Evaluation of Homogeneity and Structuring of Phenotypic Diversity of Maize (Zea mays L.) Lines of the Fourth Generation Derived from Induced Mutation in Daloa, Côte d'Ivoire

Abstract

In Côte d’Ivoire, maize is one of the most extensively grown cereal crops. Its importance extends beyond its contribution to human and animal diets, as it also provides essential raw material for various agro-industrial applications. Today, the impacts of climate change severely constrain maize production, primarily through water deficits that affect the crop throughout its developmental stages. To mitigate this limitation and enhance maize productivity sustainably, mutant lines were developed by subjecting the EV8728 variety to gamma irradiation. This study aimed to evaluate the phenotypic homogeneity within fourth-generation maize lines and to structure the genetic diversity among them. A total of 49 mutant lines, along with the non-irradiated EV8728 variety as a control, were evaluated using a randomized complete block design. Line homogeneity was assessed through the mean coefficient of variation for all traits, using a 20% threshold. The results revealed strong phenotypic stability across all studied lines, with mean coefficients of variation well below 20%. In addition, substantial genetic variability was detected among the lines. Principal Component Analysis (PCA) structured this variability into four distinct groups, each representing an important genetic pool for the improvement of maize in Côte d’Ivoire.