The domesticated Vigna species still need some of the beneficial characters that exist in the wild Vigna species, despite the improvements obtained so far. This study was carried out to enhance our understanding of the Senegalese wild Vigna diversity by exploring the agro-morphological characteristics of some accessions using 22 traits. The phenotyping was carried out in a shaded house for two consecutive rainy seasons (2021 and 2022) using the alpha-lattice experimental design with 55 accessions. Multiple correspondence analysis was carried out based on the qualitative traits, which showed considerable variability for the wild species (Vigna unguiculata var. spontanea, Vigna racemosa, Vigna radiata and the unidentified accession). The quantitative traits were subjected to statistical analysis using descriptive statistics and ANOVA. Our results revealed that ninety-five percent (95%) pod maturity ranged from 74.2 to 125.8 days in accession 3 of V. unguiculata and in accession 92 (V. racemosa), respectively. In addition, accession 14 of V. radiata recorded the highest weight for 100 seeds with a value of 4.8 g, while accession 18 of V. unguiculata had the lowest (1.48 g). The ANOVA showed significant differences for the accessions during each season (p ≤ 0.05). Seasonal effects (accession × season) were observed for some quantitative traits, such as the terminal leaflet length and width, time to 50% flowering and 95% pod maturity, pod length and 100-seed weight. Principal component analysis showed that reproductive traits, such as the time to 50% flowering, number of locules per pod, pod length, pod width and 100-seed weight, were the major traits that accounted for the variations among the wild Vigna accessions. The genetic relationship based on qualitative and quantitative traits showed three clusters among the wild Vigna accessions. Indeed, the diversity observed in this study could be used to select parents for breeding to improve the cultivated species of Vigna.

Understanding the genetic basis of domestication-related traits (DRTs) is crucial for crop improvement. In this study, we developed an interspecific backcross population by crossing the elite cowpea variety Sam with a wild accession of Vigna unguiculata var. spontanea from Senegal. Using a mid-density single nucleotide polymorphism panel, we constructed a high-quality genetic linkage map consisting of 1,046 polymorphic markers spanning 1,131.6 cM across 11 chromosomes and used it as a framework for dissecting the genetic architecture of key DRTs. Over 2 consecutive years, we identified 65 quantitative trait loci (QTLs) associated with 17 key domestication traits, with 73.8% of these QTLs consistently detected across both years. Notably, we observed a significant clustering of domestication-related QTLs within 4 major genomic regions on chromosomes Vu01, Vu03, Vu08, and Vu09, particularly for organ size and phenological traits. The co-location of QTLs for traits such as pod shattering, growth habit, and flowering time suggests pleiotropy or potential co-selection of linked genes during domestication. Furthermore, our findings support the hypothesis of 2 independent domestication events in cowpea, as evidenced by similarities as well as differences in QTL regions between our study and previous reports. We hypothesized that common as well as different loci may have been selected during the 2 independent domestication events of cowpea, paralleling the dual domestication in common beans. While wild cowpea species contributed limited major-effect QTLs for yield-related traits, they remain an essential reservoir of genetic diversity, particularly for pest and disease resistance. These insights enhance our understanding of cowpea domestication and offer valuable genetic resources for breeding programs.