EVALUATION AND SELECTION FOR YIELD AMONG SIXTEEN OPEN POLLINATED MAIZE (ZEA MAYS L.) VARIETIES

Abstract

This study aimed at (i) investigating the magnitude and nature of genetic variability present in sixteen open-pollinated maize varieties for yield (ii) assessing the extent of association among characters responsible for yield and its component traits and; (iii) identifying and selecting the best performing varieties in terms of yield. The experiments were laid out in a randomized complete block design with three replications at the Teaching and Research Farm of The Federal University of Technology, Akure under rain fed conditions during the 2018 and 2019 cropping seasons to estimate analysis of variance, phenotypic and genotypic coefficients of variation, heritability in broad sense, genetic advance and character associations for yield and yield attributes in sixteen late/intermediate maturing OPV maize. Path coefficient analysis and principal components analysis were used to determine the characters responsible for yield. Data were collected on plant stands per plot, days to 50% silking, days to 50% tasselling, plant height, ear height, number of plants at harvest, number of ears at harvest, moisture content, field weight and grain yield. Results showed significant differences among genotypes (G) for all traits evaluated. Also, year (Y) effect was significant for all traits except days to 50% silking, days to 50% tasselling, plant height, field weight and grain yield while genotype by year interaction (GxY) was significant for all traits. Moderate heritability coupled with moderate genetic advance observed in plant stands per plot, number of plants at harvest and number of ears at harvest indicated the additive nature of their inheritance. Significant positive phenotypic correlations existed between grain yield and plant stands per plot, plant height ear height, number of plants at harvest, number of ears at harvest, and field weight for both years, respectively. Significant positive genotypic correlations existed between grain yield and plant stands per plot plant height, ear height, number of plants at harvest, number of ears at harvest, and field weight for both years, respectively. However, days to 50% silking and tasselling correlated significantly but negatively with grain yield at both phenotypic and genotypic level in both years of study. Path analysis revealed that days to 50% tasselling, plant height, number of ears at harvest, and field weight had positive direct effect on grain yield. While plant stands per plot, days to 50% silking, ear height and moisture content exerted negative direct effect on grain yield. In 2018, the first four PCs gave Eigen-values greater than 1.0 and cumulative variation accounted for 98.85%. In 2019, the first four PCs jointly accounted for 99.5% of total variation among the genotypes. The variation among the genotypes followed similar trend in both years as the variation in both PC1 of both years were mainly associated with plant height and ear height, while PC2 of both years were associated with plant stands per plot, number of plants at harvest and number of ears at harvest. Thus, the presence of variation could serve as basis for selection for yield improvement in maize. The overall performance of the genotypes was higher in 2018 relative to 2019. However, G6-F and G3-C were consistently high yielding, and recorded higher yields than the average mean yields in both years, suggesting relative stability of performance. RSI also identified both genotypes, as well as G7-G, G14-N, G4-D as most promising genotypes. G6-F had the overall best performance with the least total rank. G14-N ranked second, followed by G7-G and G4-D. On the other hand, G15-O, G12-L, G8-H and G5-E had the poorest overall performance.