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One of the main alternative to current field crop protection strategies against cryptogamic diseases (use of fungicides; introduction of major resistance genes with high risk of breakdown) is a better use of varietal resistance. The socio-political choice to move towards agricultural systems that are less dependent on pesticides, combined with the loss of efficacy of some fungicides (widespread resistance), confirms the importance of breeding solutions. Biocontrol methods, currently not operational in field crop systems, alone will not be able to keep the impact of diseases below thresholds acceptable to producers and consumers.

The research project of our team is based on the application of scientific ecological concepts to the sustainable management of agrosystems (agro-ecology). It focuses on a central, unifying issue: characterizing the interactions between pathogen populations, host populations and environmental conditions, to improve the effectiveness and the sustainability of wheat resistance to fungal wheat disease (mainly Septoria tritici blotch and, more recently, stem rust) at different spatial scales (gene, plant, field, landscape) and temporal scales (intra- and interepidemic periods).

We postulate that the most effective and sustainable strategies of varietal resistance deployment are based on a multi-scale heterogeneity of host populations: plant (pyramiding of resistance sources within plant), field (varietal mixtures, landraces), and landscape scales (spatio-temporal alternation). We seek to verify the validity of this postulate under different conditions, in collaboration with academic and professional partners, by analyzing how different types of heterogeneity slow down the evolution of pathogen populations. The need to consider several dynamic processes occurring ate different spatio-temporal scales (e.g. dispersal, survival, selection) legitimized the combination of experimental and modelling approaches.

Topic 1 - Multi-scale host-pathogen adaptation: host specialization and response to qualitative and quantitative resistances

Topic 2 - Adaptive responses of plant pathogens to their abiotic environment: from individual to population scale

Topic 3 - Epidemic processes focused on the inoculum: impact of interepidemic period on adaptive dynamics of pathogen populations

Topic 4 - Sustainable management of varietal resistances: from the identification of agroecological solutions to the assessment of multi-scale deployment strategies