April 24, 2017
New Yellow Rust Risk Management Scheme
A new national yellow rust risk management scheme has been introduced by Agrii this season to help wheat growers reduce their danger of being caught out by sudden and dramatic changes in variety susceptibility.
Developed with Dr Rosemary Bayles and Bill Angus, the scheme is informed by the company’s nationwide disease monitoring programme of untreated variety plots and key yellow rust race differentiator varieties in tussock trials.
Recognising the growing complexities that have led to the withdrawal of long-established UKCPVS Yellow Rust Diversification Scheme, it takes a broader approach, classifying varieties by pedigree and pathology group to highlight their likelihood of having yellow rust resistance genes in common as well as their levels of resistance to current races.
“It’s notoriously difficult to predict the effects of future race changes on individual varieties,” commented Agrii head of R&D, David Langton. “But we know from recent experience with varieties like Reflection, JB Diego and Zulu just how sudden, dramatic and damaging resistance breakdowns can be.
“To cater for the speed with which yellow rust races are able to change we’ve always based our variety resistance ratings on scores from the latest monitoring across our own extensive trial network. Linking this with ancestry information in our new scheme identifies varieties with high levels of yellow rust resistance that may be at particular risk of breakdown by virtue of the genes they share with those susceptible to races in current circulation.
“For instance, Marston currently has complete yellow rust resistance. But it shares significant parentage with notably susceptible KWS Lili in one pedigree group and Belgrade and KWS Zyatt in another,” he pointed out. “So growing it alongside these varieties would be a higher risk strategy than choosing a resistant variety from one of our other three pedigree groups.
“Alongside with the early warning of race changes we provide from our national disease monitoring programme, our risk management scheme gives growers the best, most timely intelligence on which to select their wheat variety mixes for the least danger from yellow rust race changes in the year ahead.”