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• Bambara groundnut productivity in South Africa is low (0.62 t/ha) compared to the attainable yield of the crop reaching up to 3 t/ha. • The low productivity is attributable to a lack of improved and high yielding cultivars that are locally bred and adapted in the country. • This paper presents baseline information on Bambara groundnut genetic profile of South African collections for effective breeding and conservation. • The magnitude of the genetic diversity and population structure of Bambara groundnut collections of South Africa using high throughput single nucleotide polymorphisms (SNP) markers are highlighted to guide current and future Bambara groundnut research and development by selection genetically unique genotypes for breeding. Bambara groundnut (Vigna subterranea [L.] Verdc) is a highly nutritious grain legume with a significant potential to develop various commercial food and feed products. It is a resilient crop able to grow under harsh climates and poor soil conditions. Bambara groundnut productivity in South Africa is low (0.62 t/ha) compared to the attainable yield of the crop reaching up to 3 t/ha. The low productivity is attributable to a lack of improved and high yielding cultivars that are locally bred and adapted in the country. Genetically diverse and locally adapted Bambara groundnut landrace varieties and exotic collections are present in South Africa for strategic breeding to improve yield and yield-related traits and nutritional quality. The objective of this study was to determine the magnitude of the genetic diversity and population structure of Bambara groundnut collections of South Africa using high throughput single nucleotide polymorphisms (SNP) markers. Ninety-three genotypes were assessed using genotyping with 2286 SNP markers and some unique complementary morpho-agronomic traits of the crop. The mean genetic diversity value was 0.32, revealing moderate genetic differences among the assessed genotypes. Cluster and structure analyses grouped the test genotypes into two distinct categories. Further, the analysis of molecular variance partitioned the total genetic variation into among genotypes (90%), within genotypes (8%) and among populations (2%). The results revealed two heterotic groups for hybridization and selection programs. The following unique genotypes were selected: ARC Bamb 37 (with spreading growth type), ARC Bamb 49 (bunch type), ARC Bamb 61 (semi-bunch) and ARC Bamb 83 (spreading) using the SNP markers and desirable agronomic traits. The study provided new insight on Bambara groundnut genetic profiles of South African collections which will assist in conservation strategy and management of the crop for effective breeding. [ABSTRACT FROM AUTHOR]

Correlations and path coefficient analysis provide knowledge on trait interrelationships and potential for simultaneous, direct, or indirect selection in plant breeding. The objective of this study was to determine the genetic and phenotypic correlations as well as the path coefficient analysis among grain yield components and nutritional quality traits in cowpea genotypes. Data for grain yield components and mineral elements were collected from 70 cowpea genotypes planted at two environments in 2017/18 and 2018/19 seasons in South Africa. Grain yield had significant (P <0.05) positive phenotypic correlations with number of seeds per pod (SPP), indicating that selection of cowpea genotypes based on SPP could be effective in maximizing grain yield. The heat map showed that grain yield was strongly associated with number of branches (NB), SPP and number of pods per plant. Among the yield components, only SPP showed significant (P <0.05) positive phenotypic correlations with Zn, Mn, and Mg. Grain yield showed no genetic correlations with yield components and nutritional quality traits. Significant (P <0.05) positive genetic correlations were observed between yield components and most of the nutritional quality traits, indicating inherent association among the traits. Path coefficient analysis identified SPP and NB as major contributors to grain yield. The PCA identified cowpea genotypes such as ARC030, ARC011, ARC016, ARC024, NGOII, ARC032, IT90K59, and ARC047 with high grain yield and good nutritional quality traits that can be used further as potential parents for crop improvement through biofortification. The clustered heat map distingished five groups of cowpea genotypes and three of those were associated with good grain yield and nutritional quality traits which could make cowpea a good choice to combat food security and malnutrition in the world. [Display omitted] • Genetic and phenotypic correlations as well as the path coefficient analysis among grain yield components and nutritional quality traits in cowpea genotypes were determined. • Correlations and path coefficient analysis provide knowledge on trait interrelationships and potential for simultaneous, direct, or indirect selection in plant breeding. • Grain yield had significant positive phenotypic correlations with number of seeds per pod, indicating that selection of cowpea genotypes based on SPP could be effective in maximizing grain yield. • Seed pods per plant showed positive phenotypic correlations with Zn, Mn, and Mg. • Path coefficient analysis identified seed per pod and branches per plant as major contributors to grain yield in cowpea. [ABSTRACT FROM AUTHOR]

• Cowpea is a highly valued fruit and leafy vegetable crop contributing to food, nutrition, and health security. • Low cowpea production and productivity in sub-Saharan Africa and globally are due to a lack of improved cultivars with multiple disease, and insect pest resistance and drought tolerant; moreover, there is a lack of seed system research in cowpea. • The extensive phenotypic and genotypic variation found in cowpea genetic resources is useful for the development of cultivars with enhanced grain yield, leafy yield and nutritional values as well as drought tolerant. Despite the contribution of cowpeas to food security and the crop's numerous nutritional and health attributes, consumers in South Africa have labelled cowpeas, among other leguminous crops as a "poor people's food" ; this contributed to the gradual decline in the cultivation and use of the crop. This, in turn, resulted in the observed high reliance on limited number of plant based protein crops and excessive consumption of livestock products. In this paper, three aspects are interrogated, i.e., genetic resource management, production constraints as well as the trade performance and consumption of cowpeas in South Africa. A clear understanding of these aspects renders an informed decision upon which recommendations for the necessary practical interventions that are needed to be put in place to spur the development of target products and cowpea's value chain. The assessment of genetic resource management and seed production constraints of cowpeas was based on a review of relevant literature, while descriptive analysis of secondary data spanning a period of 10 years (2010-2019) obtained from Trade Map and FAOSTAT databases was used to interrogate the trade performance and consumption of cowpeas. Findings reveal that seed production constraints are largely anchored on the limited attention government and policy making institutions have accorded to the seed system of orphaned crops, thereby compromising their potential by failing to supply affordable good quality seeds to smallholder and commercial farmers. However, South Africa has one of the largest and most diverse collections of cowpea germplasm housed at the Agricultural Research Council. With regard to trade performance and consumption, results show that South Africa is a net exporter of cowpeas, with a 10 years' period annual average worth R2.9 million. Given that South Africa does not re-export cowpeas, yet on average 4848 tonnes are produced annually, it is a clear indication that the country produces lightly more than what is consumed domestically – on average 4634 tonnes per annum. Therefore, recommendation is made to bolster cowpea production and productivity through mainstreaming the legume seed system towards boosting local and export markets as well as strongly enhancing local consumption by creating awareness of the nutritional and health benefits of cowpeas. Furthermore, there is a need to increase awareness about the nutritional and health benefits of cowpeas and other leguminous crops, among other socio-economic benefits. This is important in spurring cowpeas consumption domestically, while countering the over reliance on animal products as protein sources and the associated risks such as such as high greenhouse gas emissions and obesity for people. [ABSTRACT FROM AUTHOR]

• Drought tolerance was assessed among 26 okra genotypes using phenotypic traits • Phenotypic variation was observed among assessed okra genotypes under drought stress condition • Positive correlations were recorded between fresh pod yield with fresh pod length, dry pod weight and number of pods per plant • The study identified genotypes such as LS01, LS06, LS09, LS17, LS18, LS19, LS21, LS22, LS24 and LS26 for production and breeding Genetic variation is fundamental for breeding drought-adapted cultivars with economic traits. The objective of this study was to determine the response of selected okra genotypes to drought stress using yield and yield-related traits to identify and select candidate genotypes for drought tolerance breeding. Twenty-six okra genotypes were evaluated in glasshouse (GH) and field (FLD) environments under drought-stressed (DS) and non-stressed (NS) conditions using a 13 × 2 α lattice design with two replications. Data were collected on the following phenotypic traits: number of branches per plant (NB), plant height (PH), days to maturity (DTM), stem diameter (SD), fresh pod length (FPL), dry pod weight per plant (DPW), dry pod length per plant (DPL), number of seeds per plant (NSP), number of pods per plant (NPP), pod yield per plant (YPP) and anthocyanin (ATY) pigmentation of the stem. Significant (P < 0.05) genotype x testing environment x water condition interaction effects were recorded for most traits allowing for selection of okra genotypes suited for drier conditions. YPP positively and significantly correlated with FPL (r = 0.66; P ≤ 0.001), DPW (r = 0.80; P ≤ 0.001) and NPP (r = 0.58; P ≤ 0.001) under DS condition in the FLD environment. The study identified genotypes with high yield and other desirable phenotypic attributes which are useful genetic resources for future crosses and selection of promising progenies based on combining ability analysis and heritability under water-limited environments. [ABSTRACT FROM AUTHOR]

• Okra is high-valued vegetable crop serving the food, pharmaceutical, paper and oil industry. • Okra production and productivity in sub-Saharan Africa and globally are hindered by a lack of improved cultivars with drought tolerance. • The extensive phenotypic and genotypic variation in okra genetic resources are useful for cultivar development with enhanced seed and oil yields, and drought tolerance. Okra (Abelmoschus esculentus L. Moench) is high-valued vegetable and oil crop serving the food, pharmaceutical, paper and oil industry. The production of okra in sub-Saharan Africa (SSA) and globally are hindered by a lack of improved cultivars with drought tolerance. Considerable phenotypic and genotypic variation present in okra genetic resources from SSA is useful for cultivar design with enhanced pod and oil yields, and drought tolerance. However, the genetic diversity present in SSA's okra germplasm collection is yet to be explored for breeding targeting economic and horticultural traits. The objective of this review was to document the research progresses on phenotypic and genotypic divergence analysis and drought tolerance breeding of okra to facilitate breeding and conservation. The review presented the diversity of okra for key agronomic, horticultural and physiological traits for ideotype breeding, gene introgression and drought tolerance improvement. This is followed by key summaries on genetic diversity using conventional and genomic tools, and use of genetic variation in selection programs involving drought-adaptive and economic traits. The review serves as a baseline information to guide future okra breeding and cultivar design under water limited environments in SSA or related agro-ecologies. [ABSTRACT FROM AUTHOR]

• Several landraces of bambara groundnut (Vigna subterannea (L.) Verdc) exist in South Africa which are but, the most underutilized and un-researched legumes. • There is variations in the bambara groundnut landraces to the nodulation responses to a given species of rhizobium. • Bambara groundnut have promiscuous nodulation properties with different rhizobia species and host specificity rule does not apply for these legumes. • Bambara groundnut exhibit more symbiotic interaction with Rhizobia species belonging to the cowpea miscellany group. Bambara groundnut (Vigna subterranea) is one of the most underutilized and neglected legume crop used for human consumption worldwide. Unlike the common food and forage legumes, the symbiotic properties of this legume have not been studied sufficiently. This study is designed to investigate the nodulation compatibility and symbiotic performance of twelve landraces of V. subterranea with five different Rhizobia species isolated from the nodules of other legumes under glasshouse conditions. Pre-germinated seeds of each landrace planted in sterile river sand medium were inoculated with 108 cfu/ml of each rhizobium inoculum suspension and monitored with regular watering using nitrogen free Hoagland's solution for six weeks. The taxonomy and phylogeny of the five rhizobia species was determined using nucleotide sequence analysis of the 16S rRNA and recA (DNA recombination protein) genes. A concatenated multiple sequence alignment was used to construct an MLSA tree to further analyze the phylogeny of the strains. Significant differences were observed among individual bambara genotypes and rhizobia strains in terms of nodule numbers and dry weight, as well as plant biomass. Statistical analysis showed that Rhizobia strains XBD2 and XS34 identified as Bradyrhizobium zhangiangens and B. centrosematis respectively exhibited the highest nodulation compatibility in terms of nodule number and nodule dry weight with one or more bambara groundnut landraces. This study demonstrated that V. subterannea does not show preference to unique rhizobia, confirming that they are promiscuously nodulated by more than one species of rhizobium belonging mainly to the cowpea miscellany cross inoculation group. The findings of this study also provide insights into the selection and development of appropriate low cost rhizobia inoculants in the sustainable production of this underutilized legume for use by smallholder farmers in South Africa. [ABSTRACT FROM AUTHOR]