Les cultivars de bananiers sont dérivés d'hybridations entre sous-espèces de Musa acuminata (génome A) et pour certains avec l'espèce M. balbisiana (génome B). Ces hybrides présentent une fertilité réduite, des méioses perturbées et de fortes distorsions de ségrégation. Ces caractéristiques attribuées à des réarrangements chromosomiques entre espèces et sous-espèces compliquent les analyses génétiques et les programmes d'amélioration variétale. Au cours de cette thèse, nous avons mis en place et testé de nouvelles approches, basées sur la récente disponibilité d'une séquence de référence du bananier et des technologies de séquençage haut-débit, pour caractériser ces différences de structures chromosomiques et comprendre leur impact sur les ségrégations chromosomiques. Ces approches ont nécessité l'amélioration de la séquence de référence du bananier. Pour cela, des outils ont été développés. Ils sont applicables à d'autres génomes et modulables en fonction des données disponibles. Le nombre de scaffolds a été divisé par 5 et 90% de la séquence est maintenant ancré aux chromosomes. Les scaffolds correspondant au génome mitochondrial ont été identifiés et le génome chloroplastique a été assemblé et annoté. Des données de re-séquençage de l'accession ‘Pahang' et de génotypage dense de sa descendance ont été utilisées pour explorer l'origine des distorsions de ségrégation impliquant les chromosomes 1 et 4. L'ensemble des données (profils de distorsion et de recombinaison, appariements à la méiose, re-séquençage), nous orientent vers l'hypothèse d'une translocation réciproque en orientation inversée, entre régions distales des chromosomes 1 et 4. Le test de nos outils de recherche de variations structurales pour comparer les génomes A et B du bananier, dont les différences de structure sont connues, montre que nos outils détectent directement les signatures de certaines variations structurales mais que pour d'autres il ne détecte que des signatures partielles. Ces dernières peuvent néanmoins être informatives en complément d'autres types d'informations provenant de cartographie génétique et d'analyses cytogénétiques. / Banana cultivars are derived from hybridization between Musa acuminata subspecies (A genome) and, for some of them, with the species M. balbisiana (B genome). These hybrids have reduced fertility, disturbed meiosis and strong segregation distortions. These characteristics attributed to chromosomal rearrangements between species and subspecies complicate genetic analyses and breeding programs. In this thesis, we have developed and tested new approaches based on the recent availability of a banana reference genome sequence and high-throughput sequencing technologies, to characterize these differences in chromosomal structures and understand their impact on chromosomal segregation. These approaches needed improvement of the banana reference genome sequence. New bioinformatics tools were developed for this purpose. They are applicable to other genomes and are flexible according to available data. The scaffolds number was divided by 5 and 90% of the assembly is now anchored to the chromosomes. Scaffolds corresponding to the mitochondrial genome were identified and the chloroplast genome was assembled and annotated. Re-sequencing data from the 'Pahang' accession and dense genotyping of its progeny were used to explore the origin of segregation distortion involving chromosomes 1 and 4. Distortion and recombination profiles, chromosomal pairing at meiosis and re-sequencing data direct us to the hypothesis of a reciprocal translocation in inverted orientation between distal portions of chromosomes 1 and 4. We tested our structural variation research tools to compare the A and B genomes of banana, for which structural differences are known. The results showed that our tools detected complete signatures of some structural changes but for others, they only detected partial signatures. The latter can still be informative in addition to other informations derived from genetic mapping and cytogenetic studies.

Dans les agroécosystèmes, la biodiversité fonctionnelle et la biodiversité associée fournissent de nombreux services à l'homme dont la pollinisation, la régulation biologique et le cycle des nutriments. L'association des cultures est une pratique agricole qui augmente la diversité des plantes dans les agroécosystèmes, fournit des ressources alimentaires alternatives et structure les communautés des arthropodes. Elle favorise les prédateurs généralistes pour la régulation biologique des ravageurs. Cette étude vise à comprendre comment la diversité des plantes, à l'échelle de la parcelle, structure les réseaux trophiques des arthropodes et peut participer à améliorer la régulation biologique des ravageurs. Tout d'abord, une méta-analyse a été réalisée afin de rechercher la relation générale liant la diversité végétale considérée à l'échelle locale et le contrôle des insectes ravageurs par les prédateurs généralistes. Ensuite, sur un réseau de 20 parcelles paysannes de la région de Njombé au Cameroun, nous avons étudié l'effet de la diversité des plantes cultivées sur la structure du réseau trophique des arthropodes. Les résultats ont montré que l'abondance des prédateurs était positivement corrélée avec la diversité des plantes alors que celle des herbivores était négativement corrélée avec la diversité des plantes. L'effet inverse de la diversité des plantes sur les abondances des prédateurs et des herbivores suggère que des effets top-down structurent la communauté des arthropodes dans les parcelles de plantain. Enfin, l'effet de trois cultures couramment associées au plantain (maïs Zea mays, macabo Xanthosoma sagittifolium, et pistache Lagenaria siceraria) sur i) la structure de la communauté des fourmis et ii) les dégâts de Cosmopolites sordidus ont été étudiés dans un essai réalisé en station expérimentale. Les trois cultures associées ont eu un effet significatif sur l'abondance de tous les taxa de fourmis collectés mais le sens et la magnitude de cet effet ont varié selon les taxa. Cela montre le levier que constituent les cultures associées pour structurer la communauté des prédateurs généralistes de l'agroécosystème. Les abondances de tous les taxa de fourmis étaient également corrélées avec les dégâts de C. sordidus. Les abondances de Camponotus spp., Monomorium spp., Paratrechina longicornis et Tetramorium sp. étaient négativement corrélées avec les dégâts de C. sordidus montrant leur potentiel de régulation de ce ravageur. Cette étude à l'échelle de la communauté de l'agroécosystème suggère qu'il est nécessaire de prendre en compte les effets de la diversité végétale à tous les niveaux trophiques pour espérer maximiser le service de régulation des ravageurs.Mots clés : Diversité des plantes, cultures associées, réseaux trophiques, arthropodes, fourmis, structure de la communauté / Functional diversity and associated biodiversity in agroecosystems provide and promote important services to human society such as pollination, biological control, and nutrient cycling. Intercropping is a practical way to increase plant diversity in agroecosystems and participates to provide alternative foods and to structure arthropod communities, including generalist predators involved in pest control. To better understand how plant diversity structures the arthropod food web and how the control of pest may be optimized, we first made one meta-analysis to understand the mechanisms linking plant diversity to pest control by generalist predators at local scale. We second studied the effect of plant diversity on the arthropod community in contrasted plantain fields. We showed that predator abundance was positively correlated with plant diversity while herbivore abundance was negatively correlated with plant diversity. This strong and inverse effect of plant diversity on herbivore and predator abundance suggests that top-down forces structure the arthropod community in plantain fields and that it should be possible to structure the predator community to better control herbivores including pests. In a third step, we measured the effect of combinations of three associated crops maize Zea mays, cocoyam Xanthosoma sagittifolium and gourd Lagenaria siceraria as intercrops on ant community structure and then the effect relation between ant abundances with Cosmopolites sordidus damages. The three associated plants had a significant effect on abundance of all ant species but in different magnitudes and with either negative or positive effect showing that the selection of plant species that are intercropped is an efficient way to structure the ant community. The abundances of all species of ants were positively or negatively correlated with the damages of C. sordidus larvae. The abundances of Camponotus spp., Monomorium spp., Paratrechina longicornis and Tetramorium sp. were negatively correlated to C. sordidus damage. These ants appear to be the best candidates for C. sordidus control. These findings will help in the design of plantain agroecosystems that enhance pest control services.Keywords: Plant diversity, intercropping, arthropod food webs, ants, interspecific interactions, habitat structure

For a long time, the scientific community underestimated the value of carbohydrates and the approach of most scientists to the complex world of glycans was apprehensive. The scenario, however, has changed today. With the development of new research tools and methodologies the study of carbohydrates and glycoconjugates has progressed rapidly, increasing our understanding of these molecules. Carbohydrates are most abundant amongst biological polymers in nature and vital for life processes. In their simplest form, they serve as a primary source of energy to most living organisms. In generalis, they exist as complex structures (glycans), and as conjugates of protein (glycoproteins, proteoglycans), lipids (glycolipids) and nucleosides (UDP-Glucose). Defined in the broadest sense, the study of glycans in all their forms and their interacting partners is termed “Glycobiology”. Glycans are ubiquitously found in nature decorating cells of almost all types with a “sugar coat”. They are also present within the cytoplasm, as well as in the extra-cellular matrix. They have key roles in a broad range of biological processes, including signal transduction, cell development and immune responses. All living organisms have evolved to express proteins that recognize discrete glycans and mediate specific physiological or pathological processes. One major class of such proteins is “Lectins”. Found in all forms of life, they are characterized by their ability to recognize carbohydrates. They are proteins of non-immune origin that bind glycans reversibly with a high degree of stereo-specificity in a non-catalytic manner. It must be emphasized that they are a different class from glycan-specific antibodies. Lectins were first discovered in plants and a large amount of work has been carried out on plant lectins to decipher their structural organization, mode of interaction with substrate and as models to study protein stability and folding. Study on animal and microbial lectins, on the other hand, gathered momentum only recently. In spite of this, more is known about their function in animals and micro-organisms rather than in plants. Lectin-glycan binding is implicated in several important biological processes such as protein folding, trafficking, host-pathogen interactions, immune cell responses and in malignancy and metastasis. Most lectins have one or more carbohydrate recognition domains (CRDs) which often share either 3-D structural features or amino acid sequence. New members of a family can be identified using either sequence or structural homology. Interestingly, it turns out that several plant and microbial lectins have structural or sequential similarity with animal lectins , revealing that these CRDs are evolutionarily related. This thesis, entitled “Structural, Biophysical and Biochemical Studies on Mannose-specific Lectins”, focuses on three lectins, Banana lectin (Banlec), Calreticulin (CRT) and Peptide-N-Glycanase (PNGase). Although all three lectins have distinct biological functions, they share a common ligand specificity at the monosaccharide level i.e. mannose. This thesis, besides characterizing these lectins, studies in detail, the difference in the mode of interaction with their ligands. Chapter 1 is a general introduction on lectins, glycan-lectin interactions and the various techniques that are employed to characterize these interactions. Several principles have emerged about the nature of glycan–lectin interactions. It has been observed that the binding sites for low molecular weight glycans are of relatively low affinity (Kd values in the high micromolar to low millimolar range). Selectivity is mostly achieved via a combination of hydrogen bonds and by van der Waals packing of the hydrophobic faces of monosaccharide rings against aromatic amino acid side chains. Further selectivity and enhanced affinity can be achieved by additional contacts between the glycan and the protein. It is notable that the actual region of contact between the saccharide and the polypeptide typically involves only one to three monosaccharide residues. As a consequence of all of the above, these lectin-binding sites tend to be of relatively low affinity, although they can exhibit high specificity. It is intriguing to observe that such low-affinity sites have the ability to mediate biologically relevant interactions. There are many different ways to study binding of glycans to proteins, and each approach has its advantages and disadvantages in terms of thermodynamic rigor, amounts of protein and glycan needed, and the speed of analysis. In examining these interactions, two broad categories of techniques are applied: (1) kinetic and near-equilibrium methods, such as titration calorimetry; and (2) non-equilibrium methods such as glycan microarray screening and ELISA-based approaches. Two of the most widely used biophysical approaches for examining glycan-lectin interactions at the molecular level are X-ray crystallography and nuclear magnetic resonance (NMR). However, as small molecules often co-crystallize with a lectin better than large molecules, a lot of our knowledge about glycan–lectin interactions at the atomic level is based on co-crystals of lectins with unnatural ligands. Thus, a great challenge exists in attempting to understand glycan–lectin interactions in the context of natural glycans present as glycoproteins, glycolipids, or proteoglycans. Chapter 2 introduces Banana lectin and describes the stability studies carried out. The unfolding pathway of Banlec was determined using GdnCl induced denaturation. Analysis of isothermal denaturation provided information on its conformational stability and the high values of ΔG of unfolding at various temperatures indicated the strength of inter-subunit interactions. It was found that Banlec is a very stable protein and denatures only at high chaotrope concentrations. The basis of the stability may be attributed to strong hydrogen bonds at the dimeric interface along with the presence of water bridges. This is a very unique example in proteins where subunit association is not a consequence of the predominance of hydrophobic interactions. High temperature molecular dynamics simulations have been utilized to monitor and understand early stages of thermally induced unfolding of Banlec. The present study investigates the behavior of the dimeric protein at four different temperatures. The process of unfolding was monitored by monitoring the radius of gyration, the rms deviation of each residue, change in relative solvent accessibility and the pattern of inter- and intra-subunit interactions. The overall study demonstrates that the Banlec dimer is a highly stable structure, the stability in most part contributed by interfacial interactions. The pattern of hydrogen bonding within the subunits and at the interface across different stages has been analyzed and has provided the rationale for its intrinsic high stability. In Chapter 3 the conformational and dynamic behaviour of three mannose containing oligosaccharides, a tetrasaccharide with α1→2, and α1→3, and a penta- and a heptasaccharide with α1→2, α1→3, and α1→6 linkages has been evaluated. Molecular mechanics, molecular dynamics simulations and NMR spectroscopy methods were used for evaluation. It is found that they display a fair amount of conformational freedom, with one major and one minor conformation per glycosidic linkage. The evaluation of their recognition by Banlec has been performed by STD NMR methods and a preliminary view of their putative interaction mode has been carried out by means of docking procedures. In Chapter 4 the conformational behaviour of three mannose containing oligosaccharides, namely, the α1→3[α1→6] trisaccharide, the heptasaccharide with α1→2, α1→3, and α1→6 linkages and the tetrasaccharide consisting of α1→3 and α1→2 linkages, when bound to Banlec has been evaluated by trNOE NMR methods and docking calculations. It is found that the molecular recognition event involves a conformational selection process, with only one of the conformations, among those available to the sugar in free state, being recognised at the lectin binding site. It is known that many proteins, including members of the Jacalin-related lectin family (of which Banlec is a member), bind the high-mannose saccharides found on the surface of the HIV-associated envelope glycoprotein, gp120, thus interfering with the viral life cycle, potentially providing a manner of controlling a variety of infections, including HIV. These proteins are thought to recognize the high-mannose type glycans with subtly different structures, although the precise specificities are yet to be clarified. This study was carried out to gain a better understanding of these protein-carbohydrate recognition events. Chapter 5 reports interactions of Calreticulin (CRT) with the trisaccharide Glcα1-3Manα1-2Man. Previously in our laboratory it was established using modeling studies the residues in CRT important for sugar binding. Here, the relative roles of Trp-319, Asp-317 and Asp-160 for sugar binding have been explored by using site-directed mutagenesis and isothermal titration calorimetry (ITC). Residues corresponding to Asp-160 and Asp-317 in calnexin (CNX) are known to play important roles in sugar binding. The present study demonstrates that Asp-160 is not involved in sugar binding, while Asp-317 plays a crucial role. Further, it is also validated that hydroxyl-pi interactions of the sugar with Trp-319 dictate sugar binding in CRT. This study defines further the binding site of CRT and also highlights its subtle differences with that of CNX. Additionally, mono-deoxy analogues of the trisaccharide unit Glcα1-3Manα1-2Man have been used to determine the role of various hydroxyl groups of the sugar substrate in sugar-CRT interactions. Using the thermodynamic data obtained by carrying out ITC of CRT with these analogues, it is demonstrated that the 3-OH group of Glc1 plays an important role in sugar-CRT binding, whereas the 6-OH group does not. Also, the 4-OH, 6-OH of Man2 and 3-OH, 4-OH of Man3 in the trisaccharide are involved in binding, of which 6-OH of Man2 and 4-OH of Man3 have a more significant role to play. Therefore, the interactions between the substrate sugar of glycoproteins and the lectin chaperone CRT are further delineated. Chapter 6 introduces Peptide-N-Glycanase (PNGase) and delineates the various interactions involved in the binding of oligomannose structures of glycoproteins to the C-terminal domain (the carbohydrate recognition module) of PNGase. ITC is used to characterize the interaction to oligosaccharides in terms of affinity, stoichiometry, enthalpy, entropy and heat capacity changes with the mouse PNGase C-terminal domain. Using the thermodynamic data obtained, it was determined that PNGase requires the tri-mannoside moiety of the native glycan on glycoproteins as the basic minimum entity for recognition and binding. Additional mannose moieties on the glycan do not significantly interact with PNGase and therefore no enhancement in binding affinity is observed (unlike CRT) which is in concordance with its role of stripping glycans from misfolded glycoproteins targeted for degradation via the ERAD (Endoplasmic reticulum assisted degradation) pathway. Chapter 7 briefly summarizes all the findings of the research carried out and presents a comparative analysis of the three lectins studied. Appendix A: Protein folding in the ER is assisted by molecular chaperones. Lectin chaperones such as CRT and CNX assist the folding of glycoproteins by their N-linked oligosaccharide chains. Dynamic processing of the original glycan chain of (GlcNAc)2(Man)9(Glc)3 to remove the terminal glucose moieties is essential for accurate folding. Proteins that attain their native conformation are then transported to the Golgi complex for further glycan modifications. In case of aberrant folding the proteins are retrotranslocated into the cytosol, ubiquitinated, deglycosylated and degraded by the proteasome. Peptide-N-glycanase is a cytosolic enzyme that releases N-glycans from glycoproteins and glycopeptides. PNGase is now widely recognized as a major participant in protein quality control machinery for ERAD or the proteasomal degradation of retrotranslocated glycoproteins. It is therefore desirable to synthesize fluorescently labeled glycoprotein substrates which will provide direct understanding of how, when and where, the interaction between the substrate and the enzyme occurs. Towards this goal, cloning of GFP and RFP tagged full length mouse and human PNGase and CRT was carried out which is described in this section.

De nombreuses bananes cultivées et consommées sont des hybrides interspécifiques triploïdes entre Musa acuminata (génome A) et Musa balbisiana (génome B). L'amélioration de ces cultivars nécessite de mettre en place des stratégies complexes liées à leur faible fertilité et leur niveau de ploïdie. De plus, le génome M. balbisiana porteur de caractères agronomiques intéressants est malheureusement porteur de séquences intégrées de Banana streak virus (ou eBSV pour endogenous BSV). Ces eBSV sont capables de produire, dans un contexte de croisements interspécifiques et sous conditions de stress abiotiques, des génomes viraux responsables de l'infection systémique du bananier. L'activation spontanée de ces eBSV est la contrainte majeure des programmes d'amélioration du bananier plantain depuis plus de 10 ans. La ségrégation des chromosomes A et B chez les clones polyploïdes interspécifiques de bananiers est encore très peu connue. Nous avons au cours de cette thèse analysé la recombinaison et la ségrégation chromosomique chez 184 plantes issues de la descendance AAAB (CRBP39) x AA (Pahang_Carbap) au moyen de 38 marqueurs SSR distribués sur les 11 chromosomes Musa et de 6 marqueurs PCR spécifiques des deux espèces BSV présentes chez CRBP39 (eBSGFV-7 et eBSOLV-1). Nous avons observé qu'au cours de la formation des gamètes chez l'allotétraploïde CRBP39, la plupart des marqueurs du tétraploïde AAAB CRBP39 ont une ségrégation de type tétrasomique et que les génomes A et B recombinent au niveau de tous les segments de chromosomes pour lesquels nous pouvions suivre les allèles du chromosome B. D'autre part, nous avons montré que 50% des descendants ont reçu, à un ou quelques loci, un ou trois allèles du parent AAAB (CRBP39) au lieu de deux. La composition allélique de ces gamètes aneuploïdes, la cartographie génétique et l'analyse des corrélations entre marqueurs suggèrent que cette particularité résulte d'une variation structurale entre génomes A et B. Un des chromosomes B correspondrait à une partie des chromosomes 1A et 3A. Nous avons également observé une distorsion de ségrégation des loci eBSV avec une surreprésentation d'individus possédant au moins une intégration eBSV (86%). La régulation des eBSV semble très complexe et nécessitera des études complémentaires pour tenter d'identifier le ou les facteurs génétiques impliqués. Finalement, notre travail a montré que des croisements de type AAAB x AA peuvent générer des plantes possédant du génome B sans aucune intégration BSV (13%). Ce résultat est important car il ouvre une voie de contournement à la contrainte eBSV dans les programmes d'amélioration génétique. / Many cultivated and consumed banana are interspecific triploid hybrids between Musa acuminata (A genome) and Musa balbisiana (B genome). The genetic improvement of these cultivars requires the implementation of complex breeding strategies due to their low fertility and ploidy level. In addition, the B genome of M. balbisiana which bears interesting agronomic traits unfortunately carries endogenous Banana streak virus sequences (eBSV). Under certain conditions such as interspecific crosses and abiotic stresses, these eBSV are able to produce infectious viral genomes responsible for systemic infection of banana. The spontaneous activation of these eBSV is the major constraint of plantains improvement programs for more than 10 years. The A and B chromosomes recombination and segregation in interspecific polyploids banana are still poorly understood. We here analyzed chromosomes recombination and segregation in 184 offspring from the cross AAAB (CRBP39) x AA (Pahang_Carbap) using 38 SSR markers distributed on the 11 Musa chromosomes and 6 specific PCR markers of both BSV species integrated in CRBP39 (eBSGFV-7 and eBSOLV-1). We noticed that during CRBP39 meiosis most of the SSR markers have tetrasomic segregation and that A and B genomes recombine at all chromosomes segments where we were able to follow chromosome B alleles. Besides, we showed that 50% of the offspring received at one or several loci, one or three alleles of the CRBP39 parent instead of two. The allelic composition of these aneuploid gametes, the genetic map and the analysis of correlations between markers suggest that this peculiar observation is due to a structural variation between A and B genomes. One of the B chromosomes would be part of chromosomes 1A and 3A. We also noticed a distorted segregation of eBSV loci with an overrepresentation of individuals harboring at least one of the eBSV (86%). eBSV regulation seems very complex and requires additional studies to identify the genetic factor(s) involved. Finally, we also showed that AAAB x AA crosses can generate plants with B genome but without eBSV. This is the case for 13% of the offspring. This result is important because it shows that we can overcome eBSV constraint in banana breeding programs.

Orientador: Sarita Leonel / Banca: Aloisio Costa Sampaio / Banca: Julinana Domingues Lima / Banca: Erval Rafael damatto Junior / Banca: Jackson Mirellys Azevedo Souza / Resumo: A bananeira 'FHIA 18' apresenta grande potencial para substituir o cultivar Prata, que é suscetível à Sigatoka-negra e ao Mal-do-Panamá. Porém, pouco se conhece sobre as necessidades nutricionais desse híbrido, principalmente em fósforo (P), elemento mineral importante para o crescimento e produção das plantas, bem como para a qualidade dos frutos. Dessa forma, o objetivo do trabalho foi avaliar o crescimento, produção, aspectos físico-químicos dos frutos e nutrição mineral da bananeira 'FHIA 18' em função da aplicação de fósforo, durante ciclos sucessivos. O experimento foi instalado no município de São Manuel-SP. Os níveis de adubação com P2O5 aplicados em três ciclos de produção foram: sem adubação com P; 20 kg ha-1 ano-1; 30 kg ha-1 ano-1; 40 kg ha-1 ano-1; 50 kg ha-1 ano-1; 60 kg ha-1 ano-1. A bananeira 'FHIA 18' requer a aplicação de 22 kg ha-1 de P2O5, no 2º e 3º ciclo agrícola, para alcançar o máximo desempenho vegetativo, em virtude do incremento no diâmetro do pseudocaule. Embora o teor de fósforo disponível no solo aumente com a aplicação de P, o máximo teor de fósforo na folha diagnóstico é estimado com a dose de 36 kg ha-1 de P2O5 ano-1. Há correlação negativa entre o teor de fósforo disponível no solo com a altura de plantas, diâmetro do pseudocaule e o número de dias do florescimento à colheita. A máxima produção por planta é atingida com a aplicação de 22 kg ha-1 de P2O5 ano-1, quantidade menor do que a recomendada para a cultura da bananeira no estado de São ... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract : The 'FHIA 18' banana plant has great potential to replace the Prata cultivar, which is susceptible to Black Sigatoka and Panama Disease; however, little is known about this hybrid's nutritional needs, especially in phosphorus (P), an important mineral element for growth and production of plants, as well as for fruit quality. Thus, the objective of this work was to evaluate growth, production, physicochemical aspects of fruits and mineral nutrition of 'FHIA 18' banana plant due to phosphorus application during successive cycles. The experiment was installed in São Manuel-SP. The levels of P2O5 fertilization applied in three production cycles were: without P fertilization; 20 kg ha-1 year-1; 30 kg ha-1 year-1; 40 kg ha-1 year-1; 50 kg ha-1 year-1; 60 kg ha-1 year-1. The 'FHIA 18' banana requires the application of 22 kg ha-1 of P2O5 in the 2nd and 3rd cropping cycle, in order to reach the maximum vegetative performance, due to the increase in the pseudostem diameter of the plants. Although the phosphorus content available in the soil increases with application of P, the maximum phosphorus level in the diagnostic leaf is estimated with 36 kg ha-1 P2O5 year-1 dose. There is a negative correlation between soil phosphorus content with plant height, pseudostem diameter and number of days from flowering to harvest. The maximum production per plant is reached with 22 kg ha-1 year-1 P2O5 application, a smaller amount than the recommended for the banana crop in São Paulo state. There is an increase in the productive traits of the first cycle for the subsequent cycles, regardless of the P dose used. Phosphorus fertilization provide an increase in phosphorus levels in 'FHIA 18' banana plant to the 100% of the recommendation application (40 kg of P2O5 ha-1 year-1). However, the application of 21 kg of P2O5 ha-1 year-1 allows obtaining less acidic fruits and with a higher maturation ... / Doutor

Die Wettbewerbsfähigkeit ist von einigen Wirtschaftswissenschaftlern lediglich als ein Schlagwort betrachtet worden, weil es keinen Konsens darüber gibt, wie dieses Allerweltswort zu definieren ist. Jedoch wird es häufig von Politikern und Geschäftsleuten benutzt, um die Position von Ländern, Sektoren, Firmen und/oder Produkten im internationalen Handel zu beschreiben. Aus diesem Grund befürwortet eine weitere Gruppe von Wirtschaftswissenschaftlern eine Verwendung des Begriffs mit der Absicht, dadurch die Defizite der klassischen Außenhandelstheorie und der Theorie des Komparativen Vorteils aufzufangen. Diese Dissertation unterstützt diese zweite Gruppe, indem die Theorie der Wettbewerbsfähigkeit auf eine bestimmte Fallstudie angewendet wird: die Wettbewerbsfähigkeit des Bananenexports ausgewählter Hersteller- bzw. Exportländer in die Europäische Union.Die vorliegende Studie ist des weiteren ein Beitrag zur Debatte über die Auswirkungen der Handelspolitik auf den Agrarsektor, insbesondere in Entwicklungsländern. Sie besteht aus zwei Teilen und vier Kapiteln. Im ersten Teil (die ersten beiden Kapitel) wird der theoretische Rahmen für die Theorie der Wettbewerbsfähigkeit und die Handelspolitik dargestellt. Im zweiten Teil (das dritte und vierte Kapitel) wird eine empirische Studie über den Bananenhandel durchgeführt, wobei mit dem cluster-value chain Modell die Bedingungen der Wettbewerbsfähigkeit analysiert werden. Das weiteren werden anhand eines partial equilibrium Modells die Auswirkungen der Handelspolitik auf die Marktanteile von Hersteller- bzw. Exportländern analysiert. Die theoretische und empirische Analyse der Wettbewerbsfähigkeit stützten folgende Hypothese: Die Handelspolitik ist lediglich einer von zahlreichen Faktoren, die bei der Analyse der Wettbewerbsfähigkeit von Bananenexporten in Betracht gezogen werden müssen.

This thesis studies the use of the functional reactive programming (FRP) framework reactive-banana in a prototype which simulates a part of a Long-Term Evolution (LTE) base station: the Radio Resource Control connection setup procedure. The investigated problem is to determine whether using this FRP framework leads to an implementation with suitable performance and improved maintainability compared to the current implementation. Enhancing the maintainability of the base station software enables quicker and more efficient maintenance activities, which lead to an improved customer satisfaction. Moreover, it means that less programmers need to work on maintenance, so they can work on developing new products instead. In order to compare the use of the FRP paradigm to the one currently used in the base station implementation, the object-oriented programming (OOP) paradigm, a second prototype using this paradigm was also implemented. Having two prototypes implementing the same designed reference model (which is a simplified version of the Radio Resource Control connection setup procedure) enables a relevant comparison of the two paradigms. The two prototypes were then compared in terms of performance and maintainability. The maintainability evaluation consisted in using both software metrics and experts’ assessment, as this has been proven to be the most efficient way to evaluate software maintainability. Four experts were asked to fill in a questionnaire after reviewing the code of the two implementations. The comparison of the two prototypes indicates that the FRP prototype is more maintainable than the OOP one, but the OOP prototype has better performances than the FRP one. Moreover, the performance of the FRP prototype during the conducted tests indicates that such an implementation of the FRP paradigm is not suitable for a real base station.

BARRETO, Carlos Alberto Pinto de. Avaliação do financiamento da fruticultura, com ênfase na cultura da banana, na microrregião cearense do Baixo Jaguaribe (1998 - 2004): aspectos econômicos, sociais e tecnológicos. 2009. 109f. – Dissertação (Mestrado) – Universidade Federal do Ceará, Programa de Pós-graduação em Avaliação de Políticas Públicas, Fortaleza (CE), 2009. / Submitted by Márcia Araújo (marcia_m_bezerra@yahoo.com.br) on 2013-09-27T13:32:31Z No. of bitstreams: 1 2009-DIS-CAPBARRETO.pdf: 678185 bytes, checksum: f121018b2195564fe320884a2aa4583d (MD5) / Approved for entry into archive by Márcia Araújo(marcia_m_bezerra@yahoo.com.br) on 2013-09-27T14:48:06Z (GMT) No. of bitstreams: 1 2009-DIS-CAPBARRETO.pdf: 678185 bytes, checksum: f121018b2195564fe320884a2aa4583d (MD5) / Made available in DSpace on 2013-09-27T14:48:06Z (GMT). No. of bitstreams: 1 2009-DIS-CAPBARRETO.pdf: 678185 bytes, checksum: f121018b2195564fe320884a2aa4583d (MD5) Previous issue date: 2009 / The purpose of this dissertative work is to show the results of the implementation of the resources from the Programa de Apoio ao Desenvolvimento Rural do Nordeste (Rural), operated by the Banco do Nordeste do Brasil, flower-culture projects in districts of the Baixo do Jaguaribe Ceará´s microregion. This way, its main objective consists of evaluating the economic social and technological effects derived from the implementation of the mentioned program in interprisings of fruit-culture with emphasys in banana-culture in the districts of Limoeiro do Norte, Quixeré, São João do Jaguaribe and Tabuleiro do Norte, between 1998 and 2004. A study has been held considering the kind of evaluation named ex post, which is held after the accomplishment of the projects. Bibliographyc and documental researches have been held related to the theme. The investigative field work consisted of making structured interviews, making use of a set of closed questions directed to twenty one banana-curturers. The colected information was analysed based on statistic treatment giving a quantitative approach to the evaluative work. From the twenty-one banana-culturers, fifteen had their bussinesses completelly stopped, not promoting jobs or profits. These fifteen workers blamed, among other reasons, the electricity cut-off in the Altinho region, which is located in Tabuleiro do Norte. They also named some failures in the elaboration and administration of the projects in the area mentioned. Otherwise, six banana-culturers were normally developing their financed projects, developing financial and technological gains and promoting regular jobs. It´s important to mention that these six workers were not members of the Altinho region. Having as a parameter what was seen, we may say that the success and non-success of the agricultural investments consists on different aspects, being the rural credit only one of these aspects. The adequate conjugation of these aspects is what enables a bigger success in this kind of investiment. Therefore, the rural credit can not be considered the only or main responsible factor for the improvement of production and productivity, increase of technological levels, jobs and income in these areas of agricultural production. / A finalidade de realizar este trabalho dissertativo foi mostrar os resultados da aplicação dos recursos do Programa de Apoio ao Desenvolvimento Rural do Nordeste (Rural), operacionalizado pelo Banco do Nordeste do Brasil, em projetos de fruticultura em municípios da microrregião cearense do Baixo Jaguaribe. Dessa forma, seu objetivo principal consiste em avaliar os efeitos econômicos, sociais e tecnológicos decorrentes da aplicação de recursos do referido Programa em empreendimentos de fruticultura, com ênfase em bananicultura, nos municípios de Limoeiro do Norte, Quixeré, São João do Jaguaribe e Tabuleiro do Norte, no período de 1998 a 2004. Foi efetuado um estudo levando-se em consideração o tipo de avaliação denominado ex post, que é aquela efetivada após a execução dos projetos. Foram realizadas pesquisas bibliográfica e documental relativas ao tema. O trabalho investigativo de campo efetuado consistiu em realizar entrevistas estruturadas, utilizando-se de um roteiro de perguntas fechadas, junto a vinte e um bananicultores. As informações coletadas foram analisadas a partir de tratamento estatístico, conferindo ao trabalho avaliativo uma abordagem quantitativa. Dos vinte e um bananicultores entrevistados, quinze encontram-se com seus empreendimentos totalmente paralisados, não gerando emprego e renda, alegando que esse fato decorre, dentre outros pontos, do corte de energia elétrica do perímetro Altinho, localizado em Tabuleiro do Norte, e de falhas na elaboração e administração dos projetos do perímetro citado. Contudo, seis bananicultores desenvolvem normalmente seus projetos financiados, auferindo ganhos financeiros e tecnológicos e gerando empregos permanentes. Ressalta-se que esses seis fruticultores não fazem parte do perímetro do Altinho. Tendo como parâmetro o que foi visto, pode-se dizer que o sucesso ou o insucesso de financiamentos agrícolas envolve diferentes variáveis, sendo o crédito rural apenas uma delas. A conjugação adequada dessas variáveis é que possibilita maior margem de sucesso desse tipo de empreendimento. Assim, o fornecimento do crédito rural não pode ser considerado como sendo o principal ou o único fator responsável pelo aumento da produção e da produtividade, melhoria nos níveis tecnológicos, de emprego e de renda nas áreas de produção agrícola.

La dispersion est un processus clef dans la dynamique et l'évolution des populations naturelles. En plus de son rôle primordial dans les processus de colonisation, la dispersion influence également les processus d'adaptation des organismes. Chez les pathogènes, une meilleure compréhension des processus de dispersion apparaît de ce fait être un enjeu majeur pour mieux les contrôler. Durant cette thèse, nous avons étudié les processus de dispersion et quantifié les flux de gènes qui en découlent chez le champignon parasite du bananier Mycosphaerella fijiensis. Cette étude a été réalisée à l'échelle locale d'un bassin de production du Cameroun (la région dite du Moungo) et nous avons combiné plusieurs approches complémentaires considérant différentes échelles spatio-temporelles. Dans un premier temps, nous avons décrit, à l'aide de marqueurs génétiques neutres, la structuration spatiale des populations de M. fijiensis dans la région du Moungo qui présente différentes barrières potentielles à la dispersion. Nous n'avons décelé aucun effet du paysage ni de la distance géographique sur la structuration génétique. Cependant, une rupture spatiale dans les fréquences alléliques, vraisemblablement de nature historique a été mise en évidence. Ces résultats suggèrent l'existence de grandes populations de M. fijiensis s'écartant de l'équilibre mutation-dérive. Dans un second temps, nous avons utilisé la théorie des clines génétiques pour étudier les forces à l'origine de la mise en en place et de l'évolution de gradients spatiaux de fréquences alléliques. En particulier, l'analyse de la variation spatio-temporelle de la discontinuité génétique précédemment détectée par un modèle de clines neutres nous a permis d'estimer l'intensité des flux géniques ( =1175 m/génération). Finalement, nous avons mesuré la distribution des distances de dispersion des deux types de spores produites par M. fijiensis à partir d'une source d'inoculum primaire. Cette expérimentation nous a permis de confirmer que les ascospores participent à une dispersion à grande distance alors que les conidies sont impliquées dans une dispersion à très courte distance. Nous avons estimé une distance moyenne de dispersion de 3,12 et de 283 mètres/génération respectivement pour les conidies et les ascospores et montré que le noyau de dispersion des ascospores est caractérisé par une queue lourde. Cette thèse a permis de préciser comment M. fijiensis se disperse et les estimations réalisées pourront être intégrées dans des modèles théoriques afin de mieux comprendre l'évolution des résistances aux fongicides et de définir des stratégies durables d'utilisation raisonnée des traitements chimiques. / Dispersal is a key process for both the dynamics and evolution of natural populations. In addition to being crucial for colonization, dispersal also influences the processes occurring during adaptation. For pathogens, a better understanding of dispersal processes may improve our capacity to control the diseases that they cause. In this thesis, we studied dispersal processes and quantified gene flow in the banana plant pathogen Mycosphaerella fijiensis at the local scale of a production area in South-West Cameroon (named Moungo). For this purpose, several approaches differing in the spatio-temporal scale to which they refer were combined. First, neutral markers were used to describe the spatial genetic structure of this pathogen in the Moungo area, which includes several potential ecological barriers to dispersal. No effects on genetic structure of landscape elements or geographical distance were found. However, we detected a spatial break in allelic frequencies that appeared to be explained by an historical event. This result suggests the existence of large M. fijiensis populations out of the mutation-migration-drift genetic equilibrium. Second, genetic cline theory was applied to study the evolutionary forces implicated in the installation and evolution of spatial gradients in allelic frequencies. More specifically, we analysed the spatio-temporal variation of the genetic discontinuity previously detected through a neutral cline model to estimate the intensity of gene flow in this area ( =1175 m/generation). Lastly, we measured the distribution of dispersal distances of M. fijiensis spores from a primary source of inoculum was. Such an experiment allowed us to confirm that conidia are implicated in short-distance dispersal whereas ascospores are responsible for spread of the disease over longer distances. The estimated mean dispersal distance travelled by spores was 3.12 and 283 metres/generation for conidia and ascospores, respectively, and the ascospore dispersal kernel was shown to be fat-tailed. This thesis adds to global knowledge of M. fijiensis dispersal and the measures of dispersal estimated in this work will be useful in parameterizing models aimed at a better understanding of the spatial patterns of fungicide resistance evolution under different management strategies.

M. Tech. (Department of Biosciences, Faculty of Applied and Computer Sciences) Vaal University of Technology / Most cultivated bananas and plantains (Musa spp. sect. Eumusa), originated from two wild diploid species, Musa acuminata Colla (AA) and Musa balbisiana Colla (BB), which contributed the A and B genomes, respectively. The two genomes confer different traits to a banana plant. Intra- and interspecific hybridization between the wild diploid species, somatic mutations and selection over many thousands of years has given rise to considerable genetic variability in cultivated bananas. Bananas are classified according to its genome composition and a number of morphological traits are used to identify the genomes of a plant. Morphological classification can be misleading since the morphology of plants can be affected by environmental factors. Molecular techniques to identify the genomes of banana have many advantages. The objective of this study was to develop a SCAR (sequence characterized amplified region) marker from a previously reported A genome-specific RAPD fragment that distinguish the A genome of banana from the B genome. This fragment designated OPA17600 was cloned, sequenced and used to design longer 20-mer SCAR primers. Verification of the SCAR primers for its fidelity to the A genome was carried out on a sample of 22 homo-and heterogenomic accessions representing landraces and hybrids of different ploidy and genome combinations. Out of six primers sets that were tested one set (SC3) produced a unique 600 bp in all the A genome containing banana accessions. However, these primers also amplified an 800 bp fragment in all the BB genotypes and some accessions containing the A and B genomes. While previous reports suggested that there was considerable differentiation between the A and B genomes, recent evidence points to the contrary. The presence of the A genome fragment in the B genome genotypes and accessions may be due to recombination between the two genomes, translocations and substitutions. The study concluded that the 600-bp SCAR sequence is conserved across the A genome in Musa and can be used to identify the A genome in banana classification and Musa breeding programmes.