Durable resistance to early blight disease in potato

Early blight caused by Alternaria solani is an important disease of potato and on the rise. In contrast to other important potato diseases no true resistance is available to early blight in the current potato cultivars grown all over the world.

So far, the only way to control the disease is to frequently apply fungicides, which is obviously not sustainable, especially since fungicide-resistant strains are emerging. Fortunately, in a recent small-scale screen, we identified genetic resistance to Alternaria in the collection of wild Solanum species at Plant Breeding (WUR). Here, we propose to jump start the development of a potato cultivar with a natural genetic resistance to early blight. We will screen the entire wild Solanum collection with our reliable disease assay to identify promising sources of resistance and subject them to cross-breeding. By focusing on species that are sexually compatible with cultivated potato, this project will yield pre-breeding material that can be used to breed early blight-resistant potato cultivars.

In addition, cross-breeding with susceptible wild Solanum genotypes will allow detailed study of the genetic basis of early blight resistance. We will use innovative technologies to sequence the genomes of the most promising wild Solanum species and to develop molecular markers linked to resistance. The available sequence information will also enable to fine-tune the action of the responsible resistance genes by using gene editing technologies, should they become available. The results from this project will enable the partners (some of whom who are not a member of HIP) to develop potato cultivars that are truly resistant to early blight.