Biocontrol of Aspergillus flavus Strains Isolated from Bambara Groundnut (Vigna subterranea (L.) Verdc.) Seeds Using Essential Oils of Lippia multiflora Moldenke, Ocimum americanum L. (Lamiaceae) and Eucalyptus cameldulensis Dehnh

In nature, plant extracts play a crucial role in defending plants against biotic and abiotic stressors. Moreover, the use of plant-based products, such as plant extracts, represents a promising alternative to synthetic fungicides, which pose potential health risks to consumers. In this study, the antifungal activity of the essential oils (EOs) of Lippia multiflora, Eucalyptus camaldulensis and Ocimum americanum was evaluated against two strains of Aspergillus flavus via the agar dilution method. These two Aspergillus flavus fungi was isolated from Bamabra groundnut seeds. Lippia multiflora essential oil (EO) showed the best results compared with the other oils, with a minimum inhibitory concentration (MIC) of 9000 μg∙mL−1. The MIC for Eucalyptus camaldulensis and Ocimum americanum EOs was 10,800 μg∙mL−1. In view of their antifungal properties, these EOs could be used to develop a new, safe antifungal agent for food preservation.

Enhancing the Productivity and Sustainability of Bambara Groundnut (Vigna subterranea (L.) Verdc.) Production Using Inorganic Phosphorus Fertilizer

Phosphorus (P) is a vital element required for nodulation, stomatal regulation and photosynthesis in legume crops. P-deficiency in tropical soils limits the growth and productivity of Bambara groundnuts. The current study focused on determining the potential suitability of underutilized crops for food security using phosphorus fertilizer as soil amendment practice. A field trial was carried out at the Council for Scientific and Industrial Research—Crops Research Institute (CSIR-CRI), over two growing seasons to determine the optimum P rate for Bambara production. This trial was laid out in a split plot in a randomized block design with three replications. Bambara genotypes represented the main plots while four P fertilizer rates (0, 30, 45 and 60 kg P2O5 ha-1) were the sub-plots. The appropriate application rate of 60 kg P2O5 ha-1 showed excellent performance based on growth and yield analysis, and the results indicate a positive significant interaction between landraces and phosphorus fertilizer rates. The biological suitability of 60 kg P2O5 ha-1 increased the number of nodules per plant for Tiga Necuru, Kenya Capstone and Nav Red by 42.8%, 51.3% and 42.1% respectively, over control plots. The same for pod yield is 12%, 28% and 52% significantly higher than when P was applied at 45, 30 and 0 kg P2O5 ha-1 respectively. The results further revealed that on days to flowering and maturity, the plant height, the number of branches and dry matter increased significantly at each level of P fertilizer rate applied. Bambara production at 0 kg P fertilizer rate might not be sufficient to enhance Bambara productivity significantly. The outcome of this study reveals the suitability of phosphorus fertilizer application in enhancing the sustainability of Bambara groundnut productivity and the potential of Bambara in diversifying crop production to ensure food security.

Alectra vogelii: A Threat to Bambara Groundnut Production under Climate Change: A Review Paper

Bambara groundnut (BGN) is a protein-rich pulse with the ability to lead to more climate-resilient agriculture. The objective of this study was to review Alectra vogelii as a potential threat to BGN production as a result of climate change. However, the crop faces biotic and abiotic stresses. Alectra vogelii is a major biotic constraint to BGN production, especially in Africa’s non-fertile semi-arid regions. Alectra vogelii (L.) Benth is a parasitic weed in the Orobanchaceae family that causes major damage by forming haustoria attached to roots to enable absorption of nutrients from the BGN. Alectra vogelii produces a large number of minute seeds that can live in the soil for up to 20 years. Based on the reviewed literature, various control mechanisms for dealing with the harmful effects of Alectra vogelii have been proposed. The aim of this research was to reveal the effect of Alectra vogelii on BGN and possible control strategies. We discuss the different control methods such as cultural and mechanical management procedures, phosphorus fertilizers and resistant host crops, herbicide use, and integrated Alectra vogelii control methods. In adaptive methods, however, new techniques remain important. The life cycle of root parasitic weeds is inextricably linked to that of their host, making it an ideal target for such new control techniques, especially when aimed at the early stages of the host-parasite relationship. This review reveals additional information on the function of parasitic seed, strigolactones and how they can be used in breeding to management parasitic weeds.

Characterization of Seed Storage Proteins in Eight Bambara Groundnut Landraces in Burkina Faso

The Bambara groundnut Vigna subterranea (L.) Verdc. is a drought-resistant indigenous African grain legume with significant nutritional and agronomic potential. This study aimed to characterize the seed storage proteins of eight Bambara groundnut landraces. Seeds of Bambara groundnut landraces were collected from local markets in Burkina Faso, and total soluble protein as well as protein fractions were extracted. Crude protein content was determined by the Kjeldahl method, and soluble proteins were quantified using Bradford dye binding assay. The average crude protein content of the seeds was found to be 18.46%, with variations ranging from 17.69% to 19.17% among the different landraces. Most of the protein content was soluble, constituting approximately 87.04% of the total crude protein. Albumin fraction was the most dominant, representing about 95.42% of the total soluble proteins. The globulin, prolamin and glutelin fractions accounted for 1.82%, 0.13% and 1.17% of the soluble proteins, respectively. The findings provide valuable insights into the protein composition of Bambara groundnut landraces and contribute to our understanding of its nutritional potential, laying the groundwork for further research on crop improvement and sustainable agriculture practices.

Physiological Resilience of Bambara Groundnut (Vigna subterranea L. Verdc) Genotypes to Intermittent Periods of Drought Stress at Different Growth Stages

Different genotypes of Bambara groundnut (Vigna subterranea L. Verdc) grow well under conducive environmental conditions, provided that adequate soil moisture is available during vegetative and reproductive phases. However, drought stress is the major limiting factor to bambara production, which accounts for up to 40% of yield losses. This situation could worsen due to drastic and rapid changes in the global climate. Landraces grown by farmers are low-yielding. Understanding the physiological response of different genotypes to drought stress is key to achieving food security through crop improvement and diversification. This study focused on variations in the response of Bambara groundnut genotypes to intermittent drought stress during the crop’s critical growth (vegetative and reproductive) stages. The experiment was undertaken at CSIR-Crops Research Institute Screen-house. The treatments were used in a factorial experiment with three replications in a randomized complete block design. The Bambara genotypes showed considerable variability in tolerance to drought stress. Drought stress during vegetative and reproductive stages significantly reduced crop growth indices, the leaf relative water content, chlorophyll content and leaf area. Drought stress during vegetative and reproductive stages had a more severe impact on the seed yield of genotype Nav Red, reducing it by 69% and 13%, respectively. Farmers should pay more attention to adopting drought-tolerant and high-yielding varieties for improved Bambara groundnut productivity and livelihoods.

Resistance to Abiotic Stress and Effectiveness of Native Rhizobia on Bambara Groundnut [Vigna subterranea (L.) Verdc.] in Benin

Bambara groundnut [Vigna subterranea (L.) Verdc.], as a legume, can establish relationships with nitrogen-fixing bacteria such as Rhizobium. However, Rhizobium efficacy is not always optimal due to the lack or poor efficient strains in the soil. This study aimed to evaluate symbiotic efficiency of endogenous Rhizobia nodulating Bambara groundnut and their resistance to abiotic conditions. Root nodules were randomly sampled from three agroecological zones across the country, surface sterilized, ground and paste plated on YEMA media. After 24 hours, the bacterial colonies were purified. The pure cultures were further characterized using morphological and biochemical methods and their resistance to antibiotics and heavy metals was evaluated. Lastly, the symbiotic efficiency of the isolates was assessed through a greenhouse experiment. A total of eighty-five presumptive strains were isolated from Bambara groundnut roots nodules obtained from the farms. The physiological characterization of the isolated showed a decrease in isolates growth when NaCl concentration was more than 7%. In addition, 47% of the isolates were tolerant to a temperature of 40°C. Most of the isolates were highly resistant to Erythromycin in all its concentration levels and to Kanamycin, Spectinomycin, Neomycin and Ampicillin at 10 μg⋅mL−1. Most of them showed resistance to Cu and Zn at 10 μg⋅mL−1. Results of the effectiveness test on two Bambara groundnut varieties yielded dry shoot matter varying from 3.33 g⋅plant−1 to 7.21 g⋅plant−1 for variety 1 and from 4.38 g⋅plant−1 to 8.38 g⋅plant−1 on variety 2. N uptake ranged between 0.09 g⋅plant−1 and 0.29 g⋅plant−1 for variety 1 and between 0.12 and 0.29 g⋅plant−1 for variety 2. The isolates yielding higher shoot dry weight and N uptake were LMSEM312, LMSEM338, LMSEM307, LMSEM351 for variety 1 and LMSEM338, LMSEM309, LMSEM307 for variety 2. The isolates showing better performance can be used to develop bio-fertilizer for sustainable Bambara groundnut production in Benin.

Influence of Cross-Inoculation on Groundnut and Bambara Groundnut-<i>Rhizobium</i>Symbiosis: Contribution to Plant Growth and Yield in the Field at Sarh (Chad) and Ngaoundere (Cameroon)

In the context of sustainable research aiming at improving seed yield and maintaining soil fertility, a study on cross-inoculation of groundnut (Arachis hypogaea L.) and Bambara groundnut (Vigna subterranean (L.) Verd.) with rhizobia strains from four crop legumes was carried out at Sarh (Chad) and Ngaoundere (Cameroon). The experiment was conducted in each site following a randomized complete block design with 6 treatments known as the control, and 5 cross-inoculation formulations (RA, RN, RS, RV and MR), each of which was replicated thrice. Results obtained show that cross-inoculation contributed to the improvement of growth (plant sizes and biomasses) of the two crop legumes, as well as their seed yield at harvest. The enhanced yield expressed in kg/ha varied from 9.83% to 63.73% for groundnut and 72.71% for Bambara groundnut. These findings suggest that groundnut and Bambara groundnut do have a symbiotic affinity with rhizobia from other crop legumes. Whereas Groundnut, Cowpea, Soybean, Bambara groundnut rhizobia (GR, CR, SR, BR) alone, and the fourth in a mixture (RM) could be used to help improving groundnut seed yields;this mixture would not be indicated for intensive cultivation of Bambara groundnut later.

Impact of <i>Cowpea mottle virus</i>on the Growth and Yield of Bambara Groundnut (<i>Vigna subterranean</i>(L.) Verdc.)

Bambara groundnut [Vigna subterranean (L.) Verdc] is a food legume with high potential for food security in Sub-Saharan Africa. However, in addition to being a neglected crop, its production is limited by several constraints among which viral diseases are most cited. In order to contribute to the improvement of Bambara groundnut in Burkina Faso, local accessions of the crop were screened for resistance to Cowpea mottle virus (CPMoV), one of the most damaging viruses in grain legumes. Seven local accessions (C1 to C7) from two agro-ecological zones were evaluated by mechanical inoculation in field conditions in 2016 and 2017. The infected plants exhibited various symptoms of chlorosis, leaf deformation, growth retardation and plant stunting. CPMoV caused a significant reduction in the number of flowers and pods. As a result, grain yield was reduced by 49.5% to 83.9% depending on the accessions. The impact of the virus in yield loss was lowest in accessions C6 and C7 which indicated their possible used in the management of Cowpea mottle virus disease in bambara groundnut.

Molecular Characterization of a Large Diversity of Bambara Groundnut Potyviruses (<i>Vigna subterranea</i>(L.) Verdc.) in Burkina Faso

Potyviruses are major constraints to grain legume production by causing significant yield losses. Potyviruses infecting Bambara groundnut (Vigna subterranea) were investigated in Burkina Faso. Leaf samples collected from three agroclimatic zones were subjected to RT-PCR and sequence analyses. Of a total of 135 samples, 36 (26.67%) were detected positive in RT-PCR tests using potyvirus universal primers. Analysis of full coat protein (cp) sequences from 24 isolates revealed the occurrence of three groups of Bambara groundnut-infecting potyviruses. Virus isolates in group 1 shared 94.5% - 100% nucleotide (nt) identity with CABMV whereas those in group 2 and group 3 were distantly related Bean common necrosis virus (BCMNV) and Passiflora virus Ugandan which were their respective closest potyviruses. Group 2 shared 77.1% nt and 78.8% - 79.9% aa identity with BCMNV and group 3 shared 77.3% - 78.3% nt and 80.7% - 81.5% aa identity with Passiflora virus Ugandan. All three groups were confirmed by phylogenetic analyses. Taking into account potyvirus demarcation criteria, group 1 isolates belonged to CABMV species. Group 2 and group 3 were assigned to a potentially new potyviruses species and designated Bambara groundnut potyvirus 1 (BGPV1) and Bambara groundnut potyvirus 2 (BGPV2).

Attenuation of oxidative stress and hepatic damage by some fermented tropical legume condiment diets in streptozotocin-induced diabetes in rats

Objective:To investigate the modulatory effect of fermented legume condiments diet on oxidative stress in streptozotocin(STZ) induced diabetic rats.Methods:Adult male Wistar rats were randomly divided into six groups with six animals in each group.Diabetes was induced by intraperitoneal injection of STZ(35 mg/kg b.w.).After being confirmed diabetic,the rats were fed with fermented Bambara groundnut.Locust bean and Soybean diets for 14 days.The plasma was obtained after 14-day treatment and analyzed for hepatic damage marker enzymes(AST,ALT and ALP) and in vivo antioxidant indices.Results:The diabetic untreated rats showed elevated (P【0.05) levels of AST,ALT.ALP and malondialdehyde with reduced activities of glutathiones -transferase,catalase as well as plasma reduced glutathione,vitamin C and total protein content.However,treatment of diabetic rats with lermenled legume condiments diets for 14 days significantly(P【0.05) reversed the above parameters towards normalcy,suggesting their modulation of oxidative stress,which mav be due to their high phenolic content and antioxidant capacity.Conclusions:The attenuation of oxidative stress and protection of hepatic tissue damage by the legume condiment diets in STZ induced diabetic rats compare favourably with that of metformin,a well known oral hypoglycemic drug.