New yellow rust strain leaves half of UK wheat crop exposed
More than half of the UK’s wheat crop has been left exposed after a new strain of yellow rust overcame a key resistance gene in major commercial varieties.
The breakdown of the Yr15 resistance gene, identified in 2025, affects over 50% of national wheat acreage — including the top three selling varieties, which together account for around a third of the UK market.
Scientists warn that without swift intervention, growers could face heavier reliance on fungicide programmes to protect yields, increasing input costs and long-term resistance risks.
Yellow rust, a fungal disease that reduces green leaf area and limits photosynthesis, can cause significant yield losses in susceptible crops if not effectively controlled.
In response, UK Research and Innovation and Defra have awarded a Rapid Response grant to a research collaboration led by the John Innes Centre, aimed at identifying new sources of genetic resistance.
The project will draw on the historic Watkins collection of wheat landraces — a diverse archive of heritage varieties — to uncover resistance genes that can be bred into modern wheat.
Researchers have already shown that the collection contains genetic traits capable of conferring resistance to the new strain.
Professor Diane Saunders, group leader at the John Innes Centre and lead of the project, described the scale of the resistance failure as unprecedented.
“Witnessing such a large-scale breakdown in yellow rust resistance in 2025 was unprecedented,” she said.
However, she said ancient landraces offer “a fantastic resource of unutilised genetic disease resistance” that can be rapidly deployed to protect harvests.
The initiative brings together rust pathology and wheat genomics expertise at the John Innes Centre, disease monitoring from Niab, and industry engagement through the Defra Wheat Genetic Improvement Network led by Rothamsted Research.
Professor Cristóbal Uauy, director of the John Innes Centre, said the speed of the response was critical.
“Responding to this emerging threat demands that we work collaboratively, and with agility,” he said, adding that the project demonstrates how scientists and breeders can “mobilize, collaborate and react rapidly” to protect crops.
Once new resistance genes are identified, breeders will work to integrate them into commercial varieties grown by UK farmers.
Dr Kostya Kanyuka, head of pathology at Niab, said the organisation would focus both on identifying additional resistance sources in wild wheat relatives and monitoring rust populations for early signs of fungicide resistance.
“This collaboration will help us respond more quickly to new rust races and support the long-term resilience of UK wheat,” he said.
Growers are being urged to monitor crops closely this season and review varietal resistance ratings as the new strain establishes.
While breeding solutions are underway, experts caution that fungicides remain a vital tool — but warn that overreliance could accelerate resistance development in the pathogen.
The project also links with the International Maize and Wheat Improvement Center (CIMMYT), ensuring new resistance genes can be incorporated into global breeding programmes as the strain spreads beyond the UK.
Professor Saunders said the international partnership will help ensure the benefits extend worldwide.
“By teaming up with international breeding programmes through our strategic partnership with CIMMYT, we can ensure these UK innovations not only help better protect future UK harvests but also help protect farmers globally,” she said.
For now, the emergence of the new rust race serves as a stark reminder of how quickly disease pressure can shift — and how dependent modern wheat production remains on robust genetic resistance.
