Host Plant Resistance to Pests and Pathogens, the Genetic Leverage in Integrated Pest and Disease Management

The development of genetic resistance is a kingpin of Integrated Pest and Disease Management, by allowing plant resistance to a large range of pests and pathogens. Genetic resistance has mainly been reported in Crop Wild Relatives and selected during plant domestication and subsequent plant breeding. In this chapter, we describe how genetic resistance can be evaluated and genetically characterized. The main molecular mechanisms underlying host plant resistance are described, namely the dominant resistance mediated by R genes, and the recessive resistance based on loss-of-susceptibility, targeting S genes. Finally, we address a major issue of developing genetic resistance in crops, i.e., the durability of resistance, and how the resistance gene repertoire must be preserved to insure its sustainability in plant breeding. A framework showing how genetic resistance fits into the Integrated Pest Management is presented.