Several popular winter wheat varieties have seen their yellow rust scores fall by up to five points, in updated ratings published by the AHDB.

Of the 38 varieties on the current Recommended List, 12 have seen their yellow rust ratings fall by two to five points, on the 1 to 9 resistance scale.

These include the Dawsum, the most widely grown variety last season, according to AHDB’s planting survey.

The changes are due to a new race of the disease overcoming the Yr15 resistance gene, which resulted in unprecedented levels of the disease being seen in winter wheat crops.

See also: Wheat yellow rust ratings set to fall for next season

First emerging in the North East of England, genotyping work suggests the Yr15 virulent strain likely evolved by a mutation in late 2024 that then spread rapidly across England.

The changes prompted the AHDB to release the 2026/27 ratings earlier than usual to help growers plan ahead. These figures are also based on a single season rather than a three-year mean, as that better reflects the current situation.

But it’s not all bad news, as about half of the winter wheat varieties on the list maintain the same rating or fall by only one point – and a few like Graham improved due to declines in other yellow rust strains.

Looking ahead

On the current list, 13 out of 38 winter wheat varieties were classified as having resistance at the young plant stage. AHDB points out that as this is likely to be linked with the gene, most varieties are expected to be classified as susceptible to yellow rust at the young-plant stage in the 2026/27 Recommended List.

While the new strain was not present in all trials – especially towards the far south of England – its virulence and the widespread use of the gene mean it is likely to spread further in 2026.

As it may take a couple of years for the yellow rust population to settle, AHDB warns that ratings may be affected further next year, although it is unlikely at the scale seen this year.

As a result, growers are advised to monitor crops closely and report any unusual outbreaks of rust to the UK Cereal Pathogen Virulence Servey (UKCPVS) to help track further changes.

Several candidate varieties are also susceptible to the new strain, which could affect their chances of Recommended List inclusion later this year.