Inra, UR407 pathologie végétale, Domaine Saint-Maurice, 84140 Montfavet, France, Inra, UR1052 génétique et amélioration des fruits et légumes, Domaine Saint-Maurice, 84140 Montfavet, France
Genetic resistances have allowed a large reduction of the impact of viral diseases in cultivated plants. Their introduction into breeding programs was facilitated by the simple genetic control of many of them. However, as for any host-parasite couple, the targeted viruses can adapt rapidly to resistances even though the durability of resistances, i.e. the amount of time during which they remain efficient in crops, is highly variable. During these last two decades, the use of genetic analysis methods in plant viruses revealed the molecular mechanisms responsible for these adaptations and, hopefully, will allow a more precise prediction of the potential durability of resistances. If the mechanisms involved in virus adaptation at the plant scale have been unravelled, those responsible for the emergence of adapted viral populations at the agroecosystem scale are largely unknown. A better knowledge of the fitness of viral genotypes, adapted or not to the resistance, to infect their different host plants and to spread in the agro-ecosystem is needed. The difficulties linked to their experimental analysis require the development of mathematical modelling approaches of these phenomena, notably to define optimal spatiotemporal strategies of cultivar deployment.