Cette thèse utilise des approches de génétique des populations et de statistique pour étudier des événements anciens de démographie humaine, inférer de l’adaptation locale dans diverses populations et étudier le déterminisme du goût. En utilisant une approche bayésienne, j’évalue les preuves génétiques d’une réduction de population entre 190 000 et 130 000 ans avant notre ère. Je trouve que les données sont en faveur d’un modèle sans goulot d’étranglement durant cette période. Dans le second article, je développe une méthode destinée à la détection d’adaptation locale basée sur l’étude des haplotypes privés. Appliquée à des données de génotypage, cette méthode permet de détecter des signaux d’adaptation connus chez l’Homme mais aussi d’étendre nos connaissances en matière d’adaptation. J’étudie ensuite les signaux d’adaptation dans des données de génomes entiers de plusieurs populations et montre que le régime alimentaire et les pathogènes ont une influence majeure sur la variabilité adaptative des populations prises en compte. J’étudie dans un dernier article les perceptions gustatives de populations ayant différents modes de vie. Je présente les résultats phénotypiques de perception des goûts, et les associe à des données de génotypage. Je montre que les gènes impliqués dans la perception des goûts ont évolué avec le mode de vie. En effectuant une étude d’association, je montre aussi que les variations dans la perception des goûts impliquent plus de gènes que les seuls gènes codant pour les récepteurs gustatifs. Mes résultats montrent l’utilité des données génétiques denses pour mieux comprendre l’évolution humaine. / This thesis uses population genetics and statistical approaches to investigate early human demography, infer local adaptation in diverse sets of populations, and study the genetic basis for taste perception. Using a Bayesian approach, I evaluate the genetic evidence of a bottleneck between 190,000 and 130,000 years ago and find that the data is in favor of a model without bottleneck at this time point. I further develop a method to detect local adaptation based on frequencies of private haplotypes. Applied to large-scale human genotype data, this method detects known signals of positive selection but also permits to improve knowledge on potential adaptation events in humans. I further investigate patterns of adaptation in whole genome data based on a diverse set of African populations. The results from the regions potentially selected show that diet and pathogens are the common driving forces of adaptation in all studied populations. I last study taste perception in populations differing on lifestyle (hunter-gatherers, farmers and nomad herders). I present taste perception phenotypes for all tastes (sweet, bitter, sour, salty and umami) and relate them to high density genotype data. I show that taste and taste-involved genes have evolved with lifestyle. By performing an association study, I also show that variation in taste perception involves more genes than only the taste receptors genes.I covered several topics of human ancient demography and adaptation and show the utility of using large-scale genetic data to better understand human history.

Please read the abstract in the 00front part of this document / Thesis (PhD (Agricultural Economics))--University of Pretoria, 2006. / Agricultural Economics, Extension and Rural Development / unrestricted

This thesis uses the substainable rural livelihoods framework to investigate the agricultural livelihoods of the Cata community of the Eastern Cape. The Cata community is a deeply rural community located on the southern slopes of the Amatole Mountains. Traditional crop production used to be the major source of income for the households in this community. Of late there has been a lesser reliance on production of food by many households. Many are no longer ploughing their fields or their homestead gardens. People from this community are now spending most of their income on purchasing basic food items that they use to produce themselves, such as vegetables. The researcher then decided to study the contemporary livelihood of this rural community so as to identify the reasons why people in Cata are no longer ploughing their fields and gardens. This study found that, rural people in the community are faced with severe obstacles to agricultural production and this has led them to abandon agriculture as a major means of household support. These obstacles include high cost of production inputs, lack of fencing and lack of mechanization tractors and implements. In order to revitalize crop production the people want to be assisted with production inputs, tractor subsides, consistent water supply and fencing of the fields. Finally, the study makes recommendations for the revitalization of crop production in the Cata.

South Africa has one of the highest unemployment rates in the world. The majority of the economically active, but unemployed people enter the informal economic sector, as a means to make ends meet. Waste recycling falls into this informal sector. On average South Africa recovers about 52 percent of all recoverable paper and 26 percent of all recoverable plastic per annum. These figures are low when compared with developed countries where up to 90 percent of recoverable paper is recovered. As recycling creates job and income generating opportunities, it thus has a vital role to play in poverty alleviation. The research examines the role of subsistence waste pickers in the recycling industry in South Africa. The research was qualitative and exploratory in nature. Data for this study was gathered through 30 semi-structured interviews with key stakeholders in the recycling industry. In total, informal waste pickers provide at least 84 percent of all recyclable materials in Johannesburg through merchants, recyclers and producers of recyclable material in Johannesburg. Informal waste pickers bring considerable socio-economic benefits to countries around the globe, providing work for the unskilled, providing a constant supply of secondary raw materials to the local manufacturing industries and significantly reducing the quantity of waste to landfill sites. However, the research will show that even in the best situations, waste pickers suffer ergonomic problems due to the physically taxing nature of their job, as well as psychological and social disadvantages stemming from their low social status. / Dissertation (MBA)--University of Pretoria, 2012. / Gordon Institute of Business Science (GIBS) / unrestricted

Thesis (M.Sc. (Geography)) --University of Limpopo, 2019 / Climate change is one of the biggest threats confronting humanity in the 21st century. There has been an increase in global average temperatures by about 0.85°C between 1880 and 2012. In South Africa, mean annual temperatures have increased by at least 1.5 times the observed global average over the last 50 years. Climate change is thus already a measurable reality in the country where it is negatively impacting on water resources, biodiversity, ecosystems, health and food security. Subsistence farmers especially, are envisaged to be facing challenges from climate change due to their limited knowledge, assets and financial resources. Little, however, is known about the adaptation process involving subsistence farmers. This study thus sought to assess the effects of subsistence farmers’ knowledge and perceptions on climate change adaptation and the role played by assets in enhancing farmers’ adaptive capacity. To collect data, the study used quantitative and qualitative research approaches which consisted of a questionnaire survey as well as in-depth interviews. Data was collected from 148 households in Ward 24 of Polokwane Local Municipality. Survey results indicate that 58% of the farmers were engaged in crop farming only, 3% in livestock farming only and 39% in mixed farming. Generally, subsistence farmers had knowledge of climate change. Their knowledge and perceptions were in line with current scientific observations on climatic and environmental changes in the country. Even though some farmers were adapting to climate change, the majority were hindered from adaptation by lack of financial resources. Assets played a significant role in climate change adaptation as households possessing different assets were using these assets to enhance their adaptive capacity and reduce their vulnerability. The study concludes that farmers’ adaptation strategies to climate in the ward was primarily influenced by the knowledge and perceptions that the farmers had on climate change. Additionally, possession of household assets played a central role in the adaptation process. The more assets that a household possessed, the more adaptive and resilient to climate change that the household was likely to be. Given this conclusion, the study recommends deploying agricultural extension officers in the study area to provide more information on climate change regarding causes, effects and the range of adaptation strategies available. Improved farming approaches should be instituted to enhance farming output, which will enable farmers to buy assets that are central to the adaptation process. Poverty alleviation programmes should also be introduced to reduce poverty and enhance the subsistence farmers’ capacity to adapt and secure their livelihoods. / National Research Foundation (NRF)

Thesis (M.Sc. (Agricultural Economics)) -- University of Limpopo, 2021 / The agricultural sector in the Limpopo Province, comprises both commercial and subsistence farming. The smallholder farmers in the province are mainly producing for subsistence purposes and play an important role in poverty alleviation and livelihood creation. These smallholder farmers produce lower quantities of products that are also of low quality. Consequently, their products are rejected in the markets and by processors, and this affects the extent to which they participate in the market. This presents a challenge since the smallholder farming is highly labour intensive and represent the main source of income-generating occupations and a source of economic relief for the majority of people residing in the former homeland areas of the Limpopo Province. This study examined the factors influencing production and market participation among smallholder tomato farmers in Madibong and Manganeng Villages, at Makhuduthamaga Municipality in Greater Sekhukhune District, using the Multiple Linear and the Logistic Regression Models. The Multiple Linear Regression Model was used to analyse the socio-economic factors influencing tomato production among smallholder farmers in the study area. The results of the model indicated that extension access, fertiliser application, marital status, use of agricultural equipment and income from production output significantly influence tomato production among smallholder farmers. The Logistic Regression Model was used to analyse the socio-economic factors influencing market participation among smallholder tomato farmers in the study area. The Logistic Regression results indicated that factors such as educational level, gender of the farmer, farming experience, marital status, and farm size positively and significantly influence market participation while market distance negatively influences market participation among smallholder tomato farmers in the study area. Based on the findings of the study, it is recommended that the local municipality invest more in rural adult education in order for the farmers to adopt new farming skills and utilise the market information provided. In addition, the investment in adult education has the potential to contribute to rural development and job creation in the study area. The study recommends that there should be a comprehensive producer support such as input subsidies, that focuses primarily on subsidising smallholder farmers when purchasing production input such as fertilisers and pesticides. / NRF (National Research Foundation)

Masters of Art / Using a qualitative feminist methodology grounded on post-modemist and postcolonial framework, this research represents an attempt to determine the factors influencing the farming and subsistence agriculture strategies used by rural women of U-Mhlanga village, in the Eastern Cape in the past and the present. It also explores what these women perceive to be their successes and highlights obstacles they encountered in the past and the present in farming. The Eastern Cape has one of the poorest populations of South Africa, and the poorest of these are women. Despite access to land, people are going hungry. This study explores this rural poverty that is feminized and goes on to highlight the social, political and economic issues related to ability or inability to utilize the resources that are accessible. The most prominent problem highlighted by these women goes back to colonial and apartheid times where discrimination in terms of race was used as a determining factor to accessing resources, and how these continue to play out today. However, despite the obstacles, my informants still believe that the local agriculture and farming can sustain rural communities.

In 2013, the Ministry of Food and Agriculture of the Republic of Ghana implemented a reformed food and agriculture sector development policy (FASDEP II) to reduce poverty among the poorest subsistence farmers in the nation. These extension efforts have been unsuccessful. The purpose of this ethnographic case study was to understand the perceptions of subsistence farmers in the Savelugu-Nanton District (SND) who participated in FASDEP II on how the program had affected their ability to meet their subsistence needs. The theoretical framework of collaborative advantage was used to analyze farmers' opinions of how the decentralized, pluralistic extension policy did or did not result in effective collaborations to benefit both farmers and support organizations. Data from unstructured interviews with 12 male farmers, selected through purposeful sampling, were analyzed by inductive coding and thematic analysis. Farmers' perspectives were confirmed through observations at a public farmers' meeting and a review of operations documents of Busaka, a FASDEP II agribusiness partner. Key findings indicated that the current pluralistic extension lacked the characteristics of collaborative advantage and farmers continued to face challenges in access to farming inputs, credit, climate change effects, and cronyism. Farmers perceived the system was more beneficial to large-scale farmers. Positive social change implications of this study include identifying factors to improve effective pluralistic extension for subsistence farmers, the poorest persons in SND; improving the financial conditions of these subsistence farmers through more sustained and equitable partner collaboration; and contributing to the economic development of SND.

Thesis (MPA.) -- University of Limpopo, 2017 / Despite the attempt by the South African government to transfer farms to black ownership, black farmers still remain poor and have to compete without technical skills. The majority of the previously disadvantaged farmers part of mostly practice subsistence agriculture characterised by low production and lack of market. The question that still remains to be answered is whether these subsistence farmers will ever grow to be commercial farmers, and white farmers continue dominating commercial farming. This prompted the researcher to engage in this study that will identify the challenges that make emerging farmers not to succeed as they should. The aim of this study is to investigate the challenges faced by black emerging farmers in the transition from subsistence to commercial farming in Ba-Phalaborwa Municipality and the role played by the Limpopo Department of Agriculture and Rural Development in ensuring that such transits take place. Data used in this study collected from 50 emerging farmers from the five villages in Ba-Phalaborwa and eight (8) extension officers from different sections in the department of Agriculture and Rural development in Ba-Phalaborwa Municipality. The researcher used mixed research design, questionnaires and semi-structured interviews to achieve the intended objectives. The finding shows that the majority of emerging farmers receive support to run their farm activities from the Department of Agriculture and Rural Development mostly in the form of extension services. The study further indicated that emerging farmers are aware of the role being played by the Department of Agriculture, and Rural Development although they are not satisfied with the support the Department is giving them and they believe that if the departments can further support them, they can improve their productions. The study established that emerging farmers have been facing several challenges, including lack of property right or title deed, insufficient farm size, shortage of money, inadequate extension services, inadequate or damaged infrastructure, and climate change, risk on production, lack of market, and lack of information, stock theft, erratic rainfall is a major challenge, lack of access to electricity, lack of access to telephone, not receiving advices on farming activities, not receiving advices on marketing of products, bookkeeping and technology. The emerging farmers’ challenges are worsened by the fact that farmers who are facing droughts are not able to get immediate funding to engage in farming activities. Despite these challenges emerging farmers want to continue with farming and in the next five years they want to see themselves in commercial farming. The concerned government departments should be encouraged to provide farm inputs and equipment like tractors, fertilisers, improved seeds, irrigation system and other types of farm inputs to emerging farmers to empower them to move from subsistence to commercial. The government departments and extension officers should be encouraged to provide skills to emerging farmers like, soil cultivation, irrigation, controlling of weed, packaging, livestock health care, hygiene, breeding and nutrition, recording skills and maintenance of farm equipment to empower emerging farmers to move from subsistence to commercial. Furthermore, policy makers should be encouraged to develop alternative strategies that will motivate emerging farmers to overcome challenges they are facing like lack of property rights of title deeds, insufficient farm sizes, climate change and shortage of money

This paper reports on efforts to improve socioeconomic conditions and natural resource use in the El Pina lito community, department of Chiquimula, Guatemala. Students participating in supervised practical training at Centro Universitario de Oriente/Universidad de San Carlos de Guatemala (CUNORI) developed projects to address these issues. A general diagnostic instrument was created for this community to assist in the development of specific work projects. Students prepared community first-aid kits, agricultural activities with school children, and instructional sessions with farmers on how to prepare a family garden and efficiently manage domestic animals. Other activities included ornamental tree preparation for female participants and a yucca demonstration plot for the Maraxco village.