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1. Cultivar architecture modulates spore dispersal by rain splash: A new perspective to reduce disease progression in cultivar mixtures.

Author

Tiphaine Vidal, Pauline Lusley, Marc Leconte, Claude de Vallavieille-Pope, Laurent Huber, and Sébastien Saint-Jean

Subjects
Medicine, Science
Abstract

Cultivar mixtures can be used to improve the sustainability of disease management within farming systems by growing cultivars that differ in their disease resistance level in the same field. The impact of canopy aerial architecture on rain-splash dispersal could amplify disease reduction within mixtures. We designed a controlled conditions experiment to study single splash-dispersal events and their consequences for disease. We quantified this impact through the spore interception capacities of the component cultivars of a mixture. Two wheat cultivars, differing in their aerial architecture (mainly leaf area density) and resistance to Septoria tritici blotch, were used to constitute pure stands and mixtures with 75% of resistant plants that accounted for 80% of the canopy leaf area. Canopies composed of 3 rows of plants were exposed to standardized spore fluxes produced by splashing calibrated rain drops on a linear source of inoculum. Disease propagation was measured through spore fluxes and several disease indicators. Leaf susceptibility was higher for upper than for lower leaves. Dense canopies intercepted more spores and mainly limited horizontal spore transfer to the first two rows. The presence of the resistant and dense cultivar made the mixed canopy denser than the susceptible pure stand. No disease symptoms were observed on susceptible plants of the second and third rows in the cultivar mixture, suggesting that the number of spores intercepted by these plants was too low to cause disease symptoms. Both lesion area and disease conditional severity were significantly reduced on susceptible plants within mixtures on the first row beside the inoculum source. Those reductions on one single-splash dispersal event, should be amplified after several cycle over the full epidemic season. Control of splash-dispersed diseases within mixtures could therefore be improved by a careful choice of cultivars taking into consideration both resistance and architecture.

Published
2017
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3. Annual dynamics of Zymoseptoria tritici populations in wheat cultivar mixtures: A compromise between the efficacy and durability of a recently broken‐down resistance gene?

Author

Tiphaine Vidal, Frédéric Suffert, Sandrine Gélisse, Sébastien Saint-Jean, Anne-Lise Boixel, Carolina Orellana-Torrejon, BIOlogie et GEstion des Risques en agriculture (BIOGER), AgroParisTech-Université Paris-Saclay-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Ecologie fonctionnelle et écotoxicologie des agroécosystèmes (ECOSYS), and ANR-17-EURE-0007,SPS-GSR,Ecole Universitaire de Recherche de Sciences des Plantes de Paris-Saclay(2017)

Subjects
0106 biological sciences, 2. Zero hunger, Genetics, 0303 health sciences, Resistance (ecology), [SDV]Life Sciences [q-bio], food and beverages, Virulence, Plant Science, Horticulture, Biology, 01 natural sciences, Durability, 03 medical and health sciences, cultivar mixtureresistance breakdownStb16qvirulencewheat disease epidemicsZymoseptoria tritici, [SDE]Environmental Sciences, Cultivar, Agronomy and Crop Science, Gene, 030304 developmental biology, 010606 plant biology & botany
Abstract

International audience; Cultivar mixtures slow polycyclic epidemics but may also affect the evolution of pathogen populations by diversifying the selection pressures exerted by their plant hosts at field scale. We compared the dynamics of natural populations of the fungal pathogen Zymoseptoria tritici in pure stands and in three binary mixtures of wheat cultivars (one susceptible cultivar and one cultivar carrying the recently broken-down Stb16q gene) over two annual field epidemics. We combined analyses of population "size" based on disease severity, and of population "composition" based on changes in the frequency of virulence against Stb16q in seedling assays with more than 3000 strains. Disease reductions were observed in mixtures late in the epidemic, at the whole-canopy scale and on both cultivars, suggesting the existence of a reciprocal protective effect. The three cultivar proportions in the mixtures (0.25, 0.5, and 0.75) modulated the decrease in (a) the size of the pathogen population relative to the two pure stands, (b) the size of the virulent subpopulation, and (c) the frequency of virulence relative to the pure stand of the cultivar carrying Stb16q. Our findings suggest that optimal proportions may differ slightly between the three indicators considered. We argue potential trade-offs that should be taken into account when deploying a resistance gene in cultivar mixtures: between the dual objectives "efficacy" and "durability," and between the "size" and "frequency" of the virulent subpopulation. Based on current knowledge, it remains unclear whether virulent subpopulation size or frequency has the largest influence on interepidemic virulence transmission.

Published
2021
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4. Cultivar mixture effects on disease and yield remain despite diversity in wheat height and earliness

Author

Pauline Lusley, Anne-Lise Boixel, M. Leconte, Tiphaine Vidal, Safa Ben Krima, Sébastien Saint-Jean, Claude de Vallavieille-Pope, BIOlogie et GEstion des Risques en agriculture (BIOGER), AgroParisTech-Université Paris-Saclay-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Ecologie fonctionnelle et écotoxicologie des agroécosystèmes (ECOSYS), and ANR-13-AGRO-0008,WHEATAMIX,Augmenter la diversité génétique au sein des parcelles de blé pour renforcer la multifonctionnalité et la durabilité de la production dans le Bassin Parisien(2013)

Subjects
0106 biological sciences, 0301 basic medicine, [SDV]Life Sciences [q-bio], Field experiment, [SDV.SA.AGRO]Life Sciences [q-bio]/Agricultural sciences/Agronomy, Puccinia striiformis f. sp. tritici, Plant Science, Horticulture, Biology, Plant disease resistance, 01 natural sciences, wheat diseases, intrafield diversity, 03 medical and health sciences, Disease severity, Yield (wine), Genetics, Cultivar, 2. Zero hunger, Wheat diseases, fungi, cultivar mixture, food and beverages, yield, component number, [SDV.BV.PEP]Life Sciences [q-bio]/Vegetal Biology/Phytopathology and phytopharmacy, 030104 developmental biology, Agronomy and Crop Science, 010606 plant biology & botany
Abstract

International audience; Cultivar mixtures can stabilize yield and reduce pathogen spread in plant populations. A field experiment was performed to determine (a) whether a large difference between the cultivars in the mixture (e.g., plant height or earliness) would have an impact on mixture performance, and (b) whether such differences would modify the classical rules for mixture design. Mixtures were constituted from wheat cultivars with diversity for many traits, including plant height, flowering date, disease resistance, and yield potential. The field experiment was conducted over 3 years, testing each year 72–90 mixtures of two, four, or eight cultivars, and their corresponding pure stands. Disease severity and yield of cultivar mixtures were strongly related to the mean values of the component cultivars in pure stands. Despite the considerable diversity of the mixtures tested, the classic rules (e.g., proportion of susceptible cultivars) already tested in mixtures with similar height and earliness were effective for decreasing disease severity. Agronomic heterogeneity for traits such as plant height, yield potential, or earliness of the cultivars in mixtures did not have a negative impact on disease severity and yield relative to pure stands. Increasing the number of cultivars in the mixture from two to eight had no impact on the mean disease severity and yield of the mixtures, but reduced the variability of disease severity and yield in the mixture relative to pure stands. These results suggest that it may be possible to increase within‐field wheat diversity by combining more contrasting cultivars in mixtures than was previously thought.

Published
2020
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5. Does the impact of cultivar mixtures on virulence dynamics in Zymoseptoria tritici populations persist after interseason sexual reproduction?

Author

Carolina Orellana-Torrejon, Tiphaine Vidal, Sébastien Saint-Jean, and Frédéric Suffert

Subjects
food and beverages
Abstract

This study follows on from a previous study showing that binary mixtures of wheat cultivars affect the evolution of Zymoseptoria tritici populations within a field epidemic from the beginning (t1) to the end (t2) of a growing season. Here, we focused on the impact of interseason sexual reproduction on this evolution. We studied mixtures of susceptible and resistant cultivars (carrying Stb16q, a recently broken-down resistance gene) in proportions of 0.25, 0.5 and 0.75, and their pure stands. We determined the virulence status of 1440 ascospore-derived strains collected from residues of each cultivar by phenotyping on seedlings. Virulence frequencies were lower in mixtures than in pure stands of the resistant cultivar, as at t2, revealing that the impact of mixtures persisted until the beginning of the next epidemic (t3). The frequency of virulence was lower in the offspring population on the susceptible cultivar and, more surprisingly, the frequency of avirulence on the resistant cultivar increased after sexual reproduction. Our findings highlight two epidemiological processes in mixtures: selection within the local pathogen population between t1 and t2 driven by asexual cross-contamination between cultivars (previous study) and sexual crosses between avirulent and virulent strains between t2 and t3 driven by changes in the probabilities of physical encounters (this study). Mixtures therefore appear to be a promising strategy for the deployment of qualitative resistances, not only to limit the intensity of Septoria tritici blotch epidemics, but also to reduce the erosion of resistances by managing evolution of the pathogen population at a pluriannual scale.

Published
2022
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6. Multiple scenarios for sexual crosses in the fungal pathogen Zymoseptoria tritici on wheat residues: Potential consequences for virulence gene transmission

Author

Carolina Orellana-Torrejon, Tiphaine Vidal, Gwilherm Gazeau, Anne-Lise Boixel, Sandrine Gélisse, Jérôme Lageyre, Sébastien Saint-Jean, and Frédéric Suffert

Subjects
Virulence, Ascomycota, Genetics, food and beverages, Microbiology, Triticum, Plant Diseases
Abstract

Little is known about the impact of host immunity on sexual reproduction in fungal pathogens. In particular, it is unclear whether crossing requires both sexual partners to infect living plant tissues. We addressed this issue in a three-year experiment investigating different scenarios of Zymoseptoria tritici crosses on wheat according to the virulence (‘vir’) or avirulence (‘avr’) of the parents against a qualitative resistance gene. Co-inoculations (‘vir × vir’, ‘avr × vir’, ‘avr × avr’) and single inoculations were performed on a cultivar carrying the resistance gene (Cellule) and a susceptible cultivar (Apache), in the greenhouse. We assessed the intensity of asexual multiplication by scoring disease severity, and the intensity of sexual reproduction by counting the ascospores discharged from wheat residues. As expected, disease severity was more intense on Cellule for ‘vir × vir’ co-inoculations than for ‘avr × vir’ co-inoculations, with no disease for ‘avr × avr’. However, all types of co-inoculation yielded sexual offspring, whether or not the parental strains caused plant symptoms. Parenthood was confirmed by genotyping (SSR markers), and the occurrence of crosses between (co-)inoculated and exogenous strains (other strains from the experiment, or from far away) was determined. We found that symptomatic asexual infection was not required for a strain to participate in sexual reproduction, and that avirulent strains could be maintained asymptomatically “on” or “in” leaf tissues of plants carrying the corresponding resistant gene for long enough to reproduce sexually. In two of the three years, the intensity of sexual reproduction did not differ significantly between the three types of co-inoculation in Cellule, suggesting that crosses involving avirulent strains are not anecdotal. We discuss the possible mechanisms explaining the maintenance of avirulence in Z. tritici populations and supporting the potential efficacy of cultivar mixtures for limiting resistance gene breakdown.HighlightsAvirulent Zymoseptoria tritici strains can reproduce sexually in wheat plants carrying the corresponding resistant gene.Symptomatic infection of plant tissues is not essential for a strain to reproduce sexually.Avirulent strains can be maintained asymptomatically “on” or “in” leaf tissues of plants carrying the corresponding resistant gene for long enough to reproduce sexually.Crosses of virulent strains with virulent and avirulent strains in a plant host carrying the corresponding resistance gene can produce offspring with similar population sizes.Several possible scenarios for sexual crosses can explain the maintenance of avirulence in Zymoseptoria tritici populations evolving in a wheat canopy, particular in cultivar mixtures.

Published
2022
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7. Annual dynamics of Zymoseptoria tritici populations in wheat cultivar mixtures: a compromise between the efficiency and durability of a recently broken-down resistance gene?

Author

Sébastien Saint-Jean, Carolina Orellana-Torrejon, Sandrine Gélisse, Suffert Frédéric, Anne-Lise Boixel, Tiphaine Vidal, Ecologie fonctionnelle et écotoxicologie des agroécosystèmes (ECOSYS), AgroParisTech-Université Paris-Saclay-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), and BIOlogie et GEstion des Risques en agriculture (BIOGER)

Subjects
0106 biological sciences, Canopy, [SDE.MCG]Environmental Sciences/Global Changes, Population, Virulence, Biology, [SDU.STU.ME]Sciences of the Universe [physics]/Earth Sciences/Meteorology, 01 natural sciences, 03 medical and health sciences, Cultivar, education, Gene, Pathogen, 030304 developmental biology, 2. Zero hunger, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, 0303 health sciences, education.field_of_study, Resistance (ecology), [SDE.IE]Environmental Sciences/Environmental Engineering, food and beverages, biology.organism_classification, [SDV.BV.PEP]Life Sciences [q-bio]/Vegetal Biology/Phytopathology and phytopharmacy, Agronomy, Seedling, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, 010606 plant biology & botany
Abstract

Cultivar mixtures slow polycyclic epidemics but may also affect the evolution of pathogen populations by diversifying the selection pressures exerted by their plant hosts at field scale. We compared the dynamics of natural populations of the fungal pathogen Zymoseptoria tritici in pure stands and in three binary mixtures of wheat cultivars (one susceptible cultivar and one cultivar carrying the recently broken-down Stb16q gene) over two annual field epidemics. We combined analyses of population ‘size’ based on disease severity, and of population ‘composition’ based on changes in the frequency of virulence against Stb16q in seedling assays with more than 3000 strains. Disease reductions were observed in mixtures late in the epidemic, at the whole canopy scale and on both cultivars, suggesting the existence of a reciprocal ‘protective’ effect. The three cultivar proportions in the mixtures (0.25, 0.5 and 0.75) modulated the decrease in (i) the size of the pathogen population relative to the two pure stands, (ii) the size of the virulent subpopulation, and (iii) the frequency of virulence relative to the pure stand of the cultivar carrying Stb16q. Our findings suggest that optimal proportions may differ slightly between the three indicators considered. We argued potential trade-offs that should be taken into account when deploying a resistance gene in cultivar mixtures: between the dual objectives ‘efficacy’ and ‘durability’, and between the ‘size’ and ‘frequency’ of the virulent subpopulation. Based on current knowledge, it remains unclear whether virulent subpopulation size or frequency has the largest influence on interepidemic virulence transmission.

Published
2021

8. Plant functional trait variability and trait syndromes among wheat varieties: the footprint of artificial selection

Author

Isabelle Goldringer, Xavier Le Roux, Sébastien Saint-Jean, Bruno Andrieu, Jonathan Gervaix, Jérôme Enjalbert, Amélie A. M. Cantarel, Vincent Allard, Sébastien Barot, Thomas Pommier, Laboratoire d'Ecologie Microbienne - UMR 5557 (LEM), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Ecole Nationale Vétérinaire de Lyon (ENVL)-VetAgro Sup - Institut national d'enseignement supérieur et de recherche en alimentation, santé animale, sciences agronomiques et de l'environnement (VAS)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Génétique Diversité et Ecophysiologie des Céréales (GDEC), Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Clermont Auvergne (UCA), Ecologie fonctionnelle et écotoxicologie des agroécosystèmes (ECOSYS), AgroParisTech-Université Paris-Saclay-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Institut d'écologie et des sciences de l'environnement de Paris (iEES Paris ), Institut de Recherche pour le Développement (IRD)-Sorbonne Université (SU)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Génétique Quantitative et Evolution - Le Moulon (Génétique Végétale) (GQE-Le Moulon), AgroParisTech-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), INRAE meta-programme EcoServ INRAE meta-programme EcoServ DIVERSITAS/Future Earth German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, DIVERSITAS/Future Earth, German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, ANR-13-AGRO-0008,WHEATAMIX,Augmenter la diversité génétique au sein des parcelles de blé pour renforcer la multifonctionnalité et la durabilité de la production dans le Bassin Parisien(2013), Institut de Recherche pour le Développement (IRD)-Sorbonne Université (SU)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), and INRAE meta-programme EcoServANR Wheatamix INRAE meta-programme EcoServ DIVERSITAS/Future Earth German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig

Subjects
0106 biological sciences, wheat variety selection, Physiology, Plant Science, Crop species, root nutrient absorption capacity, 010603 evolutionary biology, 01 natural sciences, [SDV.EE.ECO]Life Sciences [q-bio]/Ecology, environment/Ecosystems, MAGIC lines, Common wheat, Triticum, Selection (genetic algorithm), 2. Zero hunger, Ecology, biology, landraces, organic farming varieties, Syndrome, 15. Life on land, biology.organism_classification, Pooideae, conventional varieties, [SDV.BV.AP]Life Sciences [q-bio]/Vegetal Biology/Plant breeding, Phenotype, Evolutionary biology, Above- and below-ground functional traits, intraspecific trait variation, Plant species, Absorption capacity, Trait, 010606 plant biology & botany
Abstract

Although widely used in ecology, trait-based approaches are seldom used to study agroecosystems. In particular, there is a need to evaluate how functional trait variability among varieties of a crop species compares to the variability among wild plant species and how variety selection can modify trait syndromes. Here, we quantified 18 above- and below-ground functional traits for 57 varieties of common wheat representative of different modern selection histories. We compared trait variability among varieties and among Pooideae species, and analyzed the effect of selection histories on trait values and trait syndromes. For traits under strong selection, trait variability among varieties was less than 10% of the variability observed among Pooideae species. However, for traits not directly selected, such as root N uptake capacity, the variability was up to 75% of the variability among Pooideae species. Ammonium absorption capacity by roots was counter-selected for conventional varieties compared with organic varieties and landraces. Artificial selection also altered some trait syndromes classically reported for Pooideae. Identifying traits that have high or low variability among varieties and characterizing the hidden effects of selection on trait values and syndromes will benefit the selection of varieties to be used especially for lower N input agroecosystems.

Published
2021
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9. Modelling Exchanges: From the Process Scale to the Regional Scale

Author

Jean-Louis Drouet, Benjamin Loubet, Isabelle Coll, Carole Bedos, Andrée Tuzet, Matthias Beekmann, Erwan Personne, Raia Silvia Massad, Sophie Genermont, Audrey Fortems-Cheiney, Sébastien Saint-Jean, Ecologie fonctionnelle et écotoxicologie des agroécosystèmes (ECOSYS), AgroParisTech-Université Paris-Saclay-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Laboratoire Interuniversitaire des Systèmes Atmosphériques (LISA (UMR_7583)), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), and Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)

Subjects
Pollutant, Process modeling, 010504 meteorology & atmospheric sciences, business.industry, Process (engineering), Scale (chemistry), Environmental resource management, Integration, Climate change, 010501 environmental sciences, 15. Life on land, 01 natural sciences, Field (geography), Chemistry-transport model, Model coupling, Air quality prediction, 13. Climate action, Agriculture, [SDE]Environmental Sciences, Environmental science, Process modelling, business, Air quality index, Soil-vegetation-atmosphere transfer, 0105 earth and related environmental sciences
Abstract

International audience; This chapter shows how the knowledge on the processes of surface exchange and atmospheric fate of different pollutants from agriculture or with an impact on agroecosystems is factored into mathematical simulation tools. It also considers the complexity of the interactions involved, the quantities of matter exchanged between agroecosystems and the atmosphere, and the measurement methods used to quantify them. The resulting models, which range from highly local (plant, leaf …) to global scales, ultimately enable to assess the impacts of changes in agricultural practices or climate change on pollutant exchanges between the atmosphere and agroecosystems. We describe different modelling approaches at the process, field, landscape and regional scales with different integrative levels. Model results are useful to understand how different processes interact and to predict how different environmental conditions, future climate or agricultural practices affect air quality. Models can also help identify levers for emission mitigation and estimate their efficiency.

Published
2020
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10. Mechanisms of Pollutant Exchange at Soil-Vegetation-Atmosphere Interfaces and Atmospheric Fate

Author

J. Lathière, Raia Silvia Massad, Eric Villenave, Raluca Ciuraru, Benjamin Loubet, Carole Bedos, Sophie Genermont, Patrick Stella, Andrée Tuzet, Laurent Huber, Sébastien Saint-Jean, Ecologie fonctionnelle et écotoxicologie des agroécosystèmes (ECOSYS), AgroParisTech-Université Paris-Saclay-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Sciences pour l'Action et le Développement : Activités, Produits, Territoires (SADAPT), UMR 5805 Environnements et Paléoenvironnements Océaniques et Continentaux (EPOC), Observatoire aquitain des sciences de l'univers (OASU), Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-École pratique des hautes études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Environnements et Paléoenvironnements OCéaniques (EPOC), Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-École Pratique des Hautes Études (EPHE), Modelling the Earth Response to Multiple Anthropogenic Interactions and Dynamics (MERMAID), and Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)

Subjects
010504 meteorology & atmospheric sciences, Physicochemical equilibria, Air pollution, Context (language use), 010501 environmental sciences, medicine.disease_cause, 01 natural sciences, Atmosphere, Soil, medicine, Biogenic processes, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment, Air quality index, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, 2. Zero hunger, Pollutant, Vegetation, Environmental engineering, 15. Life on land, Dispersion, Transfer, Surface, Chemistry, Deposition (aerosol physics), 13. Climate action, Atmospheric chemistry, [SDE]Environmental Sciences
Abstract

International audience; The presence in the atmosphere of pollutants emitted from agriculture or impacting crop production, their concentration levels and their residence time depend on a series of physical, chemical and biological processes. This chapter describes the basic mechanisms and the main factors involved in air pollutant emissions and fate in agricultural systems. These include emissions to the atmosphere from fields or livestock husbandry, atmospheric transfers at various scales – from the proximity of the sources to regional and global scales –, atmospheric chemistry and deposition to ecosystem. These concepts are necessary to understand the context and various choices that can be made in terms of measuring air concentrations and emission/deposition fluxes and of modelling emissions, atmospheric fate – dispersion, transport, degradation – and deposition. The knowledge on these processes contributes to modelling the impact of agricultural sources on air quality and the impact of air pollution on ecosystems. It also helps identify levers for mitigating emissions from agriculture and impacts of air pollution on crops.

Published
2020
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11. Current knowledge and future research opportunities for modeling annual crop mixtures. A review

Author

Jochem B. Evers, Wopke van der Werf, Noémie Gaudio, Jean-Louis Durand, Gaëtan Louarn, Philippe Hinsinger, Eric Justes, Abraham J. Escobar-Gutiérrez, Hélène Marrou, Sébastien Saint-Jean, Jacques Eric Bergez, Sebastian Munz, Christophe Pradal, Pierre Casadebaig, Ela Frak, Marie Launay, Loïc Pagès, Frédéric Gérard, Romain Barillot, Didier Combes, Nathalie Colbach, AGroécologie, Innovations, teRritoires (AGIR), Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut National de la Recherche Agronomique (INRA), Unité de Recherche Pluridisciplinaire Prairies et Plantes Fourragères (P3F), Institut National de la Recherche Agronomique (INRA), Wageningen University and Research Centre [Wageningen] (WUR), Ecologie fonctionnelle et biogéochimie des sols et des agro-écosystèmes (UMR Eco&Sols), Institut National de la Recherche Agronomique (INRA)-Institut de Recherche pour le Développement (IRD)-Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro)-Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro), Agroécologie [Dijon], Institut National de la Recherche Agronomique (INRA)-Université de Bourgogne (UB)-AgroSup Dijon - Institut National Supérieur des Sciences Agronomiques, de l'Alimentation et de l'Environnement-Université Bourgogne Franche-Comté [COMUE] (UBFC), University of Hohenheim, UE Agroclim (UE AGROCLIM), Fonctionnement et conduite des systèmes de culture tropicaux et méditerranéens (UMR SYSTEM), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Institut National de la Recherche Agronomique (INRA)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro)-Centre International de Hautes Etudes Agronomiques Méditerranéennes - Institut Agronomique Méditerranéen de Montpellier (CIHEAM-IAMM), Centre International de Hautes Études Agronomiques Méditerranéennes (CIHEAM)-Centre International de Hautes Études Agronomiques Méditerranéennes (CIHEAM)-Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro), Unité de recherche Plantes et Systèmes de Culture Horticoles (PSH), Amélioration génétique et adaptation des plantes méditerranéennes et tropicales (UMR AGAP), Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro)-Institut National de la Recherche Agronomique (INRA)-Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro), Scientific Data Management (ZENITH), Laboratoire d'Informatique de Robotique et de Microélectronique de Montpellier (LIRMM), Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Inria Sophia Antipolis - Méditerranée (CRISAM), Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria), Ecologie fonctionnelle et écotoxicologie des agroécosystèmes (ECOSYS), Institut National de la Recherche Agronomique (INRA)-AgroParisTech, Institut National de la Recherche Agronomique (INRA)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Université de Toulouse (UT), Wageningen University and Research [Wageningen] (WUR), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Institut de Recherche pour le Développement (IRD)-Institut National de la Recherche Agronomique (INRA)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro)-Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro), Agroclim (AGROCLIM), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Institut National de la Recherche Agronomique (INRA)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro)-Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro), European Union, INRA Environment and Agronomy Division through the project IDEA, European Project: 727217,ReMIX(2017), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées, Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro), Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro)-Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Institut de Recherche pour le Développement (IRD)-Institut National de la Recherche Agronomique (INRA), Université de Bourgogne (UB)-Institut National de la Recherche Agronomique (INRA)-Université Bourgogne Franche-Comté [COMUE] (UBFC)-AgroSup Dijon - Institut National Supérieur des Sciences Agronomiques, de l'Alimentation et de l'Environnement, Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro), Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Inria Sophia Antipolis - Méditerranée (CRISAM), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Institut National de la Recherche Agronomique (INRA)-Centre International de Hautes Etudes Agronomiques Méditerranéennes - Institut Agronomique Méditerranéen de Montpellier (CIHEAM-IAMM), Centre International de Hautes Études Agronomiques Méditerranéennes (CIHEAM)-Centre International de Hautes Études Agronomiques Méditerranéennes (CIHEAM)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro)-Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro), Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), and URP3F, INRAE, Lusignan, France

Subjects
0106 biological sciences, Niche complementarity, F08 - Systèmes et modes de culture, Agricultural engineering, Large range, Quantitative Biology - Quantitative Methods, 01 natural sciences, Individual-based models, modèle de cultures, ComputingMilieux_MISCELLANEOUS, Quantitative Methods (q-bio.QM), 2. Zero hunger, annual crop mixtures, intercrops, genotypes mixtures, crop models, individual-based models, functional-structural plant models, model users, 04 agricultural and veterinary sciences, Research opportunities, PE&RC, Genotypes mixtures, Agricultural sciences, Crop simulation model, Crop and Weed Ecology, Modèle mathématique, Environmental Engineering, culture en melange, Model users, systeme de culture, Annual crop mixtures, Crop, Culture sous couvert végétal, Culture intercalaire, Intercrops, culture annuelle, Plante de couverture, Plante annuelle, Quantitative Biology - Populations and Evolution, business.industry, Mélange de semences, Populations and Evolution (q-bio.PE), Sowing, 15. Life on land, [INFO.INFO-MO]Computer Science [cs]/Modeling and Simulation, Functional–structural plant models, Agriculture, Modélisation, FOS: Biological sciences, 040103 agronomy & agriculture, 0401 agriculture, forestry, and fisheries, Environmental science, Crop models, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, U30 - Méthodes de recherche, business, Agronomy and Crop Science, Cropping, Sciences agricoles, 010606 plant biology & botany
Abstract

Growing mixtures of annual arable crop species or genotypes is a promising way to improve crop production without increasing agricultural inputs. To design optimal crop mixtures, choices of species, genotypes, sowing proportion, plant arrangement, and sowing date need to be made but field experiments alone are not sufficient to explore such a large range of factors. Crop modeling allows to study, understand and ultimately design cropping systems and is an established method for sole crops. Recently, modeling started to be applied to annual crop mixtures as well. Here, we review to what extent crop simulation models and individual-based models are suitable to capture and predict the specificities of annual crop mixtures. We argued that: 1) The crop mixture spatio-temporal heterogeneity (influencing the occurrence of ecological processes) determines the choice of the modeling approach (plant or crop centered). 2) Only few crop models (adapted from sole crop models) and individual-based models currently exist to simulate annual crop mixtures. 3) Crop models are mainly used to address issues related to crop mixtures management and to the integration of crop mixtures into larger scales such as the rotation, whereas individual-based models are mainly used to identify plant traits involved in crop mixture performance and to quantify the relative contribution of the different ecological processes (niche complementarity, facilitation, competition, plasticity) to crop mixture functioning. This review highlights that modeling of annual crop mixtures is in its infancy and gives to model users some important keys to choose the model based on the questions they want to answer, with awareness of the strengths and weaknesses of each of the modeling approaches., Comment: 42 pages, 5 figures

Published
2019
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12. Unfolding the potential of wheat cultivar mixtures : a meta-analysis perspective and identification of knowledge gaps

Author

Jérôme Enjalbert, Isabelle Goldringer, Lars Pødenphant Kiær, Arnaud Gauffreteau, Sébastien Barot, Christophe Lecarpentier, Sébastien Saint-Jean, Julie Borg, Génétique Quantitative et Evolution - Le Moulon (Génétique Végétale) (GQE-Le Moulon), Centre National de la Recherche Scientifique (CNRS)-AgroParisTech-Université Paris-Sud - Paris 11 (UP11)-Institut National de la Recherche Agronomique (INRA), Department of Plant and Environmental Sciences [Copenhagen], Faculty of Science [Copenhagen], University of Copenhagen = Københavns Universitet (KU)-University of Copenhagen = Københavns Universitet (KU), Agronomie, AgroParisTech-Institut National de la Recherche Agronomique (INRA), Ecologie fonctionnelle et écotoxicologie des agroécosystèmes (ECOSYS), Institut National de la Recherche Agronomique (INRA)-AgroParisTech, Institut d'écologie et des sciences de l'environnement de Paris (iEES Paris), Institut National de la Recherche Agronomique (INRA)-Sorbonne Université (SU)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS), Institut National de la Recherche Agronomique (INRA)-Université Paris-Sud - Paris 11 (UP11)-AgroParisTech-Centre National de la Recherche Scientifique (CNRS), University of Copenhagen = Københavns Universitet (UCPH)-University of Copenhagen = Københavns Universitet (UCPH), and Institut d'écologie et des sciences de l'environnement de Paris (IEES (UMR_7618 / UMR_D_242 / UMR_A_1392 / UM_113) )

Subjects
0106 biological sciences, Biodiversity, Soil Science, Stress gradient hypothesis, Meta-regression, Plant disease resistance, 01 natural sciences, Disease reduction, Cultivar, Agroecology, Mathematics, 2. Zero hunger, Phenology, [SDE.IE]Environmental Sciences/Environmental Engineering, food and beverages, 04 agricultural and veterinary sciences, Overyielding, 15. Life on land, [SDV.BV.PEP]Life Sciences [q-bio]/Vegetal Biology/Phytopathology and phytopharmacy, Agronomy, Homogeneous, Cultivar mixtures, Meta-analysis, Wheat, 040103 agronomy & agriculture, 0401 agriculture, forestry, and fisheries, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, Agronomy and Crop Science, Cropping, 010606 plant biology & botany
Abstract

International audience; Increasing the biodiversity of cropped plants is a key leverage for agroecology, aiming to replace chemical inputs by ecological processes and regulations. Cultivar mixtures are a straightforward way to increase within-crop diversity, but they have so far been poorly used by farmers and they are not encouraged by advisory services. Based on the methodology developed by Kiær et al. (2009), we achieved a meta-analysis of cultivar mixtures in wheat. Among the 120 publications dedicated to wheat, we selected 32 studies to analyze various factors that may condition the success or failure of wheat mixtures by calculating overyielding, i.e. the difference in productivity of a variety mixture compared with the weighted mean of its component varieties in pure stand. The analysis highlighted a significant global overyielding of 3.5%, which reached 6.2% in condition of high disease pressures. Overyielding was not affected by seeding density or plot size. Under high disease pressure, overyielding increased by 3.2% point per added component variety. Overyielding was respectively 5.3% and 3.3% higher for mixtures heterogeneous in disease resistance or phenology than for homogeneous ones, and did not vary when considering height. Overyielding reached its highest values in the 1980s and 1990s, which reflects the predominance of disease-focused studies during this period. Our results confirm that cultivar mixtures are a potential way to increase yield relatively to pure varieties, especially under low pesticide cropping systems. Literature suggests that mixture practice is impeded by the lack of general rules that could help to mixing varieties. To design such rules it is needed to (1) achieve new experiments manipulating the heterogeneity in variety traits, (2) determine experimentally the ecological mechanisms underlying mixture performance and (3) develop new models allowing testing and analyzing these mechanisms.

Published
2018
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13. Reduction of fungal disease spread in cultivar mixtures: Impact of canopy architecture on rain-splash dispersal and on crop microclimate

Author

Brigitte Durand, Anne-Lise Boixel, Laurent Huber, Sébastien Saint-Jean, Claude de Vallavieille-Pope, Tiphaine Vidal, Ecologie fonctionnelle et écotoxicologie des agroécosystèmes (ECOSYS), Institut National de la Recherche Agronomique (INRA)-AgroParisTech, BIOlogie et GEstion des Risques en agriculture (BIOGER), AgroParisTech-Institut National de la Recherche Agronomique (INRA), and ANR-13-AGRO-0008,WHEATAMIX,Augmenter la diversité génétique au sein des parcelles de blé pour renforcer la multifonctionnalité et la durabilité de la production dans le Bassin Parisien(2013)

Subjects
0106 biological sciences, Canopy, short susceptible cultivar was used. The resistant companion was either short (homogeneous) or tall (heterogeneous). Two proportions of resistant cultivar were tested in homogenous mixture. Mixtures were compared to pure stands of component cultivars. The level of resistance of each cultivar was assessed through disease measurements in pure stand. A diversity of canopy architecture was obtained at the flowering stage: the leaf area index ranged from 2.2 to 4.4 m2/m2 and flag leaf insertion height from 0.65 m (standard height) to 1.20 m (tall plants). Spore fluxes were measured during two rain events and microclimate variables including air temperature, could provide a strategy to enhance disease reduction in cultivar mixtures in the case of splash-dispersed diseases, Atmospheric Science, which led to a microclimate favorable to disease development. Leaf wetness duration was in fact longer in the pure stand constituted of standard height resistant plants, Microclimate, [SDV.SA.AGRO]Life Sciences [q-bio]/Agricultural sciences/Agronomy, Context (language use), whereas their architecture is rarely taken into account. However, Plant disease resistance, Biology, canopy architecture has an impact on spore dispersal and microclimate, relative humidity and leaf wetness duration were recorded from the booting stage onwards. Disease assessments were carried out weekly in mixtures and pure stands. Disease on susceptible plants was significantly lower in heterogeneous mixtures than in pure stands. In homogeneous mixtures, 01 natural sciences, disease reduction was similar. On the other hand, respectively. Our results suggest that the impact of canopy architecture on microclimate and spore dispersal can significantly contribute to the reduction of disease propagation in cultivar mixtures. We therefore suggest that taking cultivar architecture into account, caused by Zymoseptoria tritici. Each cultivar mixture was composed of a susceptible and a resistant cultivar. A single, spore dispersal and the propagation of splash-dispersed disease, Cultivar, Leaf area index, which had the densest canopy. In the two homogeneous mixtures that differed by the proportion of resistant plants, Leaf wetness, 2. Zero hunger, Global and Planetary Change, septoria tritici blotch, fungi, food and beverages, Forestry, 04 agricultural and veterinary sciences, 15. Life on land, Mixtures of cultivars with different disease resistance levels make it possible to manage plant disease in a context of fungicide reduction. The cultivars composing a mixture are often chosen for their contrasted disease resistance levels, Plant disease, [SDV.BV.PEP]Life Sciences [q-bio]/Vegetal Biology/Phytopathology and phytopharmacy, a high proportion of resistant plants was associated with high canopy density, Agronomy, heterogeneous mixtures had a lower canopy density and lower spore fluxes than homogeneous mixtures. Compared to the susceptible pure stand, 040103 agronomy & agriculture, in addition to the level of resistance to disease, 0401 agriculture, forestry, and fisheries, both of which contribute to disease development. Disease spread by rain-splash occurs over short distances and is expected to be modulated by canopy structure. Our objective was to assess the impact of wheat cultivar mixtures that differ by their canopy architecture on crop microclimate, the area under the disease progress curve of susceptible plants was reduced by 68% in the heterogeneous mixture and by 32% and 34% in the homogeneous mixtures with 75% and 25% of resistant plants, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, Agronomy and Crop Science, 010606 plant biology & botany
Abstract

International audience; Mixtures of cultivars with different disease resistance levels make it possible to manage plant disease in a context of fungicide reduction. The cultivars composing a mixture are often chosen for their contrasted disease resistance levels, whereas their architecture is rarely taken into account. However, canopy architecture has an impact on spore dispersal and microclimate, both of which contribute to disease development. Disease spread by rain-splash occurs over short distances and is expected to be modulated by canopy structure. Our objective was to assess the impact of wheat cultivar mixtures that differ by their canopy architecture on crop microclimate, spore dispersal and the propagation of splash-dispersed disease, septoria tritici blotch, caused by Zymoseptoria tritici. Each cultivar mixture was composed of a susceptible and a resistant cultivar. A single, short susceptible cultivar was used. The resistant companion was either short (homogeneous) or tall (heterogeneous). Two proportions of resistant cultivar were tested in homogenous mixture. Mixtures were compared to pure stands of component cultivars. The level of resistance of each cultivar was assessed through disease measurements in pure stand. A diversity of canopy architecture was obtained at the flowering stage: the leaf area index ranged from 2.2 to 4.4 m2/m2 and flag leaf insertion height from 0.65 m (standard height) to 1.20 m (tall plants). Spore fluxes were measured during two rain events and microclimate variables including air temperature, relative humidity and leaf wetness duration were recorded from the booting stage onwards. Disease assessments were carried out weekly in mixtures and pure stands. Disease on susceptible plants was significantly lower in heterogeneous mixtures than in pure stands. In homogeneous mixtures, a high proportion of resistant plants was associated with high canopy density, which led to a microclimate favorable to disease development. Leaf wetness duration was in fact longer in the pure stand constituted of standard height resistant plants, which had the densest canopy. In the two homogeneous mixtures that differed by the proportion of resistant plants, disease reduction was similar. On the other hand, heterogeneous mixtures had a lower canopy density and lower spore fluxes than homogeneous mixtures. Compared to the susceptible pure stand, the area under the disease progress curve of susceptible plants was reduced by 68% in the heterogeneous mixture and by 32% and 34% in the homogeneous mixtures with 75% and 25% of resistant plants, respectively. Our results suggest that the impact of canopy architecture on microclimate and spore dispersal can significantly contribute to the reduction of disease propagation in cultivar mixtures. We therefore suggest that taking cultivar architecture into account, in addition to the level of resistance to disease, could provide a strategy to enhance disease reduction in cultivar mixtures in the case of splash-dispersed diseases.

Published
2017
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14. Cultivar architecture modulates spore dispersal by rain splash: A new perspective to reduce disease progression in cultivar mixtures

Author

M. Leconte, Claude de Vallavieille-Pope, Tiphaine Vidal, Sébastien Saint-Jean, Pauline Lusley, Laurent Huber, Ecologie fonctionnelle et écotoxicologie des agroécosystèmes (ECOSYS), Institut National de la Recherche Agronomique (INRA)-AgroParisTech, BIOlogie et GEstion des Risques en agriculture (BIOGER), AgroParisTech-Institut National de la Recherche Agronomique (INRA), and Saint-Jean, Sébastien

Subjects
0106 biological sciences, 0301 basic medicine, Canopy, Leaves, Atmospheric Science, Rain, lcsh:Medicine, Plant Science, Plant Reproduction, 01 natural sciences, Septoria, Fungal Reproduction, Cultivar, lcsh:Science, Flowering Plants, Triticum, Disease Resistance, 2. Zero hunger, Multidisciplinary, biology, [SDE.IE]Environmental Sciences/Environmental Engineering, Plant Anatomy, Eukaryota, food and beverages, Plants, Spores, Fungal, Plant Physiology, Physical Sciences, Wheat, Disease Progression, Interception, Research Article, Materials by Structure, [SDE.MCG]Environmental Sciences/Global Changes, Materials Science, Mycology, Plant disease resistance, [SDU.STU.ME]Sciences of the Universe [physics]/Earth Sciences/Meteorology, 03 medical and health sciences, Plant Spores, Meteorology, Ascomycota, Disease management (agriculture), Grasses, Fungal Spores, Plant Diseases, lcsh:R, fungi, Organisms, Biology and Life Sciences, Plant Pathology, biology.organism_classification, Spore, [SDV.BV.PEP]Life Sciences [q-bio]/Vegetal Biology/Phytopathology and phytopharmacy, 030104 developmental biology, Agronomy, Mixtures, Earth Sciences, Biological dispersal, lcsh:Q, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, 010606 plant biology & botany
Abstract

International audience; Cultivar mixtures can be used to improve the sustainability of disease management within farming systems by growing cultivars that differ in their disease resistance level in the same field. The impact of canopy aerial architecture on rain-splash dispersal could amplify disease reduction within mixtures. We designed a controlled conditions experiment to study single splash-dispersal events and their consequences for disease. We quantified this impact through the spore interception capacities of the component cultivars of a mixture. Two wheat cultivars, differing in their aerial architecture (mainly leaf area density) and resistance to Septoria tritici blotch, were used to constitute pure stands and mixtures with 75% of resistant plants that accounted for 80% of the canopy leaf area. Canopies composed of 3 rows of plants were exposed to standardized spore fluxes produced by splashing calibrated rain drops on a linear source of inoculum. Disease propagation was measured through spore fluxes and several disease indicators. Leaf susceptibility was higher for upper than for lower leaves. Dense canopies intercepted more spores and mainly limited horizontal spore transfer to the first two rows. The presence of the resistant and dense cultivar made the mixed canopy denser than the susceptible pure stand. No disease symptoms were observed on susceptible plants of the second and third rows in the cultivar mixture, suggesting that the number of spores intercepted by these plants was too low to cause disease symptoms. Both lesion area and disease conditional severity were significantly reduced on susceptible plants within mixtures on the first row beside the inoc-ulum source. Those reductions on one single-splash dispersal event, should be amplified after several cycle over the full epidemic season. Control of splash-dispersed diseases within mixtures could therefore be improved by a careful choice of cultivars taking into consideration both resistance and architecture.

Published
2017
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15. Using virtual 3-D plant architecture to assess fungal pathogen splash dispersal in heterogeneous canopies: a case study with cultivar mixtures and a non-specialized disease causal agent

Author

C. Gigot, Sébastien Saint-Jean, C. de Vallavieille-Pope, Laurent Huber, Environnement et Grandes Cultures (EGC), AgroParisTech-Institut National de la Recherche Agronomique (INRA), BIOlogie et GEstion des Risques en agriculture (BIOGER), and Institut National de la Recherche Agronomique (INRA)-AgroParisTech

Subjects
Canopy, quantitative resistance, Rain, Population, Triticum aestivum, structural plant modelling, Plant Science, Plant disease resistance, Biology, Models, Biological, mechanistic modelling, 3-D plant modelling, Computer Simulation, Cultivar, fungal pathogen, education, Triticum, Disease Resistance, Plant Diseases, 2. Zero hunger, education.field_of_study, splash dispersal, Functional, Ecology, Host (biology), cultivar mixture, Fungi, food and beverages, Articles, 15. Life on land, Plant disease, Plant Leaves, Agronomy, intra-field diversity, [SDE]Environmental Sciences, Host-Pathogen Interactions, Spatial ecology, Biological dispersal, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, wheat disease
Abstract

International audience; Background and Aims Recent developments in plant disease management have led to a growing interest in alternative strategies, such as increasing host diversity and decreasing the use of pesticides. Use of cultivar mixtures is one option, allowing the spread of plant epidemics to be slowed down. As dispersal of fungal foliar pathogens over short distances by rain-splash droplets is a major contibutor to the spread of disease, this study focused on modelling the physical mechanisms involved in dispersal of a non-specialized pathogen within heterogeneous canopies of cultivar mixtures, with the aim of optimizing host diversification at the intra-field level. Methods Virtual 3-D wheat-like plants (Triticum aestivum) were used to consider interactions between plant architecture and disease progression in heterogeneous canopies. A combined mechanistic and stochastic model, taking into account splash droplet dispersal and host quantitative resistance within a 3-D heterogeneous canopy, was developed. It consists of four sub-models that describe the spatial patterns of two cultivars within a complex canopy, the pathway of rain-splash droplets within this canopy, the proportion of leaf surface area impacted by dispersal via the droplets and the progression of disease severity after each dispersal event. Key Results Different spatial organization, proportions and resistance levels of the cultivars of two-component mixtures were investigated. For the eight spatial patterns tested, the protective effect against disease was found to vary by almost 2-fold, with the greatest effect being obtained with the smallest genotype unit area, i.e. the ground area occupied by an independent unit of the host population that is genetically homogeneous. Increasing both the difference between resistance levels and the proportion of the most resistant cultivar often resulted in a greater protective effect; however, this was not observed for situations in which the most resistant of the two cultivars in the mixture had a relatively low level of resistance. Conclusions The results show agreement with previous data obtained using experimental approaches. They demonstrate that in order to maximize the potential mixture efficiency against a splash-dispersed pathogen, optimal susceptible/resistant cultivar proportions (ranging from 1/9 to 5/5) have to be established based on host resistance levels. The results also show that taking into account dispersal processes in explicit 3-D plant canopies can be a key tool for investigating disease progression in heterogeneous canopies such as cultivar mixtures.

Published
2014
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16. A White Paper on Global Wheat Health Based on Scenario Development and Analysis

Author

Serge Savary, Paul D. Esker, Pawan K. Singh, J. Kumar, Jonathan Yuen, Laetitia Willocquet, Laurence V. Madden, Vittorio Rossi, Sébastien Saint-Jean, J. M.C. Fernandes, E. M. Del Ponte, C. Pope de Vallavielle, Andrea Ficke, Pierce A. Paul, Laurent Huber, Neil McRoberts, Annika Djurle, Université de Toulouse, Swedish University of Agricultural Sciences (SLU), Norwegian Institute of Bioeconomy Research (NIBIO), Università Cattolica del Sacro Cuore, Universidad de Costa Rica (UCR), Empresa Brasileira de Pesquisa Agropecuária (Embrapa), Ministério da Agricultura, Pecuária e Abastecimento [Brasil] (MAPA), Governo do Brasil-Governo do Brasil, Universidade Federal de Vicosa (UFV), Ohio State University, Partenaires INRAE, Dept Plant Pathol, University of California [Davis] (UC Davis), University of California-University of California, International Maize and Wheat Improvement Center (CIMMYT), Consultative Group on International Agricultural Research [CGIAR], Ecologie fonctionnelle et écotoxicologie des agroécosystèmes (ECOSYS), Institut National de la Recherche Agronomique (INRA)-AgroParisTech, Université Paris Saclay (COmUE), BIOlogie et GEstion des Risques en agriculture (BIOGER), SMaCH, (RAW) Workshop, CNPq, AGroécologie, Innovations, teRritoires (AGIR), Institut National de la Recherche Agronomique (INRA)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées, Istituto di Entomologia e Patologia vegetale, Centre for Environmental Biology, Lisbon University, University of Lisbon, G.B. Pant University of Agriculture & Technology, Ohio State University [Columbus] (OSU), University of California, Université Paris-Saclay, AgroParisTech-Institut National de la Recherche Agronomique (INRA), JOSE MAURICIO CUNHA FERNANDES, CNPT., Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Universidade de Lisboa (ULISBOA), Consultative Group on International Agricultural Research [CGIAR] (CGIAR), and AgroParisTech-Université Paris-Saclay-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)

Subjects
0106 biological sciences, [SDV]Life Sciences [q-bio], Plant Science, 01 natural sciences, SMALL-GRAIN CEREALS, Theoretical, Doença de planta, Models, wheat, Plant Pathosystems, Triticum, Epidemiology, 2. Zero hunger, CLIMATE-CHANGE, FUSARIUM HEAD BLIGHT, Environmental resource management, food and beverages, MYCOSPHAERELLA-GRAMINICOLA, 04 agricultural and veterinary sciences, WINTER-WHEAT, Plant disease, Wheat, [SDE]Environmental Sciences, Settore AGR/12 - PATOLOGIA VEGETALE, Risk assessment, Crops, Agricultural, Risk, Risk analysis, Climate Change, [SDE.MCG]Environmental Sciences/Global Changes, Climate change, Crops, Trigo, Biology, Scenario development and analysis, agrosystem, Computer Simulation, Scenario analysis, Epidemiologia, Plant Diseases, YELLOW DWARF VIRUS, Agricultural, SEPTORIA-TRITICI BLOTCH, Plant disease epidemiology, business.industry, NORTH-WEST EUROPE, Simulation modeling, pathogens, Models, Theoretical, 15. Life on land, [SDV.BV.PEP]Life Sciences [q-bio]/Vegetal Biology/Phytopathology and phytopharmacy, A white paper, MAPPING POTENTIAL EPIDEMICS, 13. Climate action, PLANT-DISEASES, 040103 agronomy & agriculture, 0401 agriculture, forestry, and fisheries, fungi, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, business, Septoria like, Agronomy and Crop Science, 010606 plant biology & botany
Abstract

International audience; Scenario analysis constitutes a useful approach to synthesize knowledge and derive hypotheses in the case of complex systems that are documented with mainly qualitative or very diverse information. In this article, a framework for scenario analysis is designed and then, applied to global wheat health within a timeframe from today to 2050. Scenario analysis entails the choice of settings, the definition of scenarios of change, and the analysis of outcomes of these scenarios in the chosen settings. Three idealized agrosystems, representing a large fraction of the global diversity of wheat-based agrosystems, are considered, which represent the settings of the analysis. Several components of global changes are considered in their consequences on global wheat health: climate change and climate variability, nitrogen fertilizer use, tillage, crop rotation, pesticide use, and the deployment of host plant resistances. Each idealized agrosystem is associated with a scenario of change that considers first, a production situation and its dynamics, and second, the impacts of the evolving production situation on the evolution of crop health. Crop health is represented by six functional groups of wheat pathogens: the pathogens associated with Fusarium head blight; biotrophic fungi, Septoria-like fungi, necrotrophic fungi, soilborne pathogens, and insect-transmitted viruses. The analysis of scenario outcomes is conducted along a risk-analytical pattern, which involves risk probabilities represented by categorized probability levels of disease epidemics, and risk magnitudes represented by categorized levels of crop losses resulting from these levels of epidemics within each production situation. The results from this scenario analysis suggest an overall increase of risk probabilities and magnitudes in the three idealized agrosystems. Changes in risk probability or magnitude however vary with the agrosystem and the functional groups of pathogens. We discuss the effects of global changes on the six functional groups, in terms of their epidemiology and of the crop losses they cause. Scenario analysis enables qualitative analysis of complex systems, such as plant pathosystems that are evolving in response to global changes, including climate change and technology shifts. It also provides a useful framework for quantitative simulation modeling analysis for plant disease epidemiology.

Published
2017
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17. Les espaces périurbains : entre pollution des villes et pollution des champs aux échelles régionale et locale

Author

Sébastien Saint-Jean, Carole Bedos, Caroline Petit, Patrick Stella, Erwan Personne, Benjamin Loubet, Sophie Genermont, Sciences pour l'Action et le Développement : Activités, Produits, Territoires (SADAPT), Institut National de la Recherche Agronomique (INRA)-AgroParisTech, Ecologie fonctionnelle et écotoxicologie des agroécosystèmes (ECOSYS), and AgroParisTech-Institut National de la Recherche Agronomique (INRA)

Subjects
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, Atmospheric Science, [SDE.IE]Environmental Sciences/Environmental Engineering, atmospheric pollution, [SDE.MCG]Environmental Sciences/Global Changes, pollution atmosphérique, périubain, periurban, Atmospheric pollution, Forestry, 15. Life on land, [SDU.STU.ME]Sciences of the Universe [physics]/Earth Sciences/Meteorology, Pollution, 12. Responsible consumption, Geography, 13. Climate action, 11. Sustainability, agriculture
Abstract

International audience; Periurban areas, zone of transition between urban and rural areas, are submitted to several sources of pollution, both gaseous and particulate. These pollutions originate from local sources such as residential sector, traffic road and agricultural activities, but also from regional ones from adjacent urban and (pseudo-)natural areas. This paper presents a synthesis of the different sources affecting air quality in periurban areas. It is clear that pollutions from anthropogenic activities cannot be fully dissociated to those from (pseudo-)natural ecosystem functioning in these areas. Finally, the atmospheric pollution issues are discussed in emphasis with periurban agriculture, already present and under development in these areas due to the development of short food supply chains and local food consumptions.; Les territoires périurbains, zones de transition entre les zones urbaines et rurales, sont soumis à de nombreuses pollutions à la fois gazeuses et particulaires. Ces pollutions proviennent de sources locales comme les activités résidentielles, le trafic routier et les activités agricoles, mais également de sources régionales issues des activités urbaines et des émissions des zones (pseudo-)naturelles adjacentes. Cet article présente une synthèse des différentes sources de pollution affectant la qualité de l’air en milieu périurbain. Il est évident que les pollutions purement anthropiques ne peuvent être dissociées de celles issues du fonctionnement des écosystèmes (pseudo-)naturels dans ces espaces. Enfin, les enjeux vis-à-vis de l’agriculture périurbaine, fortement présente et en développement du fait d’une volonté de consommer des productions locales, sont discutés.

Published
2016
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18. Protective effects of a wheat cultivar mixture against splash-dispersed septoria tritici blotch epidemics

Author

C. de Vallavieille-Pope, C. Gigot, Marc Leconte, Claude Maumene, B. Kerhornou, Laurent Huber, Sébastien Saint-Jean, Environnement et Grandes Cultures (EGC), AgroParisTech-Institut National de la Recherche Agronomique (INRA), BIOlogie et GEstion des Risques en agriculture (BIOGER), ARVALIS - Institut du Végétal [Ouzouer le Marché] (ARVALIS), ARVALIS - Institut du végétal [Paris], Institut National de la Recherche Agronomique (INRA)-AgroParisTech, French Ministry of Agriculture [CTPS C-03-2010], ARVALIS - Institut du Vegetal, and French Ministry of Research and Education

Subjects
0106 biological sciences, disease resistance, INTRASPECIFIC MIXED STANDS, Plant Science, Horticulture, Plant disease resistance, 01 natural sciences, Green leaf, SPECIALIZED FUNGAL PATHOGENS, cultivar mixtures, Septoria, wheat, Genetics, Cultivar, CEREAL CULTIVARS, STRIPE RUST, 2. Zero hunger, septoria tritici blotch, MULTILINE CULTIVARS, splash dispersal, biology, PLANT-DISEASE, fungi, food and beverages, MYCOSPHAERELLA-GRAMINICOLA, 04 agricultural and veterinary sciences, WINTER-WHEAT, biology.organism_classification, Agronomy, 13. Climate action, Mycosphaerella graminicola, [SDE]Environmental Sciences, 040103 agronomy & agriculture, 0401 agriculture, forestry, and fisheries, LEAF BLOTCH, Agronomy and Crop Science, 010606 plant biology & botany
Abstract

The use of cultivar mixtures to control foliar fungal diseases is well documented for windborne diseases, but remainscontroversial for splash-dispersed diseases. To try to improve this strategy, a cultivar mixture was designed consistingof two wheat cultivars with contrasted resistance to Mycosphaerella graminicola, responsible for the rainborne diseaseseptoria tritici blotch (STB), in a 1:3 susceptible:resistant ratio rather than the 1:1 ratio commonly used in previousstudies. The impact of natural STB epidemics in this cultivar mixture was studied in field experiments over 4 years.Weekly assessments of the number of sporulating lesions, pycnidial leaf area and green leaf area were carried out onthe susceptible cultivar. In years with sufficient STB pressure, disease impacts on the susceptible cultivar in the mixturewere always significantly lower than in the pure stand (e.g. 42% reduction of pycnidial leaf area for the three upperleaves in 2008 and 41% in 2009). In years with low STB pressure (2010 and 2011), a reduction of disease impactswas also shown but was not always significant. After major rainfall events, the number of sporulating lesions observedon the susceptible cultivar after one latent period was reduced on average by 45% in the mixture compared to the purestand. All the measurements showed that a susceptible cultivar was consistently protected, at least moderately, in amixture under low to moderate STB pressure. Therefore, the results prove that the design of an efficient cultivar mix-ture can include the control of STB, among other foliar diseases.Keywords: cultivar mixtures, disease resistance, Mycosphaerella graminicola, septoria tritici blotch, splash dispersal,wheat

Published
2012
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19. Les pathogènes et les associations variétales

Author

Sébastien Saint-Jean, Ecologie fonctionnelle et écotoxicologie des agroécosystèmes (ECOSYS), and Institut National de la Recherche Agronomique (INRA)-AgroParisTech

Subjects
céréale, association variétale, [SDV]Life Sciences [q-bio], maladie des plantes, phytopathogène
Abstract

Les pathogènes et les associations variétales. Les Journées Scientifiques. Partenariat entre l'enseignement technique, l'enseignement supérieur et la recherche. Agro-écologie, de quoi parle-t'on?

Published
2016

20. Increasing within-field diversity to foster agro-ecosystem services and cope with climate change

Author

Jerome Enjalbert, Xavier Le Roux, Vincent Allard, Bruno Andrieu, Sébastien Barot, Julie Borg, Dominique Descoureaux, Claude Pope de Vallavieille, Arnaud Gauffreteau, Isabelle Goldringer, Stephane Lemarié, Sébastien Saint-Jean, Emmanuelle Porcher, Génétique Quantitative et Evolution - Le Moulon (Génétique Végétale) (GQE-Le Moulon), Centre National de la Recherche Scientifique (CNRS)-AgroParisTech-Université Paris-Sud - Paris 11 (UP11)-Institut National de la Recherche Agronomique (INRA), Laboratoire d'Ecologie Microbienne - UMR 5557 (LEM), Institut National de la Recherche Agronomique (INRA)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-VetAgro Sup - Institut national d'enseignement supérieur et de recherche en alimentation, santé animale, sciences agronomiques et de l'environnement (VAS)-Ecole Nationale Vétérinaire de Lyon (ENVL), Génétique Diversité et Ecophysiologie des Céréales (GDEC), Institut National de la Recherche Agronomique (INRA)-Université Blaise Pascal - Clermont-Ferrand 2 (UBP), Ecologie fonctionnelle et écotoxicologie des agroécosystèmes (ECOSYS), Institut National de la Recherche Agronomique (INRA)-AgroParisTech, Institut de Recherche pour le Développement (IRD [France-Ouest]), Chambre d'Agriculture du Loir et Cher (CA 41), BIOlogie et GEstion des Risques en agriculture (BIOGER), Agronomie, Laboratoire d'Economie Appliquée = Grenoble Applied Economics Laboratory (GAEL), Université Pierre Mendès France - Grenoble 2 (UPMF)-Institut National de la Recherche Agronomique (INRA), Muséum national d'Histoire naturelle (MNHN), Wheatamix Project, Génétique Quantitative et Evolution - Le Moulon (Génétique Végétale) ( GQE-Le Moulon ), Institut National de la Recherche Agronomique ( INRA ) -Université Paris-Sud - Paris 11 ( UP11 ) -AgroParisTech-Centre National de la Recherche Scientifique ( CNRS ), Ecologie microbienne ( EM ), Centre National de la Recherche Scientifique ( CNRS ) -Ecole Nationale Vétérinaire de Lyon ( ENVL ) -Université Claude Bernard Lyon 1 ( UCBL ), Université de Lyon-Université de Lyon-Institut National de la Recherche Agronomique ( INRA ) -VetAgro Sup ( VAS ), Génétique Diversité et Ecophysiologie des Céréales ( GDEC ), Institut National de la Recherche Agronomique ( INRA ) -Université Blaise Pascal - Clermont-Ferrand 2 ( UBP ), Ecologie fonctionnelle et écotoxicologie des agroécosystèmes ( ECOSYS ), Institut National de la Recherche Agronomique ( INRA ) -AgroParisTech, Institut de Recherche pour le Développement ( IRD [France-Ouest] ), Chambre d'Agriculture du Loir et Cher ( CA 41 ), BIOlogie GEstion des Risques en agriculture - Champignons Pathogènes des Plantes ( BIOGER-CPP ), Laboratoire d'Economie Appliquée de Grenoble ( GAEL ), Université Pierre Mendès France - Grenoble 2 ( UPMF ) -Institut National de la Recherche Agronomique ( INRA ), Muséum National d’Histoire Naturelle ( MNHN ), Institut National de la Recherche Agronomique (INRA)-Université Paris-Sud - Paris 11 (UP11)-AgroParisTech-Centre National de la Recherche Scientifique (CNRS), Université de Lyon-Université de Lyon-Ecole Nationale Vétérinaire de Lyon (ENVL)-VetAgro Sup - Institut national d'enseignement supérieur et de recherche en alimentation, santé animale, sciences agronomiques et de l'environnement (VAS)-Centre National de la Recherche Scientifique (CNRS), Université Pierre Mendès France - Grenoble 2 (UPMF)-Institut National de la Recherche Agronomique (INRA)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Ecole Nationale Vétérinaire de Lyon (ENVL)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de la Recherche Agronomique (INRA)-VetAgro Sup - Institut national d'enseignement supérieur et de recherche en alimentation, santé animale, sciences agronomiques et de l'environnement (VAS), AgroParisTech-Institut National de la Recherche Agronomique (INRA), Laboratoire d'Economie Appliquée de Grenoble (GAEL), and Institut National de la Recherche Agronomique (INRA)-Université Pierre Mendès France - Grenoble 2 (UPMF)

Subjects
[ SDE.MCG ] Environmental Sciences/Global Changes, Diversité génétique, [SDE.MCG]Environmental Sciences/Global Changes, Variabilité génotypique, Couvert végétal, Association culturale, Triticum
Abstract

During the 20th century, agriculture experienced major gains in productivity via homogenization and intensive use of inputs. This model is jeopardized by the awareness of rapid global change, in particular climate change, and the need for greater agricultural sustainability. Crop genetic diversity should play an essential role in this context, as it could promote various ecosystem services essential for adaptation to climate change. Increasing within field diversity through the use of cultivar mixtures is a timely option, testified by with some significant “success stories” in the past. Despite the abundant bibliography demonstrating the interest of intra-specific crop diversity, cultivar mixtures are poorly developed worldwide. In this context, the WHEATAMIX project studies the interest of mixing wheat genotypes to reinforce the sustainability and resilience of agricultural production and the provision of various ecosystem services. Based on a highly multidisciplinary approach we analyze the interactions among genotypes and with the environment, to develop new methods for breeding and/or combining wheat varieties to obtain performing blends in a global change context. Complementary experimental approaches are being deployed: i) a main diversity experiment (Eighty- eight wheat plots with 1, 2, 4 or 8 varieties, under low input) to quantify over several years the variety diversity effects on ecosystem services; ii) replicates of the same diversity experiment in 4 sites across France, to test the robustness of wheat diversity effects under a wide range of soil and climate conditions; iii) a network of 50 farms, encompassing agro-climatic variability in the Paris basin, to compare the ecological and techno-economic performance of blends with that of monocultures, using direct links with key stakeholders. The first results provide a comprehensive characterization of the multiple ecosystem services provided by genetic diversity (yield stability; regulation of foliar diseases; insect pest and weed biocontrol; maintenance of soil fertility; biodiversity conservation), and the trade-offs and synergies that exist among ecosystem services. The result also guide the selection of variety mixtures and corresponding bundles of functional traits that can deliver particular groups of services to tackle the climate change issue.

Published
2015

21. ECHAP : un projet pour identifier les possibilités de réduction de l’utilisation des fongicides en utilisant l’architecture des couverts

Author

Corinne Robert, Christian Fournier, Mariem Abichou, Bruno Andrieu, Marie-Odile Bancal, Enrique Barriuso, Carole Bedos, Pierre Benoit, Valerie Bergheaud, Marc Bidon, Bernard Bonicelli, Camille Chambon, Chapuis, R., Eric Cotteux, Da Costa, J., Brigitte Durand, Nathalie Gagnaire, Damien Gaudillat, Christophe Gigot, Guillaume Girardin, David Gouache, Josiane Jean-Jacques, Laure Mamy, Bertrand Ney, Paveley, N., Benjamin Perriot, Samuel Poidevin, Stéphanie Pointet, Valerie Pot-Genty, Christophe Pradal, Richard, C., Sébastien Saint-Jean, Jérôme Salse, Carole Sinfort, Smith, J., Ter Halle, A., Den Berg, E., Anne-Sophie Walker, Ecologie fonctionnelle et écotoxicologie des agroécosystèmes (ECOSYS), Institut National de la Recherche Agronomique (INRA)-AgroParisTech, Écophysiologie des Plantes sous Stress environnementaux (LEPSE), Institut National de la Recherche Agronomique (INRA)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro)-Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro), Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA), ARVALIS - Institut du végétal [Paris], Agricultural Development and Advisory Service, Amélioration génétique et adaptation des plantes méditerranéennes et tropicales (UMR AGAP), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Institut National de la Recherche Agronomique (INRA)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro)-Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro), Modeling plant morphogenesis at different scales, from genes to phenotype (VIRTUAL PLANTS), Inria Sophia Antipolis - Méditerranée (CRISAM), Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de la Recherche Agronomique (INRA)-Amélioration génétique et adaptation des plantes méditerranéennes et tropicales (UMR AGAP), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Institut National de la Recherche Agronomique (INRA)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro)-Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro)-Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Institut National de la Recherche Agronomique (INRA)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro)-Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro), Département Systèmes Biologiques (Cirad-BIOS), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad), Université Blaise Pascal - Clermont-Ferrand 2 (UBP), Génétique Diversité et Ecophysiologie des Céréales (GDEC), Institut National de la Recherche Agronomique (INRA)-Université Blaise Pascal - Clermont-Ferrand 2 (UBP), ALTERRA, BIOlogie et GEstion des Risques en agriculture (BIOGER), Groupe Français des Pesticides (GFP). FRA., Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro)-Institut National de la Recherche Agronomique (INRA)-Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro), Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro)-Institut National de la Recherche Agronomique (INRA)-Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro)-Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro)-Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro), Université Blaise Pascal (Clermont Ferrand 2) (UBP), Génétique Diversité et Ecophysiologie des Céréales - Clermont Auvergne (GDEC), Institut National de la Recherche Agronomique (INRA)-Université Clermont Auvergne (UCA), Alterra Green World Research (ALTERRA), AgroParisTech-Institut National de la Recherche Agronomique (INRA), Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro), Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Institut National de la Recherche Agronomique (INRA)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro)-Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro), Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro)-Institut National de la Recherche Agronomique (INRA)-Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro)-Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro)-Institut National de la Recherche Agronomique (INRA)-Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro)-Inria Sophia Antipolis - Méditerranée (CRISAM), and Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)

Subjects
architecture, ComputingMilieux_THECOMPUTINGPROFESSION, GeneralLiterature_INTRODUCTORYANDSURVEY, traitements, [SDV]Life Sciences [q-bio], septoriose, stomatognathic diseases, fongicides, architechure, InformationSystems_MODELSANDPRINCIPLES, blé, ComputingMilieux_COMPUTERSANDEDUCATION, ComputerSystemsOrganization_SPECIAL-PURPOSEANDAPPLICATION-BASEDSYSTEMS, modélisation
Abstract

ECHAP : un projet pour identifier les possibilités de réduction de l’utilisation des fongicides en utilisant l’architecture des couverts. 45e Congrès du Groupe Français des Pesticides Devenir et impact des pesticides : verrous à lever et nouveaux enjeux

Published
2015

22. Relationship between pathogen splash dispersal gradient and Weber number of impacting drops

Author

Antonino Testa, Laurent Huber, Sébastien Saint-Jean, Laurence V. Madden, Environnement et Grandes Cultures (EGC), and Institut National de la Recherche Agronomique (INRA)-Institut National Agronomique Paris-Grignon (INA P-G)

Subjects
Atmospheric Science, Global and Planetary Change, Splash, Pathogen dispersal, Ecology, Drop (liquid), Rain-splash, food and beverages, Forestry, Mechanics, Negative exponential, Power law, Wheat Rust, [SDE]Environmental Sciences, Biological dispersal, Weber number, Environmental science, Agronomy and Crop Science, Surface tension force
Abstract

International audience; We examined the potential of the dimensionless Weber number of an impacting water drop for predicting the associated gradient of pathogen dispersal. Previously shown to be related to the mechanisms of splash droplet formation, the Weber number compares the inertial forces to surface tension force of the drop. Based on new data on tomato late blight and previously published data on wheat rust diseases and on strawberry diseases, the number of spores splashed by incident drops at a given distance from the source is expressed as a negative exponential function of distance multiplied by the pathogen deposition term in the immediate vicinity of the source. Results show strong evidence that the pathogen deposition term is well described by a power law function of the Weber number.

Published
2006
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23. Using wheat cultivar mixtures as a control method against Septoria tritici blotch: Experimental and modeling approaches

Author

Gigot, C., Sébastien Saint-Jean, Huber, L., Vallavieille-Pope, C., Environnement et Grandes Cultures (EGC), Institut National de la Recherche Agronomique (INRA)-AgroParisTech, University of California [Davis] (UC Davis), University of California, Ecologie fonctionnelle et écotoxicologie des agroécosystèmes (ECOSYS), BIOlogie et GEstion des Risques en agriculture (BIOGER), and AgroParisTech-Institut National de la Recherche Agronomique (INRA)

Subjects
[SDV]Life Sciences [q-bio], food and beverages
Abstract

Poster abstract no 229-P; Septoria tritici blotch (STB), caused by Zymoseptoria tritici, is a worldwide wheat disease of concern that may lead to major yield-damaging epidemics. Because STB is rain-splash dispersed at short distances during the host growing season, cultivar mixtures are expected to provide a rather low efficiency in disease reduction. However, quantitative data are still lacking to specify what it actually is. We used both experimental and modeling approaches in order to figure out how mixing cultivars can decrease STB severity. From 2008 to 2012, field experiments were conducted on binary wheat mixtures, with a 1:3 moderately susceptible:moderately resistant ratio. The number of sporulating lesions, and the diseased and green leaf areas were assessed on a weekly basis. All the results showed consistent reductions of STB symptoms on the more susceptible cultivar (ca. 40% less diseased area over the five years), without significantly affecting the more resistant cultivar, comparatively to their respective pure stands. In parallel, a biophysical model was developed to extend our experimental findings. It relied on the combination of virtual 3D wheat-like canopies with heterogeneous host resistance levels, and mechanical description of trajectories of pathogen-bearing splash droplets. Using this modeling approach, we pointed out the necessity to consider the accurate cultivar resistance levels in order to find the optimal cultivar ratio, maximizing the mixture efficiency.

Published
2014

24. WHEATAMIX Project : Increasing within-field wheat diversity to foster ecosystem services in the Parisian basin

Author

Vincent Allard, Bruno Andrieu, Sébastien Barot, Julie Borg, Amélie Cantarel, Céline Cervek, François Coléno, Claude Pope de Vallavieille, Dominique Descoureaux, Florence Dubs, Jerome Enjalbert, Feret, M., Nathalie Galic, Arnaud Gauffreteau, Gilet, J. D., Isabelle Goldringer, Mourad Hannachi, Houivet, G., Sophie Pin, Marie-Helene Jeuffroy, Christian Kerbiriou, Pierre Labarthe, Jean Christophe Lata, Christophe Lecarpentier, Lejars, L., Lemain, B., Stephane Lemarié, Leny, F., Xavier Le Roux, Le Viol, M., Christophe Montagnier, Audrey Niboyet, Omond, B., Piaud, S., Franck Poly, Thomas Pommier, Emmanuelle Porcher, Sébastien Saint-Jean, Sandrine Salmon, Didier Tropee, Tiphaine Vidal, Génétique Diversité et Ecophysiologie des Céréales (GDEC), Institut National de la Recherche Agronomique (INRA)-Université Blaise Pascal - Clermont-Ferrand 2 (UBP), Environnement et Grandes Cultures (EGC), AgroParisTech-Institut National de la Recherche Agronomique (INRA), Institut de Recherche pour le Développement (IRD [France-Ouest]), Génétique Quantitative et Evolution - Le Moulon (Génétique Végétale) (GQE-Le Moulon), Centre National de la Recherche Scientifique (CNRS)-AgroParisTech-Université Paris-Sud - Paris 11 (UP11)-Institut National de la Recherche Agronomique (INRA), Laboratoire d'Ecologie Microbienne - UMR 5557 (LEM), Centre National de la Recherche Scientifique (CNRS)-Ecole Nationale Vétérinaire de Lyon (ENVL)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de la Recherche Agronomique (INRA)-VetAgro Sup - Institut national d'enseignement supérieur et de recherche en alimentation, santé animale, sciences agronomiques et de l'environnement (VAS), Chambre Régionale d'Agriculture du Centre, Sciences pour l'Action et le Développement : Activités, Produits, Territoires (SADAPT), Institut National de la Recherche Agronomique (INRA)-AgroParisTech, BIOlogie et GEstion des Risques en agriculture (BIOGER), CA 41, Chambre d'Agriculture du Loir et Cher, France., Chambre d'Agriculture du Loir et Cher (CA 41), Chambre d'Agriculture de l'Indre (CA 36), Agronomie, FDGEDA Cher, Centre d'Ecologie et des Sciences de la COnservation (CESCO), Muséum national d'Histoire naturelle (MNHN)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Institut d'écologie et des sciences de l'environnement de Paris (IEES), Centre National de la Recherche Scientifique (CNRS)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut National de la Recherche Agronomique (INRA), Chambre d'Agriculture du Loiret, Laboratoire d'Economie Appliquée de Grenoble (GAEL), Institut National de la Recherche Agronomique (INRA)-Université Pierre Mendès France - Grenoble 2 (UPMF), Chambre d'Agriculture de l'Eure (CA 27), Domaine expérimental de Versailles-Grignon (UEVG), Institut National de la Recherche Agronomique (INRA), Chambre d'Agriculture de la Seine et Marne, Institut National de la Recherche Agronomique (INRA)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-VetAgro Sup - Institut national d'enseignement supérieur et de recherche en alimentation, santé animale, sciences agronomiques et de l'environnement (VAS)-Ecole Nationale Vétérinaire de Lyon (ENVL), Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Muséum national d'Histoire naturelle (MNHN), Institut d'écologie et des sciences de l'environnement de Paris (iEES), Laboratoire d'Economie Appliquée = Grenoble Applied Economics Laboratory (GAEL), Université Pierre Mendès France - Grenoble 2 (UPMF)-Institut National de la Recherche Agronomique (INRA), Génétique Diversité et Ecophysiologie des Céréales ( GDEC ), Institut National de la Recherche Agronomique ( INRA ) -Université Blaise Pascal - Clermont-Ferrand 2 ( UBP ), Environnement et Grandes Cultures ( EGC ), AgroParisTech-Institut National de la Recherche Agronomique ( INRA ), Institut de Recherche pour le Développement ( IRD [France-Ouest] ), Génétique Quantitative et Evolution - Le Moulon (Génétique Végétale) ( GQE-Le Moulon ), Institut National de la Recherche Agronomique ( INRA ) -Université Paris-Sud - Paris 11 ( UP11 ) -AgroParisTech-Centre National de la Recherche Scientifique ( CNRS ), Ecologie microbienne ( EM ), Centre National de la Recherche Scientifique ( CNRS ) -Ecole Nationale Vétérinaire de Lyon ( ENVL ) -Université Claude Bernard Lyon 1 ( UCBL ), Université de Lyon-Université de Lyon-Institut National de la Recherche Agronomique ( INRA ) -VetAgro Sup ( VAS ), Sciences pour l'Action et le Développement : Activités, Produits, Territoires ( SADAPT ), Institut National de la Recherche Agronomique ( INRA ) -AgroParisTech, BIOlogie GEstion des Risques en agriculture - Champignons Pathogènes des Plantes ( BIOGER-CPP ), Chambre d'Agriculture du Loir et Cher ( CA 41 ), Chambre d'Agriculture de l'Indre ( CA 36 ), Centre d'Ecologie et des Sciences de la COnservation ( CESCO ), Centre National de la Recherche Scientifique ( CNRS ) -Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Muséum National d'Histoire Naturelle ( MNHN ), Institut d'écologie et des sciences de l'environnement de Paris ( IEES ), Institut National de la Recherche Agronomique ( INRA ) -Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Université Paris-Est Créteil Val-de-Marne - Paris 12 ( UPEC UP12 ) -Centre National de la Recherche Scientifique ( CNRS ), Laboratoire d'Economie Appliquée de Grenoble ( GAEL ), Université Pierre Mendès France - Grenoble 2 ( UPMF ) -Institut National de la Recherche Agronomique ( INRA ), Chambre d'Agriculture de l'Eure ( CA 27 ), Domaine expérimental de Versailles-Grignon ( UEVG ), Institut National de la Recherche Agronomique ( INRA ), Institut National de la Recherche Agronomique (INRA)-Université Paris-Sud - Paris 11 (UP11)-AgroParisTech-Centre National de la Recherche Scientifique (CNRS), Université de Lyon-Université de Lyon-Ecole Nationale Vétérinaire de Lyon (ENVL)-VetAgro Sup - Institut national d'enseignement supérieur et de recherche en alimentation, santé animale, sciences agronomiques et de l'environnement (VAS)-Centre National de la Recherche Scientifique (CNRS), Institut National de la Recherche Agronomique (INRA)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS), Université Pierre Mendès France - Grenoble 2 (UPMF)-Institut National de la Recherche Agronomique (INRA)-Centre National de la Recherche Scientifique (CNRS), ProdInra, Archive Ouverte, and Muséum National d'Histoire Naturelle ( MNHN ) -Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Centre National de la Recherche Scientifique ( CNRS )

Subjects
[SDE.MCG] Environmental Sciences/Global Changes, [ SDV.BV ] Life Sciences [q-bio]/Vegetal Biology, [ SDE.MCG ] Environmental Sciences/Global Changes, triticum, [SDE.MCG]Environmental Sciences/Global Changes, région parisienne, [SDV.BV]Life Sciences [q-bio]/Vegetal Biology, [SDV.BV] Life Sciences [q-bio]/Vegetal Biology, service écosystémique, winter wheat
Abstract

WHEATAMIX Project : Increasing within-field wheat diversity to foster ecosystem services in the Parisian basin. 3. International Conference on Biodiversity and the UN Millennium Development Goals,Biodiversity and Food Security – From Trade-offs to Synergies

Published
2014

25. Impacts of plant growth and architecture on pathogen processes and their consequences for epidemic behaviour

Author

Jean Baptiste Burie, Sébastien Saint-Jean, Bernard Tivoli, Ivan Sache, Agnes Calonnec, Sébastien Guyader, Michel Langlais, Unité Mixte de Recherche en Santé Végétale (INRA/ENITA) (UMR SAVE), Institut des Sciences de la Vigne et du Vin (ISVV)-École Nationale d'Ingénieurs des Travaux Agricoles - Bordeaux (ENITAB)-Institut National de la Recherche Agronomique (INRA), Institut de Mathématiques de Bordeaux (IMB), Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS), Environnement et Grandes Cultures (EGC), AgroParisTech-Institut National de la Recherche Agronomique (INRA), BIOlogie et GEstion des Risques en agriculture (BIOGER), Institut National de la Recherche Agronomique (INRA)-École Nationale d'Ingénieurs des Travaux Agricoles - Bordeaux (ENITAB)-Institut des Sciences de la Vigne et du Vin (ISVV), Unité Mixte de Recherche en Santé Végétale (INRA/ENITA) (UMRSV), Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1 (UB)-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS), Agrosystèmes tropicaux (ASTRO), Institut National de la Recherche Agronomique (INRA), Institut National de la Recherche Agronomique (INRA)-AgroParisTech, Institut de Génétique, Environnement et Protection des Plantes (IGEPP), Institut National de la Recherche Agronomique (INRA)-Université de Rennes (UR)-AGROCAMPUS OUEST, Projet financé par l'Agence Nationale de la Recherche (ANR) ARCHIDEMIO ANR-08-STRA-04, ANR-08-STRA-0004,ARCHIDEMIO,Modéliser les interactions entre développement et architecture de la plante et épidémies de maladies fongiques aériennes, pour une gestion durable des cultures.(2008), Institut National de la Recherche Agronomique (INRA)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-AGROCAMPUS OUEST, and Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)

Subjects
0106 biological sciences, Ecology (disciplines), Population, Disease transmission, Microclimate, Plant Science, Horticulture, Biology, 01 natural sciences, Crop, 03 medical and health sciences, education, Pathogen, 030304 developmental biology, agriculture, 2. Zero hunger, 0303 health sciences, education.field_of_study, Ecology, business.industry, Host (biology), fungi, food and beverages, Life Sciences, Host-pathogen models, Plant Pathology, Architectural traits, Agriculture, general, [SDE]Environmental Sciences, Biological dispersal, Canopy structure, business, Plant sciences, Agronomy and Crop Science, 010606 plant biology & botany
Abstract

International audience; As any epidemic on plants is driven by the amount of susceptible tissue, and the distance between organs, any modification in the host population, whether quantitative or qualitative, can have an impact on the epidemic dynamics. In this paper we examine using examples described in the literature, the features of the host plant and the use of crop management which are likely to decrease diseases. We list the pathogen processes that can be affected by crop growth and architecture modifications and then determine how we can highlight the principal ones. In most cases, a reduction in plant growth combined with an increase in plant or crop porosity reduces infection efficiency and spore dispersal. Experimental approaches in semi-controlled conditions, with concomitant characterisation of the host, microclimate and disease, allow a better understanding and analysis of the processes impacted. Afterwards, the models able to measure and predict the effect of plant growth and architecture on epidemic behaviour are reviewed

Published
2013
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26. Using wheat cultivar mixtures to reduce severity of septoria tritici blotch, a rain-borne disease

Author

Gigot, C., Sébastien Saint-Jean, Huber, L., Leconte, M., Maumené, C., Vallavieille-Pope, C., Environnement et Grandes Cultures (EGC), AgroParisTech-Institut National de la Recherche Agronomique (INRA), BIOlogie et GEstion des Risques en agriculture (BIOGER), Institut National de la Recherche Agronomique (INRA)-AgroParisTech, and ARVALIS - Institut du végétal [Paris]

Subjects
Septoria tritici blotch, fungi, Mycosphaerella graminicola, Modeling, food and beverages, Cultivar mixture, Splash dispersal, [SDE.ES]Environmental Sciences/Environmental and Society
Abstract

International audience; Increasing plant diversity using cultivar mixtures is a worthwhile strategy that has been shown as a way of reducing wind-borne disease severity on crops and prolonging the efficacy period of plant resistance genes. The relevancy of this cultural practice remains to be assessed in the case of rain-borne diseases, such as septoria tritici blotch. This last one, due to the pathogen fungus Mycosphaerella graminicola, is a predominant foliar disease on wheat crops, able to cause substantial yield losses (up to 40%). Field experiments were conducted on a binary wheat mixture, with a 1:3 susceptible:moderately high resistant ratio, at Grignon (Yvelines, France) every year since 2008. The results showed a consistent decrease of septoria tritici blotch severity on the more susceptible cultivar (on average, 42% less pycnidial leaf area on the three upper leaves), without significantly affecting the more resistant cultivar, comparatively to their respective pure stands. In addition, a mechanistic-stochastic model is specifically developed to describe the progression of septoria tritici blotch within a heterogeneous virtual 3D-canopy. This theoretical approach combines physics and epidemiology, firstly, to compute the raindrop interceptions with the plant organs and the trajectories of the rain-splash droplets within the canopy, and secondly, to take into account the cultivar resistance levels and the polycyclic nature of the pathogen agent. This model will be first compared with the experimental results, and then, it will be aimed to extend our findings to other cultivar mixture conditions such as cultivar proportions or cultivar spatial distributions.

Published
2012

27. Impacts of plant growth and architecture on pathogen processes and consequences for the epidemic behaviour

Author

Agnes Calonnec, Burie, J. B., Langlais, M., Sébastien Guyader, Sébastien Saint-Jean, Ivan Sache, Bernard Tivoli, Santé Végétale (SV), Institut National de la Recherche Agronomique (INRA)-École Nationale d'Ingénieurs des Travaux Agricoles - Bordeaux (ENITAB), Institut de Mathématiques de Bordeaux (IMB), Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS), Unité Mixte de Recherche en Santé Végétale (INRA/ENITA) (UMR SAVE), Institut National de la Recherche Agronomique (INRA)-École Nationale d'Ingénieurs des Travaux Agricoles - Bordeaux (ENITAB)-Institut des Sciences de la Vigne et du Vin (ISVV), Agrosystèmes tropicaux (ASTRO), Institut National de la Recherche Agronomique (INRA), Environnement et Grandes Cultures (EGC), AgroParisTech-Institut National de la Recherche Agronomique (INRA), BIOlogie et GEstion des Risques en agriculture (BIOGER), Institut de Génétique, Environnement et Protection des Plantes (IGEPP), Institut National de la Recherche Agronomique (INRA)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-AGROCAMPUS OUEST, Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1 (UB)-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS), Unité Mixte de Recherche en Santé Végétale (INRA/ENITA) (UMRSV), Institut National de la Recherche Agronomique (INRA)-AgroParisTech, Institut National de la Recherche Agronomique (INRA)-Université de Rennes (UR)-AGROCAMPUS OUEST, and Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)

Subjects
[SDV.SA]Life Sciences [q-bio]/Agricultural sciences, Canopy structure, Disease transmission, Architectural traits, Micro-climate, Host-pathogen models
Abstract

KEYNOTEKEYNOTE; Epidemics are dynamical processes with variable rates of disease progress. How much of these changes in disease rate are triggered by the host population is still a pending issue. An epidemic is driven by its effective reproduction number: the product between the proportion of susceptible tissue, the rate of disease transmission, and the duration of the infectious period. Then, any modification in the host population, either quantitative or qualitative (distribution of plants or of susceptible organs) may have an impact on the epidemic dynamics. The growth of the host population is modified by architectural features or by cultural or agronomical practices. The production of new organs continuously modifies the porosity of the plant or of the canopy and its level of susceptibility if organ susceptibility changes with age (ontogenic resistance). Indirectly, plant growth modifies the micro-climatic environment inside the canopy, generating favourable or unfavourable conditions for pathogens. The organ susceptibility, or their susceptibility period, may also be modified by cultural practices disrupting the crop-pathogen synchronisation. These variations within host populations do impact disease incidence, severity or spread. However, they have rarely been explicitly taken into account in epidemiological models. Tracking back from the global dynamics of an epidemic the pathogen processes that are impacted and ranking the host traits involved in their modifications represents a challenge. In this paper, we will 1) review evidence of epidemic variations attributed to plant growth and architecture in main pathosystems, 2) list the pathogen processes impacted, and give some clue to identify and assess them in different epidemic contexts and 3) explore models able to measure and predict the effect of plant growth and architecture on epidemics.

Published
2012

28. Effect of wheat canopy architecture and rain characteristics on on septoria splash-borne pcynidiospore

Author

Girardin, G., Gigot, C., Cédric Robert, Vallavieille-Pope, C., Suffert, F., Sébastien Saint-Jean, Environnement et Grandes Cultures (EGC), Institut National de la Recherche Agronomique (INRA)-AgroParisTech, BIOlogie et GEstion des Risques en agriculture (BIOGER), and AgroParisTech-Institut National de la Recherche Agronomique (INRA)

Subjects
fungi, Septoria tritici blotch, Mycosphaerella graminicola, food and beverages, Wheat architecture, [SDE.ES]Environmental Sciences/Environmental and Society, Splash dispersal
Abstract

International audience; Canopy architecture and distances between organs of plants susceptible to fungal airborne diseases are two factors influencing disease epidemics. It has been shown that wheat architecture can affect the progression of septoria tritici blotch (STB) within the canopy. During the epidemic stage, STB progression is mainly due to rain splash, which induces upward vertical, and lateral transport of spores. We investigated, in controlled conditions, the effects of both plant architecture and rainfall characteristics on one dispersal cycle of conidia of Mycosphaerella graminicola, which are spores coming from the asexual reproduction of the pathogen fungus responsible of STB. The experiment was performed using a simulator of artificial rainfall on wheat micro-canopies (1 m2), grown in a regulated temperature greenhouse. To avoid the influence of different varietal resistance genes on disease progression, two quasi-isogenic wheat lines of the cultivar Mercia, differing only by the RHT dwarf gene, were chosen (from the John Innes Centre). A linear inoculum source of conidia suspension (106 conidia per mL), located at the centre of the canopy was set up. Each canopy was exposed to two different rainfall events: a classical stratiform-like rain with distribution of raindrop diameters centred on 2.5 mm, and a (heavy) thunderstorm-like rain with distribution of raindrop diameters centred on 3.0 mm. Just before each rainfall event, some architecture components (internode lengths, wheat heights and leaf sizes) were assessed. During each rainfall event, splash droplets were collected at different locations within the canopy to quantify spore fluxes. Thereafter, canopies were incubated in a mist chamber for 4 days, and kept 3 weeks in a greenhouse at about 20°C during the symptomless phase (corresponding to the latency period). Disease progression resulting from rain splashes in the different leaves of the plants was precisely assessed, by measurements of diseased and non-green leaf areas. We observed a strong effect of the canopy structure on the spore dispersal. A 43% smaller (and denser) canopy had a higher level of disease severity: 10 and 7 times higher for stratiform-like and thunderstorm-like rains, respectively. The smallest canopy often concentrated disease symptom on a given foliar level and the percentages of non-green foliar areas were 2 times larger than for the other canopy. Such effects were amplified with thunderstorm-like rain. Our experiment allowed quantifying the effects of the canopy architecture and the kind of rainfall event in spores dispersal and identifying interaction between them.

Published
2012

29. The ECHAP project: Reducing fungicide use by associating optimal treatment strategies and canopies promoting disease escape

Author

Corinne Robert, Mariem Abichou, Bruno Andrieu, Marie-Odile Bancal, Enrique Barriuso, Carole Bedos, Pierre Benoit, Valerie Bergheaud, Marc Bidon, Bernard Bonicelli, Camille Chambon, Eric Cotteux, Jessica da Costa, Brigitte Durand, Christian Fournier, Nathalie Gagnaire, Damien Gaudillat, Christophe Gigot, Guillaume Girardin, David Gouache, Josiane Jean-Jacques, Laure Mamy, Bertrand Ney, Neil Paveley, Benjamin Perriot, Samuel Poidevin, Valerie Pot-Genty, Christophe Pradal, Catherine Richard, Sébastien Saint-Jean, Jerome Salse, Carole Sinfort, Smith, Julie A., Alexandra ter Halle, Erik van den Berg, Anne Sophie Walker, Agronomie, AgroParisTech-Institut National de la Recherche Agronomique (INRA), Environnement et Grandes Cultures (EGC), Écophysiologie des Plantes sous Stress environnementaux (LEPSE), Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro)-Institut National de la Recherche Agronomique (INRA)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro), Environnement Méditerranéen et Modélisation des Agro-Hydrosystèmes (EMMAH), Avignon Université (AU)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Physico-chimie et Ecotoxicologie des Sols d'agrosystèmes contaminés, Institut National de la Recherche Agronomique (INRA), Amélioration génétique et adaptation des plantes méditerranéennes et tropicales (UMR AGAP), Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro)-Institut National de la Recherche Agronomique (INRA)-Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro), Génétique Diversité et Ecophysiologie des Céréales (GDEC), Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-Institut National de la Recherche Agronomique (INRA), Information – Technologies – Analyse Environnementale – Procédés Agricoles (UMR ITAP), Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro), BIOlogie et GEstion des Risques en agriculture (BIOGER), Institut National de la Recherche Agronomique (INRA)-AgroParisTech, Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro), Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut National de la Recherche Agronomique (INRA)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Institut National de la Recherche Agronomique (INRA)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro)-Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro), Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro), Institut National de la Recherche Agronomique (INRA)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro)-Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro), Institut National de la Recherche Agronomique (INRA)-Université Blaise Pascal - Clermont-Ferrand 2 (UBP), Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA), and Physicochimie et Ecotoxicologie des SolS d'Agrosystèmes Contaminés (PESSAC)

Subjects
resistance, [SDV.SA]Life Sciences [q-bio]/Agricultural sciences, architecture, evaluation, fungicide, interception, septoria tritici
Abstract

absent

Published
2012

30. Cultivar and species mixture effect on wheat septoria tritici blotch spreading

Author

Lebon, V., Gigot, C., Leconte, M., Pelzer, E., Vallavieille-Pope, C., Sébastien Saint-Jean, Environnement et Grandes Cultures (EGC), AgroParisTech-Institut National de la Recherche Agronomique (INRA), BIOlogie et GEstion des Risques en agriculture (BIOGER), Agronomie, and Institut National de la Recherche Agronomique (INRA)-AgroParisTech

Subjects
food and beverages, Cultivar mixture, Splash dispersal, Mycosphaerella graminicola, Septoria tritici blotch, Canopy architecture, Nitrogen supply, [SDE.ES]Environmental Sciences/Environmental and Society, Cultivar mixture, Splash dispersal, Mycosphaerella graminicola, Septoria tritici blotch, Canopy architecture, Nitrogen supply
Abstract

International audience; Within the framework of pesticide reduction policy, it is necessary to find alternative practices to control wheat diseases. For air-borne diseases such as rusts and powdery mildew, cultivar and species mixtures can reduce severity by 40 to 80% compared to the mean of the pure stands. However, for rain-borne diseases such as septoria tritici blotch (STB), caused by the pathogenic fungus Mycosphaerella graminicola, severity may be reduced by only 6 to 27% (de Vallavieille-Pope, 2004). The benefits of cultivar and species mixtures (such as disease management and agronomic performance) rely on combinations of disease pressure, cultural practices (e.g. fertilization), and mixture proportions. The main factors involved in the reduction of disease severity in mixtures are the proportion of susceptible/resistant host leading to the genetic barrier effect, and the induced resistance (Finckh et al., 2000). In the case of foliar fungal disease dispersed by rain splash, a physical barrier to the transfer of splash droplets carrying the spores also contributes to the reduction of the disease severity (Saint-Jean et al., 2008). Thus, in order to control STB epidemics, it is necessary to study the fungus dispersal within mixtures. For the particular case of species mixtures such as cereals/legumes there are nitrogen exchanges between the two components, which leads us to investigate the effects of the nitrogen quantity and origin on the STB development. An experiment was set up at Grignon for several years. Different proportions of a susceptible and a resistant wheat cultivars were tested. Mixtures with the susceptible wheat cultivar and pea were also tested. Two levels of nitrogen supply were applied on each mixture. Diseased surfaces, emergence of necrotic surface, were assessed weekly. Meteorological and spore fluxes were also assessed during the epidemic seasons. Depending on the disease pressure and the direct and indirect nitrogen supply, our findings show that the emergence of leaf necrotic (diseased) surfaces can be reduced by 60% in cultivar mixtures compared to the pure stands.

Published
2012

31. Biophysical characteristics of maize pollen: Variability during emission and consequences on cross-pollination risks

Author

Sébastien Saint-Jean, Xavier Foueillassar, Benjamin Loubet, Laurent Huber, Alexis Marceau, Environnement et Grandes Cultures (EGC), Institut National de la Recherche Agronomique (INRA)-AgroParisTech, and AgroParisTech-Institut National de la Recherche Agronomique (INRA)

Subjects
0106 biological sciences, Pollination, Vapour Pressure Deficit, Stamen, Soil Science, Biology, medicine.disease_cause, Atmospheric sciences, 01 natural sciences, Zea mays, Emission, 03 medical and health sciences, Settling, Pollen, Botany, medicine, Water content, 030304 developmental biology, Settling velocity, 0303 health sciences, Dehydration, Air humidity, Pollen dispersal, Viability, [SDE]Environmental Sciences, Agronomy and Crop Science, 010606 plant biology & botany
Abstract

International audience; Modelling of cross-pollination risks using physical-based model of pollen dispersal requires estimations of pollen viability rate as well as settling velocity distribution of viable pollen grains at emission. These two biophysical characteristics are mainly determined by pollen water content. Three years of experiments were carried out to measure biophysical characteristics of pollen at different times of emission within the day. In a first part, we proposed a simple model to predict pollen water content at emission as a function of air vapour pressure deficit. We found that by setting a constant duration of pollen dehydration in the anthers the model predicts accurately pollen water content variations at emission. In a second part, we related pollen water content and settling velocity distribution of viable and non-viable pollen grains. We used with success settling velocity distribution as a proxy to estimate fraction of spheroid pollen, water content distribution of spheroid pollen and pollen viability rate. In addition, we validated with success the estimations of viability rate. In a third part, based on above models, we estimated the effects of air humidity on cross-pollination risks.

Published
2012
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32. Climate and plant pest dynamics: scales matter

Author

Michaël Chelle, Pincebourde, S., Ivan Sache, Saudreau, M., Sébastien Saint-Jean, François Bussière, Laurent Huber, Frederic Bernard, Alexandre Leca, Caillon, R., Christophe Gigot, Environnement et Grandes Cultures (EGC), AgroParisTech-Institut National de la Recherche Agronomique (INRA), Institut de recherche sur la biologie de l'insecte UMR7261 (IRBI), Université de Tours-Centre National de la Recherche Scientifique (CNRS), BIOlogie et GEstion des Risques en agriculture (BIOGER), Laboratoire de Physique et Physiologie Intégratives de l'Arbre Fruitier et Forestier (PIAF), Institut National de la Recherche Agronomique (INRA)-Université Blaise Pascal - Clermont-Ferrand 2 (UBP), Agrosystèmes tropicaux (ASTRO), Institut National de la Recherche Agronomique (INRA), ARVALIS - Institut du végétal [Paris], Institut National de la Recherche Agronomique (INRA)-AgroParisTech, and Université de Tours (UT)-Centre National de la Recherche Scientifique (CNRS)

Subjects
scale, plant pest, climat, canopy architecture, [SDV]Life Sciences [q-bio], reaction norms, climate, epidemics, phylloclimate
Abstract

SESSION 2.2: Effects of plant and canopy architecture on microclimatic variables and epidemiological processes - Keynote BSESSION 2.2: Effects of plant and canopy architecture on microclimatic variables and epidemiological processes - Keynote B; Ben Ari et al. (2011) stated that for “plague and climate, scales matter!” What about plant pest dynamics within canopies? Climate influences the micro-environment and the dispersal of plant pests within plant canopies, as determined by multiscale mass and energy fluxes. Climate influence has been studied following two approaches. First, correlative approaches, extensively used in disease forecasting, statistically link disease and climate variables, e.g. air temperature and humidity. These approaches lack robustness and sensitivity; they cannot satisfyingly explain how an epidemic actually interacts with climate within a canopy and how it would evolve with climate change. Second, mechanistic approaches study the interactions between pests and their physical environment at the individual’s scale and integrate them from organ to canopy scale. Such interactions are described by the ecological concept of reaction norms, which relates performance, plasticity, and evolution (Angilletta et al., 2003). Establishing such reaction norms requires the characterization of phylloclimate (Chelle, 2005), that is the climate actually perceived by individuals (pest, plant organ) involved in the plant-pest interactions. Phylloclimate is highly variable in time and space. This comes from the pest’s energy budget, which non-linearly depends on microclimatic variables, and from the complex transfer of mass and energy from above the canopy to pest, mediated by canopy architecture. Top-canopy microclimate depends it-self on mesoclimate (1km2) through the actions of elements such as hedges, neighboring forests, hills, lakes, roads, etc, which define the landscape architecture. In addition to its downscaling function (from mesoclimate to phylloclimate), canopy architecture is an important component of the integration of many local pest-leaf-phylloclimate relationships, like the processes of infection, latency, lesion growth, and sporulation in fungi. The non-linearity of reaction norms to phylloclimate adds, however, great complexity to this integration. Thus, we will discuss questions raised by such integration, from a spatial and temporal point of view, little being known on the role of phylloclimate on the evolution and plasticity of pests and hosts. Finally, we will list pending issues and show how multiscale interactions between climate and pests could provide innovative levers for pest management, from current climate to future one.

Published
2012

33. Strategies to mitigate particle emissions from agriculture: links between primary particles and ammonia

Author

Juliette Faburé, Rogier, Sylvestre S., Génermont, Sophie S., Cellier, Pierre P., Carole Bedos, Sébastien Saint-Jean, Fiani, E. E., Benjamin Loubet, Environnement et Grandes Cultures (EGC), Institut National de la Recherche Agronomique (INRA)-AgroParisTech, Service entreprises et écotechnologies, Agence de l'Environnement et de la Maitrise de l'Energie, Saisissez le nom du laboratoire, du service ou du département., Ville service., and AgroParisTech-Institut National de la Recherche Agronomique (INRA)

Subjects
[SDV.SA]Life Sciences [q-bio]/Agricultural sciences
Abstract

absent

Published
2011

34. Strategies to mitigate particle emissions from agriculture: links between primary particles and ammonia

Author

Faburé, J., Rogier, S., Sophie Génermont, Cellier, P., Bedos, C., Sébastien Saint-Jean, Fiani, E., Environnement et Grandes Cultures (EGC), AgroParisTech-Institut National de la Recherche Agronomique (INRA), and Institut National de la Recherche Agronomique (INRA)-AgroParisTech

Subjects
[SDE]Environmental Sciences, ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2011

35. Sharing efforts for modelling plant systems: from publications to reusable software components

Author

Christophe Pradal, Alban Verdenal, Bruno Andrieu, Kai Ma, Sébastien Saint-Jean, Corinne Robert, Frédéric Boudon, Christian Fournier, Christophe Godin, Abraham J. Escobar-Gutiérrez, Michaël Chelle, Thomas Cokelaer, Jessica Bertheloot, Didier Combes, Gaëtan Louarn, Modeling plant morphogenesis at different scales, from genes to phenotype (VIRTUAL PLANTS), Amélioration génétique et adaptation des plantes méditerranéennes et tropicales (UMR AGAP), Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro)-Institut National de la Recherche Agronomique (INRA)-Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro)-Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro)-Institut National de la Recherche Agronomique (INRA)-Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro)-Inria Sophia Antipolis - Méditerranée (CRISAM), Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria), Écophysiologie des Plantes sous Stress environnementaux (LEPSE), Institut National de la Recherche Agronomique (INRA)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro)-Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro), Développement et amélioration des plantes (UMR DAP), Centre National de la Recherche Scientifique (CNRS)-Université Montpellier 2 - Sciences et Techniques (UM2)-Institut National de la Recherche Agronomique (INRA)-Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad), Environnement et Grandes Cultures (EGC), AgroParisTech-Institut National de la Recherche Agronomique (INRA), Unité de recherche Pluridisciplinaire Prairie et Plantes Fourragères [Lusignan], Institut National de la Recherche Agronomique (INRA), Unité de recherche d'Écophysiologie des Plantes Fourragères (UEPF), Environnement Méditerranéen et Modélisation des Agro-Hydrosystèmes (EMMAH), Avignon Université (AU)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Inria Sophia Antipolis - Méditerranée (CRISAM), Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de la Recherche Agronomique (INRA)-Amélioration génétique et adaptation des plantes méditerranéennes et tropicales (UMR AGAP), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Institut National de la Recherche Agronomique (INRA)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro)-Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro)-Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Institut National de la Recherche Agronomique (INRA)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro)-Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Institut National de la Recherche Agronomique (INRA)-Université Montpellier 2 - Sciences et Techniques (UM2)-Centre National de la Recherche Scientifique (CNRS), Institut National de la Recherche Agronomique (INRA)-AgroParisTech, Unité de Recherche Pluridisciplinaire Prairies et Plantes Fourragères (P3F), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Institut National de la Recherche Agronomique (INRA)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro)-Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro), Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Institut National de la Recherche Agronomique (INRA)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro)-Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro), Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro), Institut National de la Recherche Agronomique (INRA)-Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro), Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro)-Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Institut National de la Recherche Agronomique (INRA)-Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro), and Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro)-Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)

Subjects
0106 biological sciences, Source code, Physiology, Computer science, 030310 physiology, media_common.quotation_subject, Interoperability, Reuse, 010603 evolutionary biology, 01 natural sciences, Biochemistry, Field (computer science), 03 medical and health sciences, Documentation, Molecular Biology, media_common, Structure (mathematical logic), 0303 health sciences, U10 - Informatique, mathématiques et statistiques, business.industry, Modèle de simulation, [INFO.INFO-MO]Computer Science [cs]/Modeling and Simulation, Software quality, C30 - Documentation et information, Software design pattern, Plante, Software engineering, business, Modèle mathématique
Abstract

http://www-sop.inria.fr/virtualplants/Publications/2009/FPCBLRCCBMSVEAG09/Alinea@Glasgow.pdf; International audience; Plant models become increasingly complex and their implementation often implies the use of advanced techniques in computer science. This evolution has been accompanied by the production of dedicated plant modelling tools, such as simulation platforms, that facilitate research in this field. However, much less sharing is observed for plant models themselves, that is for computer programs produced by scientists to address their specific questions. Yet, these programs could be highly valuable for other researchers, to avoid redundant development of similar code or to help non-specialists to simulate parts of a complex system. Model descriptions found in academic publications, even combined with code sources, are generally not sufficient for model reuse. Most difficulties come from the heterogeneity of language used, the structure of the programs, the download and installation procedures, the accessibility to the source code of the model, and the availability of documentation. The OpenAlea initiative (http://openalea.gforge.inria.fr) has been launched to address these problems by providing plant modellers with collaborative tools and guidelines to increase software quality, hence re-usability of their models. The Alinea pilot project further tested these concepts in a sample community of ecophysiologists and biophysicists. Based on this experience, we illustrate pros and cons of the approach and discuss future direction of progress. We foresee three steps towards a better re-usability of models: a better interoperability of existing tools and simulation platforms, the emergence of design patterns for plant modelling, and the definition of standardised data structures.

Published
2009
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36. Rain-splash pathogen dispersal: some results from leaf to regional scale

Author

Sébastien Saint-Jean, Hendawi, M., Zurfluh, O., Testud, J., Huber, L., Environnement et Grandes Cultures (EGC), AgroParisTech-Institut National de la Recherche Agronomique (INRA), and Institut National de la Recherche Agronomique (INRA)-AgroParisTech

Subjects
[SDE]Environmental Sciences, ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2008

37. A method for measuring the settling velocity distribution of large biotic particles

Author

Benjamin Loubet, Sébastien Saint-Jean, Laurent Huber, Nathalie Jarosz, Environnement et Grandes Cultures (EGC), AgroParisTech-Institut National de la Recherche Agronomique (INRA), Écologie fonctionnelle et physique de l'environnement (EPHYSE - UR1263), Institut National de la Recherche Agronomique (INRA), Institut National de la Recherche Agronomique (INRA)-AgroParisTech, and Écologie fonctionnelle et physique de l'environnement (EPHYSE)

Subjects
0106 biological sciences, Lycopodium, Gravity (chemistry), 010504 meteorology & atmospheric sciences, [SDV]Life Sciences [q-bio], Immunology, Geometry, Plant Science, 01 natural sciences, Maximum error, Standard deviation, symbols.namesake, Settling, Immunology and Allergy, 0105 earth and related environmental sciences, Mathematics, biology, PARTICLE STANDARDS, Reynolds number, biology.organism_classification, FALLING SPEED, PHYSIQUE, Classical mechanics, Distribution (mathematics), Particle diameter, symbols, MAIZE POLLEN, PARTICLE TRACKING, 010606 plant biology & botany, LYCOPODIUM SPORES
Abstract

A simple method for measuring the settling velocity (V s) distribution of pollen and spores 30–100 μm in diameter is detailed and evaluated. The method is called the ‘settling tower' and consists in taking sequential pictures of particles falling under gravity in calm air. The scene is illuminated by a cold light source, while a camera takes 15 pictures per second. Between 20,000 and 100,000 images are analysed to obtain the distribution of V s for a given set of particles. The method was validated using two standard particles with mean diameters of 68 and 108 μm, respectively, as well as Lycopodium spores, with a mean diameter of 35 μm. For each set of particles, the theoretical V s distribution was estimated from the particle diameter distribution and the volumetric mass using a non-Stokian law, as the Reynolds numbers of the particles were large. The mean V s was measured with the ‘settling tower' with less than 12% error, while the standard deviation of the V s distribution was estimated with less than 51% error. The maximum error on the mean V s was 12% for the Lycopodium spores and less than 2% for the two larger particles. The mean V s of Lycopodium spores was 4.2 cm s−1, and its standard deviation was 0.7 cm s−1. The reason for the small overestimation of V s for Lycopodium spores by the ‘settling tower' method is discussed. Preliminary measurements shows that, the ‘settling tower' could be of great practical interest for measuring the distribution of V s of maize pollen as well as other types of pollen or spores.

Published
2007
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38. Splash dispersal of Leptosphaeria maculans pycnidiospores and the spread of blackleg on oilseed rape

Author

Renaud Travadon, Sébastien Saint-Jean, H. Brun, L. Bousset, Ivan Sache, Environnement et Grandes Cultures (EGC), AgroParisTech-Institut National de la Recherche Agronomique (INRA), BIOlogie et GEstion des Risques en agriculture (BIOGER), and Institut National de la Recherche Agronomique (INRA)-AgroParisTech

Subjects
0106 biological sciences, Population, Blackleg, leptosphaeria maculans, Asexual reproduction, Plant Science, champignon phytopathogène, Horticulture, 01 natural sciences, brassica napus var oleifera, 03 medical and health sciences, dispersal gradient, Leptosphaeria maculans, Genetics, épidémiologie végétale, education, COLZA, 030304 developmental biology, rain‐splash, 0303 health sciences, education.field_of_study, biology, Brassica napus, quantitative epidemiology, biology.organism_classification, phoma lingam, Spore, maladie de la jambe noire, Agronomy, [SDE]Environmental Sciences, Phoma, Biological dispersal, Pycnidium, Agronomy and Crop Science, 010606 plant biology & botany
Abstract

International audience; The fungus Leptosphaeria maculans causes blackleg (phoma stem canker), one of the most serious diseases of oilseed rape. The role of pycnidiospores produced during asexual reproduction is poorly documented and limits the understanding of the pathogen's population dynamics. The objectives of this study were to assess rain-splash dispersal of pycnidiospores of L. maculans from phoma leaf spots, and transmission of the disease from oilseed rape stubble carrying pycnidia. The work was conducted in still air with either a drop generator or a rain simulator. The impact of simulated incident drops on phoma leaf spots resulted in the dispersal of L. maculans pycnidiospores within splash droplets. Ninety per cent of the spores were collected within 14 cm of the source and a few were regularly observed up to 40 cm. Pycnidiospores produced on oilseed rape stubble and dispersed by simulated rain infected oilseed rape trap plants in a spatial pattern that matched the spatial dispersal of the pycnidiospores. In the field, rain-splash dispersal of pycnidiospores could increase the pathogen population and may enhance sexual reproduction by facilitating the mating of initially spatially separated isolates of opposite mating type.

Published
2007
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39. Use of a green fluorescent protein marker for studying splash dispersal of sporangia of Phytophthora infestans

Author

Laurence V. Madden, Sophien Kamoun, Antonino Testa, Sébastien Saint-Jean, Environnement et Grandes Cultures (EGC), and Institut National de la Recherche Agronomique (INRA)-Institut National Agronomique Paris-Grignon (INA P-G)

Subjects
Splash, Sporangium, fungi, Plant Science, Horticulture, Biology, biology.organism_classification, Spore, Green fluorescent protein, Botany, Phytophthora infestans, [SDE]Environmental Sciences, Fluorescence microscope, Biological dispersal, Agronomy and Crop Science
Abstract

International audience; The purpose of this study was to develop a new technique to evaluate the number of spores incorporated in splash droplets by the use of an engineered fluorescent pathogen strain and image analysis hardware and software. The inoculum source consisted of a tomato leaflet infected with a Phytophthora infestans strain transformed with the gene encoding the green fluorescent protein (GFP). Splash droplets formed after impact of incident drops on sporulating lesions were collected on microscope slides located at different distances from the source. Each slide was examined using a fluorescent microscope to visualize the GFP expressing sporangia. Photographs were taken and assessed using image processing to count the sporangia incorporated in each droplet. Data analysis confirmed characteristics of splash dispersal shown using other methods. The use of fluorescent sporangia also facilitates the selective detection and counting of viable (living) sporangia, and is a tool that can be use in the study of splash dispersed diseases.

Published
2005
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40. Modelling water transfer by rain-splash in a 3D canopy using Monte Carlo integration

Author

Michaël Chelle, Laurent Huber, Sébastien Saint-Jean, Unité de recherches en bioclimatologie, Institut National de la Recherche Agronomique (INRA), Environnement et Grandes Cultures (EGC), and Institut National de la Recherche Agronomique (INRA)-Institut National Agronomique Paris-Grignon (INA P-G)

Subjects
0106 biological sciences, Canopy, Atmospheric Science, 010504 meteorology & atmospheric sciences, Terminal velocity, Meteorology, Rain-splash, Atmospheric sciences, 01 natural sciences, MODELISATION TRIDIMENSIONNELLE, [SDV.SA.SF]Life Sciences [q-bio]/Agricultural sciences/Silviculture, forestry, Dispersion (water waves), ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, Global and Planetary Change, Splash, MODELE NUMERIQUE, Forestry, 3D canopy, 15. Life on land, 13. Climate action, [SDE]Environmental Sciences, Biological dispersal, Particle, Environmental science, Monte Carlo integration, Interception, Agronomy and Crop Science, Splash dispersal, 010606 plant biology & botany
Abstract

International audience; Rain-splash is a very effective process in the short distance dispersal of biotic and abiotic particles leading to potential biological or chemical contamination within crop ecosystems. A physical approach to simulate water transfer by rain-splash in a 3D canopy structure is presented. This new approach is based on the explicit parameterisations of the mechanisms such as raindrop propagation, production and transport of splash droplets and their interception by canopy elements. The model theory and its numerical solution were based on the Monte Carlo integration technique. The calculation of droplet trajectories was validated by comparison with the previous published measured data (R2=0.99 for the terminal velocity and R2=0.93 for the distance travelled by droplets). Simulated patterns of splash dispersal through artificial canopies consisting of vertical cylinders compared well with measured patterns (R2=0.90). This new modelling approach is promising for studying particle dispersal by rain-splash in complex canopy structures.

Published
2003
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41. Etude expérimentale et numérique du mécanisme de transfert d'eau par éclaboussement de gouttes de pluie dans une structure tridimensionnelle. Application au cas d'une structure végétale en vue de l'analyse de processus de contamination à courte distance

Author

Sébastien Saint-Jean, ProdInra, Migration, Unité de recherches en bioclimatologie, Institut National de la Recherche Agronomique (INRA), and Université Paris Sud - Paris 11

Subjects
PHYSIQUE, [SDV] Life Sciences [q-bio], [SDE] Environmental Sciences, DISPERSION DE PARTICULES, MODELISATION TRIDIMENSIONNELLE, [SDV]Life Sciences [q-bio], TRANSFERT D'EAU, [SDE]Environmental Sciences, SURFACE VEGETALE, these
Abstract

* UMR INRA INAPG Environnement et Grandes Cultures de Grignon Diffusion du document : UMR INRA INAPG Environnement et Grandes Cultures de Grignon Diplôme : Dr. d'Université

Published
2003

42. The fragmentation of a line of balls by an impact

Author

E. J. Hinch, Sébastien Saint-Jean, Department of Applied Mathematics and Theoretical Physics / Centre for Mathematical Sciences (DAMTP/CMS), University of Cambridge [UK] (CAM), Environnement et Grandes Cultures (EGC), AgroParisTech-Institut National de la Recherche Agronomique (INRA), Department of Applied Mathematics and Theoretical Physics (DAMTP), and Institut National de la Recherche Agronomique (INRA)-AgroParisTech

Subjects
Physics, Impulse wave, General Mathematics, beads, [PHYS.MPHY]Physics [physics]/Mathematical Physics [math-ph], General Engineering, General Physics and Astronomy, Newton's cradle, rebound, Mechanics, 01 natural sciences, 010305 fluids & plasmas, [MATH.MATH-MP]Mathematics [math]/Mathematical Physics [math-ph], fragmentation, solitary waves, 0103 physical sciences, Ball (bearing), impact, impulse wave, 010306 general physics, Long line
Abstract

International audience; When a long line of stationary touching balls is hit on its end by another ball, the line fragments: some balls fly off at the far end, some in the middle hardly move, and the impacting ball rebounds backwards taking with it some nearby balls. Two laws for the contact force are studied, both elastic and cohesionless. First a simple law linear in the compression and then the nonlinear 3 over 2-power law of Hertz for touching spheres. For the linear force and for a line of N balls being impacted by a ball at velocity V, {1.5N1/3balls} fly off from the far end, the furthest at a velocity {1.4VN-1/6}, the others at similar but slower speeds, while the majority rebound, the impacting ball at {-0.13V} and the nth from the end at a velocity {-0.16Vn-5/6at} large n. For the nonlinear Hertz law, only two balls fly off from the far end with significant velocities, at {0.986V} and {0.149V}, the majority hardly move, and a few rebound, the impacting ball at {-0.07V} and the nth from the end at a velocity {-0.084Ve-0.55n.}

Published
1999
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43. Use of a green fluorescent protein marker for studying splash dispersal of sporangia of Phytophthora infestans.

Author

Sébastien Saint-Jean, Antonino Testa, Sophien Kamoun, and Laurence. V. Madden

Abstract

Abstract The purpose of this study was to develop a new technique to evaluate the number of spores incorporated in splash droplets by the use of an engineered fluorescent pathogen strain and image analysis hardware and software. The inoculum source consisted of a tomato leaflet infected with a Phytophthora infestans strain transformed with the gene encoding the green fluorescent protein (GFP). Splash droplets formed after impact of incident drops on sporulating lesions were collected on microscope slides located at different distances from the source. Each slide was examined using a fluorescent microscope to visualize the GFP expressing sporangia. Photographs were taken and assessed using image processing to count the sporangia incorporated in each droplet. Data analysis confirmed characteristics of splash dispersal shown using other methods. The use of fluorescent sporangia also facilitates the selective detection and counting of viable (living) sporangia, and is a tool that can be use in the study of splash dispersed diseases [ABSTRACT FROM AUTHOR]

Published
2005

44. An experimental design to test the effect of wheat variety mixtures on biodiversity and ecosystem services

Author

Florence Dubs, Le Roux, X., Vincent Allard, Andrieu, B., Barot, S., Cantarel, A., Vallavielle-Pope, C., Gauffreteau, A., Goldringer, I., Montagnier, C., Pommier, T., Porcher, E., Sébastien Saint-Jean, Borg, J., Bourdet-Massein, S., Carmignac, D., Duclouet, A., Forst, E., Galic, N., Gerard, L., Hugoni, M., Hure, A., Larue, A., J-C, Lata, Lecarpentier, C., Leconte, M., Le Saux, E., Le Viol, I., Hote, P. L., Lusley, P., Mouchet, M., Audrey Niboyet, Rémi Perronne, Pichot, E., Pin, S., Salmon, S., Tropée, D., Vergnes, A., Tiphaine Vidal, Enjalbert, J., Dubs, Florence, and Viabilité et Adaptation des Ecosystèmes Productifs, Territoires et Ressources face aux Changements Globaux - Augmenter la diversité génétique au sein des parcelles de blé pour renforcer la multifonctionnalité et la durabilité de la production dans le Bassin Parisien - - WHEATAMIX2013 - ANR-13-AGRO-0008 - AGROBIOSPHERE - VALID

Subjects
[SDE] Environmental Sciences, [SDE.BE] Environmental Sciences/Biodiversity and Ecology
Abstract

Website: https://www6.inra.fr/wheatamix The present document details how the Wheatamix consortium, inspired by ecological experiments exploring relationships between plant biodiversity and ecosystem functioning (e.g. the Jena experiment Weisser et al. 2017), selected bread wheat (Triticum aestivum L.) lines, phenotyped them across a range of functional traits and used this information to set up an experimental design able to unravel the effects of variety number and of the functional diversity and identity within variety mixtures for evaluating the impact of intraspecific crop diversity on a range of ecosystem services. Wheat line selection The Wheatamix project investigates the potential benefits of variety mixtures in the Paris basin wheat supply chain, and therefore focuses on varieties and lines adapted to the local climate. A consensus list of 57 wheat lines (Table 1) was thus settled on these grounds and to meet the expectations of agronomists, geneticists, phytopathologists and ecophysiologists of the group. This list is composed of i) 32 elite bread wheat varieties registered in the French catalogue, selected for their high yields under conventional farming, ii) 5 modern varieties bred for organic farming (OF), iii) 10 landraces resulting from farmers' mass-selection, cultivated in France in the early 1900es, and iv) 11 lines from an INRA-MAGIC multiparental and highly recombinant population (Thepot et al., 2015), adapted to Northern France. Due to the heterogeneity of information available for each variety and line, various criteria were used for this selection. The 32 elite bread wheat varieties were chosen on the basis of their wide use in the Paris Basin, and to ensure representativeness of the diversity for earliness, disease resistance or bread-making quality, using the available information in the variety

45. An integrated and modular model for simulating and evaluating how canopy architecture can help reduce fungicide applications

Author

Christian Fournier, Christophe Pradal, Mariem Abichou, Bruno Andrieu, Marie-Odile Bancal, Carole Bedos, Pierre Benoit, Camille Chambon, Romain Chapuis, Cotteux, E., Laure Mamy, Neil Paveley, Valérie Pot, Sébastien Saint-Jean, Carole Sinfort, Claire Richard, Alexandra ter Halle, Eric van den Berg, Anne Sophie Walker, Corinne Robert, Écophysiologie des Plantes sous Stress environnementaux (LEPSE), Institut National de la Recherche Agronomique (INRA)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro)-Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro), Modeling plant morphogenesis at different scales, from genes to phenotype (VIRTUAL PLANTS), Inria Sophia Antipolis - Méditerranée (CRISAM), Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de la Recherche Agronomique (INRA)-Amélioration génétique et adaptation des plantes méditerranéennes et tropicales (UMR AGAP), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Institut National de la Recherche Agronomique (INRA)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro)-Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro)-Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Institut National de la Recherche Agronomique (INRA)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro)-Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro), Amélioration génétique et adaptation des plantes méditerranéennes et tropicales (UMR AGAP), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Institut National de la Recherche Agronomique (INRA)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro)-Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro), Environnement et Grandes Cultures (EGC), Institut National de la Recherche Agronomique (INRA)-AgroParisTech, Information – Technologies – Analyse Environnementale – Procédés Agricoles (UMR ITAP), Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro), Plant Disease Management (ADAS), ADAS, Institut de Chimie de Clermont-Ferrand (ICCF), Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-SIGMA Clermont (SIGMA Clermont)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Alterra [Wageningen] (ESS-CC), Centre for Water and Climate [Wageningen], BIOlogie et GEstion des Risques en agriculture (BIOGER), Risto Sievänen and Eero Nikinmaa and Christophe Godin and Anna Lintunen and Pekka Nygren, Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro), Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut National de la Recherche Agronomique (INRA)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro), Institut National de la Recherche Agronomique (INRA)-Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro), Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro)-Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Institut National de la Recherche Agronomique (INRA)-Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro), Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro)-Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad), Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro), Institut de Chimie du CNRS (INC)-SIGMA Clermont (SIGMA Clermont)-Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-Centre National de la Recherche Scientifique (CNRS), Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro)-Institut National de la Recherche Agronomique (INRA)-Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro)-Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro)-Institut National de la Recherche Agronomique (INRA)-Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro)-Inria Sophia Antipolis - Méditerranée (CRISAM), Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria), Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro)-Institut National de la Recherche Agronomique (INRA)-Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro), AgroParisTech-Institut National de la Recherche Agronomique (INRA), Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA), and Centre National de la Recherche Scientifique (CNRS)-Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-Sigma CLERMONT (Sigma CLERMONT)

Subjects
Pesticide, architecture, Wheat, Septoria, disease escape, simulation, [INFO.INFO-MO]Computer Science [cs]/Modeling and Simulation
Abstract

[Departement_IRSTEA]Ecotechnologies [TR1_IRSTEA]INSPIREISBN 978-951-651-408-9; International audience; An integrated model coupling architectural canopy development, disease dynamics, pesticide application, pesticide decay and effect of pesticide on disease dynamics has been developed. It allows simulation of the dynamics of epidemics overall a growth season, together with the evaluation of impacts on environment, yield reduction and erosion of pesticide efficiency. This tool allows for a multi-criteria evaluation of different fungicide applications strategies and for designing new strategies that reduce pesticide applications by increasing natural resistance linked to canopy architecture.

46. Mécanismes : échanges de polluants aux interfaces sol-végétation-atmosphère et devenir dans l’atmosphère

Author

Sébastien Saint-Jean, Carole Bedos, Raluca Ciuraru, Sophie Génermont, Laurent Huber, Juliette Lathiere, Benjamin Loubet, Raia Silvia Massad, Patrick Stella, Andrée Tuzet, Eric Villenave, Ecologie fonctionnelle et écotoxicologie des agroécosystèmes (ECOSYS), Institut National de la Recherche Agronomique (INRA)-AgroParisTech, Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Sciences pour l'Action et le Développement : Activités, Produits, Territoires (SADAPT), AgroParisTech-Université Paris-Saclay-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Environnements et Paléoenvironnements OCéaniques (EPOC), Observatoire aquitain des sciences de l'univers (OASU), Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-École pratique des hautes études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Bedos, C., Génermont, S., Castell, J.F., Cellier, P., Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-École Pratique des Hautes Études (EPHE), and Durivault, Anaïs

Subjects
[SDE] Environmental Sciences, [SDE.MCG] Environmental Sciences/Global Changes, [SDE.MCG]Environmental Sciences/Global Changes, [SDE]Environmental Sciences
Abstract

International audience

47. Emission factors of particulate matter due to agricultural practices: a review

Author

Juliette Faburé, Loubet, B., Génermont, Sophie S., Carole Bedos, Sébastien Saint-Jean, Cellier, P., Environnement et Grandes Cultures (EGC), AgroParisTech-Institut National de la Recherche Agronomique (INRA), and Institut National de la Recherche Agronomique (INRA)-AgroParisTech

Subjects
[SDE]Environmental Sciences, ComputingMilieux_MISCELLANEOUS
Abstract

International audience

48. Modélisation des échanges : de l’échelle des processus aux échelles régionales

Author

Raia Silvia Massad, Andree Tuzet, Erwan Personne, Carole Bedos, Matthias Beekmann, Isabelle Coll, Jean-Louis Drouet, Audrey Fortems-Cheiney, Sophie Genermont, Benjamin Loubet, Sébastien Saint-Jean, Durivault, Anaïs, Bedos, C., Génermont, S., Castell, J.F., Cellier, P., Ecologie fonctionnelle et écotoxicologie des agroécosystèmes (ECOSYS), Institut National de la Recherche Agronomique (INRA)-AgroParisTech, Laboratoire Interuniversitaire des Systèmes Atmosphériques (LISA (UMR_7583)), and Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS)

Subjects
[SDE] Environmental Sciences, [SDV] Life Sciences [q-bio], [SDE.MCG] Environmental Sciences/Global Changes, [SDE.MCG]Environmental Sciences/Global Changes, [SDV]Life Sciences [q-bio], [SDE]Environmental Sciences, ComputingMilieux_MISCELLANEOUS
Abstract

International audience

49. Reduction of Septoria leaf blotch propagation in cultivar mixtures: exploring mechanisms through controlled conditions experimentation and modelling

Author

Tiphaine Vidal, Pauline Lusley, Marc Leconte, Claude Pope de Vallavieille, Laurent Huber, Sébastien Saint-Jean, Ecologie fonctionnelle et écotoxicologie des agroécosystèmes (ECOSYS), Institut National de la Recherche Agronomique (INRA)-AgroParisTech, BIOlogie et GEstion des Risques en agriculture (BIOGER), and AgroParisTech-Institut National de la Recherche Agronomique (INRA)

Subjects
modelling, variété en mélange, Septoria leaf blotch, wheat, [SDV]Life Sciences [q-bio], fungi, cultivar mixture, food and beverages, septoriose, modélisation
Abstract

Cultivar mixtures can contribute to a sustainable management of foliar diseases such as septoria leaf blotch. Mixing cultivars differing by their resistance genes makes it possible to partially protect a susceptible cultivar by a resistant cultivar. Architectural properties of the mixture cultivar components can have an impact on their capacity to intercept spores and therefore on disease reduction mechanisms within mixture such as reduction of susceptible host density and barrier of resistant cultivar on spore dispersion. Efficient mixture design is often difficult, given the high number of possible combinations and the complexity of mechanisms involved. Modelling can therefore be a powerful tool to better understand disease reduction mechanisms and identify characteristics of mixtures of interest. However, few models take into account both architecture and resistance heterogeneity of canopies. A modelling approach based on experimental data was used to investigate dispersal mechanisms in mixed canopies with components differing by both their varietal resistance and architecture. A controlled experiment was performed with three types of canopies of 1m2: a mixture of two cultivars and pure stands of these cultivars. A linear inoculum source consisting of an aqueous suspension of spores was disposed in the middle of each canopy and then placed under a rain simulator generator to generate reproducible spore flux. Horizontal and vertical spore fluxes were measured at different points in the canopy using traps composed of microscope slides. Varietal resistance was assessed in parallel. After incubation, disease severity was measured at leaf level on plants sampled from each canopy. Architecture characterization allowed reconstruction of realistic 3D mockups of experimental canopies. A bio-physical model was used to compute splash droplets interception by leaves in 3D canopies. For each leaf of the virtual canopy, lesion area was deduced from the amount of intercepted inoculum and from individual leaf resistance level. Simulated spore fluxes and disease gradients were consistent with experimental measurements. In particular, high leaf area density resulted in higher spore interception by the canopy and higher disease severity. In mixed canopies, resistant plants had higher densities and therefore provided an efficient barrier effect. This modelling approach, now validated on detailed experimental data, can be used to reconstruct dispersal events observed in the field and understand dispersal mechanisms involved in complex canopies such as cultivar mixtures.

50. ADEL-Wheat: a 3D Architectural Model of wheat development

Author

Fournier, C., Andrieu, B., Ljutovac, S., Sébastien Saint-Jean, Environnement et Grandes Cultures (EGC), Institut National de la Recherche Agronomique (INRA)-Institut National Agronomique Paris-Grignon (INA P-G), Hu, B.-G. and Jaeger, M., Unité de recherches en bioclimatologie, Institut National de la Recherche Agronomique (INRA), ProdInra, Migration, Saint-Jean, Sébastien, and Hu, B.-G. and Jaeger, M.

Subjects
[SDE] Environmental Sciences, Virtual Plant, Tiller, [SDV]Life Sciences [q-bio], Emergence, Development, [SDV] Life Sciences [q-bio], SYSTEME DE LINDENMAYER, MODELISATION TRIDIMENSIONNELLE, Coordination, Wheat, Architecture, [SDE]Environmental Sciences, Elongation Kinetic, L-System, ComputingMilieux_MISCELLANEOUS
Abstract

A 3D architectural model of winter wheat development is presented. The model simulates the kinetics of elongation of individual organs, together with their geometric shape. With the inclusion of two additional parameters, it was possible to model the development of tillers using the same parameter values as for the main stem. The duration of organ extension was found to be the same amongst phytomers, and the kinetics of extension of any organ could be simulated from its final length and two parameters. Finally, lengths of mature organs were found to follow simple functions of phytomer position. The resulting model simulates development of the whole plant with a small number of parameters, characterising the size and geometry of mature organs and the timing of collar appearance.

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