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Bioactivity of Powder and Extracts from Garlic, Allium sativum L. (Alliaceae) and Spring Onion, Allium fistulosum L. (Alliaceae) against Callosobruchus maculatus F. (Coleoptera: Bruchidae) on Cowpea, Vigna unguiculata (L.) Walp (Leguminosae) Seeds  [PDF]
Abiodun A. Denloye
Psyche , 2010, DOI: 10.1155/2010/958348
Abstract: Laboratory bioassays were conducted to investigate the bioactivity of powders, extracts, and essential oils from Allium sativum L. (Alliaceae) and A. fistulosum L. (Liliaceae) against adults, eggs, and larvae of Callosobruchus maculatus F. (Coleoptera: Bruchidae). On the basis of 48?hr median lethal toxicity ( L C 5 0 ), test plant powders and extracts from A. sativum were more toxic to C. maculatus adults than those from A. fistulosum. The 48?hr L C 5 0 values for the powder against the test insect species were 9.66?g/kg and 26.29?g/kg for A. sativum and A. fistulosum, respectively. Also the 48 hr L C 5 0 values obtained show that aqueous extracts of the test plant species, 0.11?g/L (A. sativum) and 0.411?g/L (A. fistulosum) were more toxic to C. maculatus than the corresponding ethanol extracts. There was no significant difference in the toxicity of vapours from the two test plant species against C. maculatus, although A. sativum gave lower values. The study shows that A. sativum and A. fistulosum have potentials for protecting stored cowpea from damage by C. maculatus. 1. Introduction Grain storage has often resulted in quantitative and qualitative losses due to physical, chemical, and most importantly biological factors such as pests which may be birds, rodents, fungi, or insects [1–3]. The most important among storage pests are insects because apart from their direct damage they create conditions that allow secondary infestation by rot organisms mainly fungi [1, 4]. Once infestation is established pest insects cause gradual and progressive damage leading to losses in weight, nutritional, organoleptic, and aesthetic quality of stored grains. Osuji [1] listed 40 insects affecting stored grains, the most important among which is the cowpea weevil, Callosobruchus maculatus F. (Coleoptera; Bruchidae) responsible for up to 100% infestation of cowpea, Vigna unguiculata (L.) Walp (Leguminosae) during storage [1, 3, 5]. These observations justify the control of insect pests like C. maculatus in order to reduce losses in stored cowpea. Several methods are used in controlling insects in stored grains, including physical (smoking, sun-drying, heating), cultural, biological (male insect sterilization, natural enemies, resistant grain varieties), and chemical (synthetic and natural products) methods. The most common and widely used is the chemical method involving mainly the use of synthetic insecticides. Several workers have reported the successful wide scale use of synthetic organic insecticides, commencing with the organochlorines in the middle 1940s,
The resistance of seeds of cowpea (Vigna unguiculata) to the cowpea weevil (Callosobruchus maculatus)
Xavier Filho, J.;
Memórias do Instituto Oswaldo Cruz , 1991, DOI: 10.1590/S0074-02761991000600019
Abstract: cowpea (vigna unguiculata) seeds are heavily damaged during storage by the bruchid callosobruchus maculatus. seeds of some nigerian varieties showed a strong resistance to this bruchid. by utilizing biochemical and entomological techniques we were able to rule out the paticipation of proteolytic enzyme (trypsin, chimotrypsin, subtilisin and papain) inhibitors, lectins, and tannins in the resistance mechanisms. fractionation of the seed meal of a resistant variety suggests that the factor(s) responsible for the effect is (are) concentrate in the globulin fraction.
Floral Biology and Pollination Ecology of Cowpea (Vigna Unguiculata L. Walp)  [cached]
Ige, O. E.,Olotuah, O.F,Akerele, V.
Modern Applied Science , 2011, DOI: 10.5539/mas.v5n4p74
Abstract: Studies on the floral biology and pollination ecology of three varieties of cowpea (Vigna unguiculata L. Walp) were carried out. The varieties studied were Var. Oloyin, Var. Sokoto, and Var. Drum. Cowpea is a self pollinated crop which is encouraged by the arrangements of the floral parts. However, Insects visiting cowpea flowers have been implicated in the movement of pollen from one cowpea plant to another. Flower opening of cowpea begins between 6:00am and 6:30am and closes between 11:30am and 12:00pm. Pollen analysis showed similarities in the pollen morphology of the cowpea varieties. Moreover Var. Drum produced the highest number of pollen grains per flower in terms of pollen productivity.
Assessment of genetic diversity in cowpea (Vigna unguiculata)
R.M.Nagalakshmi, R. Usha Kumari and M. B. Boranayaka
Electronic Journal of Plant Breeding , 2010,
Abstract: Sixty six genotypes of cowpea (Vigna unguiculata (L.) Walp) were investigated to understand the extent of genetic diversitythrough twelve quantitative traits. Mahalanobis’s D2 analysis established the presence of wide genetic diversity among thesegenotypes by the formation of 23 clusters. Cluster I had the maximum number of genotypes i.e 22 and cluster 23 had onlyone genotype. Intra cluster distance analysis revealed that the minimum intra cluster distance was observed in the cluster II.The inter-cluster distance (D) was found to be the maximum between the clusters XXII and XXIII and the same wasminimum between clusters II and V. The results indicated that grain yield per plant contributed maximum to the totaldivergence followed by 100 seed weight and days to 50% flowering. Number of branches per plant had least contribution tothe total divergence followed by petiole length. The existence of wide genetic diversity among the types chosen from thesame geographical location was obviously seen. In the present study, the variety Vellayani local had the maximum value forplant height and pod length and thereby distinguished from other varieties and it is present singly in the cluster XXIII. Henceit is proved to be widely divergent, since its yield is high, it can be used for further crossing and yield improvement. Thecluster XVIII had the highest cluster mean values for number of clusters per plant and the cluster XIV has the highest meanvalue for grain yield per plant. These two clusters may be utilized in crossing programme which may yield in a widespectrum of variability and for selection for seed yield in the subsequent generations. The clustering pattern of the varietiesin the present study clearly indicated that there was no parallelism between genetic and geographic diversities. Based on themean performance and genetic divergence, the genotypes Vellayani local, NBC 7, Lola, CP 18, CP 150, ACM 05-07 can beused for crossing and further selection.
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.
Moisture and Planting Density Interactions Affect Productivity in Cowpea (Vigna unguiculata)
G. Lemma,W. Worku,A. Woldemichael
Journal of Agronomy , 2009,
Abstract: The aim of this study was to examine the effects of planting density and inter-row spacing on cowpea (Vigna unguiculata L. Walp.) productivity at two contrasting moisture regimes. A field experiment was conducted under controlled moisture conditions during the 2007 off-season, at Hawassa University, College of Agriculture, Southern Ethiopia. Treatments were made from a factorial combination of four densities (71428, 95238, 133333 and 200000 plants ha-1), two inter-row spacings (50 and 70 cm) and two levels of water regimes (well watered and dry). The experiment was laid out in a split- split plot design and had three replications with watering regime, inter-row spacing and planting density as main plot, sub-plot and sub-sub-plot factors, respectively. Grain yield and all yield attributes, total biomass and harvest index were decreased by water limitation while none of those traits were significantly affected by inter-row spacing. Moisture x planting density interaction was significant for grain yield ha-1, number of pods m-2 and total biomass ha-1. The interaction indicated that an increase in both grain and total biomass yield ha-1 was observed with increasing planting density under the wet regime. Grain yield plateau was reached at a density of 160000 plants ha-1 under the wet regime. On the other hand, an increase in planting density decreased grain yield and total biomass ha-1 under the water-limited condition with the highest yield at the lowest density of 71428 plants ha-1. Thus, farmers could get more out of cowpea by matching their planting density with available moisture. The two inter-row spacings can be used interchangeably by choosing whichever is convenient for management.
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