Scientists identify genes for slug-resistant wheat
Scientists have identified three genetic regions in wheat that could help breeders develop varieties naturally resistant to grey field slugs, one of arable farming’s most costly pests.
The discovery, made by researchers at the John Innes Centre through the Defra-funded SLIMERS project, could give plant breeders new tools to reduce crop losses, input costs and environmental impact.
Slug damage is estimated to cost UK farming £43.5m a year, making the findings a potentially important step in future crop protection.
SLIMERS is a three-year project bringing together scientists, farmers and industry partners to develop more sustainable approaches to slug control.
The findings build on research that began in 2015, when John Innes Centre scientists screened wheat varieties from the historic Watkins Collection for natural slug resistance.
That work identified four promising accessions, with Watkins 788 standing out. The landrace was originally collected in Turkestan, part of modern-day Kazakhstan.
BOFIN later worked with the John Innes Centre to launch the Slug Resistant Wheat project, with farmers testing wheat varieties under real farm conditions.
That work confirmed Watkins 788 as potentially slug resistant and helped lead into the wider SLIMERS programme.
As part of the project, BOFIN’s “Slug Sleuth” farmers trialled breeding lines developed from a cross between Watkins 788 and the commercial wheat variety Paragon.
The trials allowed researchers to assess how the lines performed under different soil types, weather conditions and levels of slug pressure.
Alongside the field work, laboratory and insectary trials at the John Innes Centre gave scientists controlled conditions to test slug feeding behaviour.
Dr Victor Soria-Carrasco and his team used grey field slugs supplied by farmers and citizen scientists known as “Slug Scouts”, who collected specimens from farms and gardens across the UK. Some of the slugs were also retained to establish breeding colonies for further research.
Dr Soria-Carrasco said using slugs from different parts of the country was important.
He said: “Having slugs from different parts of the country was important.
“We know slug populations can vary, so using a wide range of grey field slugs helped us ensure the results represented real-world conditions.”
Researchers tested 77 breeding lines alongside their parent lines, all of which had already been genetically sequenced.
This allowed scientists to identify the genomic regions linked to slug resistance more quickly than would previously have been possible.
The strong laboratory results encouraged project partners to move into on-farm trials in autumn 2025.
However, researchers said further field trials are needed, after low slug numbers meant the on-farm results could not provide firm conclusions.
Professor Keith Walters, of Harper Adams University, who analysed the trial results, said the laboratory work still showed clear potential.
He said: “Overall, however, the laboratory work demonstrates obvious potential which makes field trials under conditions with greater slug pressure an urgent requirement.”
The discovery of genomic regions linked to slug resistance could give plant breeders a practical route to developing commercial wheat varieties with natural resistance.
Dr Simon Griffiths, of the John Innes Centre, said the feeding trials had generated thousands of data points.
He said: “The thousands of data points collected in the feeding trials helped us identify the specific molecular markers or parts of the chromosome, linked to slug resistance.
“With that understanding, and the screening protocol we have developed, plant breeders can now select for those markers to produce a slug resistant variety.”
Tom Allen-Stevens, founder of BOFIN and SLIMERS project lead, said the potential for arable farmers was significant.
He said: “Slugs are one of the biggest challenges for arable farmers so developing wheat varieties with natural resistance would help reduce crop losses and input costs, lower environmental impact and increase resilience.
“What’s particularly encouraging is that not only have these results been proven in the lab, but there were many enthusiastic farmer volunteers wanting to test them on commercial farms, demonstrating the confidence of industry players in the amazing advances we can make when farmers and scientists work together.”
The SLIMERS project, which stands for Strategies Leading to Improved Management and Enhanced Resilience Against Slugs, is a £2.6m research programme involving more than 100 UK farms and seven partners.
It is working on new approaches to slug control, including patch prediction, precision mapping and autonomous slug treatment using nematodes.
BOFIN leads the consortium alongside technical lead the UK Agri-Tech Centre, with Harper Adams University, the John Innes Centre, Agrivation, Fotenix and Farmscan Ag.
The project is funded through Defra’s Farming Innovation Programme, delivered in partnership with Innovate UK.
