Updated: Jan 31
RAGT is testing a new range of winter wheat material for BYDV resistance, including potential milling varieties and feed types that could be on farm within two to three years.
This is the third season that the company has been conducting trials to test the ability of the Bdv2 resistance gene to protect wheat plants under extreme pressure, by inoculating early sown plots with virus-laden aphids several times during the autumn and the spring.
The fully replicated trials involve several RAGT varieties containing the Bdv2 gene and a range of widely grown commercial varieties.
Two Bdv2 feed varieties in the trial, RW42046 and RW42047, which are currently in National List 2 trials, are also resistant to orange wheat blossom midge.
A year behind these are three potential milling wheats. One is a Skyfall cross with BYDV and midge resistances. The other two are RGT Illustrious crosses, which also contain both BYDV and midge resistance. Several other wheat lines further down the pipeline are also being examined
As in previous seasons, plots will be scored weekly for disease symptoms from mid-April to produce a visual assessment score, and viral loads will be assessed in the lab prior to harvest. All plots will be taken to yield.
Last year RAGT’s Bdv2 material showed no BYDV symptoms in the trial, apart from a few isolated traces of yellowing, which can occur under high pressure.
All the commercial winter wheats exhibited severe symptoms, including multiple infection sites, multiple red leaves and stunted growth – up to 50% in the worst cases.
Yield reflected these observations. The two feed varieties mentioned above, RW42046 and RW42047, took first and second place respectively, producing yield equivalents around 10.5t/ha.
Other feed varieties without the gene struggled to varying degrees under the intense BYDV pressure, yielding 8.8 to 9.2t/ha.
These reflect the 2020 findings when eight out of 10 popular conventional varieties yielded between 5% and 18% less than the Bdv2 lines, none of which lost yield.
Other BYDV trials are being carried out across the country this season include an RAGT/NIAB TAG trial in Devon and several merchant trials.
“Given the mild winter we are having, many growers could be looking at the results with interest,” says Dr Cathy Hooper, technical sales manager at RAGT Seeds.
‘Bird cherry counts in Rothamsted suction traps were consistently higher throughout last autumn than 2020, with over three times as many being caught overall.
“A huge peak was seen in October, but significant numbers were still turning up in November.
“Interestingly, aphids were being found in sizeable numbers in areas where you wouldn’t normally expect them such as the north west, and in my travels I saw signs of infection as far north as Dundee.
“Many areas have only had a couple of frosts this season so aphids could still be a threat, and it will be worth checking crops on warmer days. We could see some significant infections next summer.”