Background: Yam (Dioscorea spp.) is multiple species with various ploidy level and considered as cash crop in many producing areas. Selection based phenotyping for yield and its related traits such as mosaic virus and anthracnose diseases resistance and plant vigor in multiple species of yam is lengthy however, marker information has proven to enhance selection efficiency. Methodology: In this study, a panel of 182 yam accessions distributed across six yam species were assessed for diversity and marker-traits association study using SNP markers generated from Diversity Array Technology platform. For the traits association analysis, the relation matrix alongside the population structure were used as co-factor to avoid false discovery using Multiple random Mixed Linear Model (MrMLM) followed by gene annotation. Results: Accessions performance were significantly different (p < 0.001) across all the traits with high broad-sense heritability (H²). Phenotypic and genotypic correlations showed positive relationships between yield and vigor but negative for yield and yam mosaic disease severity. Population structure revealed k = 6 as optimal clusters-based species. A total of 22 SNP markers were identified to be associated with yield, vigor, mosaic and anthracnose diseases resistance. Gene annotation for the significant SNP loci identified some putative genes associated with primary metabolism, pest and resistance to anthracnose disease, maintenance of NADPH in biosynthetic reaction especially those involving nitro-oxidative stress for resistance to mosaic virus, and seed development, photosynthesis, nutrition use efficiency, stress tolerance, vegetative and reproductive development for tuber yield. Conclusion: This study provides valuable insights into the genetic control of plant vigor, anthracnose, mosaic virus resistance, and tuber yield in yam and thus, opens an avenue for developing additional genomic resources for markers-assisted selection focusing on multiple yam species.

The capability of winged bean to support food and nutrition security in sub-Saharan Africa is recurrently being affected by several constraints, which include a lack of genetic improvement. The dearth of adequate information on the level of available genetic diversity in winged bean germplasm has been a major setback in planning appropriate improvement programs. Fifteen winged bean accessions were assessed for genetic diversity using 10 quantitative traits and 10 simple sequence repeat (SSR) markers. The accessions were laid out in RCBD with three replicates for two growing seasons. Leaf samples were obtained from 10 plants representing each accession for SSR marker genotyping. The accessions exhibited significant (p < 0.05) differences for measured traits. Broad-sense heritability estimates varied from 10.31% for days to first plant maturity to 72.67% for pod weight. Pod weight had a positive and significant correlations with pod length (0.53, p < 0.05), pod width (0.70, p < 0.01), and number of seeds per pod (0.64, p < 0.01). However, the number of seeds per pod was negatively correlated with days to maturity (−0.71, p < 0.01). Number of seeds per pod was positively predicted by pod weight, seed thickness, and days to maturity. Cluster analysis delineated the accessions into two distinct groups. Average number of alleles of 4.2, gene diversity of 0.25, and polymorphic information content of 0.22 were recorded. Analysis of molecular variance revealed intra-accession variation of 95% as compared to inter-accession variation of 5%. Two primary genetic groups were identified and only three accessions, namely TPt-6, TPt-126, and TPt-48, showed genetic purity. The results of this study provide the basis for exploiting the existing diversity for winged bean improvement.

African yam bean (Sphenostylis stenocarpa Hochst, Ex. A. Rich. Harms) is an important grain legume in Sub-Saharan Africa because of its nutritional value and adaptability to various agroecological zones. To foster the varietal development of improved African yam bean (AYB) genotypes with economic traits, it is necessary to validate parental polymorphism for key markers in selecting progenies from crosses between desired parents. This study aims to analyze the genetic fidelity between parents and F1 progenies in African yam bean through putative cowpea simple sequence repeat (SSR) markers. Hence, a total of seventy-seven progenies were derived from four sets of biparental crossings using drought-susceptible (TSs-96, TSs-363, and TSs-274) and drought-tolerant (TSs-417, TSs-111, and TSs-78) AYB accessions. These were validated using 120 cowpea primers targeting SSRs under optimal PCR conditions, and the size of the PCR-amplified DNA fragments was checked using gel electrophoresis. Twenty primers exhibited polymorphism in the parental lines, while ten displayed higher levels of the same polymorphism. The average polymorphism level for the surveyed SSR markers was 0.36. Given these findings, our study demonstrates that cowpea SSR markers are a reliable method for the regular testing and clear identification of AYB crosses, indicating potential AYB improvements.

Winged bean productivity and the potential to enhance food and nutrition security in sub-Saharan Africa are recurrently affected by several constraints, including but not limited to the lack of genetic improvement. The dearth of adequate information on the genetic diversity that guides the choice of progenitors’ selection among other advantages has been a major setback in planning appropriate improvement programs. This study assessed 15 winged bean accessions for genetic diversity using 10 quantitative traits and 10 microsatellites (SSRs) markers. These accessions were evaluated using RCBD with three replicates for two growing seasons. Ten plants constitute each accession during evaluation from where leaf samples were obtained for SSR marker genotyping. Phenotypic results revealed significant variation (p < 0.05) in the performances of the accessions for the measured traits. H2 estimates varied from 18.92% for seed length to 72.67% for seed weight per plant. Pod weight had a positive and significant correlation with pod length (0.53), pod width (0.70), and number of seeds per pod (0.64). However, the number of seeds per pod negatively correlated with days to maturity (-0.71). The number of seeds per pod was positively predicted by pod weight, seed thickness, and days to maturity. Cluster analysis revealed two genetic groups characterized by different traits. The ten SSRs revealed an average allele count of 4.2, gene diversity of 0.25, and polymorphic information content of 0.22. Analysis of molecular variance revealed within the population of 95% as compared to between population variance of 5%. Phylogeny analysis revealed two primary genetic groups from where five secondary genetic subgroups were identified and only three accessions (TPt-6, TPt-126, and TPt-48) showed genetic purity. This study provides the basis for further studies aimed at exploiting existing variations in winged bean germplasm for its improvement.

African yam bean (Sphenostylis stenocarpa Hochst, Ex. A. Rich. Harms) is an important grain legume in sub-Saharan Africa because of its nutritional value and adaptability to various agroecological zones. To foster the varietal development of improved African yam bean (AYB) genotypes with economic traits, it is necessary to validate parental polymorphism for key markers in selecting progenies from crosses between desired parents. The study aims to analyze the genetic fidelity between parents and F1 progenies in African yam bean through putative cowpea Simple sequence repeat (SSR) markers. Hence, a total of seventy-seven progenies were derived from four sets of biparental crossings using drought-susceptible (TSs-96, TSs-363, and TSs-274) and drought-tolerant (TSs-417, TSs-111, and TSs-78) AYB accessions. These were validated using 120 cowpea primers targeting SSR under optimal PCR conditions, and the size of the PCR-amplified DNA fragments was checked using gel electrophoresis. Twenty primers exhibited polymorphism in the parental lines, while ten displayed higher levels of the same polymorphism. The average polymorphism level for the surveyed SSR markers was 0.36. Given these findings, our study demonstrates that cowpea SSR markers are a reliable method for regular testing and clear identification of AYB crosses, indicating potential AYB improvements.