BYDV-resistant wheat thrives despite high aphid pressure
Updated: Jun 18, 2020
RAGT’s breakthrough BYDV-resistant wheat RGT Wolverine is living up to its promise of delivering season-long protection against the virus, reducing the reliance on foliar-applied insecticide sprays.
The hard Group 4 feed wheat variety, which will be available in limited quantities for sowing this autumn, has showed no signs of the yield-sapping disease in RAGT’s trials in Cambridgeshire up to the first week of June, despite multiple inoculations with virus-laden aphids.
Ten popular Recommended List varieties in the trial were all affected by the disease, particularly when early sown. Sypmtoms ranged from a few yellow and red leaved plants to multiple stunted areas with severe leaf loss.
To help ensure all plots were exposed to the same BYDV pressure, plants inoculated with aphids were placed next to each plot, four times in the autumn and five times in the spring. The aphids, supplied by Rothamsted Research, were infected with the most common BYDV strain, PAV.
Each plot was then assessed weekly for BYDV symptoms starting from mid April, a process that will continue through to senescence. Scores ranged from zero (no signs) to four (very obvious symptoms and multiple stunted sites).
There were stark differences in terms of how much virus was present and how quickly it developed (see graph).
“The results clearly demonstrate the effectiveness of the Bdv2 resistance gene in our BYDV-resistant material,” says cereal and OSR product manager Tom Dummett. “This builds on earlier findings from our laboratory and field experiments as well as almost two decades of commercial experience with Bdv2 varieties in Australia.
“Growers who choose RGT Wolverine can rely on the plant to protect itself against the virus. They will also benefit from the variety’s very high output and strong agronomic features, whether the virus is present or not.”
Four other resistant varieties due to be entered into National List trials this coming season, which share the same Bvd2 resistance gene, also came through the trial unscathed.
The RAGT trial also examined the effect of a single autumn-applied pyrethroid insecticide, applied at secondary aphid migration, on BYDV levels across all varieties.
In early sown plots, this made little difference to symptom scores at the first assessment in mid April. However, it did reduce build-up thereafter, with most RL varieties at least halving their untreated scores by the end of May.
“However, infection levels are still building and the data will change over the coming weeks,” says Tom. “All plots will be taken to yield to assess the effects.
“Plants do use energy to ward off disease, so it will also be interesting to see if applying insecticide to the BYDV-resistant varieties might provide a yield uplift.”
To learn more about RGT Wolverine click here.