This study aimed at assessing the magnitude and nature of genetic variation present in seventeen pro-vitamin A (PVA) maize varieties, investigate the extent of association among agronomic characters responsible for yield and its components in the maize varieties and evaluate the performance of the maize varieties. The field experiment was carried out at the Teaching and Research Farm of the Rivers State University, Nkpolu, Port Harcourt under rain fed conditions in May, 2018 and were laid out in a randomized complete block design with three replications. Data were collected on established plants per plot, days to 50% silking, days to 50% anthesis, anthesis-silking interval, plant height, ear height, final stand count, number of ears harvested, grain moisture content, field weight and grain yield. Results showed significant differences (P < 0.01) among varieties for all traits evaluated. PVASYN-13 had the highest grain yield per hectare among other varieties. High heritability estimates coupled with high genetic advance were observed in established plants per plot, anthesis-silking interval, final stand count, number of ears harvested, field weight and grain yield, an indication of the additive nature of their inheritance. Thus, the presence of variation could serve as basis for selection for yield improvement in maize.

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.

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