The root-knot nematode (RKN) species Meloidogyne incognita and M. javanica cause substantial root system damage and suppress yield of susceptible cowpea cultivars. The narrow-based genetic resistance conferred by the Rk gene, present in some commercial cultivars, is not effective against Rk-virulent populations found in several cowpea production areas. The dynamics of virulence within RKN populations require a broadening of the genetic base of resistance in elite cowpea cultivars. As part of this goal, F₁ and F₂ populations from the cross CB46-Null (susceptible) x FN-2-9-04 (resistant) were phenotyped for M. javanica induced root-galling (RG) and egg-mass production (EM) in controlled growth chamber and greenhouse infection assays. In addition, F_2:3 families of the same cross were phenotyped for RG on field sites infested with Rk-avirulent M. incognita and M. javanica. The response of F₁ to RG and EM indicated that resistance to RKN in FN-2-9-04 is partially dominant, as supported by the degree of dominance in the F₂ and F_2:3 populations. Two QTLs associated with both RG and EM resistance were detected on chromosomes Vu01 and Vu04. The QTL on Vu01 was most effective against aggressive M. javanica, whereas both QTLs were effective against avirulent M. incognita. Allelism tests with CB46 x FN-2-9-04 progeny indicated that these parents share the same RKN resistance locus on Vu04, but the strong, broad-based resistance in FN-2-9-04 is conferred by the additive effect of the novel resistance QTL on Vu01. This novel resistance in FN-2-9-04 is an important resource for broadening RKN resistance in elite cowpea cultivars.

Development and analysis of Multiparent Advanced Generation Inter-Cross (MAGIC) populations have been conducted with several crop plants to harness the potential for dissecting the genetic structure of traits and improving breeding populations. We developed a first MAGIC population for cowpea ( Vigna unguiculata L. Walp.) from eight founder parents which are genetically diverse and carry many abiotic and biotic stress resistance, seed quality and agronomic traits relevant to cowpea improvement in sub-Saharan Africa (SSA) where cowpea is vitally important in the human diet and in local economies. The eight parents were inter-crossed using structured matings to ensure the population would have balanced representation from each of the founder parents, followed by single-seed descent, resulting in 365 F8 recombinant inbred lines (RILs) each carrying a mosaic of genome blocks contributed from all founders. This was confirmed by SNP genotyping with the cowpea Illumina 60K iSelect BeadArray. Following filtering to eliminate duplicates, sister lines and accidental selfing events, a core set of 305 F8 RILs was chosen as the primary population. The F8 lines were on average 99.74% homozygous while also diverse in agronomic traits including flowering time, growth habit, maturity, yield potential and seed characteristics across environments. Trait-associated SNPs were identified for most of the parental traits. Loci with major effects on photoperiod sensitivity and seed size were also verified by genetic mapping in biparental RIL populations. The distribution of recombination frequency varied considerably between chromosomes, with recombination hotspots distributed mostly in the telomeric regions. Due to its broad genetic base, this cowpea MAGIC population promises breakthroughs in genetic gain and high-resolution genetic mapping for gene discovery, enhancement of breeding populations and, for some lines, direct releases as new varieties.

Fall armyworm, Spodoptera frugiperda (J.E. Smith), has emerged as one of the most damaging invasive pests affecting maize production and household food security across sub-Saharan Africa since its first detection in 2016. This systematic review synthesizes empirical evidence published between 2016 and 2025 to assess the agronomic, livelihood, and food security impacts of FAW on smallholder farming systems across Eastern, Southern, Western, and Central Africa. Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines and the Population, Intervention, Comparison, Outcome, Time, and Setting (PICOTS) framework, 20 studies (17 empirical and 3 contextual) were identified through comprehensive searches of academic databases and institutional repositories and were included in the final synthesis after methodological screening. The evidence indicates that FAW invasion causes substantial maize yield losses ranging from approximately 20% to 50%, with the greatest reductions reported in rain-fed systems with limited access to pest management technologies. Infestation rates frequently exceeded 50%, particularly during early invasion phases. Beyond agronomic losses, several studies reported reduced household income, constrained food availability, and livelihood disruptions, including increased labor requirements, higher production costs, and reliance on short-term coping strategies. Only a small proportion of studies (n = 4) directly assessed nutrition-related indicators, but the available evidence indicates declines in dietary diversity in severely affected communities. Overall, the agronomic impacts of FAW are consistently documented across regions, whereas the socioeconomic and nutrition outcomes remain comparatively underreported, indicating a significant evidence gap. These findings highlight FAW as both an agronomic and livelihood challenge, underscoring the need for integrated pest management strategies, strengthened extension services, and coordinated policy responses to safeguard food and income security among smallholder farmers in Africa.

Background/Objective: Maize (Zea mays L.) is a globally important cereal crop widely cultivated for food, feed, fodder, biofuel production, and various industrial applications. Maize landraces represent a valuable source of genetic diversity that supports adaptationand resilience across diverse agroecological environments. However, evidence on phenotypic diversity based on agro-morphological traits in these landraces remains fragmented across regions and varying analytical approaches. This review synthesized global evidence on phenotypic variation, heritability patterns, experimental designs, statistical methods, and the extent of integration between phenotypic and molecular data. Methods: A systematic literature search was conducted in GoogleScholar, ScienceDirect, PubMed and AGRIS for studies published between 2000 and 2025 evaluating phenotypic diversity in maize landraces. The review followed PRISMA 2020 guidelines, and f50 studies from 30 countries met the eligibility criteria. Results: Substantial and structured phenotypic diversity was consistently reported across studies, with flowering time, plant architecture, and ear and kernel traits emerging as major contributors to landrace differentiation. Traits with moderate to high heritability were mainly morphological and phenological, suggesting relative genetic control and potential suitability for phenotypic selection. In contrast, grain yield showed greater environmental sensitivity and variable heritability, reflecting complex inheritance and genotype × environment interactions. Although molecular markers were incorporated in a some studies, integrative analyses linking phenotypic and genetic data remained limited. Conclusions: Phenotypic evaluation remains a reliable approach for characterizing maize landrace diversity. However, standardized methodologies, greater integration with molecular data and cross-environment validation are needed to strengthen inference and utilization in breeding and conservation. The review also provides recommendations for improving agro-morphological assessment in maize landraces.

Assessment of the severity of Fusarium wilt disease in cowpea and other crops relies mainly on visual rating scales which are prone to errors, which can compromise the reproducibility of the data. Furthermore, the rating scales require considerable practical training and routine experience for reliable assessment. Two objective metrics, stem vascular discoloration length (%VDL) and number of Fusarium necrotic vessels (NFNV), for quantitative measurement of vascular damage incited by Fusarium oxysporum f. sp. tracheiphilum race 4 (Fot4) of cowpea, were compared and their utility as a measure of disease severity and potential usefulness in other crop pathosystems is proposed. The metrics were tested in seven F ₂ populations and one F _2:3 population, segregating for wilt response, and inoculated with race Fot4 at the seedling stage. %VDL and NFNV were highly correlated with plant wilting for all populations ( r = 0.51 – 0.93 and 0.52 – 0.94, respectively). Furthermore, the relationships between the variables were linear in all populations ( R ² = 0.81 to 0.87 and 0.71 to 0.91), indicating that they can provide accurate and reliable measurement of severity of Fusarium wilt disease. Also, %VDL and NFNV were strongly correlated ( r = 0.88 - 0.97) and demonstrated a linear relationship ( R ² = 0.69 – 0.94). Analysis of goodness-of-fit in two F ₂ populations revealed that errors in measurement of vascular discoloration length can result in higher segregation distortion when compared to enumeration of necrotic vessels. However, both metrics were highly effective in accounting for the severity of vascular damage caused by Fusarium wilt disease.

Background/Objectives: Despite its economic importance, the genome-wide genetic diversity of sesame germplasm conserved in the Ethiopian national ex situ collection, a proposed center of origin, remains inadequately characterized. This study assessed genome-wide genetic diversity and population structure in 188 sesame accessions from six Ethiopian Agricultural Research Centers using DArTSeq-based SNP markers. Methods: After quality filtering, 5163 high-quality markers were retained from the original set of 12,302 SNPs. Mean expected heterozygosity (He = 0.201) exceeded observed heterozygosity (Ho = 0.193), reflecting sesame’s predominantly self-pollinating nature. Results: The SNPs showed a transition/transversion ratio of 1.17:1 and an uneven distribution across 16 linkage groups. STRUCTURE, PCA, DAPC, and neighbor-joining cluster analyses revealed a clear hierarchical population structure with distinct clusters and varying admixture. Accessions from Assosa (AARC) and Bako (BARC) were genetically uniform, whereas Werer (WARC) and Gambella (GaARC) were major diversity reservoirs, exhibiting high heterozygosity and gene diversity. Pairwise FST values ranged from 0.001 to 0.356, and AMOVA indicated that 30–43% of variation occurred among collections and 57–70% within collections, highlighting substantial intra-collection diversity. Conclusions: The findings highlight that specific research centers were identified as key sources of genetic variation for breeding, conservation, and association mapping to enhance the improvement in agronomic and adaptive traits in sesame for the Ethiopian sesame gene pool.