Making the Most of Disease Resistance
Researchers find in a collection of cultivated and wild potato many genetic sources of disease resistance to meet future needs.
Traditional diseases mutate, and new threats to the major food crops of the world continually emerge. Climate change will only make these problems worse. At the International Potato Center (CIP) in Lima, Peru, breeders are preparing for coming battles by working t o maintain a continuous flow of genetic diversity to use in breeding work. A team of CIP scientists is systematically looking for new and varied sources of robust resistance to disease in the collection of wild and cultivated germplasm conserved and held in trust by this agricultural research Center supported by the CGIAR.
Late blight is one of the worst diseases affecting potato. Breeding for resistance to late blight started in the 1920s, but the fungus-like organism that is responsible for the disease, Phytophthora infestans, mutates continuously, so that varietal resistance is rapidly overcome if it has a narrow genetic basis. |
Photo: Paul Stapleton
Wild species of Andean potato are proving to be a valuable source of
extreme disease resistance.
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The strategic use of genetic resources, including wild relatives native to regions with year-round pressure from Phytophthora infestans, is a key to improving potato’s resistance to late blight. A broad genetic base of resistance is expected to be more lasting, as it should delay the pathogen’s ability to overcome the genes and mechanisms responsible.
“We want to make wild species’ resistance more amenable for use in breeding populations,” says Dr. Meredith Bonierbale of CIP, who runs the project.
Four species have been found that are strongly resistant to late blight, and work progresses to develop hybrids as upgraded sources of traits for further breeding. “ Our interdisciplinary approach to the screening and characterization of late blight resistance in these groups represents the essential first step towards the efficient transfer of late blight resistance from underutilized wild species to the cultivated potato,” says Bonierbale.
New sources of resistance to the economically important potato leaf roll virus (PLRV) have also been identified among CIP genebank accessions, confirming again the valuable potential that can exist in a comprehensive collection of genetic resources.
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