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Prevalence of mealybug wilt-associated viruses in pineapple 'Queen Victoria' cultivars in Reunion Island and the potential of virus-free vitroplants for disease management
Get PDFMealybug wilt disease of pineapple (MWP) poses a significant threat to global pineapple production, yet its etiology remains poorly understood. The disease is believed to involve mealybugs, multiple pineapple mealybug wilt-associated viruses (PMWaVs, genus Ampelovirus), and possibly other viruses from the Badnavirus, Secovirus, and Vitivirus genera. This study examines the distribution and prevalence of three ampeloviruses (PMWaV1, PMWaV2, PMWaV3) and two badnaviruses (PBERV, PBCOV), previously associated to MWP symptoms, across 15 pineapple plots of the 'Queen Victoria' cultivar in Reunion Island. A total of 450 symptomatic and asymptomatic leaf samples were analyzed using PCR and RT-PCR-based diagnostics. Globally, 93 % of samples were infected with at least one virus, and 76 % were co-infected with two to four viruses. PMWaV1 (78 %) and PBCOV (87 %) were the most prevalent, while PBERV was not detected. Virus presence was associated with leaf dieback, wilting, and curling. Leaf reddening and yellowing, commonly associated with MWP, were not associated with viral infection, suggesting that other biotic or abiotic factors may be responsible for these symptoms. Viral infections and MWP symptoms were significantly lower in plots planted with vitroplants (VPs) compared to those using suckers, highlighting the potential of VPs in reducing viral infections. These findings highlight the complexity of MWP and underscore the potential benefits of using virus-free VPs to manage the disease
Etude de faisabilité portant sur la mise sur pied dans la région de l'est d'une unité de production de bois-énergie par conversion thermochimique de la biomasse forestière - Rapport d'avancement
No full textMATES: A tool for appraising the completeness with which a meta-analysis has been reported
Get PDFMeta-analysis is commonly a core component of systematic reviews and has become an important method to reconcile conflicting findings, increase statistical power, and chart new research directions. However, poor reporting practices make it challenging to evaluate the validity of meta-analyses. Despite the existence of reporting checklists, a specifically designed tool has yet to be developed to appraise the completeness with which a meta-analysis has been reported. To bridge this gap, we introduce the Meta-analysis Appraisal Tool for Environmental Sciences (MATES). To develop MATES, we adapted a Delphi process involving experts in meta-analysis methodologies, researchers with experience in guideline/appraisal tool development, and editors of relevant journals. The Delphi process had five steps, including three workshops (11–16 participants), a survey (193 participants), and a validation task (30 participants). This iterative development process resulted in a 14-item appraisal tool that reflects the environmental science and research syntheses community's consensus on essential elements to appraise the completeness with which a meta-analysis has been reported. Validation across 50 meta-analyses demonstrated that the tool is repeatable (average agreement rate: 88.97 %) and time-efficient to implement (17.00 ± 12.23 min). We also outline guidance for interpreting MATES results, describe its potential applications, and reflect on the development process. The authors provide practical implementation guidance for each MATES item, illustrated with real examples in the supplementary material. We also report an extended development methodology to support reproducibility. Finally, we built created a ShinyApp that includes both a training module and an application tool to enhance the usability of MATES (https://kylemorrisonisshiny99.shinyapps.io/MATES_shiny/). Overall, MATES provides authors, readers, stakeholders, and editors with a reliable and accessible tool for appraising the completeness with which a meta-analysis in environmental sciences has been reported
Carbon fluxes and partitioning in Eucalyptus and Pinus plantations across a climatic gradient in Brazil
No full textBrazilian Eucalyptus and Pinus forests are the most productive forests worldwide. The growth rates of these intensively managed plantations depend strongly on environmental conditions and matching genotypes to local environments. Changing climates underscore the value of understanding the intricacies of how these plantations can fix high amounts of carbon (C) and grow so much wood. We measured the full C budgets of Eucalyptus and Pinus forests across climate gradients in Brazil, focusing on the rates of C uptake, the allocation of C to belowground roots and mycorrhizae, and stem growth. We found that gross primary production (GPP) varied more than sixfold across the climate conditions in Brazil. Maximum temperature was the main climatic driver of productivity, where extreme temperatures reduced fluxes to stem production while increasing fluxes to root production. Net ecosystem production varied with management and age across the sites. The ecophysiological investigation presented in this work is fundamental for understanding C partitioning behavior under extreme temperature conditions. In this way, our results provide tools for forest managers to support their decision-making processes as well as starting points for strategies to be implemented in projects aimed at mitigating the effects of climate change
Can the non-market economy help to improve diet quality? Findings from a survey in New Caledonia
No full textThe Pacific archipelago of New Caledonia is undergoing a nutritional transition that began several decades ago. In a political context dominated by questions of self-determination that reveal deep divisions, agriculture also mirrors this dichotomy, observed through the coexistence of traditional non-market agriculture primarily practiced on Kanak tribal reserves and so-called 'modern' and capitalistic, market-driven agriculture. Based on a survey of 180 tribal and non-tribal producers in the north of the main island of the Caledonian archipelago, we analysed whether self-consumed and gifted produce could improve the diet of the rural population. Our findings show an underconsumption of fruits, vegetables, legumes, milk, and fish among the domestic groups surveyed, contrasting with excessive consumption of sugars. Non-market practices only partially promote better nutrition. Thus, being a fruit and vegetable producer or a fisherman is associated with adequate consumption of these products, while gifting food, a common practice in tribes, protects against the overconsumption of sweeter products by sustaining traditional tuber-based diets
Agri-STAMP: A spatial model representing the use and fate of pesticides over the long term
No full textThe widespread use of pesticides in agriculture has long been associated with serious health risks, including cancer, diabetes, neurological disorders, and reproductive issues. However, pinpointing the specific pesticides responsible for these health effects remains a challenge due to limited datasets and the delayed onset of diseases. Traditional epidemiological studies often rely on case-control studies methods, with in recent approaches land use as a proxy for pesticide exposure. In this study, we introduce Agri-STAMP, a spatial process-based model designed to estimate pesticide contamination over time by accounting for agricultural practices, pesticide application techniques, and environmental factors. We applied Agri-STAMP to Guadeloupe, French West Indies, where the pesticide chlordecone has had significant health impacts. The model integrates diverse data sources, including soil types, rainfall patterns, land use, and pesticide application records. Simulations were run from 1972 to 2014 on 65 pesticide active substances used in banana, sugar cane and market gardening crop systems in Guadeloupe. Results indicated strong correlations between predicted and observed pesticide concentrations (Kendall's τ comprised between 0.46 and 0.6), suggesting the model's potential for accurate predictions. Moreover, the quantities of pesticide active substances simulated by the Agri-STAMP model were significantly correlated with the actual quantities sold according to the national database on crop pesticide sales between 2009 and 2014 (Pearson R = 0.95, CI = 0.92–0.97). The proposed modeling approach, which is adaptable to different agricultural contexts, offers valuable insights into historical and current pesticide contamination, which can be used to support epidemiological studies on cancer incidence and guide public health policies. The Agri-STAMP tool also provides a basis for discussing and guiding land management decisions to mitigate health risks, making it a promising asset for future research and policy-making
Caractérisation de la résistance de la canne à sucre à la rouille orangée causée par Puccinia kuehnii et diversité génétique de l'agent pathogène
No full textLa production mondiale de canne à sucre (Saccharum spp.) repose sur des variétés modernes hautement polyploïdes et aneuploïdes (2n = 10-13x = ~120), issues d'hybridations entre les espèces S. officinarum et S. spontaneum. Cette production est actuellement impactée par la rouille orangée causée par Puccinia kuehnii. Identifiée à Java en 1890, cette maladie est longtemps restée confinée à l'hémisphère Est avant d'être observée pour la première fois dans l'hémisphère Ouest en 2007, en Floride. À La Réunion, la rouille orangée s'est rapidement répandue sur toute l'île depuis son signalement en 2018. La lutte contre cette maladie repose principalement sur la création et le déploiement de variétés tolérantes ou résistantes. Cependant, le déterminisme génétique de la résistance, ainsi que la diversité génétique mondiale de l'agent pathogène, sont encore très mal connus. Cette thèse visait à acquérir des connaissances sur ces aspects afin de faciliter la conception de travaux performants d'amélioration génétique de la résistance. En premier lieu, une étude a été conduite sur une centaine de variétés expérimentales dans un dispositif multi-local d'essais répétés pour mieux appréhender l'évaluation de la maladie en conditions naturelles d'infection à La Réunion. L'héritabilité multi-locale de la résistance à la rouille orangée s'est avérée élevée (0,76-0,91), ce qui reflète une forte composante génétique. Ce dispositif a également permis d'évaluer l'impact de la maladie sur le rendement des variétés les plus sensibles dans les cinq zones agro-climatiques étudiées. Les pertes potentielles estimées sur le tonnage de cannes, en moyenne de 15% pour les cinq zones, atteignent 26% dans les environnements les plus humides. Dans un deuxième temps, les bases génétiques de la résistance à la rouille orangée ont été déterminées par deux approches d'association pangénomique (GWAS) et à l'aide d'un panel de 526 variétés en cours de sélection. Ces variétés ont été évaluées pour leur résistance en conditions naturelles d'infection et génotypées avec près de 183000 marqueurs SNP. Cinq quantitative trait loci (QTLs) de résistance nommés Oru1 à Oru5 et provenant de l'espèce ancestrale S. spontaneum ont été identifiés par une GWAS single-locus. Un sixième QTL (Oru6) issu de l'espèce ancestrale S. officinarum a été détecté par une GWAS multi-locus. Les allèles de résistance des six QTLs procurent des effets phénotypiques modérés à majeurs chez les individus qui les possèdent. La précision de prédiction du niveau de résistance à la rouille orangée fondée sur les seules données génotypiques aux cinq QTLs (Oru1-5) était relativement élevée (0,6). Dans une dernière partie, la diversité génétique mondiale d'isolats de P. kuehnii provenant de 20 zones géographiques a été caractérisée. Aucune diversité significative n'a été identifiée en utilisant 19 marqueurs SSR ayant précédemment permis de révéler différents génotypes de l'agent pathogène au Brésil. Cependant, la différence génétique existant entre les isolats des hémisphères Ouest et Est (Afrique incluse) a été confirmée en analysant l'allèle au SNP PkITS1-183A>G de la région ITS1 de l'ADN ribosomique. Les isolats de P. kuehnii varient également sur la base de séquences partielles de régions codant pour trois effecteurs. Ces résultats, associés à l'identification formelle de P. kuehnii dans deux nouveaux pays africains (Gabon et Kenya), soutiennent l'hypothèse d'une divergence de l'agent pathogène des Amériques à partir de celui qui s'était préalablement propagé en Afrique, et plus précisément au Gabon dès 2006 ou avant. Les isolats de P. kuehnii de La Réunion, génétiquement proches de ceux de l'hémisphère Est, ont montré une importante diversité représentative de la diversité génétique mondiale. L'ensemble de ces résultats apporte des connaissances nouvelles qui seront très utiles au développement de stratégies d'amélioration variétales robustes pour la résistance de la canne à sucre à la rouille orangée
Des pièces de théâtre forum pour explorer les sentiments d'injustice socio-environnementale au Sénégal. Une méthode d'enquête pragmatique
No full textComment saisir en situation les sentiments d'injustice socio-environnementale en tant qu'expérience ? Comment faire de ces sentiments des objets d'enquête partagée entre les chercheurs et les informateurs ? C'est pour répondre à de telles questions que des dispositifs d'enquête ont été développés à partir de performances de théâtre forum au Sénégal. Cet article présente ces dispositifs selon une perspective pragmatique. Cette méthode s'appuie sur la représentation de situations qui affectent de manière différentielle des acteurs constitués en public. Contrairement aux méthodes classiques d'enquêtes qualitatives, la dimension affective structure ces processus d'investigation. Une telle démarche répond d'enjeux éthiques de la recherche en définissant des situations d'enquête partagées entre chercheur et informateur. La parole des informateurs est au coeur du dispositif théâtral : parole mise en corps et en scène, elle devient critique et analytique dans le cadre des forums associés aux représentations. Cependant, l'article souligne certains effets de cadrage et risques éthiques associés à ces méthodes d'enquête qui ouvrent, en même temps qu'elles les explorent, la possibilité de nouveaux mondes
Overall performances of Leucaena leucocephala and Morus alba in high-density protein banks at maturity in western Burkina Faso
No full textThe objective of this work was to carry out long-term monitoring of protein banks (PB) established under the real-low-input-farm conditions of Burkina Faso, characterized by a Sudano-Sahelian climate type with wide variations in rainfall. The PBs, planted in 2016–2017 with Leucaena leucocephala (LL) and Morus alba (MA) at a high density (20,000 plants/ha), were monitored from 2016/2017 to 2021 for their biomass (fodder) production, chemical composition and nutritional value of the edible fodder, and their impacts on soil carbon content. The average annual fodder production of LL for the 6 PBs (1, 2, 3, 4, 5, and 6) was 11.4 ± 2.12 t DM/ha/year, while that of MA was 3.8 ± 1.2 t DM/ha/year for the 3 PB (1, 2, and 3). Such differences are related to higher adaptive capacity for LL in such climatic conditions. Crude protein was higher in LL (19% versus 17%), but dry matter digestibility (65% versus 77%) was superior in MA. Soil carbon increased during the five monitored years, an exciting result for these poor, low-fertility soil conditions. Our results demonstrate the technical and environmental feasibility of establishing this low-input agroforestry technology in these conditions and inspire the potential of sustainable agriculture as an agroecological alternative to overcoming feed shortages for local livestock farming. However, the successful management of a PB relies on selecting the right suitable species, protecting them, and managing them during the establishment and fodder production periods with suitable cutting frequency and appropriate post-harvest management
Revealing hydrodynamic key factors in dripper clogging: A coupled optical coherence tomography and numerical milli-fluidic simulation
No full textThis study introduces a novel method for analysing emitter clogging in drip irrigation systems by comparing optical tomography images (OCT) of clogging with hydrodynamic modelling (CFD) through statistical analysis. Utilising Principal Component Analysis (PCA) on data coming from modelling and images on a comparable format, turbulence kinetic energy was identified as the key hydrodynamic parameter influencing both kaolinite and biological clogging. The results indicate that turbulence kinetic energy is minimal at the inlet, correlating with the most severe clogging observed in this region. Two flow conditions were tested, with Reynolds numbers of 300 and 400. The higher Reynolds number (400) resulted in accelerated biofilm development and reduced kaolinite clogging compared to the lower Reynolds number (300), indicating a feeding effect correlated to flow speed and shear stress. This methodology offers new ways to study the relationship between modelling and images, leading to insights to understand mechanisms and optimise dripper designs. This method enables the determination of clogging localisation within drippers based on their geometry and can therefore be applied to various designs to enhance maintenance