Cowpea (Vigna unguiculata) is a highly nutritious, drought tolerant crop with several agronomic advantages over other legumes. This study demonstrated the association of different cowpea phenotypes with specific phenolic profiles, antioxidants activity, anti-inflammatory properties on non-malignant colonic (CCD18co) cells challenged with a lipopolysaccharide (LPS), and the effect of boiling on their individual and total flavonoid content. Only the black and green phenotypes had detectable anthocyanins; and their levels were highest in the black IT95K-1105-5 variety. The red cowpea phenotypes had the highest level of flavonols (858 - 941 micrograms/g cowpea flour) and white Early Acre variety had the least. Quercetin derivatives were the major flavonols detected, followed by myricetin derivatives. Monomeric, dimeric and polymeric procyanidins also made up a large proportion of cowpea phenolics. The light brown 09FCV-CC27M cowpea variety had the highest average flavan-3-ol content (13,464 micrograms/g cowpea flour); whereas white and green varieties did not contain detectable levels of flavan-3-ols. Thus, seed-coat color was a good indicator of the accumulation of specific flavonoids in cowpeas. The black, red and light-brown cowpeas had the highest antioxidant activity measured by ORAC and ABTS methods, correlating with their higher total phenol content (TPC) and condensed tannin content (CTC); whereas the white and green varieties had the least. Boiling significantly affected the phenolic profiles, TPC and CTC of all cowpea varieties studied, as well as the antioxidant activity associated with these compounds. The net reduction in antioxidant activity after boiling was less than the net TPC reduction, indicating that the heat-induced phenolic products may still have radical scavenging capacity. Overall, proinflammatory genes regulation, intracellular ROS inhibition, and modulation of miR-126 and its target gene VCAM-1 by cowpea were found to be dependent on cowpea variety, phenolic composition and concentrations. The underlying mechanism by which cowpea induced miR-126 may be associated with inhibition of ROS and down-regulation of transcription factor NF-These results emphasize the importance of the cancer inhibitory potential of phenolic compounds from cowpea and their possible role in preventing anti-inflammatory disorders. Further in vivo studies with cowpea diets are required to validate their clinical relevance to human health.

Thesis (Ph.D.(Botany))--University of Pretoria, 2003. / Includes bibliographical references.

The responses of two cowpea (Vigna unguiculata (L.) Walp.) cultivars inoculated with granular inoculum (a mixture of rhizobia) at different levels of applied nitrogen were evaluated. California Blackeye 5 (Ca5) and Knuckle Purple Hull (KPH) cowpeas were examined under field conditions for percent nodulation, nodule number, and nodule mass per plant, and nitrogenase activity at various times during the 1983 and 1984 growing seasons. Data were also obtained for shoot and root dry weights, seed yield, and protein content. Significant differences between inoculated and uninoculated plots were found at all nitrogen treatments for both cultivars with respect to nodulation percentage, nodule number, nodule mass, and nitrogenase activity. An inverse trend linear and quadratic was noted between nitrogen increments and nodulation (nodule number and nodule mass) of Ca5 and KPH cowpeas. High N (168 kg N ha('-1)) was more inhibitory to nodulation than low (28 kg N ha('-1)) N applied. Nitrogenase activity of both cultivars was significantly stimulated with low and inhibited by high levels of ammonium nitrate. Effects of nitrogen treatments on nodulation and nitrogenase activity were influenced by the stage of growth and cowpea cultivar. At the pod-fill stage, higher nodule numbers and nitrogenase activity were recorded for Ca5 as compared to KPH cowpeas. Morphological differences, with Ca5 plants being erect with few vines, whereas KPH plants were semi-erect and bushy, were observed between inoculated and uninoculated plants of Ca5 and KPH cowpeas at all levels of applied nitrogen. Dry weights of vegetative components of both cultivars were significantly improved when low (28 kg N ha('-1)) rather than high (168 kg N ha('-1)) nitrogen was added. Inoculation significantly increased seed yield of Ca5 cowpeas. When conditions were favorable seed yield of inoculated Ca5 exceeded that of inoculated KPH in all comparisons within the same increments of applied N. Seed yield of both cultivars was adversely affected when high levels of nitrogen were applied. Seed, leaf, petiole, and stem protein content were significantly higher with respect to inoculated than uninoculated plots. However, nitrogen fertilizers tended to decrease protein content of the measured parameters for Ca5 and KPH cowpeas.

Thesis (Ph.D.)(Food Science))--University of Pretoria, 2006. / Includes bibliographical references. Available on the Internet via the World Wide Web.

Cowpea is a worldwide-distributed crop, and is important to the livelihood of poor people in developing countries. Cowpea is also susceptible to a wide range of pests and pathogens, which can cause damage to the crop at all stages. Seedling diseases caused by pathogens such as Rhizoctonia solani Fusarium solani and Pythium spp. affect cowpea and result in low yields especially in rural areas where there are few or no control measures against these pathogens. This research aimed at evaluating the efficacy of a biological control agent and fungicides against fungal seedling diseases of cowpea. The bacterium, Bacillus cereus1, and the fungicides, Apron®, Subdue® and Celest® were screened for the control of cowpea seedling diseases, after obtaining promising in vitro results on their effectivity against Rhizoctonia solani, Pythium ultimum and Fusarium solani. The experiment was conducted in a greenhouse using seedling trays with 128 cells, each filled with pasteurised growing medium (Braaks lawn dressing). Seedling trays were placed randomly on greenhouse tables with four replication per treatment, each replication consisting of 56 plants. Cowpea seeds (Cultivar-Pietersburg blue) were obtained from the Dry Bean Seeds Producers Organisation. The pasteurised growing medium was artificially inoculated with the three fungi. Two plugs of actively growing fungal mycelium of the three pathogens were inoculated in each cell of the polystyrene seedling trays. Trays were drenched with Bacillus cereus1 at 106 cells/ml (3 ml per tray cell) at planting and fungicides were applied on the 14th and 28th days at the recommended rate. The experiment was conducted at temperatures ranging from 22-25 oC. Plants were harvested on the 35th day after planting and percentage germination, diseased height of the plants and dry mass of roots and shoots were determined. Results indicated that the biological control agent (B. cereus1) was able to significantly reduce the damage done by the pathogens Rhizoctonia solani, Pythium ultimum and Fusarium solani in all trials. It was also confirmed that the application of the biological control agent during planting could reduce disease incidence. The biological control agent increased seed emergence rate and shoot length. All three fungicides significantly reduced the disease incidence caused by all pathogens. All fungicides treatments applied increased emergence rate and shoot length. Seedling diseases should be given too much attention, as they cause severe losses to many crops. There is a need for future research on the effectivity of B. cereus1 as relatively little work has been published on its antagonistic behaviour against seedling diseases. There are also few registered fungicides available for the control of these seedling diseases on cowpea, therefore research on these and other potential products is required as seedling diseases play a major role in reducing yield of many crops. / Dissertation (MInstAgrar)--University of Pretoria, 2008. / Microbiology and Plant Pathology / unrestricted

The purpose of this research problem is to determine the chemical composition of the blackeyed pea and to make a comparative study of the results. The value of the blackeyed pea as food, its chemical nature, and possible industrial uses are studied and recorded.

Characterization studies on the genetic diversity among cultivated cowpea (Vigna unguiculata (L.) varieties are valuable tools to optimize the use of available genetic resources by farmers, local communities, researchers and breeders. Eight cowpea (Vigna unguiculata (L.) genotypes ( Vegetable cowpea, Ivory grey, Okhalweni, Fahari, Fahari dark, 97K-1069-8, IT93K-73h, and 129-3) were subjected to molecular, morphological and agronomical characterization. DNA amplification fingerprinting markers were used to evaluate the genetic diversity among the eight genotypes. Nine random arbitrary primers were used to screen the eight genotypes to assess their ability to reveal polymorphisms in cowpea, and seven of them were selected for use in characterizing the total sample. A total of 43 bands were generated which are all polymorphic. On the average, the primers generated a total of 6.1 polymorphic bands. The resulting data-matrix included 43 analysed bands with a total of 344 characters. Neighbour joining analysis was used to generate the dendrogram, clustering the genotypes into two groups at an agglomerate coefficient of 0.30 irrespective of their geographical origins. The results also showed the presence of significant differences in morphological and quality traits among the genotypes. Fahari yielded the highest concentration of crude protein (46.51 mg/mg dry leaf) while Vegetable cowpea yielded the lowest (24.41 mg/mg dry leaf). The influence of manure was also found to be effective by increasing the crude protein content of the genotypes as shown by Fahari dark with an average of 53.53 mg/mg dry leaf as opposed to 39.85 mg/mg dry leaf without manure application. Although some small clusters grouped accessions of the same growth habits, a general lack of agreement between clustering and morphological features was observed. It can therefore be concluded that the significant differences between the molecular genetic analysis using DAF-PCR markers, morphologic characters and yield traits can be important tools to identify and discriminates the different cowpea genotypes.

Thesis (M.Sc. (Agricultural Agronomy)) --University of Limpopo, 2015 / Refer to document / Department of Agriculture Forestry and Fisheries (DAFF)

Thesis (M.Sc. Agriculture (Agricultural Economics)) -- University of Limpopo, 2019 / Agriculture plays a significant role also serves as a critical economic sector in Limpopo province in terms of its contribution to the economy, and the number of employment opportunities it produces within local communities. The majority of people involved in agricultural practices are emerging farmers and smallholder/small scale farmers. These farmers try to earn a living from the production of livestock, broilers, fruits & vegetables, and cereals. Cowpea is a drought-tolerant legume that also serves as a staple food for the majority of Africans alongside maize and other typical staple foods consumed by most Africans. The crop is regarded as a key protein source for urban and rural poor, and plays an important role as a cash crop. Despite several nutritional benefits, economic importance and welfare enhancing potential of cowpea, farmers still do not have sufficient information on knowledge about the value that can be added to their cowpea production also the potential and competitiveness of this traditional leafy vegetable. The aim of the study was to map the value chain and determine the marketing efficiency of smallholder cowpea farmers in Capricorn and Waterberg districts of Limpopo province. The specific objectives were to: identify and describe socioeconomic characteristics of smallholder cowpea farmers in Capricorn and Waterberg districts of Limpopo province, identify and define the participants along the cowpea value chain and identify marketing constraints among smallholder cowpea farmers. Structured questionnaire was used to collect data from 80 smallholder cowpea farmers in Ga-Molepo of Capricorn district and Bela-Bela of Waterberg district using purposive sampling technique. Value chain mapping, descriptive statistics and binary logistic regression model were used in addressing the objectives. In identifying and defining the participants along the cowpea value chain, a value chain map was constructed to show the different stages cowpea goes through before reaching the final consumer. Two null hypotheses were formulated. The first hypothesis that stated smallholder cowpea farmers were inefficient in marketing cowpea was rejected. Marketing efficiency measure used to determine each farmer’s marketing efficiency revealed that 66% of smallholder cowpea farmers were efficient. The determinants of marketing efficiency were examined using binary logistic regression model. The second hypothesis stated that socioeconomic characteristics of smallholder cowpea farmers have no effect on the marketing efficiency. The v hypothesis was also rejected based on binary logistic results that revealed that age, household size, years in schooling, years in farming cowpea, income generated from selling cowpea, quantities of cowpea sold and occupation of the farmers were found to be significant in determining marketing efficiency of smallholder cowpea farmers. Pests, lack of access to formal markets and lack of information on how to process cowpea were major constraints farmers were faced with. It was recommended that value chain analysts, policy makers and extension workers together with other stakeholders assist in ensuring that food value chain relationships are established so that market opportunities can be created for smallholder cowpea farmers. In addition, farmer schools need to be introduced in rural areas were agricultural practices are dominant. At these schools, farmers can be taught about basic knowledge relating to agricultural production. Training should also be given to farmers on adopting technology as it can potentially assist in making production more efficient. / Water Research Commission (WRC)

Water Stress caused reduction of seed yield in cowpea plants by decreasing total biomass and photosynthesis. The source leaf, pod and seed water potential of stressed cowpea were lower than water potential in non-stressed plants. No differences in water potential and turgor were observed between pod walls and seed of cowpea plants. Partitioning of the total above ground dry matter was similar for both stressed and nonstressed cowpea plants. Photosynthetic rates of single leaves from cowpea were greater for nonstressed than stressed plants. The duration of seed growth of cowpea was not different between stressed and nonstressed plants; however, rate of seed growth at the end of seed filling period was greater in nonstressed plants. Seed growth rate of both stressed and nonstressed cowpea plants declined at about the same time photosynthesis of the source leaf declined. Leaf area index was greatest in nonstressed cowpea.