Genetic Characterization and Variability of Cassava (Manihot esculenta) Accessions Cultivated in Southwest and North Central Nigeria Using Agromorphological Markers

Understanding the genetic variability among Nigerian cassava accessions is a crucial prerequisite for its improvement. The objective of this study was to estimate the genetic variability among 477 cassava accessions and to classify them based on their genetic similarities for effective utilization in breeding programs. The accessions were evaluated at the Federal University of Agriculture, Abeokuta experimental site from 2023–2024, using an augmented randomized complete block design with two checks (TME 419 and NR 87184). Agromorphological descriptors were collected at 3-month intervals for 12 months. Broad sense heritability and genetic advance as percent of mean (GAM) were high, indicating that the overall phenotypic expressions observed were largely influenced by genetic factors. Multiple correspondence analysis (MCA) showed that petiole color, number of leaf lobes, color of leaf veins, and parenchyma contributed the most to the overall variability observed in the study population. Principal component analysis (PCA) identified petiole length, length of leaf lobe, width of leaf lobe, and plant height as primary contributors to the overall phenotypic variations observed in the population. Hierarchical clustering of accessions using Euclidean distance revealed two and three clusters based on qualitative and quantitative traits respectively. This study has shown the existence of wide genetic variations in several cassava traits, providing a valuable resource for breeding programs.