The adoption of new crop varieties by local farmers has been a key technological innovation for improving productivity and profitability. Plant breeding, carried out either by farmers or professional breeders, has been the main tool for the development and dissemination of these new varieties. Its role will continue to increase in importance over the coming decades in a time of major challenges for sustainable plant production due to factors such as global climate change, food insecurity and the degradation of natural resources. A successful example of an Agricultural Knowledge System (AKS) is participatory plant breeding which combines the local knowledge of traditional farmers and the scientific knowledge of modern scientists applied at a global level, thus allowing for efficient local innovation in the context of global challenges. The lessons learned and the future prospects of this participatory approach are analysed.