Mission d'évaluation de l'agrumiculture au Bénin : du 28 septembre au 9 octobre 2009

Ce document présente en premiere partie l'introduction qui décrit l'historique et le contexte de l'agrumiculture béninoise, les objectifs de la mission ainsi que la méthode et les contacts pour atteindre les objectifs assignés à la mission. En deuxième partie, c'est le bilan général de la mission qui comprend les observations générales et les particularités en fonction des zones de production. Pour la troisème partie, ce sont les recommandations, qui permettront d'améliorer la qualité du matériel végétal, de gerer les maladies et ravageur et d'analyser la gestion des exploitations et de la mise en marché. Enfin quatrième partie qui conclut sur les enjeux importants pour la filière agrumes au Bénin, ses atouts, ses limites et contraintes à traiter en priorité, ainsi que la mise en place d'un projet national coordonnant action de recherche et de développement qui demeure essentielle

Analyse du partenariat dans l'étape d'évaluation des produits de la sélection

Cet article propose une grille d'analyse du partenariat lors de l'évaluation du matériel génétique obtenu en fin de sélection. La grille porte sur l'identification des partenaires et les rôles qu'ils peuvent jouer. Elle est ensuite appliquée à l'analyse des quatre projets présentés dans les parties précédentes des actes. (Résumé d'auteur

Inventaire, fluctuations des populations et importance des dégâts des espèces de mouches des fruits (Diptera Tephritidae) inféodées au manguier dans le département du Borgou (Bénin) en 2005 et 2006 : [Draft]

La zone d'excellence de production de la mangue se trouve dans la zone soudanienne des différents pays Ouest Africains producteurs. Au Bénin elle se situe dans la partie septentrionale du pays dont le département du Borgou où nous sommes intervenus durablement au niveau de plusieurs grands vergers de manguiers tant en 2005 et qu'en 2006. Nous avons effectué des observations préliminaires dans le Nord du Bénin durant la campagne de mangues en 2005 afin d'identifier les principales espèces de Tephritidae, de suivre leurs fluctuations de populations et d'estimer les pertes qui leur sont imputables. Ces études ont été répétées et approfondies en 2006. Parmi une douzaine d'espèces de mouches des fruits ayant émergé des mangues au Bénin, quatre peuvent être considérées comme ayant actuellement une importance économique: Ceratitis cosyra, C. quinaria, C. silvestrii et B. invadens. Deux espèces parmi elles provoquent les dégâts les plus préjudiciables: C. cosyra et B. invadens. Pendant les saisons sèches 2005 et 2006, C. cosyra était l'espèce la plus abondante et ses dégâts prévalaient surtout au niveau des fruits des cultivars précoces. B. invadens devenait dominante en début de saison des pluies en corrélation avec les stades de pré-maturité et maturité des fruits des cultivars de saison et des cultivars tardifs. Le schéma général de ces fluctuations annuelles de populations des Tephritidae du manguier reste donc identique d'une année à l'autre même si l'abondance de B. invadens a légèrement diminué en 2006. La moyenne des dégâts dus aux mouches des fruits fluctue de 9% (début avril) à plus de 60% (en juin), toutes espèces de Tephritidae confondues pour l'année 2006. La plupart des espèces de Tephritidae ayant émergé des mangues au cours de nos expérimentations avaient déjà été inventoriées précédemment dans d'autres pays Ouest Africains à l'exception de B. invadens, espèce invasive découverte par l'IITA au Bénin (2004) et récemment décrite (2005). Des études écologiques et de comportement seront nécessaires afin de planifier et d'appliquer des méthodes de lutte optimales vis-à-vis de ce nouveau ravageur d'importance économique majeure dans toute l'Afrique de l'Ouest. (Résumé d'auteur

MULTI-STAKEHOLDER VARIETAL INNOVATION PLATFORMS. A SOCIOTECHNICAL PARTNERSHIP RESEARCH SCHEME ASSESSED IN BENIN

International audienceParticipatory plant breeding research may be hampered by the fact that results that have been obtained in very specific localized settings cannot be disseminated and scaled. Varietal innovation platforms aim to overcome this problem by ensuring that the viewpoints of people involved in assessments are representative of broad interest groups and that assessment results will be validated and disseminated by an organization. Each platform is designed as a sociotechnical scheme consisting of a five-member steering committee (SC), a club with a membership of 25 local users and experts (CLUE), a common varietal test plot and a network of around 15-20 on-farm plots. The aim is to describe, evaluate and disseminate improved varieties to target groups of stakeholders faced with the same environmental, agricultural and socioeconomic constraints. Partnerships between all of these stakeholders are set up, organized and managed according to six principles outlined in a charter—legitimacy, competence, efficiency, democracy, solidarity and transparency. Two experimental platforms were set up in the villages of Zé and Tori-Bossito, in southern Benin, to assess plantain varieties released by the Centre africain de recherche sur le bananier et le plantain (CARBAP). These platforms were monitored 20 months following their creation. The survey showed that the two platforms had successfully carried out all of their initially planned activities. The CLUEs identified four interesting varieties. The survey focused on the future plans made by SC and CLUE members to tap the benefits of knowledge acquired during 18 months. It showed that: (i) their plans provided conditions favorable for varietal dissemination and scaling, (ii) SC plans were based on transfer of the platform scheme whereas the CLUE plans were based on varietal dissemination, and (iii) the Tori plan was collective while the Zé plan was more individually focused. Our analysis highlighted that the respect of the legitimacy, skill and solidarity principles was most required to expect successful dissemination of the results obtained on the platforms

Occurrence of Banana bunchy top virus in banana and plantain (Musa sp.) in Benin

In July 2011, banana and plantain that displayed stunting and leaf symptoms typical of banana bunchy top disease were observed to be widespread in Dangbo Commune, Ouémé Department, Benin. To identify the cause of the disease, a roving survey was conducted in December 2011 in nine locations in Avrankou, Dangbo, Akpro-Missérété and Porto-Novo Communes, in Ouémé. In each location, the incidence of symptom-bearing plants was estimated from counts of 15 mats, and samples were collected for Banana bunchy top virus (BBTV) assessment. Approximately 60% of the 94 banana mats assessed had plants exhibiting typical symptoms of BBTV infection - chlorotic leaf margins, dark green streaks on petioles, narrow leaves that bunched at the top, and severe stunting. Total DNA was extracted from 25 leaf samples collected from plants with symptoms; they were then tested for BBTV by polymerase chain reaction. The sequences showed 100% nucleotide sequence identity with a BBTV isolate from Cameroon (FJ580970) and 99-100% identity with several other BBTV isolates from the GenBank database belonging to the South Pacific group, which consisted of BBTV isolates from Africa, Australia, India and South Pacific. This finding confirmed that the virus isolate associated with the diseased plants in Benin was of the BBTV South Pacific type. This is thought to be the first report of BBTV in Benin. The disease is widespread in all the four communes surveyed

Dissection of the major late blight resistance cluster on potato linkage group IV

Potato is consumed worldwide and represents the fourth most important staple food crop after rice and wheat. Potato cultivars display a large variety of color, shape, taste, cooking properties and starch content but are all derived from the same species; Solanum tuberosum. Potato breeding is an economic important activity for international breeding companies, but also plays an important role in breaking the circle of poverty for small farmers. In the Andean region, most farmers use many different potato genotypes combined with farming practices transmitted orally over thousands of years. The most prominent menace to potato production is Late Blight caused by the oomycete Phytophthora infestans which destroys leaves, stems and tubers. Differences of breeding methods between the potato grown in South America and in the rest of the world is related to differences in the consequences of Late Blight infection. In the 19th, century, entire potato fields in Ireland were devastated while in South America P. infestans proliferation was readily inhibited. This difference is found in the biodiversity reserve such as that of the Chiloé archipelago in Chile where local people cultivate about 200 varieties of native potato. Obviously, the genetic diversity of cultivated native potato acts as a shield against this versatile pathogen. Inspired by this model to solve the problems raised by the extensive use of potato monoculture, growers and breeders need to maintain genetic diversity in the European staple food crops. In exploring the South American native potato collection, Solanum demissum and later on Solanum bulbocastanum appeared to be a source of resistance genes (Rpi) to P. infestans. The S. demissum Rpi genes were transmitted to potato breeding clones by traditional introgression breeding. However the fading of their ability in providing effective resistance against Late Blight infection was witnessed within a decade. In the pursuit to provide a hopefully more durable protection in existing potato cultivars, plant breeding scientists proposed to directly introduce South American native potato Rpi genes in modern potato varieties by using a so-called cisgenic approach. This in contrast to transgenic plants which can contain genes which have originated from non related genera or even different kingdoms. Breeding of cisgenic plants is on its way to public acceptance because of its inherent resemblance to natural crossing and because efforts are made by the scientific community to explain the principles of cisgenesis. Lessons were learned from the flexibility of P. infestans to overcome the effect of newly introduced Rpi genes and, therefore, efforts are still ongoing to discover and clone new Rpi genes from native potatoes. With this in mind, a new family of Rpi genes represented by Rpi-blb3, Rpi-abpt, R2, R2-like and Rpi-mcd1.1 were characterized in clones derived from S. bulbocastanum, S. demissum, S. edinense and S. microdontum. We accomplished in this research the physical isolation of these genes, the molecular characterization of their functionality and the allelic distribution in the Petota collection. Rpi-blb3, Rpi-abpt, R2, R2-like and Rpi-mcd1.1 belong to the potato linkage group IV and all contain signature sequences characteristic of LZ-NBS-LRR proteins. The closest known R gene so far is RPP13 from Arabidopsis thaliana which shares an amino-acid sequence similarity of 35%. The LRR domains of Rpi-blb3, Rpi-abpt, R2 and R2-like proteins are highly homologous, whilst LZ and NBS domains are more polymorphic with those of R2 being the most divergent. All four Rpi genes recognize the recently identified RXLR effector protein PiAVR2 which is secreted by P.infestans in the cytoplasm of plant cells during the infection process. Unlike Rpi-blb3, Rpi-abpt, R2 and R2-like , the S. microdontum resistance gene Rpi-mcd1.1 does not interact with PiAVR2 and provides a different resistance spectrum. Rpi-mcd1.1 shares 90% nucleotide identity with Rpi-blb3 and polymorphic nucleotides are mainly located in the LRR region. The S. bulbocastanum haplotypes of Rpi-blb1, Rpi-blb2 and Rpi-blb3 were discovered in several Mexican diploid as well as polyploid species closely related to S. bulbocastanum. These three resistance genes occurred in different combinations and frequencies in S. bulbocastanum accessions and their distribution is confined to Central America. A selected set of genotypes was tested for their response to the avirulence effectors IPIO-2, Avr-blb2 and Pi-Avr2, which interact with Rpi-blb1, Rpi-blb2 and Rpi-blb3, respectively, as well as by disease assays with a diverse set of isolates. Using this approach some accessions could be identified that contain novel, yet unknown, Late Blight resistance factors in addition to the Rpi-blb1, Rpi-blb2 and Rpi-blb3 genes Analysis of the sequences obtained in different allele mining strategies suggests an evolution of the major late blight locus on linkage group IV through recombination and point mutations. By making use of the sequence information provided by the alleles, we identified the repeats and amino acids in the LRR domain which are specific for PiAVR2 recognition. Finally, we discussed the results described in this thesis in a potato/ P. infestans co-evolution context. <br/

Adaptive Learning Gain in Asset Pricing

This paper delves into the complexities of asset pricing, emphasizing the need to go beyond prevailing paradigms and constant learning gain assumptions. We examine the influence of personal experiences, adaptive learning processes, and subjective return expectations on asset pricing. By incorporating the concept of time-varying learning gain, we provide a more realistic portrayal of asset pricing. Empirical analysis reveals a consistent negative correlation between experienced real payout growth and subsequent returns, indicating counter-cyclical behavior. Our findings also support the mean-reversion hypothesis in stock returns, although caution is needed due to some scenarios lacking statistical significance. Theoretical exploration uncovers that higher uncertainty or variability compels investors to seek additional compensation, thus elevating the equity risk premium. Moreover, the information structure does not form a filtration, leading to no convergence to a specific value in the long run. Agents perceive future increments as negatively serially correlated but lack the memory to effectively exploit this correlation for forecasting. Consequently, the Law of Iterated Expectations does not hold. We propose the resale valuation method as ideal for agents with adaptive learning gains. These findings contribute to an innovative asset pricing model with adaptive learning gains, enhancing our understanding of market dynamics. While this study does not provide calibration or validation, we outline the model’s theoretical foundations and implications for future research. Our work adds to the evolving landscape of asset pricing theory, highlighting the significance of adaptive learning in capturing complex dynamics

Ten Years of Experience Training Non-Physician Anesthesia Providers in Haiti.

Surgery is increasingly recognized as an effective means of treating a proportion of the global burden of disease, especially in resource-limited countries. Often non-physicians, such as nurses, provide the majority of anesthesia; however, their training and formal supervision is often of low priority or even non-existent. To increase the number of safe anesthesia providers in Haiti, Médecins Sans Frontières has trained nurse anesthetists (NAs) for over 10 years. This article describes the challenges, outcomes, and future directions of this training program. From 1998 to 2008, 24 students graduated. Nineteen (79%) continue to work as NAs in Haiti and 5 (21%) have emigrated. In 2008, NAs were critical in providing anesthesia during a post-hurricane emergency where they performed 330 procedures. Mortality was 0.3% and not associated with lack of anesthesiologist supervision. The completion rate of this training program was high and the majority of graduates continue to work as nurse anesthetists in Haiti. Successful training requires a setting with a sufficient volume and diversity of operations, appropriate anesthesia equipment, a structured and comprehensive training program, and recognition of the training program by the national ministry of health and relevant professional bodies. Preliminary outcomes support findings elsewhere that NAs can be a safe and effective alternative where anesthesiologists are scarce. Training non-physician anesthetists is a feasible and important way to scale up surgical services resource limited settings

Adoption and yield impacts of improved groundnut varieties in Nigeria: Application of the potential outcomes framework

Using potential outcomes framework, we estimate adoption gap, adoption drivers and impact of adopting improved groundnut varieties (IGVs) on groundnut yield among smallholder farmers in Nigeria. The results showed a significant 34% adoption gap attributable to lack of exposure of farmers to IGVs. With full exposure, adoption rate could increase from the current 31% to about 65%. To close this adoption gap, policy options that empower agricultural extension staff to visit farmers more frequently, engage farmers in agricultural technology development, testing and scaling activities and encouraging farmers to join farmer groups are critical. Similarly, enabling households to access credit and input and output markets will lead to increased probability of adopting IGVs. Further, the study revealed a significant positive impact of 148 kg/ha on the yield of IGVs and this represents a 20% average treatment effect on the treated (ATT) and 22% average treatment effect on the untreated (ATU)