Genetic Variability Assessment and Agro-morphological Profiling of Elite Maize (Zea mays L.) Genotypes

Abstract

Maize (Zea mays L.) is important to nutrition and farmers’ revenue in Nigeria. Forty-four genotypes of the crop were evaluated in Randomized Incomplete Blocks with three replications in 2021 to investigate the extent of genetic variability for grain yield and agro-morphological traits and to profile the genotypes for the traits. Data were collected on number of days to silking, plant and ear heights (cm), husk cover, plant and ear aspects, number of ears plant-1, leaf angle (o) and grain yield (kg/ha). Genetic components were estimated and principal component and cluster analyses were also performed. A genotype × yield-trait biplot was constructed to profile the genotypes. Phenotypic variance and coefficient of variance estimates were higher than genotypic values, underscoring the roles of genotype and environment in the observations. Heritability estimates were low and ranged from 0.03 to 18% for number of ears plant-1 and plant height, respectively, suggesting the possibility of low response to selection. The first three principal component axes controlled ≈ 60% of total variation and identified grain yield, ear and plant aspects, and husk cover as the main contributors. Cluster analysis produced four distinct clusters which suggested there was variability within the maize genotypes for selection. Genotype DK 920 Yellow was associated with number of ears per plant while LY1501-1, LY1914-14, LY1501-8, LY20001-5, and LY1901-23 were associated with the other measured traits. Genotypes could be selected across clusters to exploit heterosis for important traits. The trait profiles of genotypes that were not profiled could be determined in other studies.