Thesis (Ph.D. (Tropical Medicine))--Mahidol University, 2007. / LICL has E-Thesis 0025 ; please contact computer services. LIRV has E-Thesis 0025 ; please contact circulation services.

Thesis (doctoral)--Landbouwhogeschool te Wageningen, 1983. / Summary in Dutch and Spanish. Vita. Includes bibliographical references (p. 227-237).

Thesis (doctoral)--Institute of Social Studies, The Hague, The Netherlands, 2003. / Includes bibliographical references (p. [369]-397).

The research draws on an ethnographic research and explores the everyday practice of collective action in Ugbawka in Enugu State by using interviews and participant observation. The study reveals that smallholder collective action is not best fitted into formal institutional arrangement but takes place within a complex and intricate process that involves interaction with diversity of institutions and actors. Equally, the interactions that occur amongst actors are mediated at the community level through interplay of socio-cultural and political factors. This study recognises and places emphasis on understanding of agency and the exercise of agency at the local level arguing that smallholder farmers are not robot but active individual who exercise their agency purposively or impulsively depending on conditions and the assets available at their disposition as well as their ability to navigate the intricate power dynamic inherent at local context. The thesis thus questioned the simplistic use of formal institutional collective action framework in smallholder collective action at the community level and argues that institutions are not static and do not determine outcomes but are informed by the prevailing conditions at the community level. The study emphasises the role of existing institutions and socially embedded principles in community governance and argues that actors should be the focus of analysis rather than the system in understanding smallholder collective action. The study concludes by advocating for further research that could explore the possibility of hybrid approach that accepts the advantages of both formal and informal institutional forms of smallholder collective action.

The research draws on an ethnographic research and explores the everyday practice of collective action in Ugbawka in Enugu State by using interviews and participant observation. The study reveals that smallholder collective action is not best fitted into formal institutional arrangement but takes place within a complex and intricate process that involves interaction with diversity of institutions and actors. Equally, the interactions that occur amongst actors are mediated at the community level through interplay of socio-cultural and political factors. This study recognises and places emphasis on understanding of agency and the exercise of agency at the local level arguing that smallholder farmers are not robot but active individual who exercise their agency purposively or impulsively depending on conditions and the assets available at their disposition as well as their ability to navigate the intricate power dynamic inherent at local context. The thesis thus questioned the simplistic use of formal institutional collective action framework in smallholder collective action at the community level and argues that institutions are not static and do not determine outcomes but are informed by the prevailing conditions at the community level. The study emphasises the role of existing institutions and socially embedded principles in community governance and argues that actors should be the focus of analysis rather than the system in understanding smallholder collective action. The study concludes by advocating for further research that could explore the possibility of hybrid approach that accepts the advantages of both formal and informal institutional forms of smallholder collective action.

Typescript. / Thesis (Ph. D.)--University of Hawaii at Manoa, 1984. / Bibliography: leaves 160-170. / Microfiche. / xiii, 170 leaves, bound ill. 29 cm

Rice (Oryza sativa L.) is the second most important cereal crop in Malawi. Rice productivity in the dominant (85%) rainfed ecosystem is very low, with mean yield of only 1.4 t ha-1. Farmers plant traditional landraces that have low yield potential and are susceptible to various stresses such as drought and diseases. Development and introduction of improved rice varieties, with stress tolerance traits from introduced varieties, such as the New Rice for Africa (NERICAs), could significantly increase productivity. Previous attempts to introduce high yielding irrigated varieties into the dominant rainfed ecosystem in Malawi have not been successful because farmers basically did not adopt the varieties, claiming that the varieties were lacking in grain traits that they preferred but that the traits were present in their landraces. The notable traits mentioned, through previous informal surveys, were long grains, medium to slender shape and aromatic grain with intermediate gelatinization temperature. No formal study has been conducted to ascertain the preferences, and the genetic control of the traits, including yield and yield related traits, have not been studied. The objectives of this study were to: 1) confirm farmers’ preferences for grain traits using participatory rural appraisal; 2) determine amount of genetic variability for yield and yield related traits in Malawi rice landraces, 3) determine the genetic control and correlations of grain length, grain shape and 1000-grain weight, 4) determine the inheritance of aroma and gelatinization temperature and, 5) determine the genetic control, correlations and path coefficients of yield and yield related traits, in F2 generations of Malawi rice landraces and NERICA varieties crosses. To confirm the farmers’ preferences for grain traits, a participatory rural appraisal was conducted in 2006 in two villages that were representative of rainfed rice growing areas in Malawi. The villages were Liundi and Nawanga in Machinga and Salima Districts, respectively. Qualitative and quantitative data were collected through questionnaires and discussions with 190 respondents, as well as through observations. To determine variability among Malawi rice landraces, 19 landraces were planted at Lifuwu in a Randomized Complete Block Design with three replicates in 2006. Data on plant height, days to 50% flowering, number of panicles per hill, panicle length, number of filled grains per panicle, 1000-grain weight, panicle weight, grain length and grain yield were collected and analyzed. Four Malawi rice landraces were crossed to four NERICA varieties in 2006 in a North Carolina Design II mating scheme to determine the genetic control of grain size. F1 plants were raised in 2007 and in 2008, 16 F2 populations together with their parents were planted in a Randomized Complete Block Design with three replicates at Lifuwu. Data on grain length, grain shape and 1000-grain weight were collected and analyzed. To determine the inheritance of aroma and gelatinization temperature, four Malawi rice landraces were crossed to four NERICA varieties in 2006 and F1 plants were raised in 2007. In 2008, 16 F2 populations together with their parents were planted in a Randomized Complete Block Design with three replicates at Lifuwu. Aroma and gelatinization temperature were evaluated. To determine the gene action of yield and yield related traits, four Malawi rice landraces were crossed to four NERICA varieties in 2006 in a North Carolina Design II mating scheme and F1 plants were raised in 2007. In 2008, 16 F2 populations together with their parents were planted in a Randomized Complete Block Design with three replicates at Lifuwu. Data on grain yield, the number of panicles per hill, days to 50% flowering, panicle length, panicle weight and 1000-grain weight were collected and analyzed The participatory rural appraisal confirmed that that long, slender or medium shape grains, with aroma and intermediate gelatinization temperature were the key traits preferred by farmers. Therefore the farmer preferred traits of long, slender grains, with aroma and medium gelatinization temperature, must be selected for in any high yielding varieties to be developed for the rainfed rice ecosystem. Results showed that differences were significant (P=0.05) for all the traits that were studied. Heritability estimates were low to moderate: 18.3% for panicle weight, 40.0% for panicles per hill and 56.3% for days to 50% flowering date. The high genetic variability among the landraces could be used in a breeding programme to develop improved varieties for various morphological traits. The number of panicles per hill and 1000-grain weight combined moderate heritabilities with relatively high genetic advance and therefore could be reliable traits for yield improvement. Genetic analysis of grain size showed that Malawi rice landraces were variable for all three grain size characteristics, namely grain length, grain shape and 1000-grain weight. NERICA varieties were variable for 1000-grain weight. Sixteen F2 progenies were variable for all three characteristics, and the variability was significant (P=0.05). Heritability estimates were high (45.4%) for grain length and low for grain shape (12.3%) and for 1000-grain weight (14.3%) suggesting that early generation selection would be effective for grain length. Predominance of additive gene action for grain length and grain shape suggested that early generation selection would be effective for these traits. Selection for 1000-grain weight would be more effective in later generations because of preponderance of non-additive gene action in the control of this trait. The correlation between grain length and grain shape was positive (r=0.769) and highly significant (P=0.01) suggesting that breeders would choose to select for both traits simultaneously, or they would choose one of the traits to develop varieties with long grains and medium shape. Crosses between aromatic and non-aromatic varieties had non-aromatic F1. The F2 progenies segregated into 3:1 ratio for non-aromatic: aromatic suggesting that, in the Malawi rice landraces, aroma was probably simply inherited through a single recessive gene. F1 progenies, between parents with high and intermediate gelatinization temperatures had intermediate gelatinization temperature. F2 progenies segregated into 1:3 ratios for high; intermediate gelatinization temperature in three out of four crosses suggesting control by one dominant gene. The segregation pattern in one cross was not significantly different from 3:13 ratio for high: intermediate suggesting that two dominant genes, one an inhibitor, were controlling the trait. Breeding and selecting for aroma and intermediate gelatinization temperature could be accomplished relatively easily because the traits are simply inherited. The genetic variability for yield and yield related traits was wide and significant (P=0.05) in the F2 populations of Malawi rice landraces and NERICA varieties crosses indicating that the populations would be valuable sources to develop varieties with improved yield. Panicle weight and the number of panicles per hill were positively correlated with, and had high direct effects on grain yield, therefore they could be used to indirectly select for high yield. Grain yield, the number of panicles per hill and plant height were predominantly controlled by additive gene action suggesting that bulk breeding methods would be adopted for these traits. The days to 50% flowering, panicle weight and 1000-grain weight were predominantly under the control of nonadditive gene action suggesting that hybrid development would be profitable for these traits. Faya Mpata, Faya Zidyana and NERICA 3 could be the best parents for improving yield and yield related traits because they had high general combining abilities for the traits. / Thesis (Ph.D.)-University of KwaZulu-Natal, Pietermaritzburg, 2010. / Thesis (Ph.D.)-University of KwaZulu-Natal, Pietermaritzburg, 2010.

Rice is an important crop ranking third after maize and wheat in Kenya. Its demand is growing at 12% per annum, while production has stagnated for quite a number of years. This situation has lead to consumption outstripping production by about 84%. There is therefore an urgent need to step up domestic production. To understand farmers’ preferences, the first survey on rice production was carried out. To supplement on this survey information, focus group discussions and key informants were incorporated to further shed more information. The farmers demonstrated their preferences for varieties that were high yielding, hybrid rice and with high nutrient use efficiency and these constituted 53.7% of their wishes. Among the crops grown by the selected farmers, rice was the most important followed by maize, however, the hectarage of maize was higher followed by rice. The farmers also identified labour costs as a factor limiting production especially for irrigated rice and thus they preferred upland rice due to its ease of production. Farmers identified land preparation, inputs, planting, weeding and harvesting as the most expensive activities. The existing varieties were viewed as being highly dependent on inputs which they could not afford. The main fertilizers used were Diammonium Phosphate (DAP), Sulphate of Ammonia (SA), Calcium Ammonium Nitrate (CAN) and NPK (23:23:0), the amounts used were low even though the farmers were aware that soil fertility was low. No studies or attempts had been carried out to determine performance of rice genotypes and their heritability parameters for adaptation to low soil nitrogen (N) and phosphorous (P) conditions identified by the farmers as a major constraint in Kenya. Since the existing genetic base was narrow, accessions were acquired to broaden the variability of the local cultivars. However, their adaptation to local conditions was important for them to be useful. Evaluation of 390 accessions showed that genotypes and soil environments were highly significant for all the ten traits studied. The degree of genetic determination (H(2)) ranged from 8.0% for 1000 grain weight to 27% for top biomass. The phenotypic coefficient of variation of genotypes ranged from 12% for days to maturity to 149% for top biomass, while, that of days to maturity ranged from 14% to 160% for top biomass. The genetic advance (GA) had values ranging from, 0.2 for phosphorous tolerance to 1081 for grain yield, while the genetic advance expressed as percent of the mean was 6% for days to maturity and 88% for top biomass. The mean values for the ten characters studied had wide variability under the four soil environments with days to maturity ranging from 188 for genotype ARCCU1Fa1-L4P3-HB under both N and P application (N+P+) to 177 for genotype CT16333(1)-CA-1-M under none N and P application (N-P-) condition. The highest yielding genotype was CT16328-CA-18-M under none N and P application with 5916 kg ha(-1). The germplasm revealed usable variability under low soil N and P adaptation and thus warrant rice improvement for traits of interest to farmers. In order to establish the genetic factors controlling upland rice adaptation to contrasting soil N and P a study was conducted to determine genotypes with better performance under the prevailing farmers’ production environments. The GCA and SCA mean squares were significant and their interactions with environment were highly significant. The GCA:SCA ratios were mostly less than 1.0 for the majority of the traits under most of the soil N and P environments, indicating preponderance of nonadditive genetic effects. The maternal and nonmaternal mean squares were significantly different from zero (P<0.05) for most of the ten traits under study, indicating influence of cytoplasm effects and cytoplasm by nuclear gene interactions, respectively. The GCA effects for the parents were significant under different experimental environments but they had both positive and negative signs indicating different directions of influencing the trait of interest. The genotypes had both specific and broad adaptation as exhibited by their diverse rankings under different environments. The relationship between leaf and grain nitrogen (N) and phosphorous (P) with actual tolerance to low and high soil N and P conditions indicated significant genotypes, environments and genotypes by environment interactions. The analysis of genetic components gave highly significant GCA and SCA mean squares for the days to heading, anthesis and maturity, phosphorous and nitrogen tolerance, top biomass, plant height, number of panicles, 1000 seed weight and grain yield under the four soil experimental environments. The general combining ability (GCA) effects for parents were significant for both F(2) and F(3) segregants for the above ten traits and under the experimental conditions. The leaf and seed N and P contents gave significant genotype mean squares values for the three mega-environments. The GCA and SCA mean squares were significant for leaf and seed N and P for the three locations. The same case was observed for GCA effects for the parents, with all the nine parents showing significant values for leaf N and P for the three locations. The GCA:SCA mean square ratios were generally larger than 1.0 values for leaf N and grain P for the three locations. This clearly manifested the predominant role of additive gene action over the dominance effects and that improvement for tolerance to low soil N and P condition was practical. The fragrance in rice is an important quality traits and an experiment was conducted to establish the association of organoleptic test and the variations in SSR marker (RM223) among the parents. Plant leaves of the parental genotypes were sampled for DNA analysis using SSR markers RM223 and RM284. The RM223 was polymorphic while, RM284 gave monomorphic results. Four alleles were detected as follows: 146, 155, 161, and 163. The GCA:SCA ratio was 1.48 indicating that the fixable additive effects were greater than the nonadditive effects in inheritance of fragrance. Test for independence using Chi-square indicated that there was no association between organoleptic and variations in SSR markers. The performance of the aromatic lines was generally lower than that of non-aromatic lines for the agronomic traits. There was negative relationship between fragrant score and other agronomic traits such as grain yield across the three soil N and P regimes. The NERICA1 was found to be a good donor for aroma based on sensory testing and can be exploited in a breeding programme. Analysis on genetic components governing grain yield was investigated using Hayman’s analysis to generate various components of variation and to elucidate their potential, utilization, and provide a thorough understanding of their role in grain yield development and improvement. The additive gene action was significant for all cases of soil N and P environments and the two mega-environments. They were also far above the dominant gene effects, indicating the need to use mass selection in the early generations of segregating populations. The narrow sense heritability (h2(ns)) for upland rice grain yield was 21.52% and 4.22% under soil P and N conditions, respectively. / Thesis (Ph.D.)-University of KwaZulu-Natal, Pietermaritzburg, 2010.

This thesis presents the results of research in a small village located in the mountains of Sichuan Province in southwestern China. The thesis argues that traditional irrigation practices vital to paddy-rice production in the village have been stressed by local weather events. It also argues that local villagers have not responded effectively to such changes, and that failure to adjust has contributed to social stress observed at the site. During the earlier years of the study period (1945 to 2012), improvements were made in local irrigation, which seem to have helped farmers continue with traditional subsistence wet-rice farming in a fragile mountain environment. However, in later years of the period village social order showed two significant signs of collapse: first, because of emigration, fewer people were left to farm higher mountain levels so farm land was being abandoned; second, social crowding in lower level riverside farming areas, partly the result of highland emigration, began reducing the amount of land being farmed there. While reducing intensive cropping of highland farming areas can result in spontaneous recovery of natural resources such as soil and water, crowding in lower areas can contribute to deterioration of natural resources in the lower village farmland. Crowding can, in addition, have a bearing on community health problems. The thesis results are of value to researchers concerned with the adaptive behavior of local farming communities trying to maintain their traditional irrigation-dependent way of life in a fragile mountain environment while experiencing the effects of changeable weather. Thesis results are of additional value to those who study the impact on society of earth-warming, especially if variable local weather in the Dabashan is shown to be related to global climate change.

There is problematic flow of Knowledge among rice farmers in Ghana, which constitutes one of the critical challenges that is face in rice production in country. Effective knowledge sharing, therefore, offers great potential for addressing the challenges of rice production in Ghana. The current study explores the knowledge sharing practices among rice farmers in the Eastern Region of Ghana in order to develop strategies to enhance knowledge sharing. The study was underpinned by the pragmatic paradigm where concurrent triangulation mixed-method design was used for the study. Data was gathered with survey and interviews. A total sample of 110 was used; involving 101 survey respondents and 9 interview participants. The survey data was analyse descriptively using Statistical Package for the Social Sciences (SPSS), version 26. The interview finding was analysed using thematic analysis. Findings revealed informal and elementary knowledge sharing practices among the rice farmers, which are mostly face-to-face. The study suggests coherent and structured strategy for knowledge sharing. It established that a successful implementation of knowledge sharing would depend on identifying and linking knowledge sharing enablers to tools and technologies. The proposed strategies would not only improve knowledge sharing among rice farmers in Ghana and add to the body of knowledge. The findings of the study may also be adopted by rice farming communities in other African countries whose rice farming context is similar to the context in Ghana. / Information Science / Ph. D. (Information Science)