No major breakdowns in varietal resistance to yellow or brown rust occurred last year, but the dynamic nature of pathogen populations means that growers and agronomists must remain vigilant and report any unusual sightings.

Latest results from the UK Cereal Pathogen Virulence Survey (UKCPVS) show that all the recommended and candidate wheat varieties tested were susceptible to brown rust at the seedling stage – with just one exception, Goldfinch.

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A total of 65 brown rust samples from 11 counties and on 31 varieties were received during the growing season last year, reports UKCPVS technical lead Huw Davis, with 10 different brown rust strains tested.

“Only Goldfinch was resistant to all 10 of the isolates, with non-recommended Diamond being resistant to nine of them.”

Goldfinch wheat © RAGT

The most samples received were the Group 1 breadmaking variety Crusoe, which has a very low resistance rating of 3, with many growers reporting control difficulties with the disease as the season progressed.

“What we found is that all of the recommended and most of the candidate varieties were susceptible to at least three of the 10 isolates tested,” adds Huw.

“Varieties that were susceptible to all 10 isolates at the young plant stage include Cheer, Zyatt, Graham and Solitaire.”

Skyfall, which has a resistance rating of 9 on the Recommended List, was susceptible to four brown-rust strains at the seedling stage.

Yellow rust

In contrast, as many as half of all the recommended and candidate wheat varieties have young plant resistance to yellow rust, reports Huw, following the testing of 25 isolates.

Some 17 recommended varieties and eight candidate varieties were resistant to yellow rust at the seedling stage, while 14 recommended and 15 candidate varieties were susceptible to between 1-16 of the 25 isolates tested.

“All varieties with an 8 or 9 resistance rating performed well at the seedling stage, which is good news.”

Graham was susceptible to 32% of the isolates, while 24% infected Redwald and Extase. The new Group 2 variety Arnie was susceptible to 64% of the isolates.

Among those resistant to all 25 isolates include Champion, Costello, Mayflower, Dawsum, Palladium, Beowulf and Cheer.

While the Recommended List has historically shown adult plant resistance ratings for yellow rust, seedling stage resistance or susceptibility is now included.

“Mild and wet winters are conducive to rust so the monitoring of varieties susceptible to multiple isolates at the young plant stage is really important.”

In the event of any suspicions or perceived differences to the ratings, samples should be sent in a paper envelope to UKCPVS.   

Huw Davis was speaking at the UKCPVS stakeholder meeting at Niab near Cambridge