Characterization of wheat pathosystems, in particular the helminthosporium blights caused by Pyrenophora tritici-repentis or Cochliobolus sativus in warm areas. Effect of the crop rotation, fertilisation, water or high temperature stress on their evolution. Cultivar resistance and factors affecting this resistance. Link between resistance to abiotic and biotic stresses. Indicators of stress resilience. Interest of fungal toxins for resistance selection.