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Dissertations / Theses on the topic 'Potatoes – Africa'

Author: Grafiati

Published: 4 June 2021

Last updated: 6 February 2022

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1

Gouws, Reinette. "Etiology and integrated control of common scab on seed potatoes in South Africa." Diss., Pretoria : [s.n.], 2006. http://upetd.up.ac.za/thesis/available/etd-08212007-102435.

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2

Wright, Jessica. "Studies on powdery scab on potatoes in South Africa." Diss., University of Pretoria, 2012. http://hdl.handle.net/2263/24746.

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Spongospora subterranea (Wallroth) Lagerheim f. sp. subterranea Tomlinson (Sss) is the causal organism of potato powdery scab. This blemish disease is of economic concern to fresh and seed-tuber producers around the world, as it diminishes both tuber quality and marketability. In this study, techniques for detecting and quantifying Sss were evaluated. Comparison of enzyme linked immunosorbent assay (ELISA), conventional PCR and real-time PCR showed that conventional PCR is more sensitive than ELISA, as conventional PCR detected Sss inoculum from both tuber and soil samples whereas ELISA only d

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3

Boukes, Gerhardt Johannes. "The in vitro biological activities of three Hypoxis species and their active compounds." Thesis, Nelson Mandela Metropolitan University, 2010. http://hdl.handle.net/10948/1228.

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The African potato is used as an African traditional medicine for its nutritional and medicinal properties. Most research has been carried out on H. hemerocallidea, with very little or nothing on other Hypoxis spp. The main aim of this project was to provide scientific data on the anticancer, anti-inflammatory and antioxidant properties of H. hemerocallidea, H. stellipilis and H. sobolifera chloroform extracts and their active compounds. The hypoxoside and phytosterol contents of the three Hypoxis spp. were determined using TLC, HPLC and GC. H. hemerocallidea and H. sobolifera chloroform extra

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4

Snyman, Johannes Hendrick. "A strategic overview of the potato supply chain in South Africa." Pretoria : [S.n.], 2009. http://upetd.up.ac.za/thesis/available/etd-12142009-134649/.

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5

Truter, Mariette. "Etiology and alternative control of potato rhizoctoniasis in South Africa." Pretoria : [s.n.], 2005. http://upetd.up.ac.za/thesis/available/etd-04122005-112047.

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6

Van, der Merwe Johanna Jacoba. "Etiology of soft rot and blackleg on potatoes in South Africa." Diss., University of Pretoria, 2009. http://hdl.handle.net/2263/28656.

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Pectobacterium carotovorum (Pbc), Dickeya spp., Pectobacterium atrosepticum (Pba), and a new, atypical strain, Pectobacterium carotovorum subsp. brasiliensis (Pbcb) can cause potato blackleg, soft rot and aerial stem rot. To determine the impact and extent of these pathogens on the South African potato industry, samples were collected from 72 potato fields in 10 potato production regions during the 2006/7 production seasons. During these seasons, blackleg outbreaks occurred in commercial production fields causing severe economic losses. Bacteria isolated from diseased material that were Gram-n

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7

Pitsi, B. E. (Boitumelo Elijah). "Causal agent and control of brown spot of potatoes in South Africa." Diss., University of Pretoria, 2013. http://hdl.handle.net/2263/43225.

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8

Purushothaman, Nair Vipin Devi Prasad. "Pharmaceutical analysis and drug interaction studies : African potato (Hypoxis hemerocallidea)." Thesis, Rhodes University, 2006. http://hdl.handle.net/10962/d1015802.

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In order for a medicinal product to produce a consistent and reliable therapeutic response, it is essential that the final composition of the product is invariable and that the active ingredient/s is/are present in appropriate, non-toxic amounts. However, due to the complexity involved in the standardization of natural products, quality control (QC) criteria and procedures for the registration and market approval of such products are conspicuously absent in most countries around the world. African Potato (AP) is of great medical interest and this particular plant has gained tremendous populari

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9

Jordaan, Estiene. "Quantification and characterization of the Streptomyces complex causing common scab of potatoes in South Africa." Diss., University of Pretoria, 2014. http://hdl.handle.net/2263/79247.

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Common scab is a disease that results in corky lesions on the surface of potatoes. These lesions can be variable in size, shape and as a result of secondary infection may appear extremely cryptic. The disease is caused by Streptomyces, a group of Actinomycetes that are largely saprophytic. For this reason lesions may also contain saprophytic Streptomyces which makes isolation and detection of pathogenic species on potatoes difficult. Symptom expression is thought to be attributed to environmental factors and prevalence of pathogenic species. Common scab causing Streptomyces isolates were colle

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10

Onkendi, Edward Makori. "Molecular characterization of root-knot nematodes (Meloidogyne spp.) parasitizing potatoes (Solanum tuberosum) in South Africa." Diss., University of Pretoria, 2012. http://hdl.handle.net/2263/24747.

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Potato (Solanum tuberosum) is regarded as one of the single most important vegetable crops in South Africa, with an average annual production of 2 million metric tons. The potato industry contributes to an average of $ 0.37b worth of potatoes annually. Over the years, potato production in South Africa has been affected by, among other factors, diseases and plant parasitic nematodes particularly root-knot nematodes (Meloidogyne spp.). In infected potato fields, root-knot nematodes cause great damage to the crop leading to substantial losses in yield and compromised produce quality. The direct a

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11

Lynch, Alisson. "Comparisons of levels of genetic diversity among Streptomyces scabies isolates of South Africa using various DNA techniques." Thesis, Stellenbosch : Stellenbosch University, 2000. http://hdl.handle.net/10019.1/51658.

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Thesis (MSc)--University of Stellenbosch, 2000.<br>ENGLISH ABSTRACT: Streptomyces spp. are responsible for a large proportion of the world-wide quality deterioration of potatoes causing a potato tuber disease called cornmon scab. Determining the genetic diversity of the Streptomyces spp., especially the main pathogen, S. scabies, has been a prerequisite for the ultimate control of common scab. Techniques responsible for the classification and determination of genetic diversity have improved with advances in DNA technology. Analysis of South African (S.A.) S. scabies isolates has been foc

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12

Baijnath, Sharika. "Effect of inoculum source, inoculum pressure and cultivar on development of black scurf on potatoes in South Africa." Diss., University of Pretoria, 2012. http://hdl.handle.net/2263/24650.

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Rhizoctonia solani inoculum can be present either as soil- or tuber-borne sclerotia or hyphae. Although both inoculum sources play a role in disease development, it is not clear which of the two is more important. Successive cultivation of potato crops increases R. solani soil inoculum load resulting in an escalation in disease incidence and severity. The use of tolerant cultivars, however, can effectively reduce inoculum levels thereby decreasing disease intensity. Four pot trials were conducted; the objective of the first two pot trials was to determine the effect of tuber and soil-borne ino

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13

Visser, Johan Christiaan. "A study of genomic variation in and the development of detection techniques for potato virus Y in South Africa." Thesis, Stellenbosch : Stellenbosch University, 2008. http://hdl.handle.net/10019.1/21878.

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Thesis (MSc)--University of Stellenbosch, 2008.<br>ENGLISH ABSTRACT: Potato virus Y (PVY) is responsible for considerable yield losses in the South African potato industry. The incidence of this virus has greatly increased over the past few years. Even more worrying is the variation of symptoms observed during PVY infection and the recent appearance of the more virulent PVYNTN strain in local fields. This project aimed to investigate the possible genetic variation within the viral genome and to establish the origin of strains. The project also aimed to establish a dependable, area specifi

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14

Brink, Pieter Paul. "Die waarde van petioolsap analise in die optimalisering van N-voeding by aartappels (Solanum tuberosum L.) in sandgronde." Thesis, Stellenbosch : Stellenbosch University, 2000. http://hdl.handle.net/10019.1/51728.

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Thesis (MScAgric)--University of Stellenbosch, 2000<br>ENGLISH ABSTRACT: Approximately 7000 ha of potatoes are cultivated under irrigation. The greatest part of the planting is entered under the South African Certification Scheme as seed potatoes, representing between 35 and 40 % of seed production in South Africa. The production of high-quality tubers is, therefore, in the interest of the entire country. Some production factors in the area, however, have a very negative influence on quality with a resultant increase in input costs. These factors include mainly low clay content of the so

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15

Marais, Carla. "Effect of inoculum source, alternative host and cultivar on development of brown spot and black pit of potatoes in South Africa." Diss., University of Pretoria, 2013. http://hdl.handle.net/2263/40339.

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In recent years two new diseases, brown spot and black pit, have been observed on potatoes in South Africa. Brown spot symptoms appear on the foliage as small brown lesions, whereas black pit symptoms appear on the tubers as small dark sunken lesions. In this study the causal organism of brown spot and black pit of potatoes in South Africa was determined. During initial isolation, one fungus and two bacteria were isolated, which were included in the trial. Only the treatments where the fungal isolate was used in inoculation resulted in the development of brown spot lesions. The causal organis

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16

Mogatle, Seloi. "African traditional medicines-antiretroviral drug interactions: the effect of African potato (Hypoxis hemerocallidea) on the pharmacokinetics of efavirenz in humans." Thesis, Rhodes University, 2009. http://hdl.handle.net/10962/d1003251.

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African Potato (Hypoxis hemerocallidea), (AP) is an African traditional medicine (TM) that is commonly used for various nutritional/medicinal purposes and also by people infected with the human immuno deficiency virus HIV and AIDS patients as an immune booster. The use of AP has also been recommended by the former Minister of Health of South Africa for use by HIV positive people. The main phytochemical component of AP is a norlignan glucoside, hypoxoside, and other relatively minor components have also been reported. A recent in vitro study reported the effects of AP extracts, hypoxoside and r

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17

Visser, Johan Christiaan. "A study of the strain evolution and recombination of South African isolates of Potato virus Y." Thesis, Stellenbosch : Stellenbosch University, 2012. http://hdl.handle.net/10019.1/71637.

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Thesis (PhD)--Stellenbosch University, 2012.<br>ENGLISH ABSTRACT: Potato virus Y (PVY) is responsible for considerable yield losses in the South African potato industry. The incidence of this virus has greatly increased over the past 20 years. In previous studies nonrecombinant strains of PVY, PVY N and PVY O, were detected in South African potatoes. In a recent study the occurrence of non-recombinant strains of PVY in South African potatoes was shown to have decreased while infection by more virulent recombinant strains, PVY NTN and PVY N-W, had increased dramatically. Infection of pota

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18

Jukes, Michael David. "The isolation, genetic characterisation and biological activity of a South African Phthorimaea operculella granulovirus (PhopGV-SA) for the control of the Potato Tuber Moth, Phthorimaea operculella (Zeller)." Thesis, Rhodes University, 2015. http://hdl.handle.net/10962/d1017908.

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The potato tuber moth, Phthorimaea operculella (Zeller), is a major pest of potato crops worldwide causing significant damage to both field and stored tubers. The current control method in South Africa involves chemical insecticides, however, there is growing concern on the health and environmental risks of their use. The development of novel biopesticide based control methods may offer a potential solution for the future of insecticides. In this study a baculovirus was successfully isolated from a laboratory population of P. operculella. Transmission electron micrographs revealed granulovirus

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19

Matzopoulos, Mark. "The development of enzyme-linked immunosorbent assays to detect potato virus Y and potato leaf roll virus using recombinant viral coat proteins as antigens." Thesis, Stellenbosch : University of Stellenbosch, 2005. http://hdl.handle.net/10019.1/16616.

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Thesis (MSc)--University of Stellenbosch, 2005.<br>ENGLISH ABSTRACT: Potato Virus Y (PVY) and Potato Leafroll Virus (PLRV) are two of the most destructive potato viruses capable of drastically diminishing crop yields by up to 80%. The presence of these viruses in planting material namely seed potato stocks are routinely diagnosed by enzyme-linked immunosorbent assay (ELISA) kits. The kits currently used by Potatoes South Africa are obtained from Europe. These kits have produced false positive and false negative results in the past. Potatoes South Africa required an ELISA that was reliable

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20

Tairo, Fred. "Molecular resolution of genetic variability of major sweetpotato viruses and improved diagnosis of potyviruses co-infecting sweetpotato /." Uppsala : Dept. of Plant Biology and Foresty Genetics, Swedish University of Agricultural Sciences, 2006. http://epsilon.slu.se/200605.pdf.

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21

Pule, Boitumelo Bronwen. "Population structure of Phytophthora infestans in selected central, Eastern and Southern African countries." Thesis, Stellenbosch : Stellenbosch University, 2010. http://hdl.handle.net/10019.1/5461.

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Thesis (MSc)--Stellenbosch University, 2010.<br>ENGLISH ABSTRACT: Late blight caused by Phytophthora infestans on potato and tomato causes major economic losses worldwide. Until the 1980s, P. infestans populations outside its centre of origin (either central Mexico or the Andean region) only consisted of one mating type (A1), which prevented the pathogen from reproducing sexually. Pathogen populations outside the centre of origin most likely only consisted of a few genotypes prior to the 1980’s. Pan globally, these genotypes probably first consisted of genotype/s that had mitochondrial D

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22

Rothmann, Adri Hilda. "An assessment of the mutation patterns in South African isolates of Potato leafroll virus and the expression of recombinant viral coat protein genes in Escherichia coli." Thesis, Stellenbosch : Stellenbosch University, 2007. http://hdl.handle.net/10019.1/19861.

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Thesis (MSc)--University of Stellenbosch, 2007.<br>ENGLISH ABSTRACT: Presently, the observed variation in symptoms of Potato leafroll virus (PLRV) infection in potato cultivars in South Africa cannot be reconciled with PLRV symptoms obtained 10-15 years ago, even if the different interactions between the pathogen and the cultivar are taken into account. In an effort to analyze this variation, mutations in the coat protein (CP) gene of South African isolates of PLRV were assessed. The CP gene of PLRV isolates from different areas within South Africa was amplified by reverse transcription-p

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23

Sylvester, Thomas Ronald. "An evaluation of the effects of two different inoculants on the quality of potato hash silage for grower pigs." Thesis, [Bloemfontein?] : Central University of Technology, Free State, 2010. http://hdl.handle.net/11462/134.

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Thesis (M. Tech.) -- Central University of Technology, Free State, 2010<br>This study evaluated the effects of two bacterial inoculants on the fermentation quality and aerobic stability of ensiled potato hash (PH) and on digestibility, growth performance and carcass characteristics of growing pigs fed the ensiled PH. In the first experiment, 700 grams of PH, was mixed with 300g wheat bran (as is basis) and ensiled in 1.5 litre anaerobic jars. The mixture had a dry matter (DM) of 41.3 g/kg, 78.05 g/kg DM of water-soluble carbohydrates (WSC) and a pH of 6.87 at day 0 and was treated with Bonsila

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24

Moabelo, Julith Tsebisi. "Analysing potato price volatility in South Africa." Thesis, University of Limpopo, 2019. http://hdl.handle.net/10386/3049.

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Thesis ( M.Sc.(Agricultural Economics)) --University of Limpopo, 2019.<br>Potato is perceived as an excellent crop in the fight against hunger and poverty. The recent high potato price in South Africa has pushed the vegetable out of reach of the poorest of the poor. The study attempts to analyse potato price volatility in South Africa and furthermore assess how various factors were responsible for the recent potato price volatility. Quarterly data for potato price, number of hectares planted, rainfall and temperature levels from 2006q1 to 2017q4 was collected from various sources and were use

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25

Roos, Wiets Gideon. "An investigation of prevalance and the detection and race identification of South African potato viruses." Thesis, Stellenbosch : Stellenbosch University, 2013. http://hdl.handle.net/10019.1/80313.

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Thesis (MSc)--Stellenbosch University, 2013.<br>ENGLISH ABSTRACT: Infection of potatoes by viral pathogens causes reduced crop yield and subsequent economic loss. In South Africa Potato virus Y (PVY) and Potato leafroll virus (PLRV) are the two most destructive viruses infecting potatoes. Several other viral pathogens exist, including Potato virus X (PVX), Potato virus M (PVM), Potato virus A (PVA), Potato virus S (PVS), Potato mop-top virus (PMTV), Tomato spotted wilt virus (TSWV) and Potato spindle tuber viroid (PSTVd). Although the aforementioned pathogens are found infecting potatoes

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26

Troskie, C. G. (Casparus Gerhardus). "The economic impact of electricity price increases on the potato industry in South Africa." Diss., University of Pretoria, 2012. http://hdl.handle.net/2263/24537.

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At the start of 2010, the National Energy Regulator of South Africa (NERSA) announced that electricity tariffs would increase at an average rate of 25 percent per year over a three year period (Njobeni, 2010). This raised fears within the economy and specifically within the agricultural sector that these increases would negatively impact the agricultural sector. Various stakeholders within the agricultural sector also raised opinions on what the true impact will be on agricultural production and market prices. The main objective of this study was to quantify the true impact of higher electrici

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27

Haverkort, A. J. "Relationships between intercepted radiation and yield of potato crops under tropical highland conditions of Central Africa." Thesis, University of Reading, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.370132.

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28

Mulovhedzi, Ntsieni. "Quantifying water use and nutritional water productivity of two sweet potato (Ipomoea batatasL.) cultivars grown in South Africa." Diss., University of Pretoria, 2017. http://hdl.handle.net/2263/65920.

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The most accurate way of quantifying water use or evapotranspiration (ET) is achieved through direct physical measurements. Therefore, quantifying water use of sweet potato using the eddy covariance (EC) system which is one of the direct methods, and calculating crop growth parameters under optimal crop growing conditions, will improve our understanding and crop management practices. Also water scarcity is becoming more and more of a threat to food and nutritional security. Therefore, it is important to produce higher nutrients per unit of water used in order to alleviate malnutrition and to c

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29

Tomlins, Keith. "Factors influencing the post-harvest quality and consumer preference of sweet potato and other products in sub-Saharan Africa." Thesis, University of Greenwich, 2009. http://gala.gre.ac.uk/5658/.

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The first theme covers sweetpotato in the marketing chain from farm to consumer. In East Africa, research explored ways of improving the handling and transport of sweetpotato, shelf life and storage of fresh roots on the farms to increase incomes and food security. Transport and handling were investigated using a novel ‘electronic sweet potato’ where it was found that it was the large number of minor vibrational type impacts that cause the most root damage. Reducing the sack weight and using fibreboard boxes reduced damage. A shelf-life investigation into the types of injury occurring through

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30

Swayeb, Amel Ahmed. "The possible effect of Hypoxis hemerocalledia (African potato) on blood glucose levels : an in vitro study." University of the Western Cape, 2015. http://hdl.handle.net/11394/5454.

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>Magister Scientiae - MSc<br>The plant Hypoxis hemerocallidea, also known as the African potato, is commonly used as a traditional medicine to treat diabetes in South Africa. The mechanism by which it lowers blood glucose levels is not known. The main aim of this research was to study the possible hypoglycemic effect of HH using RIN-5 F pancreatic tumor cells. To accomplish this, the study was divided into three parts: (1) to test whether exposure of RIN-5F cells to glucose and HH extract affect the cell proliferation and cell viability, (2) to test whether the HH extract have an effect o

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31

Muller, Cornelis Hermanus. "Coercive agrarian work in South Africa, 1948 - 1965 : 'farm labour scandals'?" Diss., University of Pretoria, 2011. http://hdl.handle.net/2263/30300.

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This dissertation puts into historical context allegations of farm labour abuse during the period 1948 to 1960 on the eastern Transvaal Highveld. It not only gives an exposition of these events, but importantly analyses these allegations of abuse in the context of the South African government’s intervention into farm labour for this period. The dissertation, however, first gives an overview of the government’s policies of regulating and providing farmers with black labour in the period 1910 to 1948. It deals specifically with the dubious measures introduced and coercive actions taken by the Na

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Jordaan, Audrey Emmerentia. "The effects of the wild african potato (hypoxis hemerocallidea) supplementation on streptozotocin-induced diabetic wistar rats reproductive function." Thesis, Cape Peninsula University of Technology, 2015. http://hdl.handle.net/20.500.11838/2234.

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Thesis (MTech (Biomedical Technology))--Cape Peninsula University of Technology, 2015.<br>Diabetes mellitus (DM) has been reported to be one of the greatest global public health threats. Statistics of the fertility status of modern society has linked increased DM to a decrease in fertility rates. Hyperglycaemia is characteristic of DM that results in a disturbance of proteins, lipids and carbohydrate metabolism leading to an increase production of reactive oxygen species (ROS). In the case where ROS overwhelms antioxidant mechanisms, the body goes into state of oxidative stress (OS). OS plays

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33

Phakdeewanich, Titipol. "The role of farmers groups in Thai politics : a case study of domestic and global pressure on rice, sugarcane, and potato farmers." Thesis, University of Warwick, 2004. http://wrap.warwick.ac.uk/55736/.

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The thesis studies the political participation of Thai farmers and focuses on two main factors, namely the domestic and the external impacts, which inform the case studies of rice, sugarcane, and potato farmers groups. Overall, the research has established that farmers groups have felt the impacts of domestic factors far more strongly than external factors. Furthermore, through comparative studies in relation to the case studies of rice, sugarcane, and potato farmers groups in Thailand, differences emerged between these three Thai farmers groups, in terms of the degree to which domestic factor

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Mongae, Aobakwe Oratile. "The interaction between root knot nematodes (Meloidogyne spp.) and soft rot Enterobacteriaceae (Pectobacterium spp.) and their host Solanum tuberosum." Diss., University of Pretoria, 2013. http://hdl.handle.net/2263/32995.

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Meloiodgyne incognita, one of the most aggressive plant parasitic nematodes species on potato in South Africa, belongs to a group of plant parasitic nematodes commonly known as root knot nematodes (RKN). This group of nematodes is widely distributed throughout the world. Meloidogyne spp. cause major economic losses to important crops such as potato and therefore decrease their market value in many countries across the world. The second stage juveniles are the only mobile and infective phase of the root knot nematode. As they infect host roots, they create wounds that can be used by other plant

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Managa, Lavheselani Rodney. "Evaluation of Iron (Fe) and Zinc (Zn) concentration among selected potato (Solanum tuberosum) genotypes in South Africa." Diss., 2015. http://hdl.handle.net/10500/19792.

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Text in English<br>Potato is an important source of energy to most micronutrient malnourished affected population in South Africa. Improvements through bio-fortification can therefore enhance access to essential micronutrients. The study was aimed at determining the level of variability of iron and zinc concentration among 20 potato genotypes as a preliminary step for future breeding program. The materials were evaluated using inductively coupled plasma optical emission spectrometry. Statistical analysis indicated significant (P<0.001) variation of Fe and Zn among the genotypes. The average co

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Visser, Diedrich. "The potato tuber moth, Phthorimaea operculella (Zeller), in South Africa: potential control in non-refrigerated store environments." Thesis, 2004. http://hdl.handle.net/2263/24831.

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Please read the abstract in the section 00front of this document. Also note that an abstract is provided for each chapter as well<br>Thesis (DPhil (Entomology))--University of Pretoria, 2005.<br>Zoology and Entomology<br>unrestricted

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Van, der Waals Jacquie E. (Jacqueline Elise). "Epidemiology of early blight on potatoes in South Africa." Thesis, 2004. http://hdl.handle.net/2263/24541.

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Early blight (Alternaria solani Sorauer)is a major foliar disease of potatoes in most growing regions of the world and is underestimated in South Africa. This project studies the epidemiology and control of the disease in South Africa. A decision support system (DSS) for early blight in South Africa was developed and evaluated in field trials. This early blight DSS is the first such system to be developed in South Africa and once incorporated with the late blight model, will represent innovative technology for use in the South African potato industry. Trends in weather variables and concentrat

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Millard, Cornelia Philipina. "Verticillium wilt of potato in South Africa." Diss., 2003. http://hdl.handle.net/2263/25929.

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Since the first report of Verticillium wilt of potato in 1950, the disease has been considered to be of minor importance in South Africa. Between 1995 and 2000, however, Verticillium spp. were isolated from 146 samples of symptomatic potato plant material received from 13 of the 14 potato production areas in the country. Of 93 Verticillium isolates that were obtained, 60% were identified as V. dahliae and 8 % V. nigrescens. V. dahliae was present in nine of the regions and V. nigrescens in seven. Unidentified Verticillium species were isolated from six of the regions. Both V. dahliae and V. ni

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Liebenberg, Denise. "Another culture of Solanum genotypes." Thesis, 1995. http://hdl.handle.net/10413/10345.

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Being the third most cultivated crop in South Africa, potatoes are of great economic importance. As potatoes originated from cooler areas in the world, they do not easily adapt to South African conditions. The main objective of potato breeding is, therefore, to extend the crop's limited genetic base. Progress in crop improvement is slow due to dominance, segregation and other factors caused by the tetraploid character of cultivated potatoes. A new breeding program for rapid progress has been initiated at the Vegetable and Ornamental Plant Institute, Roodeplaat, South Africa, which comprises th

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Jansen, van Rensburg Willem Sternberg. "The development of a SCAR marker for the identification of the potato cultivars Astrid and Mnandi." Thesis, 2012. http://hdl.handle.net/10210/5524.

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M.Sc.<br>Mnandi and Astrid are two commercially important potato cultivars in South Africa. These two cultivars are closely related and are morphological virtually identical. It is, however, necessary to be able to distinguish between these two cultivars, because each of these cultivars has certain desirable characteristics. It was decided to use DNA markers, since DNA markers are not influenced by the environment and the polymerase chain reaction (PCR) based DNA markers are relatively easy, cheap and fast. It was decided to develop a sequenced characterized amplified region (SCAR) due to the

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Bothwell, Kier C. "Rotten potatoes: redefining perceptions and integrating the police station in city and suburban." Thesis, 2014. http://hdl.handle.net/10539/15499.

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Living in a country plagued by high crime rates and negative perceptions of the South African Police Service, South Africans are relying more and more on devices such as siege architecture and fortification to attain a sense of safety and security. However, these fortified enclaves do not just provide people with a sense of safety, they also serve as manifestations of Apartheid memory: intensifying segregation and ‘othering’, discouraging the growth of community and working against the development of healthy and inspiring civic spaces. At the same time, society’s obsession with police criminal

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42

Dube, Joel Prince. "Characterization of Alternaria alternata isolates causing brown spot of potatoes in South Africa." Diss., 2014. http://hdl.handle.net/2263/43326.

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Alternaria alternata (Fr.) Keissler is now widely recognized as the causal agent of brown spot and black pit of potatoes. Brown spot is a foliar disease with potential to cause 30% yield loss and postharvest losses of up to 10%. Losses are mainly due to premature defoliation. In this study, morphological and epidemiological characteristics of A. alternata were studied in order to understand the extent to which different light regimes influence radial growth, sporulation and pathogenicity of this pathogen. The role of low temperatures on initial sporulation was also investigated. Exposure

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Sivparsad, Benice. "The development of transgenic sweet potato (Ipomoea batatas L.) with broad virus resistance in South Africa." Thesis, 2013. http://hdl.handle.net/10413/10038.

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Sweet potato (Ipomoea batatas Lam.) is ranked as the seventh most important food crop in the world and its large biomass and nutrient production give it a unique role in famine relief. However, multiple virus infection is the main disease limiting factor in sweet potato production worldwide. The main objective of this research project was to develop a transgenic sweet potato cultivar with broad virus resistance in South Africa (SA). A review of current literature assembled background information pertaining to the origin, distribution and importance of the sweet potato crop; viruses and complex

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Nxumalo, Nokukhanya Nokuphila. "Occurrence, identification and a potential management strategy of Fusarium species causing wilt of potatoes in South Africa." Diss., 2013. http://hdl.handle.net/2263/33188.

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Fusarium is a soilborne fungus which can live in soil for long periods of time. It is known to cause wilt, root rot and crown rot diseases in a diverse group of crop plants. Of all the diseases caused by Fusarium the most important are the vascular wilts. Pathogens that cause wilting usually enter their host plant through young roots and then grow into and up the water-conducting vessels of the root and stem. The vessels become blocked and water supply to the leaves is limited. This results in the potato plant being weak resulting in yellowing of leaves, browning of stems and production

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Mutavhatsindi, Tshilidzi Faith. "Effects of fibrolytic enzyme and bacterial inoculants on the fermentation, chemical composition and aerobic stability of ensiled potato hash." Thesis, 2016. http://hdl.handle.net/11602/430.

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Chalwe, Joseph Musonda. "Assessing the genetic diversity of Alternaria Bataticola in South Africa using molecular markers." Thesis, 2015. http://hdl.handle.net/10352/298.

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M. Tech. (Biotechnology, Department of Biotechnology, Faculty of applied and computer sciences) Vaal University of Technolog<br>Sweetpotato (Ipomoea batatas) is an important food crop that is grown in many countries. A number of viral and fungal sweetpotato diseases have been reported worldwide. One of the major and most economic diseases of the sweetpotato is Alternaria blight which is caused by the fungal pathogen Alternaria bataticola. This disease can be managed in a short term using fungicides and cultural practices. However, a long term and inexpensive approach is through the development

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Domola, Mapula Julia. "Survey and characterisation of sweet potato viruses in South Africa." Diss., 2004. http://hdl.handle.net/2263/24205.

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Omotobora, Babajide Olusegun. "Evaluation of selected sweetpotato (Ipomoea batatas) accessions for drought tolerance." Diss., 2013. http://hdl.handle.net/10500/10490.

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Sweetpotato (Ipomoea batatas) is a major staple food in Africa and the rest of the world where they are discovered to be a good source of carbohydrates, vitamin A, vitamin C and protein. The maximum production potential of the crop is being hampered by severe drought which ravages most parts of Africa. The main aim of this project therefore is to screen collected accessions of sweetpotatofor drought tolerance in a quick screening method with a view to identify cultivars that can perform well under water stress conditions. Fifty selected sweetpotato accessions consisting of cultivars and bree

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Libago, Khuliso. "Profitability of sweet potato enterprises in Limpopo Province: A case study of Vhembe District." Diss., 2017. http://hdl.handle.net/11602/688.

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MSCAGR (Agricultural Economics)<br>Department of Agricultural Economics<br>This research aimed to assess the profitability of sweet potato production enterprises. The focus areas were on: determining differences in profitability of different sweet potato enterprises located in different villages; identifying factors that affect the profitability of sweet potato enterprises; determining differences in the sweet potato markets; and identifying marketing channels utilised by sweet potato enterprises. The study was carried out in 8 villages in Makhado and Thulamela local municipalities of the Vhem

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Nkosi, Brightness Zama. "Characterisation of Fusarium oxysporum species complex associated with Fusarium wilt of sweet potato in South Africa." Diss., 2020. http://hdl.handle.net/10500/26613.

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Sweet potato is a popular food security crop in South Africa and has a considerable commercial value. Fusarium wilt (FW), caused by the fungal pathogen Fusarium oxysporum formae speciales (f. sp.) batatas, has been reported worldwide and is widespread in sweet potato production areas in South Africa. Preliminary molecular identification of South African isolates from diseased sweet potato plants indicated that there are other formae speciales besides F. oxysporum f. sp. batatas associated with FW. The objectives of the study were to conduct a field survey and to characterise the isolates of th

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