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The grapevine single-berry clock, practical tools and outcomes
No full textInternational audienceThe dynamic sequence of physiological events along the three-months of berry development from anthesis to ripe stage has been thoroughly investigated. Most studies were performed on average samples, taking care to crush enough fruits to fairly represent the overall trend of the future harvest. However, phenological stages like 30% caps off (EL25) highlights the asynchronous nature of this population. Consequently, softening, onset of sugar accumulation and coloration were melted by asynchrony in a developmental mumbo jumbo, until their respective timing could be clarified by single berries approaches. To alleviate any statistical bias from pooling unsynchronized fruits, we have gathered a set of approaches on single berries, including non-destructive analysis of time-lapse images, Near InfraRed Spectrometry, basic phenotyping, transcriptomics and metabolomics. In this pertinent reference system, the sugar and acid pathways noticeably accelerated and metabolic transitions were sharpened. Transcripts encoding membrane transporters abruptly switched on during either growth phases were identified, enlightening the special design and bioenergetics of the phloem unloading and vacuolar accumulation pathways, in full quantitative agreement with our new appraisal of the sugar/acidity ratio. Single berries did not depart from strict developmental paths on PCAs from transcriptomic or metabolomic data. It led to the identification of a very small set of genes differentially expressed between clones, without interfering with developmentally regulated ones. This study shows that single berry omics alleviates random noise and temporal ambiguities inherent to mixed fruits, thereby improving the accuracy of the molecular clocks to just a few days
Contribution of C-Band Radar Data to the Description of Vegetation Dynamics in the Surface Soil Moisture Retrieval in Semi-Arid Region
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La recherche interdisciplinaire en santé animale : Bilan et perspectives
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The distribution and drivers of tree cover in savannas and forests across India
No full textInternational audienceThe distribution of forest and savanna biomes and the role of resources (climate and soil) and disturbances (fire and herbivory) in determining tree-grass dynamics remains elusive and variable across geographies. This is especially problematic in Indian savannas which have been historically misclassified as degraded forests and are targeted for tree-planting. Here, we examine biome distribution and determinants through the lens of tree cover across India. Our analyses reveal four distinct zones of differing tree cover, with intermediate zones containing savanna vegetation. Rainfall seasonality determines maximum possible tree cover non-linearly. Once rainfall seasonality is factored out, soil sand fraction and topography partially explain residual variation of tree cover. High domestic livestock herbivory and other anthropogenic pressures reduce tree cover. Lastly, lack of detectable fires precludes robust conclusions about the relationship between fire and tree cover. By considering these environmental drivers in restoration planning, we can improve upon simplistic tree planting initiatives that may be detrimental to Indian savannas
FCAvizIR: Exploring Relational Data Set’s Implications Using Metrics and Topics
No full textInternational audienceImplication is a core notion of Formal Concept Analysis and its extensions. It provides information about the regularities present in the data. When one considers a relational data set of real-size, implications are numerous and their formulation, which combines primitive and relational attributes computed using Relational Concept Analysis framework, is complex. For an expert wishing to answer a question based on such a corpus of implications, having a smart exploration strategy is crucial. In this paper, we propose a visual approach, implemented in a web platform named FCAvizIR, for leveraging such corpus. Comprised of three interactive and coordinated views and a toolbox, FCAvizIR has been designed to explore corpora of implication rules following Schneiderman’s famous mantra “overview first, zoom and filter, then details on demand”. It enables metrics filtering, e.g. fixing a minimum and a maximum support value, and the multiple selection of relations and attributes in the premise and in the conclusion to identify the corresponding subset of implications presented as a list and Euler diagrams. An example of exploration is presented using an excerpt of Knomana to analyze plant-based extracts for controlling pests
Adaptation rather than adoption: a case study of cropping system change in West Africa
No full textInternational audienceThe top-down approach, whereby scientists design “ready-to-use” packages to be adopted as they are by farmers, is being increasingly called into question. In reality, farmers often do not just adopt new systems that interest them, but adapt proposed systems to their own situation. Yet, these adaptations are seldom encouraged by agronomists and are even less so a focus of research. In this study, we designed and tested a new collective and individual learning-based approach to support farmers’ adaptation of innovative cropping systems, and applied this approach to increasing legume cultivation in cropping systems in a region of Burkina Faso where legumes have been neglected in favor of cotton. The approach is based on a sequence of three steps. First, collective exchanges during “farmers’ field days” were organized in each village around prototyping trials comparing different legume-based cropping system options proposed by agronomists. Second, farmers could choose the cropping system option that most interests them for implementation. Third, farmers progressively adapted this cropping system, in dedicated adaptation plots. Various degrees of adjustments and adaptations were observed between the options displayed in the prototyping trials and the adaptations made in the plots over a 2-year period. We classified these adaptations into five types of dynamics of change. We found that (i) farmers adapted the cropping system options differently depending on the flexibility as well as the farmer’s knowledge of the system, and (ii) the adaptations made by farmers were influenced by the discussions (both peer-to-peers and with the agronomists) that took place during field days. We thus show that collective exchanges on prototyping trials could contribute to support farmers embarking on a trajectory of change through step-by-step design
Enhancement of soil aggregation and physical properties through fungal amendments under varying moisture conditions
No full textInternational audienceSoil structure and aggregation are crucial for soil functionality, particularly under drought conditions. Saprobic soil fungi, known for their resilience in low moisture conditions, are recognized for their influence on soil aggregate dynamics. In this study, we explored the potential of fungal amendments to enhance soil aggregation and hydrological properties across different moisture regimes. We used a selection of 29 fungal isolates, recovered from soils treated under drought conditions and varying in colony density and growth rate, for single-strain inoculation into sterilized soil microcosms under either low or high moisture (<=-0.96 and -0.03 MPa, respectively). After 8 weeks, we assessed soil aggregate formation and stability, along with soil properties such as soil water content, water hydrophobicity, sorptivity, total fungal biomass and water potential. Our findings indicate that fungal inoculation altered soil hydrological properties and improved soil aggregation, with effects varying based on the fungal strains and soil moisture levels. We found a positive correlation between fungal biomass and enhanced soil aggregate formation and stabilization, achieved by connecting soil particles via hyphae and modifying soil aggregate sorptivity. The improvement in soil water potential was observed only when the initial moisture level was not critical for fungal activity. Overall, our results highlight the potential of using fungal inoculation to improve the structure of agricultural soil under drought conditions, thereby introducing new possibilities for soil management in the context of climate change
Forest politics in the context of Global China : Essays on Chinese presence in Ghana's rosewood sector
No full textDiplomatic relations between Ghana and China date back to the very day the former gained independence from Great Britain. On that occasion, Chinese vice-premier Nieh Jungchen represented his country at Ghana's independence celebrations on 6 March 1957. Recently, the exploitation of natural resources and 'rosewood' in particular, has been one of the main drivers of trade relations between China and Ghana. Rosewood, also known as hong mu in Mandarin, refers to a group of thirty-three species of tropical hardwood, many of which are also endangered species. Excessive demand for rosewood in China has led to increased and often illegal logging in many Asian producer countries and more recently in Africa.Theoretically and conceptually, this thesis draws on access theory, commons theory, incentive theory and the analytical approach to power relations centered on actor strategies. It is based on original empirical research carried out mainly in Ghana, where the first series of data collection took place from April to August 2022, followed by a second series from April to July 2023. The thesis analyses how several players in the rosewood trade chain gain access to this natural resource. It assesses the impact of the growing presence of Chinese actors on the governance of rosewood and the consequences of this presence on the 'commons' in rural Ghana. It also assesses the relative effects of governance structures and power dynamics observed between the main players in the rosewood trade between China and Ghana over a two-decade period (2000-2023).One of the main conclusions of the thesis is that there is a significant asymmetry of power and negotiating capacity between Ghanaian and Chinese players in the rosewood industry. In most cases, the latter regularly take advantage of the disorder and institutional weaknesses of the former. The thesis specifically highlights certain factors that affect the processes of access to rosewood in Ghana: modes of land appropriation, cultural beliefs, the financial capacities of stakeholders, the quality of government regulations and the degree to which they are implemented. This research makes an original contribution to the determinants and conditions of access by Chinese actors to natural resources in African contexts characterized by the persistence of 'political disorder'. More specifically, it reveals the realities of Ghana's institutional architecture around the exploitation of natural resources and forest governance in Ghana. Finally, this work lays the foundations for fundamental questions about the future of Ghana's sustainable forest management policies in light of China's growing influence in Africa.Les relations diplomatiques entre le Ghana et la Chine datent du jour même où le premier a obtenu son indépendance de la Grande-Bretagne. A cette occasion, le vice-premier ministre chinois Nieh Jungchen, représenta son pays lors de la célébration de l'indépendance du Ghana le 6 mars 1957. Récemment, la question de l'exploitation des ressources naturelles, et du ‘bois de rose' a été l'un des principaux leviers des relations commerciales entre la Chine et le Ghana. Le bois de rose, également connu sous le nom de hong mu en mandarin, désigne un groupe de trente-trois espèces de bois durs tropicaux, dont beaucoup sont également des espèces en voie de disparition. La demande excessive de bois de rose en Chine a conduit à une exploitation accrue et souvent illégale dans de nombreux pays producteurs d'Asie et plus récemment en Afrique.Sur le plan théorique et conceptuel, cette thèse s'inspire de la théorie de l'accès, de la théorie des biens communs, de la théorie des incitations et de l'approche analytique des relations de de pouvoir centré sur les stratégies d'acteurs. Elle est basée sur une recherche empirique originale menée principalement au Ghana, où la première série de collecte de données s'est déroulée d'avril à août 2022, puis une seconde fut conduite d'avril à juillet 2023. La thèse analyse comment une pluralité d'acteurs de la chaîne commerciale du bois de rose procède pour avoir accès à cette ressource naturelle. Elle évalue l'impact de la présence croissante des acteurs chinois sur la gouvernance du bois de rose et les conséquences induites par cette présence sur les "biens communs" en zone rurale au Ghana. Elle évalue également les effets relatifs structures de gouvernance et les dynamiques de pouvoir observées entre les principaux acteurs du commerce du bois de rose entre la Chine et le Ghana pour une période de deux décennies (2000 - 2023).L'une des principales conclusions de la thèse est qu'il existe une importante asymétrie de pouvoir et de capacité de négociation entre les acteurs ghanéens et les acteurs chinois de la filière bois de rose. Dans la majorité des cas, les seconds tirent régulièrement profit du désordre et des faiblesses institutionnelles des premiers. La thèse met spécifiquement en évidence certains facteurs qui affectent les processus d'accès au bois de rose au Ghana : les modes d'appropriation foncière, les croyances culturelles, les capacités financières des acteurs, La qualité des réglementations gouvernementales et le degré de leur mise en œuvre. Cette recherche apporte une contribution originale sur les déterminants et conditions d'accès, par les acteurs chinois, aux ressources naturelles dans des contextes africains caractérisés par la persistance d'un "désordre politique". Elle dévoile plus précisément les réalités de l'architecture institutionnelle ghanéenne autour de l'exploitation des ressources naturelles et de la gouvernance forestière au Ghana. Enfin, ce travail pose les bases d'un questionnement fondamental sur l'avenir des politiques de gestion durable des forêts ghanéennes au regard de l'influence croissante de la Chine en Afrique
Selnetime: A new method inferring demography and selection from genomic time series data
No full textInternational audienceTraditionally, contemporary individuals are sampled to determine demographic patterns or regions under selection. However, genetic data can be affected by various confounding factors, including both selection and demography. To mitigate these effects, time series data can be used. These data, which can be obtained from monitoring natural populations, experimental populations or ancient DNA, have several applications. They are valuable for population management, for understanding the genetic basis of traits of interest, and for characterising evolutionary history
DigitAg's interdisciplinary and interprofessional efforts in digital agriculture
No full textInternational audienceIn this paper, using DigitAg as a case study, we explore the opportunities and challenges associated with interdisciplinary research on the creation of knowledge and technologies for niche, small-scale agriculture, thereby enhancing their adoptability by farmers.DigitAg is one of the Convergence Institutes, supported by the French National Research Agency to tackle major societal challenges by creating a critical mass through a multidisciplinary network across public and private partners. Founded in 2016 with a lifespan of 8 years, DigitAg's objective is to establish the scientific foundations necessary for the harmonious deployment of digital agriculture. The project stands out for its emphasis on interdisciplinarity and low-cost technologies for small-scale exploitation. To achieve this, it brings together more than 570 experts from agronomic sciences, engineering sciences, and social and management sciences and has produced approximately 70 interdisciplinary PhD theses, in addition to research collaboration and two Flagship projects.Against this backdrop, we explore how DigitAg's imperative of interdisciplinarity has unfolded through research collaboration and technological developments at the practical level. With its emphasis on interdisciplinarity, DigitAg has made efforts to enable the co-creation of knowledge, which includes industrial and agricultural partners. How has this endeavor, both interdisciplinary and intersectoral, occurred during the formulation of new research questions and the conception of technologies? What specific challenges have emerged in initiating conversations between diverging actors? We discuss these questions based on interviews with project members and direct observations