Genetic variability and divergence analysis in cassava (Manihot esculenta Crantz) accessions for storage root yield and other agronomic characters

Understanding the character of genetic variability and diversity is crucial to enhancing selection efficiency in plant breeding programs. This study aimed to estimate the magnitude of genetic variability and diversity among 64 accessions based on quantifiable characteristics to provide valuable information for breeding programs and conservation. The 64 accessions were evaluated in the two locations using an 8x8 lattice design. Analysis of variance showed a significant difference among the tested accessions for the characters studied, indicating the presence of variability and the possibility of character selection and improvement. The highest genotypic coefficient of variation revealed for the aboveground biomass, storage root yield, and storage root number indicates that the possibility of selection of those characters might be effective for their improvement. High heritability along with high genetic advance as a percent of the mean was observed for number of storage roots, length of storage roots, storage root yield, aboveground biomass, and harvest index, suggesting the existence of additive gene effects. The first three principal components explained 49 % of the total variation, with PC I accounting for 22.5 %, PC II for 15.6 %, and PC III for 10.9 % of the total variation. The 64 accessions were grouped into five clusters, and the number of accessions in each cluster was varied from 3 in cluster V to 31 in cluster II. The maximum inter-cluster diversity was found between IV and V (82.60), while cluster V (6.12) had the highest intra-cluster diversity. Accessions G8, G16, G40, G43, G46, G53, and G57 have been identified as the best candidates for the breeding program in terms of storage root yield. The various analyses performed in the present study confirmed the presence of wide variability & diversity among accessions, which could be used to develop cassava cultivars with optimal storage root yield through effective selection.