This dissertation is composed of three essays examining adoption and impact of agricultural technologies. The first two papers estimate adoption and impact of iron-biofortified bean varieties in Rwanda. These varieties are bred to have high iron content and high yields to improve the health and livelihoods of rural households. The third essay estimates the spillover effects of seed producer groups (SPGs) in Nepal on nearby non-SPG member households. These SPGs were established to produce and sell stress tolerant rice varieties (STRVs) and other improved rice varieties and were trained on a number of improved management practices for rice cultivation. The first essay, titled "Promoting rapid and sustained adoption of biofortified crops: What we learned from iron-biofortified bean delivery approaches in Rwanda" uses duration modeling to estimate how a number of delivery approaches designed to distribute iron-biofortified bean varieties to farmers have increased the speed of adoption, reduced the speed of disadoption, and increased the speed of readoption of iron-biofortified bean varieties. We find that these delivery approaches have been very effective at promoting adoption and reducing disadoption. Policy makers can learn lessons from this research regarding distribution of biofortified crops in Rwanda and elsewhere. The second essay, titled "The impact of iron-biofortified bean adoption on bean productivity, consumption, purchases and sales" examines the impact of adoption of the most popular iron-biofortified bean variety, RWR2245, on adopting households. We use a control function approach with instrumental variables related to iron-biofortified bean delivery approaches to control for selection bias of adoption. We find that adoption increases yield, household bean consumption from own-production, and bean sales while reducing bean purchases. This implies that iron-biofortified bean adoption has a strong potential to improve nutrition and food security of adopting households, as beans make up a large portion of the average Rwandan diet. The third and final essay, titled "The spillover effects of seed producer groups on non-member households in local communities in Nepal" examines the spillover benefits of SPGs onto non-member farmers in villages with an SPG or are adjacent to a village with an SPG. We find that SPGs have increased adoption of STRVs, improved the seed replacement rate, and increased use of some best management practices among non-members within SPG villages, and have increased adoption of the STRVs in at least one past seasons among non-members in adjacent villages. / Doctor of Philosophy / This dissertation consists of three essays that examine adoption and impact of agricultural technologies that are designed to help rural households in developing countries improve their livelihoods. The first two papers focus on iron-biofortified bean varieties in Rwanda. These bean varieties have high iron content and are also high yielding. They are designed to combat iron-deficiency within the country. The government of Rwanda distributed the bean varieties to households using a number of different delivery approaches. We study the influence of these approaches and find that households who are closer to them adopt the varieties faster and disadopt the varieties more slowly, indicating that they have been successful in promoting adoption. The second paper of this dissertation studies the impact that one of the iron-biofortified bean varieties has had on adopting households. We find that adoption increases household bean yields and bean consumption from own-production, while reducing bean purchases and increasing the likelihood that a household sells beans. This provides evidence that iron-biofortification improves iron consumption for households that adopt the varieties, because they consume greater quantities of their iron-rich bean harvests, and improves household income through reductions in purchases and increased likelihood of sales. Finally, our third paper examines Seed Producer Groups (SPGs) in Nepal in which member farmers produce and sell rice varieties that are tolerant to drought. We find that for non-SPG members, living in or near a village with an SPG increases their likelihood of growing a drought-tolerant variety. Overall, this dissertation contributes to the literature on adoption and impacts of agricultural technologies and provides useful guidelines for policy makers wishing to promote these and other technologies. This can inform future funding allocation and maximize impacts of development projects.

Sorghum is considered a staple food for most rural communities in Kenya. Sorghum is mainly favoured for its ability to thrive in adverse climatic conditions. This study was carried out to determine sorghum consumption in selected rural communities in western Kenya. This was done by determining how much sorghum the children aged 2-5 years consume daily, what the consumption patterns of sorghum are and also to determine if biofortification of sorghum with protein, Vitamin E, Vitamin A, iron and zinc will make any significant contribution to the children‘s nutrient intake. A cross-sectional food consumption survey was conducted using an interviewer administered Quantitative Food Frequency Questionnaire (QFFQ) to 102 mothers and caregivers. The QFFQ was run concurrently with focus group interviews as data collection tools. The results indicated that the diet consumed by the children in the selected communities offered a variety of foods resulting in sufficient nutrient intake for the majority of the children. The daily contribution made by sorghum, however, was low with 36.4 g soft porridge (uji) and 26.2 g stiff porridge (ugali) being the average amounts given daily to the children. The nutrient contribution made by sorghum was; energy 140 kJ (2%), protein 0.9 g (1.7%), iron 0.3 mg (4.3%), zinc 0.1 mg (2.1%), Vitamin A (0%), Vitamin E (0%). The proportion of the population who consumed a diet deficient in one or more of these nutrients was 36.3% energy, 4.9% protein, 48% iron, 21.6% zinc, 46.1% Vitamin A and 17.6% Vitamin E. The small contribution made by sorghum to the diet made it a minor component in the children‘s diet. For the deficient children, the insufficient nutrient intake from the diet is an indication that the diet quantity rather than the quality needs to be improved. A multiple dietary approach that is practical and sustainable for rural people through dietary diversification would be more beneficial. The multiple dietary approach would ensure that people consume a variety of locally available foods that contain a rich source of micronutrients and energy in order to address shortfalls in the diet quality and quantity. Biofortification of sorghum would not make any significant contribution to the children‘s nutrient intake because of the fact that the children are consuming a very small amount of sorghum daily. For biofortification of sorghum to make a significant difference in the children‘s nutrient intake in these communities, the people in these communities need to be encouraged to consume more sorghum than they are currently consuming. Educating the rural communities about the importance of growing locally adapted crops such as sorghum and incorporating them in their diets would assist in improving the micronutrient status of rural people. / Dissertation (dissertation)--University of Pretoria, 2009. / Food Science / unrestricted

Dans un contexte où les carences en micronutriments constituent un problème majeur de santé publique touchant particulièrement les jeunes enfants, l'étude de la rétention et de la biodisponibilité du fer et du zinc dans les plats les plus fréquemment consommés peut constituer une stratégie de lutte contre les carences en ces minéraux. Une enquête de consommation alimentaire par pesées auprès de 630 enfants de 6 à 36 mois au Burkina Faso a permis de dégager les principales caractéristiques de l'alimentation de complément des jeunes enfants. Les résultats mettent en évidence une couverture des apports recommandés en fer et en zinc très faible, des apports élevés en fibres et en phytates. Le jour de l'enquête, plus de 90% des enfants avaient consommé du mil, du sorgho ou du maïs, essentiellement sous forme de tô, une pâte très consistante, de bouillie ou de galettes. Des suivis de préparation de ces plats dans les ménages ont permis d'identifier les principales opérations unitaires susceptibles d'avoir un effet sur les teneurs en fer et en zinc et leur biodisponibilité. Le décorticage traditionnel, manuel ou mécanique, entraine d'importantes pertes en fer (50% dans le mil pour 10% de perte de MS) et en zinc (23% dans le sorgho pour 7% de perte de MS). Les variétés biofortifiées présentent un comportement similaire, mais permettent tout de même une amélioration significative du rapport molaire phytate/zinc. La mouture, lorsqu'elle est réalisée à l'aide d'un moulin à meules, entraine une contamination en fer, allant jusqu'à tripler la teneur en fer initiale des grains. Mais la bioaccessibilité de ce fer est extrêmement faible. L'acceptabilité des variétés de mil biofortifiées, testées sur différents plats, reste inférieure à celle de la variété locale. L'amélioration des procédés combinée à l'utilisation de variétés biofortifiées pourrait être promue afin de contribuer à la lutte contre les carences en fer et zinc. / In contexts where micronutrient deficiencies are a major public health concern, the improvement of the retention and bioavailability of iron and zinc in dishes frequently consumed by young children could be part of a food-based strategy to combat these deficiencies. A food consumption survey using weighing records was carried out on 630 children from 6 to 36 months in Burkina Faso. This permitted to highlight the main characteristics of the children diet. Iron and zinc intakes were far below the recommended intakes. High fibre and phytate intakes were also observed. More than 90% of the young children consumed millet, sorghum or maize in the day of the survey. A detailed monitoring of the traditional processing of the cereal dishes permitted the identification of the main unit operations that could have an effect on iron and zinc content and bioavailability. Important losses in iron content (50% in millet for 10% DM loss) and zinc (23% in sorghum for 7% DM loss) were observed after traditional dehulling, either manual or mechanical. Biofortified varieties showed similar behaviour but their phytate/zinc molar ratio was still improved. During milling in local mill with grindstones, iron contamination occurred, and tripled the initial iron content. But the bioaccessibility of this contaminant iron was very low. The acceptability of the biofortified varieties of millet, tested on various dishes, was lower than that of the local variety. The improvement of the processing methods combined with the use of biofortified varieties could be advantageously promoted to contribute to alleviate iron and zinc deficiencies.

Selon l’Organisation Mondiale de la Santé, environ 30% de la population mondiale souffre de carence en fer. Une des stratégies proposées afin d’endiguer l’anémie due à cette carence est d’augmenter le contenu en fer et sa disponibilité dans les parties consommées des plantes, en particulier les graines. Pour répondre à ce défi, il est important de comprendre les mécanismes de stockage du fer dans la graine. Chez la plante modèle Arabidopsis thaliana, le fer est stocké au sein des vacuoles des cellules entourant les tissus vasculaires de l’embryon. Le transporteur AtVIT1 est impliqué dans l’entrée de fer au sein de ces vacuoles. Le mutant vit1-1 présente un patron de distribution du fer modifié : le fer est accumulé dans les cellules sous épidermiques abaxiales des cotylédons et les cellules corticales de la radicule. AtNRAMP3 et AtNRAMP4 fonctionnent de manière redondante permettant la sortie du fer vacuolaire lors de la germination. En conditions de carence en fer, le double mutant nramp3nramp4 présente un arrêt développemental associé à une forte chlorose dus à son incapacité à utiliser ses stocks de fer vacuolaire. Pour identifier de nouveaux gènes impliqués dans l’homéostasie du fer au sein de la graine, nous avons criblé une population de double mutant nramp3nramp4 mutagénisé à l’EMS à la recherche de suppresseurs du phénotype du double mutant sur un milieu carencé en fer. Nous avons nommés ces mutants isv pour “bypass iron storage in vacuoles”. Nous avons confirmé et classifié 29 candidats selon le patron de distribution du fer de leurs embryons : 20 présentent un patron similaire au type sauvage, 3 dont le patron est semblable à celui du mutant vit1-1 et enfin 6 ne présentent pas de colorations dans la plupart de leurs embryons. Les 3 mutants isv présentant un patron similaire à vit1-1ont été caractérisés de manière plus approfondie. Chez deux d’entre eux, nous avons démontré que des mutations dans le gène AtVIT1 sont responsables du phénotype suppresseur. Ce résultat établit un lien génétique et fonctionnel entre le stockage du fer dans les vacuoles endodermiques par AtVIT1 et sa libération par AtNRAMP3 et AtNRAMP4. Le troisième mutant isv au patron semblable à vit1-1 ne porte pas de mutations dans la séquence codante d’AtVIT1. L’identification du gène affecté apportera sans doute des informations sur la régulation de VIT1. Enfin, pour sept autres mutants isv, nous disposons actuellement des populations F2 dont l’analyse par séquençage haut débit permettra de déterminer la mutation responsable du phénotype suppresseur. / Over 30% of the world population is iron deficient (WHO resources). One strategy proposed to fight iron deficiency is to improve iron (Fe) content and availability in crops, especially in seeds. To address this challenge, it is crucial to decipher the mechanisms that control Fe storage during seed development. In Arabidopsis thaliana seeds, iron is stored in the vacuoles of cells surrounding the vasculature of the embryo. The AtVIT1 transporter is involved in Fe influx into vacuoles. The vit1-1 mutant displays an altered Fe pattern: Fe is accumulated in abaxial cells of the cotyledons and radicle peripheral cells. AtNRAMP3 and AtNRAMP4 function redundantly in Fe retrieval from vacuoles during germination. When germinated under iron deficient conditions, nramp3nramp4 double mutant development is altered as a consequence of impaired Fe mobilization. To identify novel genes involved in seed Fe homeostasis, we screened an EMS mutagenized population of nramp3nramp4 for mutations restoring the growth of nramp3nramp4 on low Fe. We named these mutants isv for “bypass iron storage in vacuoles”. The 29 confirmed isv mutants identified by the screen have been classified according to the iron localization pattern in their embryo after Perls/DAB staining: 20 display a wild type pattern, 3 display a pattern of Fe localization similar to vit1-1 mutant and 6 do not show any staining in most embryos. The three isv mutants displaying a vit1-1 like pattern were further investigated. In two of them, mutations in the AtVIT1 gene were shown to be responsible for the suppressor phenotype. This result establishes a genetic and functional link between Fe loading in endodermal vacuoles by AtVIT1 and its retrieval by AtNRAMP3 and AtNRAMP4. The third isv mutant with a vit1-1 like iron localization pattern does not carry any mutation in AtVIT1 coding sequence. Identification of the mutated gene will likely uncover molecular mechanisms regulating VIT1 action. For seven other confirmed isv mutants, F2 populations are available. High-throughput sequencing of batched segregants from these F2 populations will allow to map and identify the mutations causing the suppression.

Inorganic cations play decisive roles in many cellular and physiological processes and are essential components of plant nutrition. Therefore, the uptake of cations and their redistribution must be precisely controlled. Vacuolar antiporters are important elements in mediating the intracellular sequestration of these cations. CAXs (for CAtion eXchanger) are members of a multigene family and appear to predominately reside on vacuoles. Defining CAX regulation and substrate specificity have been aided by utilizing yeast as an experimental tool. Studies in plants suggest CAXs regulate apoplastic Ca2+ levels in order to optimize cell wall expansion, photosynthesis, transpiration and plant productivity. CAX studies provide the basis for making designer transporters that have been used to develop nutrient enhanced crops and plants for remediating toxic soils. In my second study, I have characterized and defined autoinhibitory domain of Arabidopsis CAX3. Several CAX transporters, including CAX1, appear to contain an approximately 40 amino acid N-terminal regulatory regions (NRR) that modulates transport through N-terminal autoinhibition. Deletion of the NRR from several CAXs (sCAX) enhances function in plant and yeast expression assays; however, to date, there are no functional assays for CAX3. In this report, we create a series of truncations in the CAX3 NRR and demonstrate activation of CAX3 in both yeast and plants by truncating a large portion of the NRR. Experiments on endomembrane-enriched vesicles isolated from yeast expressing activated CAX3 demonstrate that the gene encodes Ca2+/H+ exchange with properties distinct from CAX1. These studies demonstrate shared and unique aspects of CAX1 and CAX3 transport and regulation. My third study is to express and purify CAX proteins for X-ray crystallographic analysis. In this study, I initiated crystallization of vacuolar membrane localized CAX protein from eukaryotes. Membrane proteins continue to be challenging targets for structural biology because of their hydrophobic nature. We have demonstrated here that eukaryotic Ca2+/H+ exchanger can be successfully expressed in E. coli based expression system. Collectively, our findings suggest that CAX protein can be successfully expressed, detergent solublized and purified from E. coli with a yield sufficient for functional and structural studies.

Magister Scientiae (Biodiversity and Conservation Biology) / This study aimed to determine the nutrient content (Co, Cr, F, I, Se and V) of various vegetable based food items collected from the Cape Town area in the Western Cape Province of South Africa. This was done to determine which vegetable crops provided the highest concentrations of essential trace elements, and how much they contribute to the daily recommended intake (DRIs) of these trace elements. It also aimed to assess the effects of the addition of the trace elements (Co, Cr, F, I, Se, Si, Sn and V) on seed germination and root growth under controlled conditions in order to calculate their phytotoxicity, and then to biofortify four vegetable crop species, grown in sand culture, with a composite treatment of the trace elements to determine how the addition of these elements will affect the vegetable crops grown under these experimental conditions. From this study, it was shown that trace element content in vegetable crops in the Western Cape Province of South Africa varied between different geographic locations and that certain trace elements were absent from several items collected from some areas. Although some crop species contained sufficient amounts of certain trace elements to satisfy our daily recommended intakes, most of the crops were found to contain insufficient amounts of many of the trace elements to satisfy our needs. Leafy vegetables and tubers were identified as the better vegetable types to biofortify with essential trace elements as they already contain higher concentrations of several of the essential trace elements and should thus be assessed for their effectiveness as crops to be biofortified. When the trace elements were applied directly to cress and lettuce seeds, it was found that all the trace elements, as well as the composite treatments, exerted phytotoxic effects on cress and/or lettuce seeds when applied athighconcentrations. Lettuce was found to be more prone to the effects of these elements. Seed germination was strongly inhibited by fluoride, while several elements affected root growth. When fluoride was left out of the composite treatment, phytotoxicity only occurred at high concentrations. The addition of the trace elements at the high concentrations to already established spinach, cabbage, lettuce and turnip plants were found to affect the uptake of several essential plant nutrients, but the concentrations of the elements affected generally remained higher than the concentrations needed for adequate growth of agricultural crops. Several of the trace elements supplied to the plants were also found to be retained in the roots of the vegetable crops however, as the concentrations supplied to the plants increased, so did the concentrations found in the edible portions of the crops

>Magister Scientiae - MSc / Micronutrient and trace element deficiencies are a problem affecting nearly two billion people globally. The people affected the most by these deficiencies are those living in poor and rural communities in the developing countries and thus cannot always afford the diverse diet as advocated by WHO and the FAO. Millions of these people living in the poor and developing countries die yearly, either directly or indirectly, as a result of micronutrient and trace element deficiencies. Thus, this study aimed to determine the nutrient content (Co, Cr, F, I, Se and V) of various vegetable based food items collected from the Cape Town area in the Western Cape Province of South Africa. This was done to determine which vegetable crops provided the highest concentrations of essential trace elements, and how much they contribute to the daily recommended intake (DRIs) of these trace elements. It also aimed to assess the effects of the addition of the trace elements (Co, Cr, F, I, Se, Si, Sn and V) on seed germination and root growth under controlled conditions in order to calculate their phytotoxicity, and then to biofortify four vegetable crop species, grown in sand culture, with a composite treatment of the trace elements to determine how the addition of these elements will affect the vegetable crops grown under these experimental conditions. From this study, it was shown that trace element content in vegetable crops in the Western Cape Province of South Africa varied between different geographic locations and that certain trace elements were absent from several items collected from some areas. Although some crop species contained sufficient amounts of certain trace elements to satisfy our daily recommended intakes, most of the crops were found to contain insufficient amounts of many of the trace elements to satisfy our needs. Leafy vegetables and tubers were identified as the better vegetable types to biofortify with essential trace elements as they already contain higher concentrations of several of the essential trace elements and should thus be assessed for their effectiveness as crops to be biofortified. When the trace elements were applied directly to cress and lettuce seeds, it was found that all the trace elements, as well as the composite treatments, exerted phytotoxic effects on cress and/or lettuce seeds when applied at high concentrations. Lettuce was found to be more prone to the effects of these elements. Seed germination was strongly inhibited by fluoride, while several elements affected root growth. When fluoride was left out of the composite treatment, phytotoxicity only occurred at high concentrations. The addition of the trace elements at the high concentrations to already established spinach, cabbage, lettuce and turnip plants were found to affect the uptake of several essential plant nutrients, but the concentrations of the elements affected generally remained higher than the concentrations needed for adequate growth of agricultural crops. Several of the trace elements supplied to the plants were also found to be retained in the roots of the vegetable crops however, as the concentrations supplied to the plants increased, so did the concentrations found in the edible portions of the crops. Agronomic biofortification of vegetable crops with simultaneous additions of multiple trace elements, under these experimental conditions, was thus considered to be a viable option to increase the concentrations of essential mineral nutrients in the edible portions of vegetable crops. However, these modified nutrient fertilizers should only be given to established crops or without the addition of fluoride. Further research on a wider variety of seeds and vegetable crops, as well as research under field conditions is needed to determine whether these findings remain relevant under these conditions.

京都大学 / 0048 / 新制・課程博士 / 博士(農学) / 甲第22487号 / 農博第2391号 / 新制||農||1076(附属図書館) / 学位論文||R2||N5267(農学部図書室) / 京都大学大学院農学研究科応用生命科学専攻 / (主査)教授 植田 充美, 教授 梅澤 俊明, 教授 栗原 達夫 / 学位規則第4条第1項該当 / Doctor of Agricultural Science / Kyoto University / DFAM

While extensive research has been carried out to examine the yield growth brought about by innovations in agricultural technology, not enough work has been done to document the economic impacts of these innovations on areas besides yields and income. This study presents two papers which contribute to our understanding of the health and environmental impacts of agricultural innovation, "Expected economic benefits of meeting nutritional needs through biofortified cassava in Nigeria and Kenya," and "Projected farm-level impacts on income of conservation agriculture in the Andean Region." The first paper is motivated by the public health consequences of vitamin and mineral deficiencies, which affect more than two billion people worldwide and can lead to increased incidence of illness, disability, and mortality. Through the use of the disability adjusted life years concept (DALYs), economic surplus analysis, and benefit-cost analysis, the authors determine the economic impact of a staple crop biofortification project. The study finds that biofortified cassava in Nigeria and Kenya is a cost effective means of reducing health problems associated with vitamin A and iron deficiency. The second paper considers the significant livelihood challenges faced by rural communities in the Andes, including poverty, food insecurity, and natural resource constraints. Through the development and implementation of a linear programming model, the study analyzes the economic impact of a conservation agriculture project in central Ecuador, and finds that certain experimental cropping activities designed to decrease soil degradation may contribute to increased incomes for farm households. / Master of Science

Les travaux présentés ici portent sur les P1B-ATPases HMA2, HMA3 et HMA4 d'Arabidopsis thaliana, transporteurs de cations présents sur différentes membranes chez les plantes. L'étude du contenu cationique de plantes mutantes hma2 et hma4 a précisé le rôle important de HMA4 dans la translocation du Zn et du Cd vers les parties aériennes et sa forte affinité pour le Cd. La mesure du contenu cationique de graines de différents génotypes a montré un effet complexe des modulations de l'expression des gènes correspondants, la surexpression du gène HMA4 conduisant à une teneur en Zn de la graine similaire à celle du mutant perte de fonction. Ces résultats confirment l'importance de HMA4, et montrent la nécessité d'adapter la construction aux objectifs biotechnologiques visés. Afin de préciser le rôle de résidus conservés au sein de la famille des P1B-ATPases, j'ai étudié l'effet de l'expression d'un variant de HMA4 pour le domaine fortement conservé CPC. Les résultats obtenus in planta suggèrent une interaction avec la version native du transporteur entraînant une perte de l'activité de HMA4. Pour mener une approche structure/fonction sur ces transporteurs, L. lactis a été défini comme le meilleur candidat pour produire HMA3. Suite à l'expression de HMA3, un gain de tolérance au Cd a été observé et a permis de valider 3 variants de HMA3, mutés au niveau du pore ou du site d'hydrolyse de l'ATP, comme affectés dans l'activité de la protéine. Les membranes de L. lactis enrichies en transporteur HMA3 ou de ses variants ont permis une reconstitution in vitro en protéoliposomes permettant de mesurer une activité de transport du Cd compétitive avec le Zn et inhibée par le vanadate. / Work presented here is about Arabidopsis thaliana P1B-ATPases HMA2, HMA3 et HMA4, cation transporters found in different plant membranes. Cation content study of mutant plants hma2 and hma4 precised important role of HMA4 in upward translocation of Zn and Cd, and its high affinity for Cd. Cation content measure of seeds from different genotypes showed a complex effect of modulations of related genes expression levels, HMA4 overexpression leading to a seed Zn content similar the loss-of-function mutant one. These results confirm the importance of HMA4 and show the needs to adapt construction to biotechnological aims. To precise the role of residus conserved among the P1B-ATPases family, I studied the effect of the expression of a HMA4 variant for the highly conserved domain CPC. Obtained in planta results suggest an interaction with the native transporter leading to a loss of HMA4 activité. To perform a structure/function study on these transporters, L.lactis has been shown as the best candidate to produce HMA3. Due to HMA3 expression, a gain of Cd tolerance has been observed and allowed to validate three HMA3 variants, mutated in the pore or the ATP hydrolysis site, as affected in the protein activity. L.lactis membranes enriched with HMA3 or variants allowed an in vitro reconstitution in proteoliposomes and the measurement of a Cd transport activity competing with Zn and inhibited by vanadate.