Yellow rust poses a serious threat to wheat production, but researchers at the University of Zurich have discovered traditional Asian wheat varieties with multiple resistance genes. These could offer long-term protection for commercial wheat, underscoring the value of genetic diversity in ensuring global food security.
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Wheat production is threatened by a major fungal disease: yellow rust. Researchers at the University of Zurich have found traditional wheat varieties from Asia that harbor several resistance-conferring genes. They may serve as a durable source of yellow rust resistance in commercial varieties in the future, highlighting the importance of genetic diversity for food security.
Yellow rust, also known as stripe rust, is caused by a fungal pathogen named Puccinia striiformis f. sp. tritici. The plant disease affects around 88% of global bread wheat production and is one of the most devastating threats to wheat yields. New strategies against the fungus are therefore urgently needed. An international team headed by researchers at the University of Zurich (UZH) has now discovered two genomic regions in traditional wheat varieties from Asia which confer resistance to the disease, according to a press release.
“If such genes can be transferred to commercial wheat varieties, they could be important in combating yellow rust,” says Kentaro Shimizu, professor at the UZH Department of Evolutionary Biology and Environmental Studies, who is responsible for a new study on the subject.
Genetic Diversity of Wheat Local Varieties
For decades, wheat breeding has prioritized high-yielding varieties to meet global food demands. While this focus has boosted production, it has also narrowed the crop’s genetic base, leaving modern varieties more vulnerable to pests, diseases, and climate extremes. In contrast, traditional wheat varieties — cultivated and preserved by farmers across diverse regions — retain broader genetic diversity. These underutilized varieties, particularly those from Asia, hold untapped potential for improving disease resistance in modern wheat.
During her PhD in Enrico Shimizu’s research group, Katharina Jung investigated resistance to yellow rust in wheat, collaborating with the International Maize and Wheat Improvement Center (CIMMYT) in Mexico and Kyoto University in Japan. She screened both traditional and modern wheat varieties from Japan, China, Nepal, and Pakistan. Field trials were conducted at Reckenholz in Switzerland and at CIMMYT in Mexico to identify plants showing resistance to yellow rust.
Through this work, Jung pinpointed two previously uncharacterized genomic regions—known as quantitative trait loci (QTLs)—that contribute to yellow rust resistance. One region was found in a traditional variety from Nepal, while the other appeared more widely across traditional lines from Nepal, Pakistan, and China in the southern Himalayan region.
These discoveries underscore the value of traditional wheat varieties as reservoirs of genetic traits that can strengthen global wheat production against emerging threats.
“Interestingly, the southern Himalayan area is believed to be the origin of the yellow rust pathogen itself. Taken together with our findings, we hypothesize that traditional varieties from this area might harbor unique and stable resistances to yellow rust,” says Jung. A more targeted search for novel yellow rust resistances from this area could potentially provide long-lasting protection against a wide range of pathogen strains.
Safeguarding Local Varieties and Farming Practices
The new results underscore the importance of conserving genetic diversity and traditional varieties in wheat to combat diseases and other threats. Farmers have cultivated and maintained these traditional varieties in different parts of the world for generations, which is of great value for future food security.
“Traditional varieties must be preserved both in gene banks and in farmers’ fields before they are lost forever. Their use and benefit-sharing should be done in close collaboration with local communities, as their knowledge and practice have paved the way to the genetic diversity we observe today,” says Jung.
Kyoto University: Important UZH Collaboration Partner in Asia
The wheat varieties provided by Kyoto University were essential for this project.
“I cannot emphasize enough how valuable such a collaboration is in making scientific progress,” says Kentaro Shimizu. The UZH Global Funding Scheme, managed by the Global Affairs office, supported this project. Collaborations between UZH and Kyoto University have existed for many years. In 2020, the alliance between two institutions was converted into a Strategic Partnership.
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