Yam (Dioscorea spp.) encompasses diverse species, including several staple food crops, of which a few were domesticated on the African continent. This study assessed yam genetic diversity in Sub-Saharan Africa (SSA) to inform breeding and conservation initiatives. A diverse collection of 1,247 yam accessions representing six species (D. rotundata, D. alata, D. praehensilis, D. bulbifera, D. cayenensis, and D. dumetorum) sourced from six African countries (Benin, Côte d’Ivoire, Democratic Republic of Congo, Ghana, Nigeria, and Uganda) was used in this study. Genetic diversity was assessed using 7,648 single-nucleotide polymorphism (SNP) markers, selected from previously sequenced datasets between the Consultative Group on International Agricultural Research (CGIAR) and National Agricultural Research and Extension Systems (NARES) collaboration. Findings showed a substantial inter- and intra-specific variation in African yam germplasm, with observed heterozygosity ranging from 0.165 to 0.464 and an average polymorphic information content (PIC) of 0.324 across populations. Population structure was assessed using ADMIXTURE (with cross-validation error for optimal K), DAPC (with BIC for K), and an IBS-based Neighbor-Joining (NJ) tree. Analysis of molecular variance (AMOVA) indicated moderate differentiation among countries (FST = 0.07), and higher differentiation among species (average FST = 0.14). Clustering patterns and phylogenetic analysis revealed the presence of evolutionary relationships among D. cayenensis, D. praehensilis, and D. rotundata, providing insights into D. rotundata domestication history in West Africa. These findings enhance our understanding of genetic relationships within the Dioscorea genus.
Arbuscular mycorrhizal fungi (AMF) are important plant symbionts, yet the infective potential and field-scale variability of indigenous AMF associated with plantain remain poorly documented in Côte d’Ivoire. We characterised AMF in three major plantain-producing fields (Site 703, 704, and 708) in Central-western Côte d’Ivoire using 40 rhizosphere samples collected at 0–30 cm depth. Soil physicochemical properties, most-probable-number (MPN) infective propagules, trap-culture spore density and viability, root colonisation, and morphology-based richness were quantified. Independent MPN estimates were compared on the logarithmic scale using standard errors reconstructed from their 95% confidence limits, followed by Holm adjustment. Site 703 had 5,400 infective propagules per 30 g of soil and exceeded site 704 by 19.29-fold (95% CI for the ratio 3.56–104.36; Holm-adjusted p = 0.0018) and site 708 by 10.00-fold (1.85–54.11; p = 0.0150); sites 704 and 708 did not differ (p = 0.4458). Total trap-culture spore density varied only from 88.23 to 100.35 spores g−1 (between-site CV = 6.52%), and 56.3–60.0% of spores were viable. Root colonisation frequency remained high (90.91–100%; CV = 5.41%), whereas whole-root intensity (24.73–76.36%; CV = 52.92%) and whole-root arbuscular abundance (18.05–68.82%; CV = 60.63%) were substantially more variable. Eleven pooled morphospecies representing four genera were identified, with Glomus accounting for six taxa. The convergence of high MPN, colonisation intensity, and arbuscular abundance identifies site 703 as the strongest candidate source for inoculum isolation. The data demonstrate the presence of infective indigenous AMF but do not establish plant growth effectiveness or identify causal edaphic drivers.
Mango is a strategic crop in Côte d’Ivoire, but its production is severely constrained by fruit flies. This study evaluates eight control strategies against fruit flies in Northern Côte d’Ivoire (2023–2024). Results reveal a strong predominance of Bactrocera dorsalis (63.73
Rhizobacteria play a major role in the functioning of agricultural ecosystems by contributing to plant nutrition and growth. However, information regarding the diversity and functional properties of bacteria associated with cashew genotypes in plot Top 24 in Lataha remains limited. This study aimed to characterize these bacterial communities and assess their potential as plant growth-promoting bacteria (PGPR). Rhizosphere soil samples were collected from cashew genotypes in plot Top 24 and from citrus trees located on the periphery. The physicochemical properties of the soils were determined,and bacteria were isolated on LB and characterized by Gram staining and biochemical tests. The main PGPR traits evaluated included phosphate solubilization, the production of indole -3- acetic acid (IAA), ammonia (NH3), and hydrocyanic acid (HCN), atmospheric nitrogen fixation, as well as nitrate reductase and urease activities. The soils studied were generally acidic (pH ranging from 3.71 to 5.24) with variations in moisture and electrical conductivity depending on the rhizosphere. Twenty-five bacterial isolates were obtained, including 21 from cashew genotypes and 4 from citrus. The majority of the strains were Gram-negative bacilli and exhibited catalase and oxidase activity. PGPR assays revealed no phosphate solubilization or HCN production, while several isolates produced AIA and a high proportion exhibited nitrogen-fixing ability and nitrate reductase activity.
