Peach breeding for multiple resistances to pests and diseases contributes to integrated fruit production
Résumé
In spite of the worldwide decline in peach production, a constant stream of new varieties are being provide to fruit growers. For the greater part most of these new varieties being produced by private peach breeders, and as a consequence very few are selected on the basis of their resistance to pests or diseases, while the demand of consumers continues to be directed towards a quality fruit product which is free of pesticide residues. Within the framework of one INRA multidisciplinary group (Avignon-Bordeaux), we have developed for several years a wide applied breeding program aiming at improving the resistance of the peach tree to three of its main enemies: the green peach aphid (Myzus persicae), peach powdery mildew (Sphaerotheca pannosa var. persicae) and sharka disease (Plum Pox Virus). This work is globally conducted in a research context oriented towards varietal innovation including fruit quality and durable resistances building. In this way, two complementary approaches have been preferentially held for respectively improving the genetic gain by time unit and a better understanding of peach-enemies relationships. First, a genetic approach integrating the quantitative trait loci or major genes mapping for the development of molecular assisted selection. Second, a functional approach (i) leaning on the study of the insect behaviour and the plant metabolites involved in the resistance to M. persicae (ii) coupled to a candidate-genes research mainly developped for PPV resistance. Whole of first results and perspectives are discussed.