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Copies of author's previously published works inserted. Includes bibliographical references (leaves 222-258). Researches the occurence and inheritance of isolated melanin pigmented wool fibres and macroscopic pigmentation in Merino sheep. The mode of inheritance of key indicators (pigmented leg fibres and pigmented birthcoat halo-hair) of isolated pigmented wool fibres is investigated and confirms an association between isolated pigmented fibres in hogget Merino fleeces and the presence and degree of types of remnant macroscopic fibre pigmentation. These associations could be exploited to improve wool quality in relation to dark fibre risk.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1975. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Thesis (Ph. D.)--University of Wisconsin, 1974. / Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 161-169).

Economic impacts of research that developed Rosette virus-resistant peanut in Uganda are estimated, including the impacts on poverty. The impacts of technology on the cost of production at the household level are determined. This information is used to compute aggregate benefits in an economic surplus model. A probit model is used to identify the determinants of adoption using household data. Information regarding the determinants of adoption is combined with impacts of technology on the cost of production to identify income changes for adopting households. Foster-Greer-Thorbecke poverty measures are used to project changes in poverty for households that adopt. It is estimated that the poverty rate will decline by 1.3 percent as a result of the research. / Master of Science

This thesis examines the effectiveness of participatory research processes as a form of agricultural extension within the Australian Dairy Industry, and specifically addresses the question : Does Action Research provide an effective methodology and method(s) for enacting farmer-driven research? The experiences of the Dairy Australian-funded Profitable Pastures Protection Project (PPP), delivered to farmers across New South Wales from 1999 to 2003, provided the context within which Action Research was assessed. Data were derived from journal records of the researcher’s personal experiences as a participant observer, a PhD candidate and project coordinator. The other main data sources were industry reports that tracked the progress, outputs and outcomes of PPP. A three-tiered research framework, consisting of Primary, Secondary, and Tertiary levels was devised as a basis to direct research, and interpret results. Conclusions are drawn that contemporary extension practice can be improved by better linking the on-and off-farm domains using participatory research processes such as Action Research. Meeting this challenge appears increasingly urgent in light of a globally relevant and strengthening off-farm environmental agenda that requires democratic engagement amongst greater numbers of agricultural stakeholders. This environmental agenda also places still greater demands on farmers, their management systems and the products and effects of the on-farm domain. / Doctor of Philosophy (PhD)

In times of tightening national budgets as a result of structural adjustment requirements, the need to make choices in Zimbabwe's publicly funded research is heightened. Adoption of quantitative priority setting methods help improve the objectivity of decision-making while fostering consistency of research priorities with the attainment of research system objectives This study develops and applies a quantitative methodology for agricultural research priority setting for Zimbabwe's Department of Research and Specialist Services (DR&SS) under multiple objectives. Such a methodology must incorporate the structural characteristics of Zimbabwe's agricultural sector: the existence of different farmer types, five different agro-ecological regions and multiple objectives. A three part procedure was used in this study to prioritize agricultural research in Zimbabwe. The first part involved identifying the research objectives, defining the list of commodity and non-commodity programs to be prioritized, defining the agro-ecological zones and collecting technology related data and published information. Researchers, extension workers, and farmer representatives were interviewed using a questionnaire to obtain technology-related data. The second part involved economic analysis to measure the contributions of agricultural research to total economic benefits and their distribution by farmer type and agro-ecological region. Net present values (NPV) of economic surplus gains by research program were used to summarize the total economic efficiency gains projected over fifteen years. Once the benefits have been estimated, the third part of the procedure involved using mathematical programming (MP) to project the optimal allocation of research resources among the various commodities under alternative weights on objectives. A ranking of the expected NPVs indicated that agricultural research priorities are different between smallholder farmers and large scale commercial farmers, with maize cotton, groundnuts, sunflower, goats, pulses and millets being of high priority for smallholder farmers, while maize, beef, cotton, coffee, wheat, dairy, stonefruit, soybeans and roses were top priority for large scale commercial farmers. Research discipline priorities for smallholder farmers include agronomy, plant breeding and chemistry and soils while for large-scale commercial farmers the priorities are plant breeding, agronomy, and plant protection. Optimal allocation of research resources given two objectives (efficiency and equity) were assessed in a series of runs with the mathematical programming model. The tradeoff costs associated with putting an extra weight of different sizes on the equity objective, given the current total budget constraint were relatively modest implying that DR&SS can allocate resources to research on smallholder farming without great loss in efficiency. / Ph. D.

Mozambique is a semi-arid area with unreliable rainfall distribution; therefore optimal planting dates are critical to ensure that maize is not stressed during critical stages. The objective of this research was to study the effect of sowing date and cultivar on maize (Zea mays L.) yields in Mozambique. A further objective was to establish whether the SWB model could be utilized to help select the optimum planting window for different maize cultivars and localities. An experiment was conducted during the 2007/08 season at the Chókwè Agricultural Research Station, Mozambique, in which a short (or early cultivar, Changalane) and long (or late) season maize cultivar (Tsangano) were sown on three different dates: 5 December 2007 (PD1), 25 December 2007 (PD2) and 15 January 2008 (PD3). Sowing date had a significant effect (p<0.05) on yield and yield components. The 25 December planting (PD2) out yielded (4.3 t ha-1) the 5 December (PD1) (2.5 t ha-1,) and 15 January (PD3) (1.5 t ha-1) plantings for cv. Changalane. However, for cv. Tsangano, PD1 (3.2 t ha-1) out yielded PD2 (2.3 t ha-1) and PD3 (0.7 t ha-1). Cultivars varied significantly in yield potential. The most responsive cultivar to water supply was Changalane, which when planted late in December (PD2), gave a water productivity (WP) of 17 kg ha-1 mm-1, while Tsangano, the late cultivar, performed better when planted early in December (PD1), with a WP of 8.5 kg ha-1 mm-1 The Soil Water Balance (SWB) model was calibrated on the data from one planting date per cultivar and successfully validated on independent data sets from the other two planting dates. Long-term historical weather data sets were obtained for Chókwè and Umbeluzi, two important dry land maize production areas in Mozambique. The calibrated SWB model was used to simulate maize yields for different planting dates to establish the best planting date for different cultivar x plant date x soil combinations. Simulation results for the two cultivars across three planting dates showed that the simulated grain yields per planting date varied substantially from year to year and between the two sites. The SWB scenario simulation results showed that for both Umbeluzii and Chókwè sites, in four out of five years, best yields can be achieved by planting Changalane late in December and Tsangano early in December. It can be concluded that the SWB model can be a very useful tool to help select the most suitable maize cultivars and planting dates for different localities, based on differences in plant water availability during the growing season. Copyright / Dissertation (MSc(Agric))--University of Pretoria, 2011. / Plant Production and Soil Science / unrestricted