The Septoria storm caused by the recent demise of the Cougar resistance used in many varieties for Septoria resistance was highly predictable, claims Bill Angus of Angus Wheat Consultants Ltd. This resistance was defeated just two years after its introduction via the variety Cougar in 2013, and its failure was highlighted in Irish trials in 2020.
“If we are not careful, we will follow the same ‘boom and bust’ cycle which has existed for yellow rust for over 60 years,” warns Mr Angus
“Breeders have done a really good job by accumulating minor genes for Septoria resistance and this has the potential to be undone by utilising major genes – often introduced from related species.
“This is why when breeding our hard milling feed wheat Garibaldi we built it on ‘old genetics’. It does not exploit the major genes used in many high-risk feed varieties – instead it has resistance based upon minor genes – thus offering growers genetic diversity in the hard milling wheat sector.
“There has been a migration by growers to varieties with high levels of disease resistance – but many of the resistances being deployed present high risks of variety breakdown, and sadly we are now seeing this in the field.
“We are likely to see variation in resistances within the Cougar derivatives as we discover just which minor genes have been carried through. A look at the pedigrees will help as just crossing Cougar with an already susceptible variety is a high risk strategy.
“Growers need to select diversity – but to help them we need to see a return of publishing variety pedigrees on the Recommended List,” adds Mr Angus.