Morphological traits variation of cowpea (Vigna unguiculata L. Walp) grown in Cte dIvoire

Abstract

The genetic diversity of a genetic resource is an indicator of its richness and offers many possibilities for improvement. Cowpea is an important source of nutrients for humans and animals. This study aimed at assessing genetic diversity and relationships present among 135 accessions in the Centre National de Recherches Agronomiques (CNRA) collection, using qualitative traits. Traits analysis revealed significant genetic variation between the studied accessions through high Shannon diversity index. Estimated for 15 morphological characters with 0.80 mean value, H' ranged from 0.55 to 1. Seed traits generally expressed mean high diversity index (0.70-0.89). Between 15 parameters assessed, 12 exhibited the most discriminating variability of collection. The three MCA factorial axes explained 19.085% of phenotypic variability. The trait seed colour being correlated to these axes could be used as a selection criterion for local cowpeas improvement. Based on MCA and HAC methods, these accessions were classified into three distinct groups. Containing most accessions, subgroup Ia includes all seeds, pod, and flower colours. Almost all accessions of subgroup Ib possessed creamcoloured, smooth and globose seeds. All cluster II accessions have a creeping habit. The CNRA collection being very diversified, it constitutes a useful resource for future cowpea improvement studies in Côte d'Ivoire.