Agromorphological divergence among four agro-ecological populations of Bambara groundnut (Vigna subterranea (L.) Verdc.) in Cote d'Ivoire

Characterization of four Bambara groundnut populations regrouping one hundred one accessions collected from four agro-ecological zones in Cote d'Ivoire was made using 19 agro-morphological traits. Descriptive statistics indicated a wide range and high phenotypic variability within each population. Analyses of variance showed highly significant agro-morphological differentiation among populations. Factorial discriminant analysis explained 93.84% of the total variability and revealed that agro-morphological diversity was structured according to the geographical origin of the populations. Traits responsible for the agro-morphological divergence among populations were phenological, vegetative and yield types. The hierarchical cluster analysis structured the populations into two diversity sets. The first set represented the northern population located in the north of the country. That region is characterized by dry climate conditions. The northern population appeared more diversified and accessions were typically of the bunch type with lower phenological, vegetative and yield traits. The second set was less diversified. It consisted of the western, central and eastern populations. It was located in wet climate conditions where accessions were of the spreading type with higher phenological, vegetative and yield traits. Rainfall and temperature seemed to be two of the most important climatic factors contributing to the differentiation of local populations. Results could help to design collection and conservation strategies and to develop breeding and improvement programs for local Bambara groundnut.