen maize varieties were sown in a randomized complete block design with three replications in a humid environment of Port Harcourt, Nigeria in 2018 under rainfed condition. Data were recorded for days to 50% anthesis, days to 50% silking, anthesis-silking interval, plant height (cm) and ear height (cm), number of plants per plot, number of plants harvested, number of ears harvested, moisture content (%), field weight (kg), and grain yield (t ha-1). Results showed number of plants per plot, number of plants harvested, number of ears harvested and field weight correlated positively and significantly both phenotypically and genotypically with grain yield. Path coefficient analysis at the genotypic level also revealed field weight and days to 50% anthesis as the characters exerting the highest positive direct effect on grain yield. Therefore, maize grain yield could be improved through indirect selection for these characters.