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Pollination and yield responses of cowpea (Vigna unguiculata L. Walp.) to the foraging activity of Apis mellifera adansonii (Hymenoptera: Apidae) at Ngaoundéré (Cameroon)
FT Fohouo, A Ngakou, BS Kengni
African Journal of Biotechnology , 2009,
Abstract: To determine the apicultural value of Vigna unguiculata (L.) Walp. (Fabaceae) and evaluate the Apis mellifera adansonii Latreille (Hymenoptera: Apidae) activity on its pod and seed yields, the bee foraging and pollinating activities were studied in Ngaoundéré. The experiment was carried out within the University of Ngaoundéré Campus on 210 flowers differentiated in two lots, based on the protection/or not of plant inflorescences against insect visits. The bee’s seasonal rhythm of activity, its foraging behaviour on flowers, the fructification rate, the number and dry weight of seeds/pod, the percentage of normal seeds/pod, and the pod length were evaluated. Results show that A. m. adansonii foraged on plants throughout the whole blooming period. Worker bees intensively and preferably harvested nectar. The greatest mean number of workers foraging simultaneously was 500 per 1000 flowers. The mean foraging speed was 8.67 flowers/min. These findings allow the classification of V. unguiculata as a highly nectariferous bee plant. The number and dry weight of seed/pod, the pod length and the percentage of normal seeds/pod from unprotected flowers were significantly higher than those of flowers protected from insects. The fructification rates were 62 and 48%, while the percentages of healthly seeds were 97.61 and 76.17%, respectively in unprotected and protected inflorescences. The installation of A. m. adansonii colonies close to V. unguiculata field could be recommended to improve its pods and seeds production in the region.
Effectiveness and efficiency of chemical mutagens in cowpea (Vigna unguiculata (L.) Walp)
D Dhanavel, P Pavadai, L Mullainathan, D Mohana, G Raju, M Girija, C Thilagavathi
African Journal of Biotechnology , 2008,
Abstract: A study was undertaken in a cowpea (Vigna unguiculata (L.) Walp.) variety CO 6 to assess the efficiency and effectiveness of chemical mutagens; ethyl methane sulphonate (EMS), diethyl sulphate (DES) and sodium azide (SA). EMS treatments were found highly effective than the other chemicals. Mutagenic effectiveness and efficiency decreased with increase in all mutagenic treatments.
Response of Cowpea (Vigna unguiculata L. Walp.) to Water Stress and Phosphorus Fertilization
V.G. Uarrota
Journal of Agronomy , 2010,
Abstract: This study was conducted in the experimental college of agriculture and forestry, in Maputo-Mozambique, in order to evaluate the response of cowpea (Vigna unguiculata L. Walp.) to irrigation and phosphorus and test the hypothesis that high levels of phosphorus improves the tolerance of plants to water stress. We used a variety IT 18 of cowpea, short cycle and ended. The experiment was subdivided into building plots complete block design with five repetitions, the irrigation factor was fixed at the main plot with two levels (with irrigation and without irrigation) and phosphorus factor in sub-plots with 3 levels (0, 20 and 40 kg ha-1 of phosphorus). The fertilization strongly influenced the yield and the number of pods per plant in both irrigation conditions. The effect of fertilizing phosphorus was higher under irrigation. The interaction was significant only for grain yield and number of pods, which means that the effect of phosphorus in these two variables has not been the same for the two levels of irrigation, high levels of phosphate fertilizer (P2O5) have improved the tolerance of cowpea when not irrigated.
Symbiotic functioning and bradyrhizobial biodiversity of cowpea (Vigna unguiculata L. Walp.) in Africa
Flora Pule-Meulenberg, Alphonsus K Belane, Tatiana Krasova-Wade, Felix D Dakora
BMC Microbiology , 2010, DOI: 10.1186/1471-2180-10-89
Abstract: Field measurements of N2 fixation revealed significant differences in plant growth, δ15N values, %Ndfa and amounts of N-fixed between and among the 9 cowpea genotypes in Ghana and South Africa. Following DNA analysis of 270 nodules from the 9 genotypes, 18 strain IGS types were found. Relating nodule function to the 18 IGS types revealed significant differences in IGS type N2-fixing efficiencies. Sequencing the 16S - 23S rDNA gene also revealed 4 clusters, with cluster 2 forming a distinct group that may be a new Bradyrhizobium species. Taken together, our data indicated greater biodiversity of cowpea bradyrhizobia in South Africa relative to Botswana and Ghana.We have shown that cowpea is strongly dependant on N2 fixation for its N nutrition in both South Africa and Ghana. Strain IGS type symbiotic efficiency was assessed for the first time in this study, and a positive correlation was discernible where there was sole nodule occupancy. The differences in IGS type diversity and symbiotic efficiency probably accounts for the genotype × environment interaction that makes it difficult to select superior genotypes for use across Africa. The root-nodule bacteria nodulating cowpea in this study all belonged to the genus Bradyrhizobium. Some strains from Southern Africa were phylogenetically very distinct, suggesting a new Bradyrhizobium species.Cowpea (Vigna unguiculata L. Walp.) is a major food crop in Africa, where its leaves, green pods and grain are eaten as a dietary source of protein. The cowpea grain contains about 23% protein and 57% carbohydrate, while the leaves contain between 27 - 34% protein [1]. The leaves and grain are also supplied as high protein feed and fodder to livestock. Cowpea is the most commonly grown food legume by traditional farmers in Sub-Saharan Africa, possibly because of its relatively wide adaptation to drought and low-nutrient environments. Cowpea freely forms root nodules with some members of the Rhizobiaceae such as Rhizobium and Bradyr
Physiological and biochemical responses of cowpea (Vigna unguiculata (L.) Walp) to ozone
Chanin Umponstira,Warin Pimpa,Suckaluck Nanegrungsun
Songklanakarin Journal of Science and Technology , 2006,
Abstract: The aim of this research was to investigate physiological and biochemical responses of cowpea (Vigna unguiculata (L.) Walp) to ozone. There were two main factors of the experiment; level of ozone concentration at 40 and 70 ppb and plant ages at 7 and 21 days. Plants were grown in fumigation chambers in which inlet air was filtered by a charcoal filter. Additional ozone was given 8 hours/day for 7 days in ozone fumigating chambers. The ozone concentration in the control chambers was less than 10 ppb. The results showed the biomass of ozone-fumigated plants was significantly lower and leaf injury of ozone fumigated plants was significantly greater compared to the control group. The major visible-injury symptom appeared as chlorosis on the upper surface of the leaves. Antioxidant levels in the charcoal filtered (CF) plants and ozoned plants had significant differences because of their detoxification role in removing ozone and its derivatives. The ozone treatment of 7-day-old plants showed superoxide dismutase (SOD), catalase (CAT) and ascorbate peroxidase (APX) levels significantly higher than in 21-day-old plants and total ascorbate concentrations significantly lower than 21-day-old plants. These results showed that different ozone concentrations exhibit different effects on antioxidant production. Analysis of antioxidants daily for 7 days found that antioxidant levels rapidly changed. Notably, SOD and total ascorbate could be selected as indicators for ozone-effect monitoring in plants. This indicates that cowpea is sensitive to ozone and may be usable as an ozone bioindicator. In conclusion, plant age, ozone concentration and the duration to exposure to ozone were the main physiological or biochemical responses of cowpea. An efficient defense system was generated from a combination of antioxidants.
Comparison of Some Cowpea (Vigna unguiculata L. Walp)  [PDF]
Erkut Peksen,Cengiz Artik
Journal of Agronomy , 2004,
Abstract: In this study, six cowpea genotypes from different locations in Turkey (Dalbah e, Doganca, Duragan, Igdir, Kirazlik 1 and Kirazlik 2) and two registered cultivars (Akkiz-86 and Karag z-86) as control were compared for their seed yield and yield related characters during 2002 and 2003 years. In addition, correlation and path coefficients between seed yield per plant and yield related characters were determined. The highest seed yields per hectare were obtained from Kirazlik 2 (1120.9 kg ha-1), Doganca (1093.1 kg ha-1), Duragan (1078.6 kg ha-1), Kirazlik 1 (1066.6 kg ha-1), Dalbah e (993.6 kg ha-1) and Igdir (922.1 kg ha-1). Seed yields of Akkiz-86 and Karag z-86 were highly significantly lower than the other genotypes. Karag z-86 was the superior for seed yield per plant (10.70 g plant-1). This followed by Doganca (8.27 g plant-1) and the rest of the genotypes were not statistically different from each other for seed yield per plant. Pod length and 100 seed weight showed a positive and highly significant correlation with seed yield per plant. Path analysis results revealed that pod length had the highest direct positive effect on seed yield per plant, followed by 100 seed weight and pods number per plant. On the other hand, seed yield per plant was directly and negatively affected by first pod height and branches number per plant.
Antioxidant Activity of the Extracts of Some Cowpea (Vigna unguiculata (L) Walp.) Cultivars Commonly Consumed in Pakistan  [PDF]
Muhammad Zia-Ul-Haq,Shakeel Ahmad,Ryszard Amarowicz,Vincenzo De Feo
Molecules , 2013, DOI: 10.3390/molecules18022005
Abstract: The present investigation has been carried out to determine the antioxidant activity of the methanolic extracts obtained from four cultivars of cowpea ( Vigna unguiculata (L) Walp.) seeds. Phenolic compounds present in the extracts showed the antioxidant and antiradical properties when investigated using a linoleic acid peroxidation model, FRAP, ORAC and TRAP assays, as well as DPPH, hydroxyl, nitric oxide and superoxide radical scavenging activity. The HPLC analysis of the cowpea extracts showed the presence of neochlorogenic acid, chlorogenic acid and caffeic acids. The results indicated that methanolic extract of the cowpea resembled in the aforementioned activities those from other leguminous seeds and pulses. Phenolic constituents contained in cowpea may have a future role as ingredients in the development of functional foods.
Genetic diversity in cowpea [Vigna unguiculata (L.) Walp.] varieties determined by ARA and RAPD techniques
La ty Fall, Diaga Diouf, Mame Arama Fall, Fran ois Abaye Badiane, Mamadou Gueye
African Journal of Biotechnology , 2003,
Abstract: Cowpea, Vigna unguiculata (L.) Walp. presents phenotypical variabilities and in order to study the genetic diversity of cultivated Senegalese varieties, two experimental approaches were used. First, a physiological characterization based on nitrogen fixation was used to assess cowpea breeding lines. Inoculation with two Bradyrhizobium strains (NGR234 and ISRA312), showed a difference in nitrogen fixation potential between the cowpea varieties. Diongoma is the highest nitrogen fixing variety, whereas Mouride is the lowest. The second approach employed genetic characterization based on DNA polymorphism to screen. Results suggest that random amplified polymorphic DNA (RAPD) technology can be used to reorganize the national germplasm in order to eliminate the putative duplicates, and to identify elite varieties. (African Journal of Biotechnology: 2003 2(2): 48-50)
Multiple shoot induction from embryo derived callus cultures of cowpea (Vigna unguiculata l.) Walp
OI Odutayo, FB Akinrimisi, I Ogunbosoye, RT Oso
African Journal of Biotechnology , 2005,
Abstract: The production of whole plant of cowpea (Vigna unguiculata) L. Walp from calli is an efficient, reliable and rapid strategy. This provides a faster method of micro propagation. Seeds of the pea were surface sterilized, and then the embryo axes were dissected and germinated. Callus growth was induced on the cut surface of the embryo of V. unguiculata. Root development in the cells was promoted by the action of the auxin, naphthalene acetic acid (NAA), at low cytokinin concentration. After five weeks, multiple shoots ranging from two to four developed from the calli cultures after being subcultured on media with high concentration of cytokinin, benzylaminopurine (BAP). Percentages shoot production from calli grown on media with 1 mM concentration of BAP was 45.5% while calli subcultured on 4 mM BAP produced 87.5% shoot production. Percentage rate of survival was between 21-26% in the hardened transplanted plantlets.
Plants regeneration from African cowpea variety (Vigna unguiculata L. Walp.)
MS Diallo, A Ndiaye, M Sagna, YK Gassama-Dia
African Journal of Biotechnology , 2008,
Abstract: Vigna unguiculata (L.) Walp. plant was efficiently regenerated from cotyledonary node explants. The shoots multiplication rate was influenced by the presence or the absence of cotyledons. Explants with two entire cotyledons from 5-6-d-old seedling produced the greater number of shoots (8.30) after two weeks on B5 medium supplemented with 1 mg.l-1 BAP. Shoots elongation is optimal on media supplemented with kinetin. Rooting is improved after an induction phase on half strength MS, producing 95.83% of rooted plants. No confined atmosphere surrounding plantlets is essential for survival during acclimatization. The regenerated plants flowered and produced pods and viable seeds.
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