title: Influence of cultivated landscape composition on variety resistance: an assessment based on wheat leaf rust epidemics.
abstract: In plant pathology, the idea of designing variety management strategies at the scale of cultivated landscapes is gaining more and more attention. This requires the identification of effects that take place at large scales on host and pathogen populations. Here, we show how the landscape varietal composition influences the resistance level (as measured in the field) of the most grown wheat varieties by altering the structure of the pathogen populations. For this purpose, we jointly analysed three large datasets describing the wheat leaf rust pathosystem (Puccinia triticina/Triticum aestivum) at the country scale of France with a Bayesian hierarchical model. We showed that among all compatible pathotypes, some were preferentially associated with a variety, that the pathotype frequencies on a variety were affected by the landscape varietal composition, and that the observed resistance level of a variety was linked to the frequency of the most aggressive pathotypes among all compatible pathotypes. This data exploration establishes a link between the observed resistance level of a variety and landscape composition at the national scale. It illustrates that the quantitative aspects of the host-pathogen relationship have to be considered in addition to the major resistance/virulence factors in landscape epidemiology approaches.
authors.affiliation: INRA, UMR 1290 BIOGER, F-78850 Thiverval Grignon, France.|INRA, UR 341 Mathématiques et Informatique Appliquées, F-78350 Jouy-en-Josas, France.
authors.forename: Julien
authors.initials: J
authors.lastname: Papaïx
authors.affiliation: INRA, UMR 1290 BIOGER, F-78850 Thiverval Grignon, France.
authors.forename: Henriette
authors.initials: H
authors.lastname: Goyeau
authors.affiliation: ARVALIS - Institut du végétal, F-78280 Guyancourt, France.
authors.forename: Philippe
authors.initials: P
authors.lastname: Du Cheyron
authors.affiliation: INRA, UR 341 Mathématiques et Informatique Appliquées, F-78350 Jouy-en-Josas, France.
authors.forename: Hervé
authors.initials: H
authors.lastname: Monod
authors.affiliation: INRA, UMR 1290 BIOGER, F-78850 Thiverval Grignon, France.
authors.forename: Christian
authors.initials: C
authors.lastname: Lannou
mesh_terms: D000383:Agriculture / Q000379:methods*; D001487:Basidiomycota / Q000302:isolation & purification / Q000472:pathogenicity; D001499:Bayes Theorem; D018556:Crops, Agricultural / Q000235:genetics / Q000276:immunology / Q000382:microbiology; D060467:Disease Resistance; D005602:France; D017343:Genes, Plant; D054884:Host-Pathogen Interactions; D015233:Models, Statistical; D010935:Plant Diseases / Q000276:immunology / Q000382:microbiology; D018515:Plant Leaves / Q000382:microbiology*; D014908:Triticum / Q000235:genetics / Q000276:immunology / Q000382:microbiology*; D014774:Virulence