Search Results (98)

This study evaluated the suitability of three floodplain environments near Iquitos for cowpea cultivar recommendations and estimated the adaptability and phenotypic stability of 12 cowpea lines evaluated in 2004. Climatic conditions between 2004 and 2020–2024 were also compared. Three field trials used a randomized complete block design with 12 lines and two replications, assessing grain yield, number of pods per plant, days to flowering, days to 50% maturity, and days to harvest. Combined Analysis of Variance (ANOVA), Duncan’s means test, Genotype + Genotype Environment Interaction (GGE) biplot, and Additive Main Effects and Multiplicative Interactions Interaction (AMMI) analyses revealed that the three sites are contrasting. The Annicchiarico index, GGE biplot, and AMMI analyses identified line CAR 3010 as having superior adaptability and stability. Paired t-tests and Mann–Kendall analyses showed that climatic conditions in 2020–2024 differed significantly from 2004. Therefore, Muyuy, Rafael Belaunde, and San Miguel are suitable locations for testing advanced cowpea lines prior to cultivar recommendation. Line CAR 3010 is recommended for breeding programs in the Peruvian Amazon in response to ongoing climate change. This research addresses a critical knowledge gap as the first study evaluating cowpea adaptability and stability across multiple floodplain locations in the Peruvian Amazon. Full article

Seed priming has become a promising technique in agriculture and crop-stress management. Several authors have shown that the positive effects of seed priming are associated with various metabolic, physiological, and biochemical modifications (enzyme activation, membrane repair, initiation of DNA/RNA, and protein synthesis) that enhance the speed, uniformity, and vigor of germination. However, the mechanisms underlying seed priming are not yet well understood. The aim of our work was to study the quantitative and qualitative metabolic changes in the embryonic axes (radicle and plumule) and cotyledons of Vigna unguiculata (L.) Walp. Seeds were subjected to osmopriming with polyethylene glycol (PEG), simple hydropriming, and double hydropriming (a novel treatment). Results indicated that all types of priming, particularly double hydropriming, strongly stimulated the hydrolysis of protein and carbohydrate reserves. This resulted in a decrease in soluble proteins and starch contents and an increase in amino acids and soluble sugars contents. Moreover, the priming promoted the biosynthesis of osmolytes such as proline and induced qualitative changes in the composition of amino acids and soluble sugars. These biochemical changes depend on the organ and treatment method applied to the seeds. It is worth noting that double hydropriming induces metabolic modifications to a greater extent than single hydropriming. Full article

Cowpeas are prone to abiotic (heat and drought) and biotic (pathogens and insect pests) stresses, with the former representing the predominant challenge, causing poor growth and reduced yield globally under changing climatic conditions. Cowpea can synthesize phytochemicals to respond to these stresses; however, there is limited information on the impact of weather on phytochemical biosynthesis in the cowpea phyllosphere. Phytochemical profiles were determined via chromatographic and spectrophotometric analyses of leaf samples from six cowpea varieties grown during 2020–2021. A total of 10 fatty acid methyl esters (FAMEs) and 62 diverse metabolites were identified across varieties and seasons, with higher levels in 2020 under elevated temperatures and rainfall. The Queen Anne (QA) variety exhibited the maximum concentration of elaidic oleic acid (cis + trans), behenate, lignocerate, methyl laurate, and methyl palmitate (with the highest concentration at 258.415 µg/mL), and the Whippoorwill Steele’s Black (WP) variety predominantly exhibited diverse phytochemicals with high peak areas during 2020, including phenolic acids, phytohormones, alkaloids, flavonoids, and amino acids. While higher overall increases were observed in 2020, some compounds and varieties peaked in 2021, including FAMEs in the Colossus (CL) variety and other phytochemicals in QA. Flavonoid, flavone, and flavonol biosynthesis; phenylalanine metabolism; and tyrosine metabolism were significantly affected, leading to the accumulation of metabolites. Understanding plant–climate interactions will help farmers with variety selection and planting decisions. This study suggests that further research on the temperature mechanism for the biosynthetic pathways of these metabolites in the screened cowpea varieties is required. Full article

Biological nitrogen (N) fixation is a well-established practice in various legumes, such as soybeans. However, it has not been widely studied in cowpeas (Vigna unguiculata L. Walp). In this context, it is important to understand how the application of nitrogen-fixing bacteria, either alone or in association, can benefit the crop’s nitrogen demand. This study aimed to determine whether co-inoculation of Bradyrhizobium and Azospirillum favors nodulation and isoflavone production, and increases the nitrogen content, in cowpea crops. The experiment was set up using a randomized block design on two cowpea varieties, with seven treatments consisting of a control and the isolated application of Bradyrhizobium japonicum and Azospirillum brasilense, as well as different co-inoculation doses (75, 150, 225 and 300 mL per 50 kg of seed for each inoculant). There were four replications. Thirty days after emergence, the number of nodules and the dry masses of the nodules, roots and shoots of the plants were assessed. N content and isoflavone content in the fully developed third trifoliate leaf from the apex of the plants were also assessed. Statistical differences were observed between treatments for all analyzed variables, with higher values generally observed for co-inoculation treatments. Co-inoculation of B. japonicum and A. brasilense in cowpea seeds can be a viable and efficient practice. A dose of 75 mL of each inoculant favored nodule formation, root development and N content, as well as contributing to isoflavone production in the cowpea crop. Full article

The cowpea (Vigna unguiculata (L.) Walp.) is well adapted to high temperatures, water deficits and low fertility soils, being widely cultivated in regions less favorable to common beans. Its grains are rich in proteins, vitamins and minerals, representing an important food source and a promising alternative for producing protein at low cost, in a short space of time, given the precocity of its cycle. However, in the state of Minas Gerais there is only a recommendation for one cowpea cultivar, the Poços de Caldas cultivar. In addition to being quite old, it is no longer found in crop production fields. Our objective was to provide local farmers with new cultivar options that exhibit high yield potential, appropriate plant architecture for mechanized cultivation, and superior grain health and quality. The experiments were conducted in Passos city, Brazil, during the second cropping season of the 2021, 2022, and 2023 years. Ten commercial cowpea cultivars were assessed in a randomized block design with five replications, considering morphophysiological traits and phytotechnical yield components. Treatment effects were analyzed using the Scott-Knott test, a statistical method that compares treatments and identifies significant differences among them. The thousand-seed weight and grain index showed a positive correlation with grain yield. The least productive cultivars had the longest pods and, consequently, the highest number of grains per pod. The 2022 and 2023 years provided the most favorable morphophysiological conditions for cowpea cultivation, which significantly enhanced productivity. Among the tested cultivars, BRS Xique-Xique, BRS Novaera, BRS Tumucumaque, and BRS Pajeú were the most suitable for a second cropping season cultivation in the Southwest region of Minas Gerais, while BRS Marataoã, BRS Itaim, and BRS Rouxinol were the least. We emphasize the need for further studies to support the establishment and expansion of cowpea cultivation in this region. Full article

Cowpea (Vigna unguiculata L. Walp.) is a species with superior tolerance to drought stress compared to other legumes. It is a promising crop with increasing importance in the face of global climate changes. Local forms, well adapted to particular agro-climatic conditions, are useful germplasm resources. Five Bulgarian cowpea landraces, which had displayed differences in osmotic stress tolerance at the germination stage, were subjected to severe stress (15% PEG 6000 in Hoagland nutrient media) during 16 days at the vegetative growth stage (plants with expanded trifoliate leaves). All local forms responded to the imposed stress by biomass and leaf area diminution, a slight increase in leaf water deficit and electrolyte leakage, proline accumulation in roots and leaves, and an increase in root starch and leaf phenol content. Roots presented more pronounced metabolic changes than leaves, including increased total antioxidant activity, phenolic and carbohydrate content, and proline accumulation. Under osmotic stress, tight control of oxidative stress and concerted upregulation of superoxide dismutase, catalase, glutathione transferase, and peroxidase activities in leaves were registered along with changes in certain specific isoforms, while glutathione reductase activity diminished. Antioxidant enzyme activities had different changes in stressed roots, compared to leaves, and among genotypes. The accession most sensitive to osmotic stress at germination presented more symptoms of oxidative stress at the vegetative growth stage. Full article

Induced mutation plays an integral part in plant breeding as it introduces new variability among the population. A study was conducted in cowpeas [Vigna unguiculata (L.) Walp] to assess the yield divergence, heritability, genetic advance, and correlation among the M5 Tswana cowpea mutants. The experiment utilized seven genotypes under rainfed and supplementary irrigation during the 2022/23 and 2023/24 cropping seasons. The mutant lines demonstrated significant variations in days to 50% emergence (DE) and days to 50% flowering (DF). Tswana emerged earlier (5–7 days) and flowered in 21–54 days across the two seasons, compared to some of the mutant lines. The yield and yield components varied among some mutant lines and the control. Most importantly, mutants outperformed the Tswana control for some of these traits, indicating potential for genetic improvement. An analysis of genetic parameters revealed minimal environmental influences on some of the observed traits (GH, PN, GY), while others showed little environmental impact. Variation in heritability (H²) and genetic advance (GA%) between the two seasons limited the contribution of genotypic effects in the expression of the studied traits. Correlation analysis revealed strong and significant positive associations between DE and GH, as well as between DF and PW. Most traits, except DF and PW, were positively correlated with grain yield (GY), although the correlations were not significantly different. Cluster analysis grouped the genotypes into four distinct clusters. Principal component analysis (PCA) revealed the superiority of mutant lines (Tswana-300Gy-214, Tswana-400Gy mutant lines, and Tswana-500Gy-31) in their association with improved GY, pod weight (PW), 100-seed weight (100-SW), and seed number per pod (SN/P). Interestingly, the Tswana control formed a separate cluster and diverged from the mutants in PCA, suggesting that induced mutagenesis effectively targeted genes controlling the traits considered in this study. Full article

Cowpea (Vigna unguiculata [L.] Walp) is a vital food security crop in sub-Saharan Africa, including Eswatini. The productivity of the crop is low (<600 kg/ha) in the country due to a lack of improved, locally adapted, and farmer-preferred varieties with biotic and abiotic stress tolerance. The objective of the study was to assess the agronomic performance of newly developed elite cowpea mutants to select best-yielding and adapted pure lines for production and genetic improvement in Eswatini. A total of 30 cowpea genotypes, including 24 newly developed advanced mutant lines, their 3 founder parents and 3 local checks, were profiled for major agronomic traits in two selected sites (Lowveld Experiment and Malkerns Research Stations) using a 6 × 5 alpha lattice design with three replications. A combined analysis of variance revealed that the genotype x location interaction effects were significant (p < 0.05) for germination percentage (DG %), days to flowering (DTF), days to maturity (DMT), number of pods per plant (NPP), pod length (PDL), number of seeds per pod (NSP), hundred seed weight (HSW), and grain yield (GYD). Elite mutant genotypes, including NKL9P7, BRR4P11, SHR9P5, and NKL9P7-2 exhibited higher grain yields at 3158.8 kg/ha, 2651.6 kg/ha, 2627.5 kg/ha, and 2255.8 kg/ha in that order. The highest-yielding mutant, NKL9P7, produced 70%, 61%, and 54% more grain yield than the check varieties Mtilane, Black Eye, and Accession 792, respectively. Furthermore, the selected genotypes displayed promising yield components such as better PDL (varying from 13.1 to 26.3 cm), NPP (15.9 to 26.8), and NSP (9.8 to 16.2). Grain yield had significant positive correlations (p < 0.05) with DG %, NSP, and NPP. The principal component analysis (PCA) revealed that 81.5% of the total genotypic variation was attributable to the assessed quantitative traits. Principal component (PC) 1 accounted for 48.6%, while PC 2 and PC 3 contributed 18.9% and 14% of the overall variation, respectively. Key traits correlated with PC1 were NPP with a loading score of 0.91, NSP (0.83), PDL (0.73), GYD (0.68), HSW (0.58), DMT (−0.60), and DTF (−0.43) in a desirable direction. In conclusion, genotypes NKL9P7, BRR4P11, SHR9P5, NKL9P7-2, Bira, SHR3P4, and SHR2P7 were identified as complementary parents with relatively best yields and local adaptation, making them ideal selections for direct production or breeding. The following traits, NPP, NSP, PDL, GYD, and HSW, offered unique opportunities for genotype selection in the cowpea breeding program in Eswatini. Full article

The genus Vigna Savi (Leguminosae Juss.) comprises approximately 150 species, classified into five subgenera, most of which exhibit a diploid chromosome number of 2n = 22. However, the wild species Vigna lasiocarpa (Benth) Verdc. (V. subg. Lasiospron) is notable for its dysploid chromosome number of 2n = 20. This study aimed to elucidate the chromosomal events involved in the karyotype evolution of V. lasiocarpa (Vla). We used oligopainting probes from chromosomes 1, 2, 3, and 5 of Phaseolus vulgaris L. and two barcode probes from the genome of V. unguiculata (L.) Walp. Additionally, bacterial artificial chromosomes (BACs) from V. unguiculata and P. vulgaris, along with a telomeric probe from Arabidopsis thaliana (L.) Heynh., were hybridized to V. lasiocarpa metaphase chromosomes to characterize Vla3, Vla7/5, and Vla9. Our findings revealed conserved oligo-FISH patterns on chromosomes 2, 6, 8, 10, and 11 between V. unguiculata and V. lasiocarpa. Paracentric and pericentric inversions were identified for Vla3 and Vla9, respectively. Our integrative approach revealed that the dysploid chromosome originated from an “end-to-end fusion” of homoeologous chromosomes 5 and 7. This is the first report on the chromosomal mechanisms underlying descending dysploidy in Vigna, providing new insights into the evolutionary dynamics of the genus. Full article

Despite the fact that cowpea is one of the most drought-tolerant legumes, some genotypes with a high yield under well-watered conditions have been shown to be susceptible to drought stress, thus requiring further improvement. The objectives of this study were to conduct a genome-wide association study (GWAS) for drought tolerance in cowpea. A total of 331 cowpea genotypes were evaluated for drought tolerance. After SNP filtering, 5,884,299 SNPs were used to conduct GWAS using BLINK. The results showed: (1) a significant GWAS peak defined by a cluster of 196 significant SNPs and mapped on a 210 kb region of chromosome 5 was identified to be a good locus candidate for tolerance to trifoliate leaf chlorosis under drought stress in cowpea, (2) a strong GWAS peak was found towards the end of chromosome 1 and this peak was a good candidate locus for tolerance to unifoliate leaf chlorosis under drought stress in cowpea, and (3) a total of 25 SNPs located on chromosomes 1, 3, 5, and 11 were significantly associated with plant greenness under drought stress. This study provides a better understanding of the molecular genetics of drought tolerance in cowpea and the findings can be expanded to other crop species. Full article

Cowpea (Vigna unguiculata (L.) Walp.) is a vital legume crop recognized for its nutritional value and adaptability to various growing conditions. However, exposure of cowpea to drought stress during the early growth stages can significantly restrict growth and yield potential. Therefore, identifying cowpea genotypes tolerant to drought during early growth and development is essential for maintaining yield potential. This study characterized 15 diverse cowpea genotypes for various physiological, pigment, and morphological traits that may contribute to drought tolerance. At the V2 stage, the cowpea genotypes were subjected to two moisture regimes: control (100% irrigation) and drought (50% irrigation) for 22 days to assess trait responses and their relationship to drought tolerance. Drought-stressed plants decreased stomatal conductance by 79%, negatively correlating with a 2.9 °C increase in canopy temperature. Under drought, the photochemical reflectance index (PRI) was strongly associated with the quantum yield of PSII and electron transport rate. Shoot biomass decreased by 51% and root biomass by 32% under drought. Leaf area and shoot weight were correlated with root traits such as total length, surface area, and weight. Among all genotypes, 280785-11 and UCR 1004 demonstrated superior rooting vigor under drought, emphasizing their efficiency in resource utilization. These findings highlight the relevance of utilizing drought-adaptive traits to improve early-season drought tolerance. Full article

Soil salinity is one of the most severe impacts of climate change, negatively affecting plant growth and development. Seed germination and seedling emergence are among the most critical stages susceptible to salt stress, making it important to explore them to identify the most resilient accessions for crop yield improvement. Cowpea (Vigna unguiculata L. Walp.) is an important crop due to its ability to fix atmospheric nitrogen, improving soil health, and its high protein content. The main objectives of this study were to screen salt-resilient cowpea accessions from a worldwide collection and to evaluate cowpea responses to salt stress at germination stage through gene expression analysis. A total of 40 cowpea accessions from sixteen different countries were subjected to two treatments: control (water) and salt stress (150 mM NaCl solution). The seeds germinated, and the seedlings grew for ten days. The germination and growth parameters and lipid peroxidation quantification were determined. The results revealed significant differences in all parameters among accessions and treatments. A high variation in salt responses was detected among accessions, allowing the selection of five accessions (Co_2, Co_4, Co_21, Co_30, Co_31) as resilient to salt stress at germination stage. Subsequently, two salt stress-related genes (DREB2 and VuEXO) were evaluated through qPCR, revealing genotype-dependent regulation. These results provide valuable insights for the early selection of salt-resilient cowpea accessions, which may be considered for the development of improved and new varieties in the future. Full article

Biochar is a multifunctional tool that enhances soil quality, with particularly positive effects on acidic soils with low nutrient content, common in tropical regions worldwide, such as in the Amazon region in Brazil. This study investigates the effects of açaí fruit waste biochar (Euterpe oleracea Mart.) amendment and phosphate fertilisation on the chemical characteristics of a Ferralsol and on the biological components of cowpea (Vigna unguiculata (L.) Walp). In a greenhouse setting, a randomised block design was employed, testing five doses of biochar (0, 7.5, 15, 30, and 60 t ha⁻¹) combined with four doses of phosphorus (P) (0, 40, 80, and 120 kg ha⁻¹), resulting in 20 treatments with three replicates and 60 experimental units. Cowpea responded to inorganic fertilisation, with lower doses of P limiting the biological components (height, leaves, leaf area, dry biomass, and dry root mass). Higher doses of biochar and P increased the soil’s available P content by up to 2.3 times, reflected in the P content of cowpea dry biomass. However, this increase in biochar and P levels led to a maximum increase of 7.7% in agronomic phosphorus efficiency (APE) in cowpea in the short term. The higher doses of biochar promoted increases in pH value, cation exchange capacity (CEC), and the contents of potassium (K), calcium (Ca), and total nitrogen (N). In contrast, a decrease in magnesium (Mg) and aluminium (Al) levels was observed, while the concentration of easily extractable glomalin (EE-GRSP) was not significantly affected during the evaluated period. We conclude that biochar altered the soil environment, promoting the increased solubility and availability of phosphorus. Full article

To face climate change, searching for alternative crops resistant to drought and heat stress becomes necessary, along with efficient germplasm management. Old landraces well-adapted to local climatic conditions, pests, and pathogens could be used as a source of desired traits. Cowpea (Vigna unguiculata L. Walp.), grown mainly in the tropical and subtropical areas, presents superior drought and heat stress adaptation compared to other legumes. Limited information is available on field performance and nutrient qualities of cowpea landraces originating from southern Bulgaria. The aim of the present study was to compare in field conditions and their impacts on plant performance, yield, and the seed biochemical composition of Bulgarian cowpea accessions, including fourteen landraces and one variety. Higher-yielding, earlier-maturing accessions were discerned. Among the landraces studied, B1E0103 was the most productive under the agro-climatic conditions in Sadovo, central Bulgaria; BOE0035 had the earliest maturity. The seed moisture content was 11.5 ± 0.3%, and the energy value was 347.9 ± 1.2 kcal/100 g. The crude protein content varied from 22.5 to 27%, the lipids were 1.6–2.55%, the carbohydrates were 56.5–61.4%, ash was 3.8–4.3%, dietary fibers were 3.1–4.5%, tannins were 16–22%, phenols were 1.3–4.4 mg/g, flavonoids were 1.85–3.7 mg/g, and the trypsin-inhibiting activity was 0.7–2.5 units/mg FW, with the lowest in BOE0010, the variety “Hrisi”, and B1E0103 and the highest in B0E0035, A9E1230, and A8E0562. Landraces are promising genetic material for future research and breeding purposes. Full article

Despite the high nutritional value of cowpea and its potential for sustainable farming, its cultivation is limited by the lack of vegetable varieties adapted to different soil and climatic conditions, which complicates the fight against food insecurity in many countries. Therefore, this study aims to conduct a comprehensive evaluation of cowpea (Vigna unguiculata (L.) Walp. subsp. sesquipedalis (L.) Verdc.) varieties with the aim of identifying genotypes with high productivity potential and resistance to the main adverse environmental factors of the Right-Bank Forest-Steppe of Ukraine. The experimental study was carried out in a three-year period (2014–2016). Depending on the variant of the experiment, cowpea germination was observed from 25 May to 30 May. The shortest sowing–shoot period (10 days) was observed in the variety ‘U-Tya-Kontou’ (China), with the longest (13 days) in the varieties ‘Kafedralna’ (Ukraine) and ‘American Improved’ (USA). In the control variant, shoots were obtained on 28 May. Flowering started from 9 July to 16 July; technical maturity (unripe (green) beans) started from 27 July to 2 July; and biological maturity of the seeds started from 30 August to 5 September. For the variety ‘American Improved’, the shortest period of seedling–technical maturity (unripe (green) beans) (58 days) and seedling–biological maturity (92 days) was recorded. By cultivar, the maximum plant height was achieved with varieties ‘Groik’ (Israel) at 100.5 cm and ‘Gasson’ (Vietnam) at 61.8 cm, which are 52 cm and 13.3 cm more than the control height. They differ by the quick growth of the main and side shoots, which allows them to be grown on supports. The highest yield of green beans was recorded in the cowpea variety ‘Gasson’ at 14.4 t∙ha⁻¹, which is 38.5% higher than the control. In the variety ‘Groik’, the yield of green beans (11.4 t∙ha⁻¹) did not differ significantly from the control (‘Kafedralna’—10.4 t∙ha⁻¹). The varieties ‘U-Tya-Kontou’ and ‘American Improved’ were characterized by the lowest yield of green beans, which reached 5.8 and 4.2 t∙ha⁻¹, respectively, which is 44.2 and 59.6% less than the control. As a result of statistical analysis of cowpea yields, the limits of its fluctuation were established as follows: fluctuations in the sum of effective temperatures by 10 °C (>10 °C) contributed to a deviation in green bean yields from 20.0 to 24.7 kg (ha)⁻¹, and fluctuations in precipitation by 10 mm contributed to a deviation in green bean yields in the range from 34.3 to 208.2 kg (ha)⁻¹. The results of the study presented in this article have practical application for the development of effective methods of growing local varieties of long-stemmed cowpea, which will increase yields and meet the needs of both farmers and consumers in regions with similar climatic conditions. Full article