Submitted by (edna.saturno@ufrpe.br) on 2016-11-24T12:33:10Z No. of bitstreams: 1 Eduardo Moreira Barros.pdf: 309180 bytes, checksum: edea775b3717bccf19c158fb0d7bf220 (MD5) / Made available in DSpace on 2016-11-24T12:33:10Z (GMT). No. of bitstreams: 1 Eduardo Moreira Barros.pdf: 309180 bytes, checksum: edea775b3717bccf19c158fb0d7bf220 (MD5) Previous issue date: 2009-02-02 / Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq / The fall armyworm, Spodoptera frugiperda (J.E. Smith) (Lep.: Noctuidae), is a cosmopolitan pest attacking several important plants. This work investigated the host selection and the life history characteristics for S. frugiperda fed corn, millet, cotton and soybean plants. Selection of hosts for oviposition was studied in plastic greenhouse using the host plants cultivated in micro-parcels with five plants each. The host colonization by S. frugiperda larvae was also studied in micro-parcels, in the field, and development and reproduction in the laboratory. Females of S. frugiperda did not select a specific host for laying eggs among the studied hosts regardless their phenology: before or after setting the reproductive structures. The success of colonization by neonate larvae, measured based on the number of surviving larvae and their weight after 10 days from releasing, showed no difference among the hosts for larval weight, but greater number of larvae was found on millet. Female moths from larvae fed cotton in the field were less fecund (1144.7 eggs) and lower longevity (13.3 days). The overall results fromfertility life table parameters estimated for individuals reared during the larval stage in the field highlighted the millet as the host more favorable to S. frugiperda. The study in the laboratory using leaves of each host, and the combination of leaf and boll of cotton as diet for S. frugiperda yielded low success of boll colonization by neonate larvae compared to only leaf. S. frugiperdafed cotton bolls exhibited longer larval, pupal and adult stages, and lower egg production. However, larvae fed leaf plus cotton bolls exhibited similar performance to corn and cotton leaves. Based on the results, the millet currently used in the crop systems with soybean, corn or cotton, is a potential host for S. frugiperda while, cotton was intermediate diet compared to corn and soybean / A lagarta-do-cartucho, Spodoptera frugiperda (J.E. Smith) (Lep.: Noctuidae) é uma praga cosmopolita importante para várias culturas. Assim, este trabalho investigou a seleção hospedeira e história de vida de S. frugiperda em milho, milheto, algodão e soja, conduzindo-se estudos de preferência de oviposição entre hospedeiros, em casa telada, e colonização de lagartas de S. frugiperda nos respectivos hospedeiros em campo, bem como desenvolvimento e reprodução em condições de laboratório. Adultos de S. frugiperda não demonstraram preferência hospedeira, independente do estádio fenológico desses (antes ou após emissão de estruturas reprodutivas). O sucesso de colonização, em campo, medido pelo peso e número de lagartas aos 10 dias após a liberação, mostrou não haver diferença no peso de lagartas entre os hospedeiros, entretanto maior número de lagartas foi encontrado no milheto. Fêmeas oriundas de lagartas criadas em algodão no campo, produziram menor número de ovos (1144,7) e tiveram a menor longevidade (13,3 dias).Os resultados da tabela de vida de fertilidade estimada para indivíduos criados durante a fase de lagarta em campo demonstram que o milheto foi o hospedeiro mais favorável ao desenvolvimento de S. frugiperda. O estudo de laboratório empregando folhas dos hospedeiros e a combinação de folha e maçã do algodoeiro como dieta mostrou baixo sucesso de colonização da maçã do algodoeiro por lagartas neonatas em relação a folhas de todos os hospedeiros. S. frugiperdacriadas em apenas maçã do algodão apresentaram maiores durações da fase de larva, pupa e adulta e, uma menor produção de ovos. No entanto, lagartas criadas em folhas mais maçã de algodão obtiveram desenvolvimento semelhante a, apenas, folhas de algodão e milho. Com base nos resultados o milheto como integrante do sistema de produçcão é um hospedeiro potencial para S. frugiperda, enquanto que folhas mais maçã do algodoeiro foram dietas intermediárias em comparação ao milho e soja.

Submitted by Erika Demachki (erikademachki@gmail.com) on 2014-12-29T15:28:36Z No. of bitstreams: 2 license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Dissertação - Déborah Patrícia Leal Oliveira - 2013.pdf: 2010212 bytes, checksum: 0c24a44129b6342788eadf59a1e31064 (MD5) / Approved for entry into archive by Erika Demachki (erikademachki@gmail.com) on 2014-12-29T15:36:19Z (GMT) No. of bitstreams: 2 license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Dissertação - Déborah Patrícia Leal Oliveira - 2013.pdf: 2010212 bytes, checksum: 0c24a44129b6342788eadf59a1e31064 (MD5) / Made available in DSpace on 2014-12-29T15:36:20Z (GMT). No. of bitstreams: 2 license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Dissertação - Déborah Patrícia Leal Oliveira - 2013.pdf: 2010212 bytes, checksum: 0c24a44129b6342788eadf59a1e31064 (MD5) Previous issue date: 2013-02-25 / Pearl millet is a rich nutritionally cereal, being a major source of protein countries of the semiarid region of the African continent. The pearl millet crops are in expansion on Brazilian Savanna due the plant characteristics that are compatible to the climate and soil of the region. However, in Brazil, the grains of millet are not widely used in food, it was noted with advantageous insertion of this cereal in the diet of the population as this has major advantages over other commonly used cereals as the lowest price, the more quantity and better quality of fiber lipid and protein. The thermoplastic extrusion was used for the preparation of products with the millet that was mixed with corn grits because it presents favorable characteristics for processing used. This study was conducted in order to develop and evaluate the nutritional quality, technological and sensory snacks, pre-gelatinized flour (FPG) and pasta-based mixture of millet [Pennisetum glaucum (L.) R. Br] and gritz of corn (Zea mays L.). For extruding the mixture of grains of millet and corn gritz was used rotational central composite design for the best moisture conditions of the raw material and temperature of the extruder zone 3. The snacks were optimized according to the expandability and pregelatinized flour according to the absorption capacity and water solubility. After optimization of flour, which showed better gelatinization was applied in the preparation of pasta. This was prepared using the mixture design with ternary composition (extruded flour, corn flour and millet raw) to find what proportion of ingredients that got the best features of cooking pasta. Snacks with 11% moisture content of the raw material and 90 ° C temperature were those with greater expansion and were the most desirable second test of desirability. When they were being flavored sensory acceptance and its nutritional composition were classified as high fiber content. The pre-gelatinized flour with highest absorption capacity and water solubility was the one with the same extrusion conditions optimized snack. The proportion of ingredients of the mass had the best cooking conditions was 10% pre-gelatinized flour, 25% corn and 65% of pearl millet flour. The pasta was accepted for flavor, texture and appearance of the panelists. However, it was possible to extrude grains of millet and corn gritz and also the development of products with good nutritional and sensory characteristics. / O milheto é um cereal rico nutricionalmente, sendo uma das principais fontes proteicas em países da região semiárida do continente Africano. No Brasil, mais especificamente no Cerrado, o cultivo deste cereal apresenta-se em expansão devida as características da planta que são compatíveis ao clima e solo da região. No entanto, no Brasil, os grãos de milheto não são muito utilizados na alimentação humana, com isso notou-se vantajoso a inserção deste cereal na alimentação da população já que este apresenta grandes vantagens em relação a outros cereais comumente utilizados, como o preço mais baixo, a maior quantidade de fibras e a melhor qualidade proteica e lipídica. A extrusão termoplástica, uma técnica bastante versátil, foi utilizada para a elaboração de produtos com o milheto que foi misturado ao gritz de milho por este apresentar características favoráveis ao processamento utilizado. Este estudo foi realizado com o objetivo de desenvolver e avaliar a qualidade nutricional, tecnológica e sensorial de snacks, farinha prégelatinizada e massa alimentícia à base de mistura de milheto [Pennisetum glaucum (L.) R. Br.] e gritz de milho (Zea mays). Para a extrusão da mistura de grãos de milheto e gritz de milho foi utilizado o delineamento composto central rotacional para obter as melhores condições de umidade da matériaprima e temperatura da 3ª zona do extrusor. Os snacks foram otimizados conforme a capacidade de expansão e a farinha pré-gelatinizada de acordo com a capacidade de absorção e solubilidade em água, ou seja, gelatinizada. A farinha pré-gelatinizada otimizada foi aplicada na elaboração de massa alimentícia. Esta foi elaborada utilizando o delineamento de misturas com composição ternária (farinha extrusada, fubá de milho e farinha de milheto crua) para encontrar qual a proporção de ingredientes que obtivesse as melhores características de cozimento da massa. Os snacks e a massa alimentícia foram analisados microbiologicamente para a realização da análise sensorial. Os snacks com 11% de umidade da matéria-prima e 90 °C de temperatura foram os que apresentaram maior expansão e foram os mais desejáveis segundo teste de desejabilidade. Ao serem aromatizados eles foram aceitos sensorialmente e em sua composição nutricional foram classificados como alto teor de fibras. A farinha pré-gelatinizada que obteve maior capacidade de absorção e solubilidade em água também foi o experimento com 11% de umidade e 90 °C de temperatura. A proporção de ingredientes da massa que teve as melhores condições de cozimento foi a de 10% farinha pré-gelatinizada, 25% de fubá de milho e 65% de farinha de milheto. A massa alimentícia foi aceita em relação ao sabor, textura e aparência entre os provadores. Contudo, foi possível a extrusão de grãos inteiros de milheto e gritz de milho e ainda a elaboração de produtos com boas características nutricionais, tecnológicas, microbiológicas e sensoriais segundo atributos sabor, aparência e textura.

Com o objetivo de avaliar os efeitos da adubação antecipada sobre a produção de matéria seca da cultura de Eleusine coracana, os caracteres produtivos, a qualidade fisiológica das sementes e a produtividade da cultura da soja em sucessão, sustentando-se a hipótese de que a produtividade da soja não é reduzida devido à antecipação da adubação de base para a cultura do capim-pé-de-galinha, foi conduzido o presente experimento na Estação Experimental Anhembi, Escola Superior de Agricultura Luiz de Queiroz (USP/ESALQ), no município de Piracicaba-SP, durante os anos agrícolas de 2001/2002, 2002/2003 e 2003/2004, em Latossolo Amarelo distrófico. A adubação consistiu da aplicação de 90 kg de P2O5 ha-1, 50 kg de K2O ha-1 e de micronutrientes (Co, Cu, Fe, Mn, Mo e Zn). O experimento adotou delineamento em blocos completos ao acaso com três repetições e 12 tratamentos que consistiram em diferentes níveis de antecipação da adubação da soja para a cultura do capim-pé-degalinha: T1= nenhuma adubação; T2= adubação convencional na soja; T3= antecipação de 50% de K, no capim-pé-de-galinha; T4= antecipação de 100% de K, no capim-pé-de-galinha; T5= antecipação de 50% de P, no capim-pé-de-galinha; T6= antecipação de 50% de P e K, no capim-pé-de-galinha; T7= antecipação de 50% de P e 100 % de K, no capim-pé-de-galinha; T8= antecipação de 100% de P, no capim-pé-degalinha; T9= antecipação de 100% de P e 50% de K, no capim-pé-de-galinha; T10= antecipação de 100% de P e K, no capim-pé-de-galinha; T11= antecipação de 100% de P e K + micronutrientes, no capim-pé-de-galinha; T12= antecipação da adubação foliar com micronutrientes, no capim-pé-de-galinha. As características avaliadas foram: a) capim pé-de-galinha: produtividade de matéria seca da parte aérea; b) soja: estande final, altura final de planta, grau de acamamento, número de ramificações por planta, número de vagens chochas por planta, número de vagens de 3 cavidades com 3, 2 e 1 semente, número de vagens de 2 cavidades com 2 e 1 semente, número de vagens de 1 cavidade com 1 semente, número total de vagens e de sementes por planta, peso de sementes por planta, peso de mil sementes e produtividade agrícola. As sementes de soja foram submetidas aos testes de germinação, de envelhecimento acelerado e de emergência em areia. Conclui-se: a) A antecipação das adubações fosfatada e potássica da soja para a semeadura do Eleusine coracana, incrementa a produtividade de matéria seca deste; b) A ausência de adubação do sistema de produção envolvendo a semeadura direta da soja em sucessão à cultura de cobertura com o capim-pé-degalinha conduz, ao longo das sucessivas safras, a perdas de produtividades agrícolas de matéria seca do capim-pé-de-galinha e de sementes de soja; c) A antecipação da adubação de base da cultura da soja para o capim-pé-de-galinha não interfere com a quantidade total de vagens formadas pelas plantas de soja; e, d) A antecipação da adubação de semeadura com fósforo e potássio da cultura da soja para a semeadura do capim-pé-de-galinha não interfere com a massa de mil sementes e nem com a produtividade agrícola da soja. / A research was carried out with the aim of evaluating the effects of anticipated fertilization on the production of Eleusine coracana dry matter as well as it productive features. In addition to it, the physiological quality of the seeds and the culture yield were also evaluated, taking into account the hypothesis that soybean yield is not reduced due to the anticipated base fertilization of the finger millet culture. The experiment was conducted at the Estação Experimental Anhembi, Escola Superior de Agricultura Luiz de Queiroz (USP/ESALQ), in Piracicaba/SP, during the growing seasons of 2001/2002, 2002/2003 and 2003/2004, in an Oxisol. The fertilization consisted on the application of 90 kg of P2O5 ha-1, 50 kg of K2O ha-1 and micronutrients (Co, Cu, Fe, Mn, Mo and Zn). The experiment adopted a completely randomized blocks design with three repetitions and twelve treatments, which comprehended different levels of anticipated soybean fertilization for the culture of finger millet, as it follows: T1= without fertilization ; T2= traditional soybean fertilization; T3= anticipation of 50% of K on finger millet; T4= anticipation of 100% of K, on finger millet; T5= anticipation of 50% of P on finger millet; T6= anticipation of 50% of K and P on finger millet; T7= anticipation of 50% of P and 100% of K on finger millet; T8= anticipation of 100% of P on finger millet; T9= anticipation of 100% of P and 50% of K on finger millet; T10 = anticipation of 100% of P and K on finger millet; T11 = anticipation of 50% of K on finger millet; T11 = anticipation of 100% of P and K + micronutrients on finger millet; T12 = anticipation of foliar fertilization with micronutrients on finger millet. The evaluated characteristics were: a) finger millet: dry matter production; b) soybean: final stand, final plant height, lodging, number of branches per plant, number of empty pods per plant, number of pods with 3 cavities with 3, 2 and 1 seed, number of pods with 2 cavities with 2 and 1 seed, number of pods with 1 cavity and 1 seed, total number of pods per plant, seed weight per plant, mass of 1,000 seeds and total yield. Soybean seeds were submitted to germination tests, accelerated ageing tests and well as tests of sand emergency. It was concluded that: a) Phosphorus and potassium anticipated fertilization on soybean applied to the Eleusine coracana (L.) Gaertn. crop can increase the finger millet dry matter yield; b) The absence of fertilization on the soybean no-tillage yield system succeeding the finger millet cover culture can cause the decrease of total yield of finger millet dry matter and soybean seeds; c) The anticipation of base fertilization of soybean culture for finger millet does not interfere with the total amount of pods generated by soybean plants; and d) Phosphorus and potassium anticipated fertilization on soybean culture for finger millet crop do not interfere with the mass of 1,000 seeds and total soybean yield.

Vinte e quatro cordeiros cruzados, machos inteiros, com aproximadamente 70 dias de idade, com peso vivo inicial de 22 ± 1,61 kg e peso vivo final de 37 ± 2,16 kg, foram alimentados com quatro dietas com alto teor de concentrado, contendo diferentes tipos de grãos (milho quebrado, milho em grão, sorgo e milheto). Os animais foram distribuídos em um delineamento em blocos ao acaso, com quatro tratamentos e seis repetições, alimentados por 66 dias e posteriormente abatidos. Durante o período experimental avaliou-se a espessura de gordura subcutânea e área de olho de lombo, entre a 12ª e 13ª costelas por ultrassonografia. Também foi avaliado o desempenho e digestibilidade dos animais. Após o abate, foram realizadas medidas de comprimento de carcaça, comprimento de perna e estabelecido o índice de compacidade das carcaças. Foram analisadas a maciez, cor e perdas por cocção. Também foram separados cinco cortes comerciais para determinação do rendimento, em relação ao peso da meia carcaça, assim como as aparas. Posteriormente foi realizada análise econômica das quatro dietas fornecidas aos animais. Os animais alimentados com milho em grão apresentaram melhor eficiência alimentar (P<0,05), sendo superiores àqueles alimentados com controle ou com sorgo, mas sem diferença do milheto. As digestibilidades de matéria orgânica, matéria seca e proteína bruta foram maiores (P<0,05) para o milho em grão e milheto, seguidos pelo sorgo e controle. Os valores de nutrientes digestíveis totais, energia digestível e energia metabolizável não diferiram entre as dietas (P>0,05). A área de olho de lombo, espessura de gordura subcutânea, maciez e perda por cocção não foram influenciadas (P>0,05) pelas diferentes fontes de grãos. O teor de vermelho (a *) foi maior na carne de animais alimentados com sorgo e milheto (P=0,0017), enquanto o teor de amarelo (b *) foi maior nos animais alimentados com dietas de grãos de milho e milheto (P=0,0025), quando comparado ao sorgo. As medidas morfométricas não diferiram entre os tratamentos, nem o rendimento dos cortes, exceto pelo lombo que teve maior rendimento nos animais que receberam milho grão e sorgo (P<0,05). Não houve diferença estatística entre a eficiência técnica dos quatro tratamentos (P>0,05). Os tratamentos à base de milho grão e milheto apresentaram maior eficiência econômica. O uso do milho quebrado em substituição ao milho grão só seria recomendado com segurança se seus preços fossem 24% mais baixos que o do milho grão. Diante dos comportamentos históricos dos preços do sorgo e do milheto, estes poderiam substituir o milho sem prejuízo estatisticamente significativo do desempenho zootécnico. / Twenty four male crossbred lambs, with mean weight and age of 22 kg and 70 days were fed with high concentrate level for 66 days in order to evaluate the effects of the inclusion of four different treatments (cracked corn, corn grain, sorghum grain and millet grain) on the carcass and meat quality. The animals were assigned to a randomized block design. During the trial period there were evaluated subcutaneous fat thickness and loin eye area, between 12th and 13th rib by ultrasound. There were also measured animals performance and digestibility. After slaughter, there were evaluated carcass and leg length and established carcass compactness index. There were analyzed shear force, meat color parameters and cooking losses. Moreover, there were separated five commercial cuts for determination of yield in relation to the half carcass weight, as well as chips. Economic analysis of the four treatments was realized. Animals fed corn grain were more efficient (P<0.05) than those fed control or sorghum, but no difference was observed to the millet treatment. Organic matter, dry matter and crude protein digestibility were higher (P<0.05) for grain corn and millet, followed by sorghum and control. The values of total digestible nutrients, digestible and metabolizable energy were not different among diets (P>0.05). Loin eye area, backfat thickness, tenderness and cooking losses were not affected (P>0.05) by different sources of grain. The red content (a *) were higher in meat from animals fed sorghum and millet (P=0.0017), while the yellow content (b *) was higher in animals fed corn and millet diets (P=0.0025) when compared to sorghum. Morphometric measurements and cut yields did not differ among treatments, except for loin, that presented higher yield in animals fed with corn grain and sorghum treatments (P <0.05). There was no statistical difference for the technical efficiency between the four treatments (P>0.05). Corn grain and millet showed highest economic efficiency. The use of cracked corn instead corn grain would only be recommended safely if corn grain prices were 24% lower than cracked corn. Given the historical behavior of sorghum and millet prices, these ingredients could replace corn without prejudice production performance.

Although work on the prolamins of pearl millet (Pennisetum glaucum) has revealed partial amino acid sequences for several alcohol-soluble storage proteins (Marcellino et al. 2002) the genes encoding them have not yet been isolated. We constructed a cDNA library from developing P. glaucum seed tissue and screened it using maize zein gene probes to isolate several α-prolamin-like gene sequences. The proteins encoded by these genes generally fall into two size classes: 20.6kD and 27.1kD, which we call the 21kD and 27kD pennisetins. Both proteins are similar in composition and sequence to α-prolamins from maize, sorghum and Coix. Protein bodies that appear as occlusions within the rough ER of P. glaucum endosperm cells are also very similar in size and shape to maize and sorghum protein bodies. The SDS-PAGE gel of the alcohol soluble protein fraction shows two distinct bands in the region corresponding to the 19kD and 22kD of maize α-zein. Both classes of pennisetins appear to be more similar to the 19kD α-zein of maize than to the 22-kD α-zein judging from sequence homology and maize antibody binding. Phylogenetic reconstruction suggests that P. glaucum may have branched from maize prior to the gene duplication which created the 19kD and 22kD α-zein families.

This dissertation consists of three chapters that address two major resource challenges faced by smallholder farmers in Sub-Saharan Africa: (i) weather shocks and (ii) limited land access for agricultural production. The first chapter looks at how weather shocks affect millet production and millet market price seasonality in Niger. In this paper, we use district-level longitudinal production and price data, along with high-resolution rainfall data to investigate the distinct impacts of positive and negative rainfall shocks on millet production and millet price seasonality in Niger. We find that a one standard deviation decrease in seasonal rainfall from historical averages is associated with declines in millet market price initially after harvest, but strong upward pressure on market prices 6 months after harvest. As a result, drought exacerbates existing price seasonality, which in turn can amplify negative impacts on households. Social protection programs need to account for potential increases in seasonal price variability in the design of programs to enhance household resilience to weather shocks. To better understand the household behavior that gives rise to the price responses observed in the first chapter, we explore weather shock impacts on household millet market participation in Niger in the second chapter. We merge a nationally representative household panel data with high-resolution spatially disaggregated rainfall data. We find that households are more likely to participate in the market as net sellers with negative rainfall shocks, but marketed quantity for net sellers decreases with negative rainfall shocks. Diversification into non-agricultural activities can mediate the impacts of negative rainfall shocks on market participation and lead to increases in volume of sales. Policies that support household involvement in the rural nonfarm economy through training and access to credit to help expand businesses may also stimulate millet market participation. In the third chapter, we use a rich dataset of 1,123 households to examine the determinants of individual household member access to groundnut fields, the predominant cash-crop in the Groundnut Basin of Senegal. The analysis also explores the implications of limited land access on groundnut productivity of young adult and female field managers. We find that young adults and females have fewer opportunities to access land compared to older and male household members. Further, we show that higher productivity may not be driving differential access to fields among older adults. Results suggest that with equal access, young adults may be as or more productive groundnut cultivators than older adults. Programs to increase young adult and female economic opportunities should focus on closing gaps in access to resources for production rather than decreasing observed production disparities. / Doctor of Philosophy / This dissertation addresses two major challenges that small farmers face in Sub-Saharan Africa: (i) erratic changes in weather patterns and (ii) land access for agricultural production. We divide the dissertation in three chapters. The first two chapters focus on weather shocks, while the third chapter focuses on land access. In the first chapter, we discuss how low and high rainfall affect the seasonal variation of market prices for the most important staple grain (millet) in Niger (West Africa). We find that lower rainfall than usual makes households sell their millet in the post-harvest period when market prices are generally low, and makes them buy back millet in the lean season when market prices are often high. As a result, policies that aim support household resilience to climate shocks should design programs that account for potential increases in seasonal price variability. In the second chapter, we study how low rainfall levels affect Niger millet farmers' decision to sell or not sell their harvest, as well as the association between low rainfall and the quantity of millet sold and bought. We distinguish three groups of farmers: (i) net buyers who have higher millet purchases than sales, (ii) autarkic who have zero millet purchases and millet sales, and (iii) net sellers who have higher sales than purchases. Our findings show that lower rainfall increases net sellers' probability to sell their millet, whereas it decreases the quantity they sell. Our results also reveal that households who diversify their sources of income into non-agricultural activities increase millet net sales even with low rainfall levels. Policies that support household involvement in these non-agricultural activities may also stimulate millet market participation. In the third chapter, we study the factors that affect household members' access to a groundnut field in Senegal with a particular focus on young adults and females. We show that females and young adults are less likely to access a field compared to older and male household members. Our results also suggest that with equal access, young adults may be as or more productive groundnut cultivators than older adults. Programs to increase young adult and female economic opportunities should focus on closing gaps in access to resources for production.

Cette thèse s'attache à étudier la notion d'événement dans la nouvelle contemporaine, à travers un corpus de recueils américains, français et italiens, parus entre 1980 et 2007. Habituellement défini comme une rupture, engageant un bouleversement ontologique pour le sujet qui l'éprouve, l'événement connaît une autre représentation dans les récits brefs ici étudiés, engageant une réflexion épistémologique sur la littérature contemporaine, entre conscience d'un monde marqué par le manque et volonté de continuer malgré tout à raconter, selon d'autres modalités. Cette réflexion est mise en évidence par le récit bref. Nos nouvelles montrent à chaque fois ce qui semble être un appauvrissement. Ainsi, l'événement connaît un évidement : sa portée est atténuée, il n'entraîne pas de changements dans la conscience du personnage. De même, nos textes font voir un désengagement des instances auctoriale et narratoriale, empêchant l'établissement d'une signification univoque et d'une morale explicite. Enfin, ces histoires narrent fréquemment un dysfonctionnement, tant matériel que du récit en lui-même. Mais à chaque fois, ces carences sont en fait le lieu d'un renouvellement. L'évidement est la possibilité de proposer un autre récit où le sensationnel est mis à distance ; le désengagement permet au lecteur d'adopter vis-à-vis du texte une attitude qui ne soit pas celle de la maîtrise absolue ; le dysfonctionnement n'inaugure pas une nouvelle ère du soupçon, mais une volonté de souligner le potentiel narratif. De cette façon, la nouvelle contemporaine comme l'événement narré affichent une tension, entre perte et renouvellement.

L'évolution climatique a été marquée ces dernières décennies par des changements importants, notamment une augmentation de température et une variation de la pluviométrie. Une des conséquences du changement climatique est son impact actuel et futur sur l'agriculture et la sécurité alimentaire. En région sahélienne, la sécurité alimentaire repose essentiellement sur quelques céréales, parmi lesquelles le mil occupe une place fondamentale. Un des traits qui permettent l'adaptation au climat de cette espèce est la date de floraison, dont la variation permet d'accomplir le cycle de vie de la plante dans des saisons pluvieuses plus ou moins courtes. Les bases génétiques de ce caractère adaptatif sont encore peu connues. Nous avons développé une méthodologie de cartographie d'association phénotype-génotype, afin d'identifier des gènes impliqués dans la variation de ce caractère. Cette étude a permis d'identifier deux gènes candidats, PHYC et MADS11, associés à la date de floraison et à la variation morphologique chez le mil. Nous avons validé ces associations par des analyses QTLs. Pour PHYC, nous avons aussi étudié le pattern de déséquilibre de liaison sur une zone d'environ 80 kb autour du gène, et développé une approche de Markov Chain Monte Carlo (MCMC) pour comparer les gènes identifiés dans la région. Cette analyse suggère que les polymorphismes à l'intérieur de PHYC sont les meilleurs candidats expliquant l'effet phénotypique observée dans cette région du génome. La seconde partie de ce projet a été consacrée à l'examen méthodologique de la cartographie d'association pour l'étude des interactions entre le génotype et l'environnement. Les résultats de cette thèse ont été discutés notamment dans la perspective de gestion de l'impact du changement climatique sur le mil, céréale majeure des zones semi-arides / In last decades, climate changes led to temperature increase and rainfall variation across the globe. One of the key consequences of these changes is their impact on agriculture and food security. In sahelian countries, food security relies on a few cereal crops, among which pearl millet plays a crucial role for population food supply. Sahel region is facing the impact of rainfall variability and drought since the 1970s. Flowering time variation is one of the main adaptations that allow pearl millet cultivation in drier and shorter rainy seasons. The genetic bases of this complex trait are still understudied. We developed an association mapping framework for the analysis of genotype-phenotype relationship in pearl millet. We successfully identified two genes associated with flowering time variation in pearl millet (PHYC and MADS11). We confirmed these associations using QTL studies. For PHYC, we also examined the pattern of linkage disequilibri um on a chromosomal region extending to 80 kb around the gene, and we developed a Markov Chain Monte Carlo approach (MCMC) to compare six genes identified in this region. Our results suggest that, among the polymorphisms observed in this region, polymorphisms in PHYC are the best candidate for a direct causative role. The second part of this project addressed methodological examination of association mapping framework to deal with genotype by environment interactions. The results of this work were discussed with regard to the challenge of pearl millet crop adaptation to climate change.

O presente experimento teve por objetivo avaliar o efeito da antecipação da adubação da cultura da soja no acúmulo de matéria seca e extração de nutrientes pelo capim-pé-de-galinha (Eleusine coracana (L.) Gaertn.) e no acúmulo de matéria seca e exportação de nutrientes pela cultura da soja em sucessão, em sistema de plantio direto. O experimento foi conduzido em área experimental da Escola Superior de Agricultura "Luiz de Queiroz" (USP/ESALQ), no município de Piracicaba - SP, durante o ano agrícola de 2001/2002, em solo LATOSSOLO AMARELO Distrófico. O cultivar de soja utilizado foi o BRS-133. A adubação, segundo a recomendação oficial para o estado de São Paulo, consistiu da aplicação de 90 kg de P2O5 ha -1 , 50 kg de K2O ha -1 e de micronutrientes (Co, Cu, Fe, Mn, Mo e Zn). Os tratamentos consistiram em níveis de antecipação da adubação da soja para a cultura do capim-pé-de-galinha (T1: 0%; T2: 50% de P; T3: 50% de K; T4: 100% de P; T5: 100% de K; T6: 50% de P e K; T7: 100% de P e 50% de K; T8: 50% de P e 100 % de K; T9: 100% de P e K; T10: micronutrientes; T11: 100% de P e K + micronutrientes; T12: controle), totalizando 12 tratamentos, delineados em blocos completos ao acaso com três repetições. As características avaliadas foram: produção de matéria seca, concentração e acúmulo dos nutrientes na parte aérea do capim-pé-de-galinha; acúmulo de matéria seca, concentração e acúmulo de nutrientes nos grãos de soja. As principais conclusões são: a) no que concerne à produtividade de matéria seca, o capim Eleusine coracana (L.) Gaertn. constitui-se em espécie recomendável à produção de palhada em sistema de produção sob plantio direto, desde que implantada em solo com média a alta fertilidade; b) considerando-se o acúmulo de nutrientes na matéria seca produzida, constata-se que o capim Eleusine coracana (L.) Gaertn. apresenta a seguinte seqüência de absorção: K > N > Ca > Mg > S > P >> Mn> Fe > Zn > Cu; c) a produção de matéria seca e o acúmulo dos nutrientes fósforo e cálcio pelo capim Eleusine coracana (L.) Gaertn. aumentam com a aplicação antecipada da adubação fosfatada de base recomendada para a soja; d) a antecipação da adubação de base da soja, por ocasião da instalação do capim Eleusine coracana (L.) Gaertn., não diminui o acúmulo de matéria seca e nem interfere com a exportação de nutrientes pelas plantas de soja. / This research was to evaluate the effect of the anticipation of soybean fertilization on dry matter production and extraction of nutrients by finger millet (Eleusine coracana (L.) Gaertn.) and on dry matter accumulation and exportation of nutrients by soybean seed cultivated in sequence, in a no-till system. The experiment was carried out at the experimental fields of Escola Superior de Agricultura "Luiz de Queiroz" (USP/ESALQ), in Piracicaba-SP, during the growing season of 2001/2002, in an Oxisol. The cultivar used was BRS-133. The soybean fertilization, according to the official recommendation to the state of São Paulo, consisted in the application of 90 kg of P2O5 ha -1, 50 kg of K2O ha -1 and of micronutrients (Co, Cu, Fe, Mn, Mo and Zn). The treatments consisted of levels of anticipation of the soybean fertilization to the finger millet crop (T1: 0%; T2: 50% of P; T3: 50% of K; T4: 100% of P; T5: 100% of K; T6: 50% of P and K; T7: 100% of P and 50% of K; T8: 50% of P and 100 % of K; T9: 100% of P and K; T10: micronutrients; T11: 100% of P and K + micronutrients; T12: controle), totaling 12 treatments, designing a complete randomized blocks with three replications. The evaluated characteristics were: dry matter production, concentration and nutrients accumulation at biomass of finger millet; dry matter accumulation, nutrients concentration and accumulation in soybean seed. The main conclusions are: a) in reference to the dry matter production, Eleusine coracana (L.) Gaertn. is a recommended specie to obtain plant residues in no-till systems, since it is growing on medium to high fertility soils; b) considering the nutrients accumulation in dry matter, it is verified that Eleusine coracana (L.) Gaertn. presents the following sequence of nutrient absorption: K > N > Ca > Mg > S > P >> Mn > Fe > Zn > Cu; c) the anticipation of the soybean fertilization to the Eleusine coracana (L.) Gaertn. sowing do not decrease dry matter accumulation nether interferes with the nutrients exportation by soybean seed; d) dry matter production and phosphorus and calcium accumulation by Eleusine coracana (L.) Gaertn. increase in response of phosphorus anticipation from soybean fertilization.

Na região dos cerrados, as principais culturas de cobertura utilizadas para a produção de palha no sistema de plantio direto são o milheto (Pennisetum glaucum R. BR.) e as aveias (Avenas spp.). No entanto, a resposta dessas espécies vegetais frente ao nematóide das lesões (Pratylenchus brachyurus) e o das galhas (Meloidogyne incognita) são escassas. O objetivo do presente trabalho é de verificar a resposta de genótipos de milhetos, aveias e outras coberturas vegetais a Pratylenchus brachyurus e de aveias a Meloidogyne incognita sob condições controladas. Desenvolveram-se quatro experimentos no total, no experimento 1, os cultivares de milhetos testados foram resistentes ao nematóide (FR<1,0) com exceção da cultivar ADR 500 (população BA). No experimento 2, as aveias pretas contribuíram para a redução populacional (resistentes) de P. brachyurus, fato oposto, pode ser verificado para as aveias branca e amarela (suscetíveis). No terceiro experimento, diferentemente do verificado no experimento 1, os milhetos se mostraram suscetíveis a P. brachyurus, e, o sorgo BRS-800 foi a cobertura que mais incrementou a densidade do nematóide, equiparando-se estatisticamente com a soja BRS 133. No quarto experimento, verificou-se aumento da densidade das três populações de M. incognita nas aveias pretas testadas, em contraposição à redução verificada na aveia branca UFRGS 17 e amarela São Carlos. / In Cerrado region, the main cover crop used in no tillage system are the pearl millet (Pennisetum glaucum) and the oats (Avena spp.). However, the response of these vegetable species to lesion nematode (Pratylenchus brachyurus) and to root-knot nematode (Meloidogyne incognita) is scarce. The aim of the present work was verify the response of the pearl millet genotypes, oats and other cover crops to P. brachyurus and of oats to M. incognita under greenhouse conditions. Four experiments were done; in experiment 1, the pearl millet cultivars tested were resistant to nematode (FR<1.0) with exception of the cultivar ADR 500 (population BA). In experiment 2, the black oats reduced the P. brachyurus population (resistant); contrarily, white and yellow oats were susceptible. In third experiment, the pearl millets showed as susceptible to P. brachyurus, and the sorghum BRS-800 was the cover crop more susceptible to nematode, statistically closed to soybean BRS 133. In experiment 4, black oats increased the three populations of M. incognita tested, instead the reduction verified in white oat UFRGS 17 and yellow São Carlos.