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1
Hamzat, Kadri Obafemi. "A semi-mechanistic model based on oil expression from groundnuts." Thesis, Cranfield University, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.333986.
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Kasanda, Ednah. "Gender and decision-making in agriculture: a case study of groundnuts farmers in Zambia." Thesis, Kansas State University, 2017. http://hdl.handle.net/2097/35785.
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Master of Agribusiness<br>Department of Agricultural Economics<br>Vincent R. Amanor-Boadu<br>Zambia’s government and its development partners continue to be challenged with how to adequately address the seeming gender inequity in Zambia’s agricultural sector. Women in Zambia’s agricultural sector face challenges in accessing resources and opportunities that could enhance their welfare. In addition, cited inequitable distribution of power in decision-making have been assumed to hamper women’s ability to enhance their own economic wellbeing. Therefore, understanding the factors that influence women’s
decision-making in agriculture and how these factors contribute to their wellbeing can provide insights into how to develop programs that help improve their economic wellbeing.
This thesis assessed the decision-making and production activities by women in Zambia’s agriculture using the groundnuts subsector as a case study. It used data from the nationally representative Rural Agricultural Livelihood Survey 2015 (RALS15), drawing a sample of rural groundnut farmers and employed a statistical and econometric analysis to explore the relationships of specific factors on women in the groundnut subsector. The following are the key findings:
i. Women make up 38% of the producers in Zambia’s groundnuts subsector but accounted for 49% of the total number of people controlling groundnut selling decisions. Women accounted for 48% of the total people controlling how income from groundnut sales are used. These distributions would challenge the prevailing perception that women have a decreasing control over decision-making as one moves from production to utilization of the income from production, at least in the case of the groundnut subsector in Zambia’s agricultural sector.
ii. The factors influencing women’s control over production include the gender of the household head, region, affiliation to women’s groups, distance between the homestead and extension service access point, distance between the homestead and the field plot, the woman’s education and household’s production assets. For example, a percentage increase in the distance to field plot reduced the women’s control by one-seventh of a percent. Similarly, the more educated the woman is, the less their control over groundnut production is.
iii. Furthermore, groundnut commercialization did not seem to influence female control over production.
The foregoing challenges some of the conclusions from previous research regarding women’s control over production decisions. It is possible that the position of groundnuts in Zambian agriculture could be an explanatory factor the results. However, it was not tested. Therefore, it is suggested that future studies explore the relationship between the crop and the empowerment women experience from its production.
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Magoke, Godfrey Zakayo. "Assessing susceptibility of village chickens to aflatoxin exposure and contamination of village grains and village chicken products in Tanzania." Thesis, The University of Sydney, 2021. https://hdl.handle.net/2123/27405.
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A study was conducted in semi-arid Manyoni District, Central Tanzania, involving eight village communities to: 1) explore dietary and agricultural practices associated with aflatoxin risk; 2) assess aflatoxin contamination of village grains and groundnuts; and 3) assess village chicken susceptibility to aflatoxin exposure.
To address the respective objectives, 1) Questionnaires were asked to 76 adult respondents randomly selected from households enrolled in a project, 2) A screening test was used on grain and groundnut samples collected peri-harvest (n=134) and ≥ 6 months in storage (n=157), followed by HPLC test on samples contaminated ≥10 µg/kg, and 3) 16 day old village chicks, randomly allocated to four groups, were fed diet with average aflatoxins ranging to 27, 102, 110, 358 µg/kg respectively, for 60 days.
Most participating village farmers were naive to food toxins, with limited extension services, did not generally use irrigation, fertilisers and pesticides on crops, had inadequate harvesting, drying and storage techniques, and often consumed unpolished grains. Aflatoxin contamination of grains and groundnuts ranged to 198 µg/kg (mean=25.46 µg/kg) in post-harvest samples and 351 µg/kg (mean=50.83 µg/kg) in stored samples, above 10 µg/kg Tanzania MTL. Chronic exposure of village chickens to as low as 30 µg/kg aflatoxin containing feed was associated with organ lesions, low weight gain, low feed consumption, and low response to Newcastle disease vaccination.
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Boakye-Yiadom, Louis. "An Economic Surplus Evaluation of Aflatoxin-Reducing Research: A Case Study of Senegal's Confectionery Groundnut Sector." Thesis, Virginia Tech, 2002. http://hdl.handle.net/10919/30860.
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In international trade involving agricultural products, attempts to safeguard the health of humans, animals, and plants, have led to the imposition of sanitary and phytosanitary (SPS) standards. Due to the fact that groundnuts are susceptible to aflatoxin contamination, stringent aflatoxin standards have been imposed on groundnut trade by many developed countries. For Senegal and other groundnut exporters in the developing world, these aflatoxin standards pose a major challenge. As a result, in Senegalâ s confectionery groundnut sector, CIRAD (a French scientific organization) has commenced research aimed at developing an aflatoxin-reducing program. This study evaluates the potential economic impact of CIRADâ s aflatoxin-reducing program.
The hypotheses underlying the study are as follows:
(i) The adoption of CIRADâ s aflatoxin-reducing program would enhance the welfare of Senegalâ s confectionery groundnut farmers
(ii) An overall welfare net-gain would be derived by Senegal from the adoption of the program.
The analysis employs an economic surplus model that incorporates trade, as well as, domestic production and consumption. Various scenarios of program-effectiveness are examined. The results support the hypotheses of the study; besides enhancing farmersâ welfare, the adoption of the aflatoxin-reducing program is expected to yield an overall net-gain ranging between US$0.56 million and US$4.25 million. The overall net-gain is, however, very small.<br>Master of Science
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Gray, James Katon. "The Groundnut Market in Senegal: Examination of Price and Policy Changes." Diss., Virginia Tech, 2002. http://hdl.handle.net/10919/28143.
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The Government of Senegal is attempting to liberalize the groundnut market. In the past, this market was highly regulated with government-set producer prices, groundnut oil processing mills owned by parastatals, and requirements that all groundnuts be sold to these quasi-governmental organizations. In recent years, these rules are being relaxed, and farmers are allowed to sell groundnuts on the open market. However, farmers continue to sell most of their groundnuts, as before, to the mills.
This study attempts to shed light on the effects of this market liberalization. First, an attempt is made to provide estimates of the farmers' short-run output supply and input demand responses to price changes. A quadratic profit function model is estimated using data collected for the current study and a similar dataset collected by Akobundu [1997]. Second, a quadratic programming model is used to examine the effects of eliminating pan-territorial prices. Results indicate that the elimination of the pan-territorial price system will have an overall benefit to Senegalese society. However, as expected, groundnut producers in areas remote from the groundnut oil processing mills would face lower prices. The effects on producers and consumers in the major producing regions, however, were found to be minimal.
Finally, the dissertation provides an extensive description of the economic activities of small-scale farm households in Senegalâ s Groundnut Basin. Differences between males and females and between household heads and other males in the household are also examined. Although females are not as involved in groundnut production, they do not seem to face discrimination in either the official or the open market.
The description of the situation facing small-scale farmers provided in this dissertation is not encouraging. The quantity and timing of the rains in the Groundnut Basin add an unwelcome uncertainty to farming. Increases in population are adding pressure to the environment and are placing heavy demands on wood and grazing lands. Only eight percent of the farmers had groundnut seed multiplication ratios less than one, and sixty-seven percent had ratios less than five.
The dissertation also indicates that farmers are not producing enough to feed their families. Fewer than twelve percent of the households produce a caloric surplus. Sixty percent produced less than fifty percent of their caloric needs. The study indicates that farmers are not earning enough from agricultural production to take care of normal expenses throughout the year. Thus, when combined with uncertain rains and a worsening environment, the farmers have little margin of safety. Therefore, any government policies affecting groundnut production in particular or agricultural production in general should take into account the situation already facing the farmers.<br>Ph. D.
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Nolte, Kara. "Extruded sorghum and Bambara groundnuts : influence of in-barrel moisture conditions on functional and nutritional characteristics." Diss., University of Pretoria, 2017. http://hdl.handle.net/2263/60848.
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Protein-energy malnutrition (PEM) and micronutrient deficiencies remain burdens among children in Africa due to monotonous cereal-based diets. Compositing with local pulses such as bambara groundnuts can be a solution. Rapidly urbanising communities in Africa, however, demand convenience-type products. To address these needs, the nutritional, physical and functional properties of extrudates of decorticated sorghum and whole grain bambara groundnut flours extruded separately and as a 50:50 composite using a twin screw extrusion cooker was investigated. The effect of two in-barrel moisture conditions, low (24%) and high (40%), were studied. Compositing sorghum with bambara groundnuts increased crude fibre (190%), protein (54%) fat (36%) and mineral (118%) contents. Zinc, calcium and magnesium contents increased by 32, 52, and 11%, respectively with bambara groundnut inclusion. In vitro protein digestibility (IVPD) and nitrogen solubility index (NSI) increased substantially with bambara groundnut inclusion because bambara groundnuts' soluble globulin-type proteins are more digestible than sorghum kafirins. Extrusion cooking caused an increase in IVPD and decrease in NSI. Hot, moist conditions in extrusion cooking probably caused the denaturation of proteins which exposed hydrophobic sites of the protein molecule and exposed more sites for proteolytic attack. Extrusion cooking at high moisture yielded a slightly higher IVPD in composite extrudates and higher NSI in bambara groundnut extrudates, as shear and heat generation would be less severe, compared to low moisture. Phytate content was reduced (12-35%) in the composite and bambara groundnut extrudates after extrusion cooking at both extrusion moistures. Inositol hexaphosphate was possibly hydrolysed to penta- and tetraphosphates. Improved Caco-2 cell zinc uptake (80-84%) was achieved through both extrusion moistures in sorghum extrudates only, probably due to lower phytate x calcium/zinc ratios in sorghum when compared to the composite and bambara groundnut flours. Bambara groundnut inclusion reduced Caco-2 cell zinc uptake due to an increase in phytate content. High extrusion moisture and bambara groundnut inclusion decreased extrudate expansion in sorghum and the composite, probably due to lower viscosity in the extruder barrel and dilution of starch, respectively. High moisture conditions yielded higher overall water absorption index (WAI), lower overall water solubility index (WSI) and higher peak, trough and final paste viscosities, probably due to less starch degradation. Bambara groundnut inclusion caused increased WSI, probably due to its soluble proteins. It also caused lower peak, trough and final paste viscosities, possibly due to starch dilution.
A 50 g (db) serving of sorghum-bambara groundnut composite extrudate can contribute 81% of the daily protein requirement for children aged 2-5 years. Improved IVPD, WAI and paste viscosities for composite extruded at low moisture suggests its application as a nutrient-dense instant porridge. Extrusion cooking of the composite at low moisture also maintains high expansion which can produce a nutritious expanded snack. Sorghum-bambara groundnut composite extruded at low moisture can produce convenience-type products with improved mineral content and excellent protein content and digestibility to address PEM.<br>Dissertation (MSc)--University of Pretoria, 2017.<br>Food Science<br>MSc<br>Unrestricted
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Murevanhema, Yvonne Yeukai. "Evaluation of bambara groundnuts (Vigna subterrenea (L.) Verdc.) milk fermented with lactic acid bacteria as a probiotic beverage." Thesis, Cape Peninsula University of Technology, 2012. http://hdl.handle.net/20.500.11838/825.
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Thesis presented in partial fulfilment of the requirements for the degree
of
Master of Technology (Food Technology)
Department of Food Technology
Faculty of Applied Sciences
Cape Peninsula University of Technology, 2012<br>The aim of this study was to evaluate bambara groundnut milk (BGNM) subjected to fermentation with lactic acid bacteria (LAB) as a probiotic beverage with a view to developing value-added product. Central Composite Rotatable Design (CCRD) was used to optimise the hydration time and temperature of BGN flour for optimum BGN milk (BGNM) production. The optimum time and temperature was 2 h at 25oC. The effect of variety was assessed on the quality and consumer acceptability of BGNM prepared from five varieties of BGN (black, red, brown, brown-eye, and black-eye) which were representatives of the BGN available in South Africa. BGNM from the five varieties differed significantly (p<0.05) in, lightness, chroma, redness, yellowness, hue and antioxidative activity, while the pH were not significantly different. The four BGNM samples were significantly different (p < 0.05) in appearance, colour, mouthfeel and overall acceptability but not in aroma and taste. A three factor design (4 x 3 x 3) consisting of probiotics (Lactobacillus acidophilus, L. bulgaricus, L. casei and L. plantarum), temperature and fermentation time, were used to estimate the optimal conditions for the production of BGN probiotic beverage (BGNPB). The optimal condition for the production of BGNPB was estimated to be 35oC for 24 h with a desirability of 0.854 for L. bulgaricus. The next promising probiotic was L. plantarum that could be fermented at 35oC for 24 h with 0.843 desirability. BGNM from the red variety were fermented with L. bulgaricus and L. plantarum and L bulgaricus (in combination), making plain and sweetened BGNPB which were evaluated for their quality and consumer acceptability. The four BGNPB samples were significantly different (p < 0.05) in aroma, taste, mouthfeel and overall acceptability but not in appearance and colour. The plain BGNPB were assessed for their proximate composition, antioxidant activity, in vitro probiotic tolerance to simulated gastric juices and bile and a 28 days shelf life study at 5, 15 and 25oC. The protein, total dietary fibre (TDF), ash and antioxidative activity of the BGNPB were significantly different while the fat and carbohydrates were not significantly different. Time and concentration of the gastric juice and bile had significant effects on the percentage bacterial survival of probiotics in the BGNPB. However, the probiotics did survive, in low numbers, in the simulated gastric juice and bile after 180 and 240 minutes of incubation. Titratable acidity, pH, microbial load and colour of the BGNPB were
significantly affected by the storage time and temperature during the shelf life study. At the 5oC storage temperature the BGNPB had a right censored shelf life on day 28. At 15oC the shelf life was 18 and 10 days for L bulgaricus and L. plantarum and L. bulgaricus respectively. The outcome of this research showed that a novel BGNPB product can be made from fermenting BGNM with LAB.
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Appleby, Joelle Helen. "Biology of bruchid pests of stored bambara groundnuts (Vigna subterranea (L.)) : with special reference to imaginal polymorphism in Callosobruchus subinnotatus (Pic.)." Thesis, Royal Holloway, University of London, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.394944.
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Molosiwa, Ozie Odireleng. "Genetic diversity and population structure analysis of bambara groundnuts (Vigna subterranea (L.) Verdc.) landraces using morpho-agronomic characters and SSR markers." Thesis, University of Nottingham, 2012. http://eprints.nottingham.ac.uk/12736/.
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Bambara groundnut is an indigenous African legume grown mainly in sub-Saharan Africa; it is an important source of protein to the rural majority. There are no established varieties and subsistence farmers grow locally adapted landraces which are generally low yielding. Bambara groundnut is a predominantly self-pollinating crop and is expected to exist as non-identical inbred lines, although the previous lack of co-dominant markers has prevented a formal assessment of heterozygosity within bambara groundnut genotypes. A total set of 75 microsatellites that were characterised in this study were used to investigate the genetic diversity of a set of 24 bambara groundnut landraces, to provide an evaluation of the markers for polymorphism and provide a link with DArT marker data that were previously analysed. Sixty eight microsatellites were identified that were found to be consistent and reproducible, from which a set of markers were selected and used for genetic variability studies of bambara groundnut, to compare the use of molecular markers with morphological markers, and to investigate using SSR markers in pure line selection. The genetic diversity of bambara groundnut was assessed based on morphological characters for two seasons; in a glasshouse experiment at the University of Nottingham, Sutton Bonington Campus, UK and in a field experiment that was conducted at the Botswana College of Agriculture (Notwane farm), Gaborone in a randomised block design with three replicates. The landraces were characterised for 24 quantitative and 13 qualitative characters. The results indicated considerable variation for quantitative characters, while significant morphological differences were also recorded for most characters. Multivariate data analysis was conducted using principal component analysis, cluster analysis and heritability estimates were developed. The low cost, simplicity and agricultural relevance of morphological characterisation makes it an important tool in germplasm genetic variation studies. Thirty four lines from field experiments were investigated for genetic diversity based on 20 microsatellites. The expected heterozygosity (He) had an average of 1 in agreement with the fact that bambara groundnut is predominantly self-pollinating. Both cluster analysis and principle component analysis (PCoA) grouped landraces based mainly on their areas of origin. A thorough molecular analysis of genetic and morphological variation in bambara groundnut was conducted to investigate the relationship between the two assessment techniques. This comparison will assist in breeders making informed decisions as to which approach is best to use in germplasm characterisation and plant breeding and how best to apply such knowledge in practical situations. DNA markers could then aid with the selection of germplasm for breeding, quality control within breeding programmes and, potentially, direct selection via Marker Assisted Selection (MAS). Euclidean distance estimates for morphological data and (Nei’s 1972) genetic distance estimates for SSR data were strongly correlated (r = 0.7; P < 0.001) in the agronomy bay and (r = 0.6; P< 0.001) in the controlled growth room. These results suggest the two approaches are generating the same pattern of genetic diversity, and as such can be used as a surrogate for each other.
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Nyau, Vincent. "Nutraceutical antioxidant potential and polyphenolic profiles of the Zambian market classes of bambara groundnuts (Vigna subterranea L. Verdc) and common beans (Phaseolus vulgaris L.)." Doctoral thesis, University of Cape Town, 2013. http://hdl.handle.net/11427/4313.
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Includes abstract.<br>Includes bibliographical references.<br>There is a growing interest in legumes and legume based foods because of the health claims associated with their consumption. The aim of the current study was to explore the nutraceutical potential of bambara groundnuts (Vigna subterranea L. Verdc) and common beans (Phaseolus vulgaris L.) commonly grown in Zambia based on the antioxidant properties and phenolic phytochemical profiles. Two market classes of bambara groundnuts (red and brown) and four of common beans (red, grey mottled, brown and white) were screened in raw dry form. Effects of cooking and sprouting on the antioxidant activities and phenolic phytochemicals of the promising market classes were assessed. The study employed in vitro antioxidant assays (DPPH and FRAP) to screen for antioxidant properties, HPLC-PDA-ESI-MS and Folin Ciocalteu assay to screen for phenolic phytochemical profiles.
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Gulu, Nontobeko Benhilda. "Functional and rheological properties of Bambara groundnut starch-catechin complex obtained by chemical grafting." Thesis, Cape Peninsula University of Technology, 2018. http://hdl.handle.net/20.500.11838/2806.
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Thesis (MTech (Food Technology))--Cape Peninsula University of Technology, 2018.<br>The aim of this study was to produce Bambara groundnut (BGN) starch-catechin complex using chemical initiators (ascorbic acid and hydrogen peroxide) and cyclodextrin (alpha and beta) with the view to obtain a functional ingredient for the food industry. BGN starch was successfully extracted from BGN flour through dry milling method, yielding 32% of BGN starch. Native BGN starch was chemically modified using ascorbic acid (1% w/w) and hydrogen peroxide (165% w/w) as redox, biocompatible initiator for grafting catechin to the BGN starch. In addition, cyclodextrin (alpha and beta) were also used as initiators for modifying BGN starch through complexation methods. Complexation methods used included the microwave, co-evaporation and kneading. The characterization of native and modified BGN starches was carried out by performing scanning electron microscopy, powder X-ray diffraction, Fourier Transform Infrared (FTIR) and fluorescence spectroscopy analysis. Functional, thermal and rheological properties of native and modified BGN starches were evaluated. The pasting properties of BGN starches were determined using the Rapid Visco Analyser (RVA). According to the SEM profile, native BGN starch had round, oval and elliptical shapes typical for legume starches. Native BGN starch displayed a typical type-C crystallinity which is common among legumes with strong peaks at 2θ of 15o, 17o and 23o. BGN starches modified through complexation methods had sharper peaks indicating an increase in starch crystallinity; however, following chemical modification there was loss in starch crystallinity which was evidenced by the amorphous region in the chemically modified BGN starches. Structure of native and modified BGN starches was confirmed by FTIR. The FTIR spectra of native BGN starch showed variable peaks at 3285.34 cm-1, 2931.69 cm-1, 1634.36 cm-1, 1336.77 cm-1 which are attributed to OH stretching, C-H stretching, water bending vibrations and C-O stretching, respectively. Furthermore, the FTIR results confirmed that native BGN starch is made up of glucose molecules just like all other starches. All modified BGN starches displayed a new absorption peak at 1020 cm-1 wavelength, thus indicating that starch modification was successful. On the other hand, all BGN starch-catechin complexes displayed a new absorption peak in the range of 1520 -1560 cm-1, attributed to the C-C stretching within the aromatic ring of the catechin. The successful grafting of catechin to BGN starch was also confirmed by the fluorescence spectroscopy results, where all the BGN starch-catechin complexes had an emission peak at 320 nm while native BGN starch had an emission peak at 270 nm. Antioxidant capacity of BGN starch was determined through DPPH and ORAC antioxidant assays. Within the DPPH assay, the antioxidant activity ranged from 2.26 to 38.31 μmol TE/g. The antioxidant activity of modified BGN starch-catechin complexes was significantly (p ≤ 0.05) higher than the ones modified without catechin. On the other hand, within the ORAC assay, the antioxidant activity ranged from 0.07 to 126.71 μmol TE/g. As opposed to the results obtained in DPPH assay, the antioxidant activity of chemically modified BGN starch-catechin complexes was significantly (p ≤ 0.05) higher than that of complexed BGN starch-catechin complexes. Chemical modification significantly increased the swelling capacity of native BGN starch while complexation methods significantly reduced it.
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Willekens, Jeroen. "Mechanism of vector resistance in groundnut to control groundnut rosette virus disease in Sub-Saharan Africa." Thesis, University of Greenwich, 2003. http://gala.gre.ac.uk/6344/.
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Analysis of biological performance parameters of Aphis craccivora on groundnut variety ICG12991 in laboratory and field trials demonstrated that ICG12991 was resistant to the aphid vector of groundnut rosette diseases and that this resistance was stable over time and under high aphid pressure. Feeding experiments related slow population development and high aphid mortality on ICG 12991 to an inhibition of phloem feeding from the sieve elements. Consequently, virus transmission of all three agents of rosette disease was almost totally absent even under very high pressure of viruliferous aphids. Further investigation of the underlying mechanism of resistance in ICG 12991 showed that the resistance was induced by aphid probes rather than constitutive. The induced plant response was described as a hypersensitive response around the aphid feeding sites. Aphid-resistance and hypersensitivity were identified in at least 7 groundnut varieties and it is proposed that more varieties are likely to express these characteristics. The results led to the recommendation to evaluate groundnut varieties for aphid resistance by evaluating aphid population development. The identification of vector resistance and its efficacy in reducing virus spread of rosette disease in the field has opened the way for novel approaches for groundnut disease management.
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Bindir, Umar Buba. "A groundnut harvesting machine for Nigeria." Thesis, Cranfield University, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.306114.
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Stirling, C. M. "Environmental effects in partitioning and development in groundnut." Thesis, University of Nottingham, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.233604.
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Massawe, Festo J. "Phenotypic and genetic diversity in Bambara groundnut landraces." Thesis, University of Nottingham, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.342048.
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Harris, Taahir. "Bambara groundnut (Vigna subterranean) from Mpumalanga province of South Africa: phytochemical and antimicrobial properties of seeds and product extracts." Thesis, Cape Peninsula University of Technology, 2017. http://hdl.handle.net/20.500.11838/2789.
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Thesis MTech (Food Technology))--Cape Peninsula University of Technology, 2017.<br>Bambara groundnut (Vigna subterranea) an indigenous legume cultivated in Sub-Saharan Africa has been proclaimed to have medicinal properties from communities and in rural areas. However, there is not enough scientific information to validate these claims. Therefore, this study aimed to identify possible medicinal properties of Bambara groundnut (BGN), by analysing the phytochemical and antimicrobial properties of BGN seed and product extracts from Mpumalanga province within South Africa. The BGN extracts (70% methanol, 70% ethanol, milli-Q water) from seeds and products (milk and yoghurt) were screened for the presence of alkaloids, flavonoids, phenols, riboflavin and thiamine using analytical laboratory methods for basic screening, high-performance liquid chromatography (HPLC) and gas chromatography (GC) for quantification. The antimicrobial activity involved direct bioautography and minimum inhibitory concentration (MIC) against six antibiotic-resistant microorganisms, Acinetobacter baumannii ATCC 19606T, Enterococcus faecalis ATCC 29212, Klebsiella pneumoniae subsp. pneumoniae ATCC 700603, Pseudomonas aeruginosa ATCC 27853, Staphylococcus aureus subsp. aureus ATCC 33591 and Candida albicans ATCC 24433. For the seed extracts, flavonoids and phenols were highly concentrated in the red and brown hulls of BGN compared to whole and dehulled BGN. Organic solvents in comparison to water yielded the highest concentration of flavonoids, whilst water yielded the highest concentration for phenols. Flavonoid compounds that were detected at the highest concentrations were rutin (24.458 ± 0.234 mg.g-1, brown hull extracted with 70% methanol), quercetin (0.070 ± 0.043 mg.g-1, red hull extracted with 70% methanol), kaempferol (0.391 ± 0.161 mg.g-1; brown hull extracted with 70% ethanol) and myricetin (1.800 ± 0.771 mg.g-1; red hull extracted with 70% methanol). For phenol compounds, gallic acid (0.009 ± 0.004 mg.g-1; brown hull extracted with milli-Q water), catechin (0.026 ± 0.041 mg.g-1; brown hull extracted with milli-Q water), methyl gallate (0.008 ± 0.013 mg.g-1; brown whole extracted with milli-Q water), chlorogenic acid (0.115 ± 0.199 mg.g-1; brown hull extracted with milli-Q water) and ellagic acid (0.105 ± 0.082 mg.g-1; red hull extracted with milli-Q water) were detected. Vitamins B1 and B2 (riboflavin and thiamine) were mostly present in milli-Q water extracts. Black-eye hull had the highest concentration of thiamine (vitamin B1) and riboflavin (vitamin B2) consisting of 0.072 mg.g-1 (extracted with milli-Q water) and 0.002 mg.g-1 (extracted with 70% ethanol and 70% methanol). Red and brown hull extracts from organic solvents (70% ethanol and 70% methanol) showed the highest antimicrobial activity, whereas the whole, dehulled and hulls (black-eye and brown-eye) extracts had no antimicrobial activity. As for BGN products extracts, flavonoid compounds that were detected at the highest concentrations were rutin (5.694 mg.g-1, whole BGN milk, milli-Q water), quercetin (0.703 mg.g-1, whole BGN yoghurt, milli-Q water) and myricetin (0.987 mg.g-1, whole BGN yoghurt, 70% ethanol).
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Abreu, F. M. S. G. "Influence of atmospheric saturation deficit on early growth of groundnut." Thesis, University of Nottingham, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.378471.
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Maphossa, Alexandre M. "A nuclear magnetic resonance investigation of Archis hypogaea L. (groundnut)." Thesis, University of Kent, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.309779.
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Maphosa, Yvonne. "Characterisation of Bambara groundnut (Vigna Subterranean (L.) Verdc.) Non-starch polysaccharides from wet milling method as prebiotics." Thesis, Cape Peninsula University of Technology, 2015. http://hdl.handle.net/20.500.11838/2342.
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Thesis (MTech (Food Technology))--Cape Peninsula University of Technology, 2015.<br>The aim of this study was to characterise the physicochemical, rheological, prebiotic and
emulsion stabilising properties of four varieties (black-eye, brown-eye, brown and red) of
Bambara groundnut (BGN) extracted using the modified wet milling method. A relatively high
yield of BGN dietary fibres was obtained with soluble dietary fibres (SDFs) ranging from 15.4
to 17.1% and insoluble dietary fibres (IDFs) ranging from 12.0 to 15.6%. Black-eye and
brown-eye dietary fibres showed superiority in terms of swelling capacities, water holding
capacities, oil binding capacities, antioxidant properties as well as thermal stabilities than red
and brown dietary fibres. In addition, black-eye and brown-eye dietary fibres were
characterised by higher lightness (L*), redness (+a*), yellowness (+b*), chroma (C*) and hue.
All four SDFs showed acceptable colour differences with ΔE < 8 ranging from 0.81 to 3.08.
The hydrolysable polyphenolic (HPP) content of SDFs ranged from 6.89 to 20.86 mg/g GAE
and that of IDFs ranged from 10.96 to 14.43 mg/g GAE. All four SDFs differed significantly
(p < 0.05) in their HPP content. BGN IDFs were very low in tannins (< 2.2 mg/g).
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Singleton-Jones, Paul. "Elevated carbon dioxide and gas exchange in groundnut and sorghum." Thesis, University of Nottingham, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.243686.
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Nakhumwa, Candida. "Smallholder market access : the case of groundnut sector in Malawi." Thesis, University of Greenwich, 2015. http://gala.gre.ac.uk/18144/.
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This thesis focussed on assessing smallholder groundnut farmers and traders’ access to markets through quality improvement and also, determine the socio-economic factors that influence groundnut farmers when deciding to adopt quality management techniques and the extent/or level of involvement. The following research questions were tested: whether Malawi smallholder groundnut farmers have poor or limited access to markets; whether smallholder farmers face unequal bargaining relations with traders due perhaps to lack of competition in trading channels; whether belonging to a farmer organisation provides a framework whereby the prospects of higher prices could lead to higher quality regulated by the association? Qualitative analysis was used to map out the main processes, key actors and relationships within the various groundnut value chains. Price spread method was used to assess market efficiency in price for the various groundnut market channels. Finally, a Selective Tobit model was used to assess factors that influence smallholder farmers to adopt technologies on quality management and decide the extent of adoption. The study results indicated that smallholder farmers manage to sell all their groundnuts brought to the market. This means that smallholder farmers do not really have problems accessing the markets. However, there is a limited availability of structured groundnut markets that offer premium price as an incentive for farmers to invest in quality management. Another important finding is that belonging to an organised farmer organisation enabled smallholder farmers to access better agricultural services such as research, extension and quality certified seed. However, it was not enough to persuade the farmers to venture into collective marketing. The results suggest that the provision of economic incentives such as premium prices persuaded farmers to engage in collective action and also invest in quality management. There is convergence of prices for less quality sensitive regional markets and quality sensitive EU markets. As such, exporters have no incentive to invest more in quality management targeting EU markets. Selective Tobit model results showed that farmers value most profitability-related variables such as land allocated, structured markets and prices when deciding level of involvement in quality management. The study results also indicate that groundnut market in Malawi is efficient in price as demonstrated by the Market Efficiency Index of greater than one. Gross margin analysis also indicated that, on average, groundnuts producers have good returns to labour if compared to the current national minimum wage rate of US$1.2 per day.
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Akobundu, Eberechukwu Jr. "Farm-Household Analysis of Policies Affecting Groundnut Production in Senegal." Thesis, Virginia Tech, 1997. http://hdl.handle.net/10919/9562.
Full textAbstract:
Since Senegal's independence in 1960, groundnuts (peanuts) have been the dominant agricultural export crop. Currently, groundnut output levels are on the decline and no clear reason for the downward trend has been found. Privatization efforts are underway as the government explores ways to breathe some life into the ailing sector, particularly as it relates to groundnut production. The 50 percent currency devaluation of 1994 constituted a major exogenous shock to the sector.
Much research has been done about the macro-level impact of the changes that are taking place. However, little work has been done recently (i.e. since the devaluation) at the micro-level. This work addressed this lack by studying the micro-level dynamics of groundnut production. Elasticities were generated and used in the analysis of policy impacts on production. The own-price elasticity of supply groundnut indicated that supply response should be positive following an increase in producer price. The increase in producer prices following the devaluation did not occasion the expected supply response. Possible reasons for this failure were explored.
It is hoped that the information revealed will complement the store of information on production in the Groundnut Basin that is already available. Thus, the present work will prove useful to public and private researchers and policy makers seeking to increase their understanding of the sector.<br>Master of Science
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Bandyopadhyay, R., A. Ortega-Beltran, A. Akande, et al. "Biological control of aflatoxins in Africa: current status and potential challenges in the face of climate change." WAGENINGEN ACADEMIC PUBLISHERS, 2016. http://hdl.handle.net/10150/622460.
Full textAbstract:
Aflatoxin contamination of crops is frequent in warm regions across the globe, including large areas in sub-Saharan Africa. Crop contamination with these dangerous toxins transcends health, food security, and trade sectors. It cuts across the value chain, affecting farmers, traders, markets, and finally consumers. Diverse fungi within Aspergillus section Flavi contaminate crops with aflatoxins. Within these Aspergillus communities, several genotypes are not capable of producing aflatoxins (atoxigenic). Carefully selected atoxigenic genotypes in biological control (biocontrol) formulations efficiently reduce aflatoxin contamination of crops when applied prior to flowering in the field. This safe and environmentally friendly, effective technology was pioneered in the US, where well over a million acres of susceptible crops are treated annually. The technology has been improved for use in sub-Saharan Africa, where efforts are under way to develop biocontrol products, under the trade name Aflasafe, for 11 African nations. The number of participating nations is expected to increase. In parallel, state of the art technology has been developed for large-scale inexpensive manufacture of Aflasafe products under the conditions present in many African nations. Results to date indicate that all Aflasafe products, registered and under experimental use, reduce aflatoxin concentrations in treated crops by > 80% in comparison to untreated crops in both field and storage conditions. Benefits of aflatoxin biocontrol technologies are discussed along with potential challenges, including climate change, likely to be faced during the scaling-up of Aflasafe products. Lastly, we respond to several apprehensions expressed in the literature about the use of atoxigenic genotypes in biocontrol formulations. These responses relate to the following apprehensions: sorghum as carrier, distribution costs, aflatoxin-conscious markets, efficacy during drought, post-harvest benefits, risk of allergies and/or aspergillosis, influence of Aflasafe on other mycotoxins and on soil microenvironment, dynamics of Aspergillus genotypes, and recombination between atoxigenic and toxigenic genotypes in natural conditions.
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Diouf, Ndiaye Awa. "Les femmes et le développement local au Sénégal : le rôle des associations féminines dans le bassin arachidier : l'exemple de Diourbel." Thesis, Bordeaux 3, 2013. http://www.theses.fr/2013BOR30026/document.
Full textAbstract:
Les femmes, élément central de la vie économique et sociale, jouent un rôle important dans la société sénégalaise. Dans cette thèse nous avons voulu mettre en valeur le dynamisme et l'héroïsme quotidien des femmes sénégalaises, de la région de Diourbel en particulier. Ce dynamisme est étudié à travers leurs activités quotidiennes, la recherche d’autonomie économique, et leurs associations. Diourbel était le centre du bassin arachidier dont les contours se sont modifiés avec le développement de l’arachide et les mutations du milieu. Ces dernières ne manquent pas de conséquences sur la vie des populations, des femmes en particulier qui doivent trouver des moyens pour s'adapter et faire face au départ des hommes et à l'accroissement des charges familiales. En partant des difficultés multidimensionnelles du vieux bassin arachidier, étudiées à travers la mauvaise articulation des politiques agricoles coloniales et nationales, qui ont participé à la crise agricole qui a été aggravée par la combinaison de facteurs anthropiques et physiques, nous avons rappelé le rôle actif des femmes dans la sphère familiale, d’abord et rendu visibles les activités collectives ou individuelles qu’elles ont déployées. Ensuite, les associations féminines se caractérisent par leur diversité dans leurs formes, leurs objectifs, leurs moyens et leur tissu relationnel. Devant les mutations observées, elles sont devenues incontournables et sont perçues comme des réponses féminines. Devant tous ces changements, les femmes du Baol ont leur mot à dire et leur force à apporter pour que l'édifice familial et social reste debout. Face aux efforts déployés par les femmes, des perspectives s'ouvrent<br>Women play an important role in Senegalese society occupying a central position in the economic and social life of the nation. In this thesis we will highlight the dynamism and the heroic levels of energy that Senegalese women invest in their daily tasks. Our observations will focus on the region of Diourbel. Their dynamism will be assessed throughout their daily activities, including their efforts to reach an economic self-sufficiency and their work within organizations. Diourbel used to be the center of the groundnut (peanut) basin. The borders of this region changed with shifts in the techniques of peanut farming and modifications in the environment. The latter has had effects on the living conditions of the inhabitants, particularly on women who had to find ways to adapt to such challenges as men migrating and increases in the cost of running a household. We highlight the active role women play within the family, demonstrating their collective and individual activities. These details are presented within the context of such multidimensional issues facing the old groundnut basin, as the incoherence of the colonial and national agricultural policies which have been aggravated by the combination of anthropogenic and physical factors. In addition the women´s associations are characterized by their variety, objectives, methods and internal relationships. The analysis will show them to be an inevitable feminine response to the observed social, economic and environmental changes. Women of Baol play a substantial role and exert significant influence on the process of maintaining both the social and familiar structures of their communities. As women carry out these efforts, our analysis will reveal how these efforts generate new perspectives
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Shamudzarira, Zondai. "Water use and dry matter production in sorghum and bambara groundnut." Thesis, University of Nottingham, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.361997.
Full text
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Gabriel, Ebunoluwa Grace. "Investigation of the emusifying properties of bambara groundnut flour and starch." Thesis, Cape Peninsula University of Technology, 2013. http://hdl.handle.net/20.500.11838/861.
Full textAbstract:
Thesis submitted in fulfillment of the requirements for the degree
Master of Technology: Chemical Engineering
In the Faculty of Engineering
At the
CAPE PENINSULA UNIVERSITY OF TECHNOLOGY
2013<br>A number of foods, pharmaceutical and industrial products are formulated as emulsions. The immiscibility of oil and water makes emulsions thermodynamically unstable, thus requiring emulsifiers. Natural and synthetic substances have been used as emulsifiers with preference for the former for safety, cost and availability purposes. Bambara groundnut (BGN) is an important source of nutrient in many African communities. Similar to soybean, flaxseed, and other leguminous products, the important blend of high protein and carbohydrate composition of BGN makes it a potential candidate as an emulsifier where, it can serve additional nutritional role in such emulsions. No literature evidence exists to support any earlier study on the potential emulsifying property of BGN. It is therefore of interest to investigate the potential of BGN flour (BGNF) and starch (BGNS) in stabilizing oil-in-water emulsions.
The current study aimed to investigate the emulsifying properties of Bambara groundnut flour and starch.
A batch of BGN was milled to produce the BGNF. BGNS was extracted from the BGNF. Emulsions were prepared using a wide range of flour-oil-water and starch-oil-water composition as generated through computational modelling. Emulsions were physically observed for stability, and then subjected to various stability studies using the Turbiscan® (which gives kinetic information on the process leading to phase separation; and allows for the detection of two kinds of destabilisation phenomena (particle migration): creaming and sedimentation) and optical microscope (which helps to detect particle size variation or aggregation in order to measure coalescence and/or flocculation). The most stable emulsions (one BGNF-stabilized and the other BGNS-stabilzed) were determined and subjected to same stability studies in the presence of varying physicochemical and physic-mechanical environmental conditions: effects of homogenization speed (9,000 – 21,000 rpm), pH (2 - 10), the presence of salt (2 – 10% w/v NaCl) and vinegar (2 – 10% v/v). Results were expressed in terms of relative stability (using creaming/sedimentation rate) and absolute oil droplet growth (coalescence and flocculation).
The emulsifier-oil compositions (emulsifier and water make 100 mL gelatinized mixture before the addition of oil) that gave the most stable emulsions were 9 g BGNF-39 g oil and 5 g BGNS-30 g oil. The two emulsions had only 15% and 30% growth in oil droplet diameter respectively by day 5, compared to over 3000% in the unstable ones. The emulsions were generally observed physically to be stable till day 5 with minimal creaming. Emulsions prepared with BGNS were physically observed to have increasing viscosity with time. There was microbial growth on the emulsions after 3 days. This might have been encouraged because of the rich nutritional composition of BGN. The stability of the emulsions increased significantly (p < 0.05) with the speed of homogenization (up to 15, 000 rpm beyond which the difference in stability was not significant). Compared to control (pH 7), emulsion stability decreased significantly (p < 0.05) with decreasing (up to 16% instability by Day-5 at pH 2) and increasing pH (10% instability at pH 10) with corresponding increase in droplet size. Emulsion stability increased significantly (p < 0.05) with increasing NaCl concentration (35% instability at 2% NaCl compared to 18% instability at 10% NaCl). Stability however decreased sharply with increasing concentration of vinegar (55% instability at 10% vinegar compared to 19% instability at 2% vinegar). The BGNF-stabilized emulsions were more stable (ordinarily and in the presence of the additives) than the BGNS-stabilized ones. Instability values in the BGNS emulsions, in most cases, double those for BGNF.
Emulsions were successfully stabilized with BGNF and BGNS. The emulsions were optimal when prepared at a homogenization speed of 15,000 rpm and at neutral pH. The higher the concentration of salt, the more stable the emulsions. Increasing concentration of vinegar however, destabilized the emulsions.
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Lima, Rayane Nunes. "Estudo das interações entre proteínas de Groundnut ringspot virus (Bunyaviridae: Tospovirus)." reponame:Repositório Institucional da UnB, 2014. http://repositorio.unb.br/handle/10482/15770.
Full textAbstract:
Dissertação (mestrado)—Universidade de Brasília, Instituto de Ciências Biológicas, Programa de Pós-Graduação em Biologia Molecular, 2014.<br>Submitted by Jaqueline Ferreira de Souza (jaquefs.braz@gmail.com) on 2014-05-27T13:14:11Z
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2014_RayaneNunesLima_Parcial.pdf: 885295 bytes, checksum: 3a9506e71c4557a00fffa96f5fd2010f (MD5)<br>Groundnut ringspot virus (GRSV) pertence ao gênero Tospovirus, o único da família de arbovírus Bunyaviridae capaz de infectar vegetais, sendo transmitido por tripes (Thysanoptera: Thripidae) de maneira circulativa propagativa. O genoma dos tospovírus é constituído por três segmentos de RNA fita simples denominados RNA S (Small), RNA M (Medium) e RNA L (Large). O RNA L codifica uma RNA polimerase dependente de RNA (RdRp); o RNA S codifica a proteína do nucleocapsídeo (N) e a proteína supressora do silenciamento gênico (NSs); e o RNA M codifica a proteína precursora das glicoproteínas Gn e Gc e a NSm, proteína de movimento viral célula-a-célula. As interações proteicas entre N e NSm são importantes para a disseminação da infecção viral na planta. Para a movimentação viral em plantas infectadas é necessária a oligomerização da proteína NSm, que forma túbulos que penetram os plasmodesmas celulares e promovem a passagem dos ribonucleocapsídeos virais de uma célula a outra. Os ribonucleocapsídeos são formados pela RNA polimerase viral (RdRp) e pelos segmentos de RNA (S, M e L) envolvidos pela nucleoproteína (N), que se oligomeriza para encapsidar todo o RNA viral. O presente trabalho investigou, pela primeira vez, as interações entre a proteína N e NSm de GRSV através da técnica de Fluorescência Bimolecular Complementar, bem como evidenciou a localização subcelular citoplasmática de cada interação. Um modelo tridimensional para a proteína N de GRSV foi construído in silico, por modelagem estrutural por homologia molecular, a partir das estruturas secundária e terciária da proteína N de LACV (La Crosse virus; Orthobunyavirus), e os domínios funcionais para a interação N x N e interação N x RNA foram definidos. A proteína N de GRSV apresenta um braço N-terminal (aa 1-32), um braço C-terminal (aa 224-258) e uma região globular com uma cavidade contendo resíduos de aminoácidos hidrofóbicos e positivos para a interação com o RNA. O alinhamento de sequências de aminoácidos da proteína N de todos os Tospovírus já caracterizados mostrou que os resíduos de aminoácidos preditos como chave para a conformação e interação da proteína N são conservados entre as espécies. Juntas, essas evidências abrem caminho para novos estudos acerca das interações proteicas a fim de elucidar o movimento célula-a-célula do GRSV e de outros Tospovírus.<br>Groundnut ringspot virus (GRSV) belongs to the genus Tospovirus, the only plant-infecting genus of the family Bunyaviridae, being transmitted by thrips (Thysanoptera: Thripidae) in a circulative propagative manner. The genome of tospoviruses consists of three single stranded RNA segments, termed S RNA (small) M RNA (Medium) and L RNA (Large). The L RNA encodes an RNA dependent RNA polymerase (RdRp). The S RNA encodes the nucleocapsid protein (N) and a gene silencing suppressor protein (NSs). The M RNA encodes the precursor protein of the Gn and Gc glycoproteins and the NSm protein, a viral cell-to-cell movement protein. Protein interactions between N and NSm are important to the viral infection spread in the plant. The NSm oligomerizes to form tubules that penetrate through plasmodesmata allowing the passage of viral ribonucleocapsids promoting cell-to-cell viral movement. The ribonucleocapsids are formed by the viral RNA polymerase (RdRp) and the RNA segments (S, M and L) surrounded by the nucleoprotein (N), which oligomerizes to encapsidate the viral RNA. This study investigated for the first time, homotypic and heterotypic interactions between N and NSm of the GRSV by Bimolecular Fluorescence Complementation (BiFC) in planta and showed the cytoplasmic subcellular localization of each interaction. A three-dimensional model for N GRSV protein was constructed in silico, by molecular homology modeling, from secondary and tertiary protein structures of N LACV (La Crosse virus; Orthobunyavirus) and the functional domains for N x N interaction and N x RNA interaction were defined. N GRSV protein presents an N-terminal arm (aa 1-32), a C- terminal arm (aa 224-258) and a globular region with a groove containing hydrophobic and positive amino acid residues for interaction with RNA. The alignment of amino acid sequences of the N protein of all characterized tospoviruses has shown that the amino acid residues important to protein fold and interaction of the N protein are conserved among all species. Together, this evidence allows further studies about the protein interactions involved to the cell-to-cell movement for GRSV and for other tospoviruses.
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Rabiu, Saidat Olajumoke. "Cloning and Expression of Antimicrobial Peptides from Vigna subterranea (Bambara Groundnut)." Thesis, Cape Peninsula University of Technology, 2018. http://hdl.handle.net/20.500.11838/2856.
Full textAbstract:
Thesis (Master of Applied Sciences in Chemistry)--Cape Peninsula University of Technology, 2018.<br>Antimicrobial Peptides (AMPs) are short peptides of about 45 - 54 amino acids that exhibit antibacterial and antifungal activities. Plant defensin is a type of AMP in plants which belong to a family of cationic peptides with a characteristic 3D folding pattern held in place by four disulfide bridges. AMPs especially defensins have been identified to have a huge biotechnological potential and are being patented for many applications. The aim of this work was to clone an antimicrobial peptide from Vigna subterranea and characterise it with bioinformatics analysis. 4 sets of primers were synthesized according to the sequences of conserved regions in AMPs i.e. defensins from legumes like Vigna unguiculata, Vigna radiata, Cicer arietinum and Cajanus cajan, amongst others, which have defensins with only a few sequence differences. The primers were designated VsDef P1 to P4. Using Vigna subterranea total genomic DNA as a template, fragments of expected sizes were successfully amplified and cloned into the pDRIVE vector and used to transform Escherichia coli JM109 cells in each case. Representative clones were sequenced and analysed using BLAST from National Center for Biotechnology Information. However, only the VIG clone was shown to be a bona fide defensin (over 90% identity, E-value of 1ex102, 99% query coverage of the nucleotide sequence, compared to Vigna unguiculata defensin). Based on this high sequence identity, a new pair of primers VsDef P5 was designed based on the Vigna unguiculata defensin sequence to specifically amplify the complete Vigna subterranea defensin gene, hereafter called VsDef1. Attempts to clone VsDef1 were however unsuccessful, and evidence of clone deletion and insert re-arrangement of insert DNA was observed. Direct sequencing of the PCR product demonstrated that it was indeed the complete VsDef1 pre-protein, composed of 433 nucleotides. In silico translation and analysis showed that VsDef1 has an intron at position 105 − 259 of the nucleotide sequences and encodes for a 78 amino acid peptide. Phylogenetic analysis revealed to be similar to the sequence of the defensins for Vigna unguiculata (96%), Vigna radiata (95%), Vigna angularis (95%) and Phaseolus vulgaris (93%) on the NCBI database. The three - dimensional structure of the peptide was modelled with SWISS-MODEL expasy and the structure was found to include one α- and three β domains, similar to those of other defensins. The failure to identify VsDef1 clone in a V. subterranea library and the failure to recover its cDNA clone are consistent with the hypothesised toxicity of VsDef1 to Escherichia coli. It is suggested that a different host, such as yeast, should be used in the future. The VsDef1 mRNA levels in germinating V. subterranea seeds was however successfully investigated using real-time reverse transcription quantitative PCR. VsDef1 mRNA is present in both the testa and embryo of dry seed and will persist through the early stages of seedling growth. This demonstrates the importance of VsDef1 in fighting off infection during germination in order to ensure successful germination. It is therefore essential to characterise more antimicrobial peptides from V. subterranea. The diversity of AMPs and their patterns of expressed genes will enable understanding of complex regulatory networks, which will likely enable identifying of genes involved in diseases and new biological processes.
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Diedericks, Claudine Florett. "Functional properties of bambara groundnut (Vigna subterranea (L.) Verdc.) non-starch polysaccharides in model and food systems." Thesis, Cape Peninsula University of Technology, 2014. http://hdl.handle.net/20.500.11838/833.
Full textAbstract:
Thesis submitted in fulfilment of the requirements for the degree
Master of Technology: Food Technology
in the Faculty of Applied Sciences
at the Cape Peninsula University of Technology<br>The aim of this study was to evaluate bambara groundnut [BGN] non-starch polysaccharides
[NSP] subject to the incorporation into model and food systems with a view to establish their
functional and physicochemical properties.
BGN insoluble dietary fibre [BGNIF] and soluble dietary fibre [BGNSF] were
successfully extracted from four varieties (black-eye: BLE, red: RED, brown: BRN and
brown-eye: BRE). Physicochemical properties evaluated revealed the high bulk density of all
BGNIF and BGNSF varieties, which could contribute to cost-effective packaging. The
microstructures of BGNIFs were irregular in shape with different sizes. The colour
parameters (lightness, redness, yellowness, chroma and hue angle) differed significantly [p ≤
0.05] across all BGNIF and BGNSF varieties; and indicated a yellowish-red colour for
BGNIFs and a light yellow colour for BGNSFs. Negligible amounts of condensed tannins
[CT] were found in BGNIFs (0.014 – 0.160 mg.g-1). Higher amounts polyphenols [PP] were
present in BGNSFs (45.42 – 55.90 mg.g-1 gallic acid equivalents [GAE]) compared to the
amount PP in BGNIFs (6.14 – 15.56 mg.g-1 GAE). Major sugars identified were
arabinose/galactose, xylose and mannose in BGNIFs, and xylose and mannose in BGNSFs.
The functional properties evaluated revealed high swelling capacity of BGNIFs (6.37 – 7.72
ml.g-1) and no significant [p > 0.05] difference in water retention capacity. Fat absorption
capacity ranged from 1.38 – 1.52 g oil.g-1 dry weight for BGNIFs and 4.04 – 4.55 g oil.g-1 dry
weight for BGNSFs. Variability in BGNIF (91.2%) and BGNSF (79.4%) physicochemical and
functional properties could both be explained by two principal components (BGNIF
component 1: PP, redness, yield; and component 2: xylose, yellowness and chroma; BGNSF
component 1: yellowness, chroma, mannose content; and component 2: redness, fat
absorption and fructose content).
Following an IV optimal mixture design, an optimum white bread formulation was
obtained using 59.5% water, 4.3% yeast and 8.5% BGNIF. Bread enriched with the four
BGNIF varieties (BLE, RED, BRN and BRE) were tested for several physicochemical
properties. Significant [p ≤ 0.05] differences existed between the control and BGNIF
enriched loaves for crumb grain characteristics (including pore area distribution, feret angle,
circularity, roundness and aspect ratio). Specific loaf volume of BGNIF enriched loaves
ranged from 3.33 – 3.85 ml.g-1 and were significantly [p ≤ 0.05] lower compared to the control
bread (4.16 ml.g-1). Favourable texture characteristics obtained with the BGNIF enriched
breads were lower hardness, chewiness and gumminess compared to the control loaf. Crust
and crumb colour parameters (lightness, redness, yellowness, chroma and hue angle) were
significantly [p ≤ 0.05] different across all loaves. BRE BGNIF bread (3.43 ± 0.20) had the
significantly [p ≤ 0.05] lowest crumb colour difference compared to the control bread; whilst
BRN (1.72 ± 0.42) and BRE (2.44 ± 0.78) loaves had the lowest significant [p ≤ 0.05] crust colour difference compared to the control. Favourable chemical properties were the high
total dietary fibre [TDF] (7.14 – 8.33%) content of all BGNIF enriched loaves compared to the
control loaf (4.96%). Significant [p ≤ 0.05] differences were also observed for some loaves
for moisture content, condensed tannins and polyphenol content. Variability in bread
physicochemical properties was differentiated by three components (component 1: bread
textural properties; component 2: specific loaf volume and bread lightness; component 3:
crumb colour parameters) which accounted for a cumulative variation of 92.8%. All bread
loaves were also sensorially acceptable as rated moderately like to like very much (>3 rating
on a 5-point hedonic scale) by consumers for all parameters (appearance, crust and crumb
colour, aroma, taste, texture and overall acceptability) evaluated.
Furthermore, brown BGNSF was tested for stabilising effects in an orange beverage
emulsion. BGNSF and orange oil were varied at two levels each based on a 22 augmented
factorial design and the effects determined on the equilibrium backscattering [BS] flux as
emulsion stability indicator. The BS profiles which resulted from the Turbiscan stability
analysis revealed flocculation at low rates as the major destabilisation mechanism. The
optimal formulation producing a stable emulsion was identified as low oil (6%) and high
BGNSF (30%) concentrations. The objective of this study was therefore achieved and
showed that positive physicochemical and functional properties are associated with BGNIF
and BGNSF from black-eye, red, brown and brown-eye varieties. Furthermore, the
incorporation of BGN fibres in white bread and a beverage emulsion was shown to contribute
positive technological properties in these systems.
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Cornelissen, Rutgerus Leonardus Evert Jan. "Modelling variation in the physiology of Bambara Groundnut (Vigna subterranea (L.) Verdc. )." Thesis, Cranfield University, 2005. http://hdl.handle.net/1826/1005.
Full textAbstract:
The aim of this PhD project was to construct a model based on physiological and socio-economic factors related to the growth, development and yield of bambara groundnut landraces in relation to their environment.
The model (BamGro) is an adaptation of the PALM (Matthews, 2005) model for a leguminous crop. It is a sink-orientated model, i.e. the number of available sinks (pods) determines the final production. The model is a stand-alone computer program written in Delphi 6 (Borland®). It uses climate data, landrace specific parameters and physiological relationships and runs on a daily time-step to determine the biomass production and yield of a landrace in a specific environment. The parameters of the model have been determined with experiments in the field (Swaziland) and glasshouses (TCRU, University of Nottingham).
Large differences between glasshouse data and field data in leaf appearance rate and consequently leaf area development were found. In this study the leaf appearance rate was typically three times higher in the field, than in the glasshouse for the same landrace. When the relation between leaf area per plant and leaf number per plant is observed, there is no difference between the UK and Swaziland. The differences between the field and the glasshouse are therefore likely to be the result of an effect of environment on the leaf initiation. These differences meant that the model had to be developed with two different parameter sets, one for the landraces used in the field and one for the landraces used in the glasshouse.
BamGro is capable of describing differences between landraces, and the influence of both drought and photoperiod are simulated using a simplified approach, and these aspects can be improved when sufficient high quality data becomes available.
BamGro has been validated against three independent sets of data. BamGro achieves an excellent fit between observed and predicted data for leaf area index and pod yield, but underestimates the total above ground biomass by 50% in the TCRU glasshouses (2003 season). For the Swaziland ‘Malkerns’ field site (2002-2003 season) BamGro predicts the total above ground biomass excellently. BamGro achieves a good fit between observed and predicted pod yield data, but underestimates the leaf area index. For the Swaziland ‘Luve’ field site (2002-2003 season) the predictions are poor, with the model underestimating the total above ground biomass, leaf area index and pod yield for most landraces. BamGro is most sensitive to its crop parameters. BamGro seems not to be sensitive to changes in seasonal rainfall or initial soil moisture content.
The unavailability of data on soil water relations and incomplete agronomic data sets meant that the water routines of the model could not be validated against field data from Namibia and Botswana. Three potential uses for BamGro have been presented.
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Ahmad, Nariman Salih. "Genetic analysis of plant morphology in bambara groundnut (Vigna subterranea (L.) Verdc.)." Thesis, University of Nottingham, 2013. http://eprints.nottingham.ac.uk/13150/.
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Bambara groundnut (Vigna subterranea (L.) Verdc.) is an important underutilised legume crop, grown mainly by female subsistence farmers in Africa under traditional low input agricultural systems. Bambara groundnut is known as being of high nutritional value, as an atmospheric nitrogen fixer and to possess high levels of drought, pest and disease tolerance. Bambara groundnut is a predominantly self-pollinated crop and is grown as locally adapted landraces. These are expected to exist as non-identical inbred lines and are generally low yielding. Strategies involving genetic analysis of this species could provide important data for breeding programmes that could enhance food security in Africa. A set of 124 SSR primers designed from different library sources were tested to screen a ‘narrow’ genetic cross (F3) and a ‘wide’ genetic cross (F2) . The former is a cross between domesticated landraces (DipC and Tiga necaru) while the latter is a cross between a domesticated landrace and a wild ancestor (DipC and VSSP11). Residual heterozygosity in the F3 ‘narrow’ cross was confirmed to be around 25% based on 33 polymorphic SSR primers, consistent with an F3 population. A ‘narrow’ cross linkage map was constructed for the first time in bambara groundnut using 269 polymorphic markers (236 DArT and 33 SSR). The map consisted of 238 markers in 21 linkage groups of two or more linked markers, totalling 608.1cM and covering a predicted 54% of the bambara groundnut genome, although the high marker-marker linkage (at 89%) suggests a more comprehensive coverage. QTL analysis was carried out for 73 bulked lines of an F3 population and plants were evaluated for traits in a controlled glasshouse suite and a field trial in Indonesia. Data from single plant analysis of the F2 generation of this cross grown in a controlled environment glasshouse was also used. Most of the QTLs detected were clustered on linkage groups 1, 4 and 12. Major QTLs for internode length and biomass dry weight were detected on LG4 and LG1, respectively, for the FutureCrop glasshouse and field datasets. The highest LOD score of 9.7 was detected for peduncle length and was located within the confidence interval for a QTL for internode length locus. Marker locus bgPabg-596774 was detected to be associated with QTL for six traits; node no./plant, pod no/plant, pod weight, seed no./plant, seed yield and biomass dry weight, on LG1 within one LOD score of confidential interval, potentially suggesting pleiotropic effects of a more limited number (or even one) gene(s). One hundred and fifty-nine additional markers (136 DArT and 23 SSR) were used to improve the existing partial ‘wide’ map (141 AFLP, 1 SSR) constructed in an F2 population of 98 plants. A total of 194 markers were assigned to 20 linkage groups spanning a total of 901 cM. The linkage map derived from the ‘wide’ cross (DipC x VSSP11) had an expected genome coverage of 79.6%. An attempt to combine both maps through 32 common markers allowed a common QTL for days to emergence to be detected in both populations in close association with the common DArT markers 601384 and 601748. The main segregating traits were found to be plant spread, internode length, growth habit, peduncle length, pod weight, seed yield and biomass dry weight. Detecting the same QTL positions for a number of traits, suggested that common underlying genes might be responsible. The QTL-DNA marker associations developed in this study could be used practically for MAS in a future breeding program of this crop.
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Marshall, Fiona M. "Resource partitioning and productivity of perennial pigeonpea/groundnut agroforestry systems in India." Thesis, University of Nottingham, 1995. http://eprints.nottingham.ac.uk/12206/.
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The productivity of two spatial arrangements of a perennial pigeonpea/groundnut agroforestry system was examined in relation to the capture and use of light and water and alterations in microclimatic conditions. Line planted (5.4 m alleys) and dispersed arrangements (1.8 x 1.2 m spacing) of pigeonpea were compared, using populations of 0.5 plants m2 for pigeonpea and 33 plants m2 (0.3 x 0.1 m spacing) for groundnut in both treatments. Sole pigeonpea and groundnut treatments were included for comparison. The experiment was conducted between July 1989 and March 1991 on a 0.6 ha plot of Alfisol at ICRISAT Center, Andhra Pradesh, India, using a randomised block design with four replications. The first groundnut harvest took place in October 1989, while pigeonpea was harvested for grain and fodder in January 1990, and was cut to a height of 0.5 m during the 1990 dry season and again in August 1990 after a second groundnut crop was sown. The second groundnut harvest took place in November 1990 and the final pigeonpea grain harvest was in January 1991. Light interception, soil and leaf temperatures and saturation deficit were continuously monitored in all treatments and at various distances from the pigeonpea in the line and dispersed treatments, whilst windspeed was monitored at a single location in each treatment. Regular destructive samples of groundnut were used to establish effects on growth and development and the results were considered in relation to the concurrent physical measurements to determine the environmental factors influencing productivity. In order to establish a water balance, rainfall records were maintained, runoff plots were installed and soil moisture content was measured regularly throughout the drying cycle. Transpiration by pigeonpea was monitored using a heat balance technique, while transpiration by groundnut and soil surface evaporation were estimated from micrometeorological data. As pigeonpea is initially slow growing, there was little reduction in groundnut yield in either the line or dispersed treatments in 1989 and there was a slight intercrop advantage in overall biomass production when expressed in the terms of the land equivalent ratios. In 1990, groundnut pod yield was reduced by 20 and 44 % in the line and dispersed treatments relative to the sole crop, despite substantial increases in the light conversion coefficient for the shaded groundnut. The lower pod yield resulted from the delayed onset of pod initiation and a slower rate of development, and was mainly due the effects of shading by the pigeonpea canopy, although mild water stress may have been a minor contributory factor. The small reductions in saturation deficit and soil and leaf temperatures experienced by the shaded groundnut had a negligible effect on growth and development. There was a considerable increase in overall biomass production in the line and dispersed treatments as compared with 1989 due to rapid pigeonpea growth, which reflected an increase in overall resource use rather than in the light conversion coefficient or water use ratios of the systems. The influence of spatial arrangement on the growth and productivity of pigeonpea became apparent after the 1990 dry season. Biomass production by pigeonpea in the dispersed treatment was approximately double that of the line planting between August 1990 and January 1991. This was entirely due to increased transpiration by the dispersed pigeonpea as a result of greater utilisation of stored soil moisture and reduced losses by surface evaporation and deep drainage. There was no difference in the water use ratio. To examine further the mechanisms responsible for the differences in productivity and water use by the line and dispersed pigeonpea, trench profile methodology was used to examine the root systems in December 1990. The root system of the dispersed pigeonpea was distributed over the entire 2.0 m depth x 2.7 m width exposed soil profile, whilst that of the line arrangement occupied no more than 50 % of the same area. The results of this work are discussed in relation to previous studies of resource use and productivity in intercropping and agroforestry systems, and possible applications and future developments are considered. Finally, the major physical and socioeconomic factors determining the potential of perennial pigeonpea/groundnut agroforestry systems for adoption by farmers in semi-arid India are discussed.
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Mwale, Simon S. "Resource use efficiency of bambara groundnut landraces in response to soil water." Thesis, University of Nottingham, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.415492.
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Mohamed, Adil Deifalla. "Water use of groundnut and sorghum in response to elevated carbon monoxide." Thesis, University of Nottingham, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.240544.
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Basu, Shravani M. "Genetic mapping and trait analysis in bambara groundnut [Vigna subterranea (L.) Verdc.]." Thesis, University of Nottingham, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.415496.
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Ramirez, Villegas Julian Armando. "Genotypic adaptation of Indian groundnut cultivation to climate change : an ensemble approach." Thesis, University of Leeds, 2014. http://etheses.whiterose.ac.uk/6372/.
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Climate change has been projected to significantly affect agricultural productivity and hence food availability during the 21st century, with particularly negative effects across the global tropics. However, the uncertainty associated with projecting climate change impacts is a barrier to agricultural adaptation. The work reported in this thesis is a contribution to the understanding of genotypic adaptation to near-term (i.e. 2030s) climate change and many of the associated uncertainties, using model ensembles. This work focuses on Indian groundnut and uses the General Large Area Model for annual crops (GLAM) and the EcoCrop niche model to investigate the response of groundnut under future climate scenarios, and to develop a genotypic adaptation strategy. Under the future representative concentrations pathway (RCP) 4.5, robust positive climate change impacts on crop productivity were found in 3 (western, northern and south-eastern) out of 5 groundnut growing regions. From the remainder of regions, one presented robust negative impacts and in the other uncertainties precluded a robust statement being made about productivity changes. Yield gains were associated with seasonal precipitation increases, a lower frequency of occurrence of terminal drought and its effect on cropping season length. Yield loss in central India was associated with less radiation interception and reductions in crop duration, whereas in the south there was large uncertainty due to temperature biases in GCMs triggering (or not) heat stress during anthesis. The latter result suggests that decisions of whether to correct or not GCM biases and the method of correction may be at least as important as the choice of climate scenario, or the choice of crop model parameters. Adaptation simulations indicated that the most critical traits for groundnut adaptation under future scenarios are increases in maximum photosynthetic rates, greater partitioning to seeds and, where enough soil moisture is available, also increases in the maximum transpiration rate. Changes to crop duration were beneficial if durations did not exceed those of the baseline, and hence allowed for enough water uptake at the end of the cropping season. Yield gains in adaptation scenarios were particularly large in eastern and northern India, and more moderate across the rest of the country.
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Adetunji, Adewole Tomiwa. "Potato and Bambara groundnut ammonium transporter (AMT1) structure and variation in expression level in potato leaf tissue in response to nitrogen form and availability." Thesis, Cape Peninsula University of Technology, 2014. http://hdl.handle.net/20.500.11838/2005.
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Thesis (MTech (Agriculture))--Cape Peninsula University of Technology, 2014.<br>Plants require nitrogen (N) to support desired production levels. Nitrogen fertilization strategy is a major consideration in field management with regard to achieving both economic and environmental objectives. For instance, in potato, insufficient N supply reduces tuber size and overall yield while excessive N supply can reduce tuber quality and increase environmental risk through nitrate (NO3-) leaching and nitrous oxide emission. Selection of an adequate N fertilizer application rate for crops is difficult, due to marked variations in soil N supply and crop N demand in both the field and over time. This research was conducted to characterise the ammonium transporter gene (AMT1) of Bambara groundnut and potato using molecular biology and bioinformatics methods. Nucleotide database sequences were used to design AMT1-specific primers which were used to amplify and sequence the core-region of the gene from Bambara groundnut and potato. Bioinformatics techniques were used to predict the structure and infer properties of the proteins. Nucleotide sequence alignment and phylogenetic analysis indicate that BgAMT1 and PoAMT1 are indeed from the AMT1 family, due to the clade and high similarity they respectively shared with other plant AMT1 genes. Amino acid sequence alignment showed that BgAMT1 is 92%, 89% and 87% similar to PvAMT1.1, GlycineAMT1 and LjAMT1.1 respectively, while PoAMT1 is 92%, 83% and 76% similar to LeAMT1.1, LjAMT1.1 and LeAMT1.2 respectively. BgAMT1 and PoAMT1 fragments were shown to correspond to the 5th - 10th transmembrane spanning-domains. Mutation of Bg W1A-L and S28A (for BgAMT1) and Po S70A (for PoAMT1) is predicted to enhance ammonium (NH4+) transport activity. Residues Bg D23 (for BgAMT1) and Po D16 (for PoAMT1) must be preserved otherwise NH4+ transport activity is inhibited. In all, BgAMT1 and PoAMT1 play a role in N uptake from the root while BgAMT1 may contribute more in different steps of rhizobia interaction.
In an investigation of the correlation between AMT1 gene expression levels and leaf chlorophyll content index (CCI) with plant N status, potato plants were grown in a hydroponic greenhouse with 0.75 or 7.5 mM NO3- and 0.75 or 7.5 mM NH4+ as forms of N supply in a completely randomized design. Leaf CCI as measured by chlorophyll content meter, showed that an increase in N supply results in increased leaf CCI in response to both forms of N. Total RNA was isolated from leaf sampled at 28 days after treatment and expression level of the AMT1 gene was determined by reverse transcription-qPCR using a second set of primers designed for qPCR. The results showed that expression levels of AMT1 increased from 8.731 ± 2.606 when NO3- supply was high to 24.655 ± 2.93 when NO3- supply was low. However, there was no significant response in AMT1 expression levels to changes in NH4+. This result suggested that AMT1 transports NO3- less efficiently than NH4+, and thus more transport channels are required in the cell membrane when NO3- levels are low. Such variation in AMT1 expression levels are not necessary for NH4+ transport since the transport mechanism for NH4+ is efficient even at low NH4+ levels.
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Karunaratne, Asha Sajeewani. "Modelling the response of Bambara groundnut (Vigna subterranea (L.) Verdc) for abiotic stress." Thesis, University of Nottingham, 2009. http://eprints.nottingham.ac.uk/10840/.
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Bambara groundnut (Vigna subterranea (L.) Verdc) is an indigenous legume that is still cultivated in subsistence agricultural systems in sub-Saharan Africa, despite the lack of any major research effort until recently. The crop is cultivated from local landraces as there are no true varieties of the species bred for specific traits. The variable and hostile climates in the region mean that annual yields of most rainfed crops including bambara groundnut are far below their agronomic or genetic potential. The lack of quantitative information on the eco-physiological responses of the crop to various abiotic factors has resulted in poor decision making on crop management practices especially in relation to sowing date and the selection of appropriate landraces for different locations. Modelling of bambara groundnut was initiated previously but there is still insufficient understanding of how growth and developmental processes can be simulated under abiotic stress and different photoperiods. The aim of this study was to develop a crop simulation model for bambara groundnut to predict growth, development and yield under drought, heat and cold stress and different daylengths. The present model (BAMGRO) is an adaptation of the established CROPGRO and previous bambara groundnut models; BAMnut and BAMFOOD project model. It uses climate data, landrace specific parameters and soil characteristics and runs on a daily time-step to determine the canopy development, biomass production and yield of a landrace in a specific environment. The parameters of the model have been determined with glasshouses data (TCRU, University of Nottingham) and published information. BAMGRO is capable of describing differences between landraces, and the influence of drought, temperature and photoperiod using a simplified approach. The present modelling approaches with BAMGRO model provide useful predictive information on canopy development, biomass production and yield formation of bambara groundnut landraces under contrasting environments. Two contrasting landraces; Uniswa Red (Swaziland) and S19-3 (Namibia) were used in the present study to evaluate the growth and yield performances under drought, heat and cold stress. BAMGRO has been primarily validated against independent data sets of two years glasshouse for two contrasting landraces; Uniswa Red and S19-3 grown under two temperatures (23 ± 5 0C, 33 ± 5 0C) with drought. Further, it was validated for field data in Botswana with two sowing dates (January 18, February 1) during the 2007 season and for Swaziland for three landraces; Uniswa Red, DipC, OM1. The model achieves a good fit between observed and predicted data for LAI (Nash and Sutcliffe (N-S), 0.78-0.98; Mean Absolute Error, ± 0.14-0.57) for tested four landraces. Pod yield simulation was correlated well with measured values especially for Uniswa Red and S19-3 (N-S 0.73-0.87; Mean Absolute Error ± 16 g m-2) while it was poor for DipC and OM1 (N-S, 0.46-0.50; Mean Absolute Error, ± 15.6-17.7 g m-2). Further, the comparison of simulated and measured data of TDM reported lower correlation compared to LAI and yield. (N-S, 0.59-0.79; Mean Absolute Error ± 48-100 g m-2) indicating overall underestimation. The performance of the BAMGRO-soil water module was tested by validating the available soil moisture and results indicating that it over estimated for upper layers while deeper layers showed lower prediction. The possible reasons for the discrepancies in measured and simulated data are differences in quality and quantity of solar radiation in UK summer and Semi-arid Africa, intra-landrace variability and poor calibration of soil water module. Four potential applications of BAMGRO and three future developments are presented in this thesis.
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Leão, Evelynne Urzêdo [UNESP]. "Caracterização do groundnut ringspot virus (grsv) e seu vetor (Frankliniella schultzei) em melancia." Universidade Estadual Paulista (UNESP), 2015. http://hdl.handle.net/11449/126555.
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000844621.pdf: 1255228 bytes, checksum: 98151853c54471172f5b1bca62465aa1 (MD5)<br>A melancia (Citrullus lanatus) é considerada uma das cucurbitáceas mais importantes no mundo e o Brasil é o quarto maior produtor, com área total cultivada de 90.000 ha e produção média de cerca de dois milhões de toneladas. No Brasil, há várias espécies de vírus descritas em melancia pertencentes ao gênero Potyvirus, Cucumovirus, sendo Zucchini lethal chlorosis virus a única espécie até então relatada no gênero Tospovirus. Considerando a alta incidência de plantas de melancia exibindo sintomas causados por vírus durante as safras 2012/2013 e a presença de tripes no campo, este trabalho teve como objetivo a identificação e caracterização do vírus e do vetor associado a sua transmissão. No primeiro capítulo intitulado Citrullus lanatus is a new natural host of Groundnut ringspot virus in Brazil, foi relatada a ocorrência de Groundnut ringspot virus (GRSV) em melancia ocasionando mosaico, deformações e lesões necróticas em folhas e manchas necróticas nos frutos. O GRSV foi coletado durante os anos de 2012 e 2013 nas regiões produtoras dos municípios de Presidente Prudente e Marília. O isolado de GRSV de melancia apresentou um círculo de hospedeiros semelhante aos isolados de GRSV provenientes de solanáceas, com a excessão de não infectar tomateiro cv. Santa Clara e Mariana. Espécimes de tripes coletados no campo foram capazes de transmitir o GRSV para melancia, pimentão e espécies de Nicotiana. Este foi o primeiro relato de infecção natural de melancia por GRSV. No segundo capítulo intitulado A Taqman real-time RT - PCR assay for detection of Groundnut ringspot virus foi possível detectar o GRSV por PCR quantitativo (qPCR) em amostras de melancia e em tripes individuais coletados no campo. A detecção do GRSV por qPCR poderá servir como uma ferramenta útil nos ...<br>Watermelon (Citrullus lanatus) is considered one of the most important cucurbits in the world and Brazil is the fourth largest producer, with a total cultivated area of 90.000 ha and average production of about two million tons. In Brazil, viruses described in watermelon belong to the genus Potyvirus and Cucumovirus and Zucchini lethal chlorosis virus is the only species of Tospovirus genre described on this culture. Considering the high incidence of watermelon plants showing symptoms caused by virus during the 2012/2013 seasons and the presence of thrips in the field, the virus and the vector associated with the disease was identified and characterized. In the first chapter entitled Citrullus lanatus is a new natural host of Groundnut ringspot virus in Brazil, the species of tospovirus Groundnut ringspot virus(GRSV) was reported causing mosaic, deformation and necrotic lesions on leaves and fruits of watermelon. The GRSV was collected during the years 2012 and 2013 in producing areas of Presidente Prudente and Marília. GRSV from watermelon, differently from GRSV strains found on solanaceas, didn't infected tomato plants cv. Santa Clara and Mariana. Thrips specimens collected in the field were able to transmit GRSV to watermelon, peppers and Nicotiana species. This was the first report of natural infection of watermelon by GRSV. In the second chapter entitled A Taqman real-time RT - PCR assay for detection of Groundnut ringspot virus a quantitative PCR test was developed to efficiently detect GRSV from watermelon and from individual thrips. The test might be useful to detect GRSV and for further studies with this virus. The third chapter Efficient detection of Frankliniella schultzei (Thripidae: Thysanoptera) by real-time PCR reports the efficient detection of Frankliniella schultzei by the analysis of the mitochondrial gene cytochrome oxidase I (mtCOI). Thrips samples were ...
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Leão, Evelynne Urzêdo 1986. "Caracterização do groundnut ringspot virus (grsv) e seu vetor (Frankliniella schultzei) em melancia /." Botucatu, 2015. http://hdl.handle.net/11449/126555.
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Orientador: Renate Krause Sakate<br>Coorientadora: Kelly Cristina Gonçalves Rocha<br>Banca: Marcelo Agenor Pavan<br>Banca: Nobuyoshi Narita<br>Banca: Jorge Alberto Marques Rezende<br>Banca: Tatiana Mituti<br>Resumo: A melancia (Citrullus lanatus) é considerada uma das cucurbitáceas mais importantes no mundo e o Brasil é o quarto maior produtor, com área total cultivada de 90.000 ha e produção média de cerca de dois milhões de toneladas. No Brasil, há várias espécies de vírus descritas em melancia pertencentes ao gênero Potyvirus, Cucumovirus, sendo Zucchini lethal chlorosis virus a única espécie até então relatada no gênero Tospovirus. Considerando a alta incidência de plantas de melancia exibindo sintomas causados por vírus durante as safras 2012/2013 e a presença de tripes no campo, este trabalho teve como objetivo a identificação e caracterização do vírus e do vetor associado a sua transmissão. No primeiro capítulo intitulado "Citrullus lanatus is a new natural host of Groundnut ringspot virus in Brazil", foi relatada a ocorrência de Groundnut ringspot virus (GRSV) em melancia ocasionando mosaico, deformações e lesões necróticas em folhas e manchas necróticas nos frutos. O GRSV foi coletado durante os anos de 2012 e 2013 nas regiões produtoras dos municípios de Presidente Prudente e Marília. O isolado de GRSV de melancia apresentou um círculo de hospedeiros semelhante aos isolados de GRSV provenientes de solanáceas, com a excessão de não infectar tomateiro cv. Santa Clara e Mariana. Espécimes de tripes coletados no campo foram capazes de transmitir o GRSV para melancia, pimentão e espécies de Nicotiana. Este foi o primeiro relato de infecção natural de melancia por GRSV. No segundo capítulo intitulado "A Taqman real-time RT - PCR assay for detection of Groundnut ringspot virus" foi possível detectar o GRSV por PCR quantitativo (qPCR) em amostras de melancia e em tripes individuais coletados no campo. A detecção do GRSV por qPCR poderá servir como uma ferramenta útil nos ...<br>Abstract: Watermelon (Citrullus lanatus) is considered one of the most important cucurbits in the world and Brazil is the fourth largest producer, with a total cultivated area of 90.000 ha and average production of about two million tons. In Brazil, viruses described in watermelon belong to the genus Potyvirus and Cucumovirus and Zucchini lethal chlorosis virus is the only species of Tospovirus genre described on this culture. Considering the high incidence of watermelon plants showing symptoms caused by virus during the 2012/2013 seasons and the presence of thrips in the field, the virus and the vector associated with the disease was identified and characterized. In the first chapter entitled "Citrullus lanatus is a new natural host of Groundnut ringspot virus in Brazil", the species of tospovirus Groundnut ringspot virus(GRSV) was reported causing mosaic, deformation and necrotic lesions on leaves and fruits of watermelon. The GRSV was collected during the years 2012 and 2013 in producing areas of Presidente Prudente and Marília. GRSV from watermelon, differently from GRSV strains found on solanaceas, didn't infected tomato plants cv. Santa Clara and Mariana. Thrips specimens collected in the field were able to transmit GRSV to watermelon, peppers and Nicotiana species. This was the first report of natural infection of watermelon by GRSV. In the second chapter entitled "A Taqman real-time RT - PCR assay for detection of Groundnut ringspot virus" a quantitative PCR test was developed to efficiently detect GRSV from watermelon and from individual thrips. The test might be useful to detect GRSV and for further studies with this virus. The third chapter " Efficient detection of Frankliniella schultzei (Thripidae: Thysanoptera) by real-time PCR" reports the efficient detection of Frankliniella schultzei by the analysis of the mitochondrial gene cytochrome oxidase I (mtCOI). Thrips samples were ...<br>Doutor
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Steenkamp, Sonia. "Host plant resistance as a management tool for Ditylenchus africanus (Nematoda: Tylenchidae) on groundnut (Arachis hypogaea) / Sonia Steenkamp." Thesis, North-West University, 2008. http://hdl.handle.net/10394/2299.
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Ezekannagha, Ezinwanne. "Assessing the climatic suitability of Bambara groundnut as an underutilised crop to future climate projections in Sikasso and Ségou, Mali." Master's thesis, Faculty of Science, 2020. http://hdl.handle.net/11427/32612.
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This study evaluates how future climatic projections will affect the suitability of bambara groundnut (Vigna subterranean(L) Verdc.), a type of underutilised crop in Sikasso and Ségou, southern Mali. This study was performed using a simulation approach, which considered the potential changes in suitability due to projected changes in two climate variables; temperature and precipitation. Monthly outputs of the two climate variables from 10 CORDEX bias-corrected regional projections under the Representative Concentration Pathway (RCP) 8.5 were applied. The suitability index range of bambara groundnut was projected, using the Ecocrop suitability model, considering three time periods: historical (1975-2005), near-term (2011-2040), and end of century (2070-2099). The results of this study showed that the model captured a long planting window for the crop in the regions across the time periods. With the projected increase in future climatic conditions, the suitability index range of bambara groundnut is projected to increase across the months suitable for planting the crop. Furthermore, Sikasso is projected to maintain a high suitability index in the near-term, and by the end of century, Ségou is expected to experience a potential increase in suitability index range and suitable areas, especially by the end of century. The results indicate that the CORDEX projections and suitability modelling technique applied in the study captured well the suitability of bambara groundnut in the regions which can help the farmers in making planting decisions. These results suggest an opportunity for optimal utilisation of the crop in the regions, as with a long planting window and expansion in suitable areas, farmers in the regions can plant multiple times and have more suitable areas to cultivate. This study contributes to improving the decision-making surrounding the promotion of underutilised crops as part of the strategy for climate-resilient agriculture and food security in Sikasso and Ségou.
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Salmon, Lesley Anne. "The occurrence of races of rust and leaf spot pathogens of groundnut (Arachis hypogaea)." Thesis, Imperial College London, 1987. http://hdl.handle.net/10044/1/46460.
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Oya, Carlos. "Groundnut production crisis and liberalisation in Senegal : a case study of large-middle farmers." Thesis, SOAS, University of London, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.271436.
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Kakani, Vijaya Gopal. "Quantifying the effects of high temperature and water stress in groundnut (Arachis hypogaea L.)." Thesis, University of Reading, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.342143.
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Dabai, Fatima D. "Nutritional and technological properties of bambara groundnut (Vigna subterranea) in infant and adult food." Thesis, University of Reading, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.317276.
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Krauss, Ulrike. "Natural senescence of roots of groundnut (Arachis hypogaea L.) and relation to parasitic infections." Thesis, University of Edinburgh, 1993. http://hdl.handle.net/1842/12111.
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Senescence of plant roots is reviewed and related to laboratory and field observations on root turnover (death and replacement) of groundnut (<I>Arachis hypogaea</I> L.). Root death was assessed by browning, which correlated with failure of cells to plasmolyse after staining with neutral red. For five cultivars of groundnut grown in pasteurised soil in transparent tubes, death of root laterals commenced 3 - 4 weeks after sowing; root laterals died in proximal regions and new laterals formed in distal regions as the tap root extended. The half-life of individual roots was 3.7 - 4.4 weeks for all cultivars. Up to the time of plant maturity (14-20 weeks for different cultivars) 72.7% - 83.2% of cumulative (total) root length had died. Similar patterns were seen in field-grown plants in Malawi. Two pathogens of groundnut (<I>Aspergillus niger, Fusarium oxysporum</I>) and two saprophytes (<I>Idriella bolleyi</I> from cereals and <I>Mucor hiemalis</I> from groundnut) were induced or selected for tolerance of benomyl or pimaricin. The mutants had reduced hyphal extension rates on agar but sporulation similar to the wild-type parents in liquid culture. Spore suspensions of these mutants and of <I>Aspergillus flavus</I> were inoculated onto groundnut root laterals of different ages in tubes of soil. After 3 weeks, <I>A. niger</I> and <I>F. oxysporum</I> were not recovered; in other studies <I>A. niger</I> was found to germinate poorly in rhizosphere soil. <I>A. flavus, I. bolleyi</I> and <I>M. hiemalis</I> were recovered in higher numbers on young roots (lower in soil profile) than on older roots. Both growth at the expense of nutrients released early during root senescence <I>(A. flavus, I. bolleyi</I>) and spread in percolating water (<I>M. hiemalis</I>) are suggested to explain these findings. Spores of <I>M. hiemalis</I> (pimaricin-tolerant) were applied to groundnut hypocotyls and to the surface on non-planted soil in an experimental field plot in Malawi. The fungus spread rapidly and progressively down the rhizosphere, reaching at least 58 cm during 51 days, but it did not move far (7 cm) in non-planted soil.
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Dodd, Josie. "A multi-scale mathematical model for simulating and optimising the growth of Bambara groundnut." Thesis, University of Reading, 2018. http://centaur.reading.ac.uk/78970/.
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A principal objective in agriculture is to maximise food production; this is particularly relevant with the added demands of an ever increasing population, coupled with the unpredictability that climate change brings. Further improvements in productivity can only be achieved with an increased understanding of plant and crop processes. In this respect, mathematical modelling of plants and crops plays an important role. In this thesis we present a two-scale mathematical model of crop yield, that accounts for plant growth and canopy interactions. A system of ordinary differential equations (ODEs) has been developed for each individual plant, where equations are coupled via a term that describes plant competition. Both analytical and numerical methods have been considered to describe this competition. This model has been formulated for an underutilised African legume called bambara groundnut, a drought tolerant crop, which is currently being investigated to be used more widely as a food source in light of climate change and food security. Like many plant species, bambara groundnut exhibits physiological diversity which may affect the overall growth dynamics and crop yield. Such plant diversity is not regularly accounted for in crop scale models. Our model not only allows us to account for plant diversity, but we can investigate the effect of individual plant traits (e.g. plant canopy size and growth rates, planting distance) on the crop scale yield. The mathematical model has been formulated and validated using experimental data collected from the Tropical Crops Research Unit (TCRU) and Future Crops greenhouses at the University of Nottingham. We find that the mathematical model developed in this thesis is able to predict the growth of a population of bambara groundnut well and we go on to optimise the arrangement of individual plants for a series of scenarios. The primary aim of this is to maximise crop yield. Whilst formulated specifically for bambara groundnut, our model may also be extended to other crop species. In this thesis we demonstrate that the model is also able to simulate the growth of oil palm. We then apply the mathematical model to maximise crop yield in an intercropping environment; the planting of two or more species together in the same field area. We again investigate a series of scenarios that require optimisation and find that the optimisation techniques are able to provide plausible recommendations. This work has been undertaken in a multidisciplinary environment involving interactions with Plant Scientists at the University of Nottingham (Nottingham and Malaysia) and the Crops for the Future Research Centre, Malaysia.
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Ogundele, Opeoluwa Mayowa. "Nutritional and functional properties of soaked and micronized Bambara groundnut seeds and their flours." Thesis, University of Pretoria, 2016. http://hdl.handle.net/2263/77104.
Full textAbstract:
Bambara groundnut (Vigna subterranean L.) is considered a good source of protein in some parts of sub Saharan African countries. Long cooking time of about three hours contributed to its limited consumption and utilisation. Micronisation is an infrared heating process. It can reduce the cooking time of pre-moisture conditioned legume small seeds size such as cowpea and lentil, but mostly tempering of seeds has been used as the pre-conditioning techniques. The resulting flour from the pre-conditioned micronised cowpea can reduce pasting viscosity and has potentials in food systems as an instant product. This study aimed at (1) determining the effects of micronisation of pre-soaked whole and dehulled bambara groundnut seeds on their cooking characteristics, (2) determining the effects of micronisation and dehulling treatment of pre-soaked bambara groundnut on physicochemical, microstructure and functional properties of the resulting flours and (3) determining the effects of micronisation of pre-soaked whole and dehulled bambara groundnut seeds on the viscosity, nutritional and health benefits of the cooked samples in order to produce a quick cooked bambara groundnut with functional, nutritional and health benefits.
Micronisation (130 ºC) at a different time (0, 5, 10 and 15 min) was used to optimise the process for pre-soaked (53% moisture) bambara groundnuts. Micronisation (130 ºC) reduced cooking time of pre-soaked (53% moisture) bambara groundnut (whole and dehulled) following cooking. Micronisation reduced the 162 min cooking of raw bambara groundnut to 109, 83, 75 and 62 min when micronized for 0, 5, 10 and 15 min. Micronisation (53% moisture, 130 ºC) caused molecular changes such as solubilisation of pectin which was responsible for the disruption of the middle lamella and separation of parenchyma cell observed by light microscopy and scanning electron microscopy (SEM). It also caused disruption in the structure of starch granule, protein matrix in the cotyledon. These changes in seeds structure and molecular properties of starch, protein and pectin, facilitate water hydration rate and cell separation during cooking, leading to the shorter cooking time of the bambara groundnuts.
Micronisation of pre-soaked (53% moisture) bambara groundnuts caused molecular changes such as partial starch gelatinisation and reduced protein solubility in the resulting flours. The changes in the starch and proteins modified the resulting flours functional properties such asincrease swelling of the resulting flours, while reducing the water solubility. The pasting viscosities of resulting flours of pre-soaked bambara groundnut reduced following micronisation due to the denatured protein matrix preventing embedded starch hydration, dispersibility and molecular entanglement during pasting.This was evident by light and confocal laser scanning microscopy (CLSM) that showed the aggregates of denatured protein matrix surrounding embedded pre-gelatinised starch granules increase with micronisation in the resulting flours and cooked soft porridge of bambara groundnut.
Micronisation has an effect on the apparent viscosity, nutritional, bioactive compound such as phenolics and hence the antioxidant properties of cooked soft porridge of bambara groundnut. All cooked soft porridge of bambara groundnut exhibited a shear thinning behavior and micronised bambara groundnut had lower viscosity increased in the starch and protein digestibility of cooked soft porridge of bambara groundnut. It also increased the phenolic content and antioxidant properties of cooked soft porridge of whole bambara groundnut, but these were reduced in cooked soft porridge of dehulled bambara groundnut due to seed coat absence.
Thus, micronisation of pre-soaked bambara groundnut (whole and dehulled) would contribute towards increased utilisation of bambara groundnut as well as improving house hold nutrition and health promoting properties.Micronisation of bambara groundnut has potential to produce a quick paste with low viscosity which depend on the pre-soaking and micronisation time of the bambara groundnut. Flours from micronised bambara groundnut can therefore be used as instant flour ingredient in food products.<br>Thesis (PhD)--University of Pretoria, 2016.<br>National Research Foundation (NRF) of South Africa<br>Food Science<br>PhD (Food Science)<br>Unrestricted
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Murata, Monica Rujeko. "The impact of soil acidity amelioration on groundnut production and sandy soils of Zimbabwe." Diss., University of Pretoria, 1995. http://upetd.up.ac.za/thesis/available/etd-08152003-155125.
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