A trial using a resistance wheat gene to control Barley Yellow Dwarf Virus is showing promising results.
Barley Yellow Dwarf Virus (BYDV) is an aphid transmitted virus prevalent in many cereals and is a major concern to arable farmers worldwide. Very little genetic resistance exists to BYDV so insecticides are used to control the aphids which spread BYDV.
In New Zealand, yield loss through BYDV has been recorded at up to 30% and cereal growers spend around $100/ha annually controlling aphids to prevent the spread of this virus in their crops.
Plant & Food Research (PFR), in conjunction with Luisetti Seeds, has been developing BYDV resistant milling wheat cultivars using the resistance gene Bdv2.
This gene was originally transferred from a wild wheat species (Thinopyrum intermedium) by the Commonwealth Science and Industrial Research Organisation (CSIRO) in Australia.
To test this resistance under NZ conditions, a breeding line, derived from the PFR/Luisetti Seeds cultivar ‘Viceroy’, containing the Bdv2 gene is undergoing a second year of field evaluation at PFR’s Lincoln Research Farm.
In the 2018-19 season, replicate plots of ‘Viceroy’ and ‘Viceroy-Bdv2’ were sown and either left untreated or sprayed with Karate at four-week intervals. Pots of barley infested with aphids carrying BYDV were placed into each plot twice during the season to maximise the infection of the entire trial.
The company,’Dronescape’, flew a drone equipped with a multispectral sensor over the wheat trial in November and December.
Visual symptoms of BYDV infection were only seen at the infection sites of plots of the susceptible, untreated ‘Viceroy’ cultivar.
A similar trial has been established this season to confirm these results.
A higher level of infection has been achieved and visual symptoms of BYDV have also been seen at the infection sites of ‘Viceroy’ even under insecticide treatment.
Using the data collected from the drone flights, the crop index Normalised Difference Red Edge (NDRE) was used to accurately measure the symptoms of BYDV.
Virus testing was also carried out on ten flag leaves from each plot. This testing confirmed that the highest level of virus was detected in untreated plots of ‘Viceroy’, followed by the insecticide treated plots of ‘Viceroy’.
As expected from the lack of visual BYDV symptoms, the ‘Viceroy-Bdv2’ lines had much lower levels of detectable virus.
Luisetti growers should be on the lookout for BYDV resistant wheat cultivars from the Luisetti/PFR cereal breeding programme in about five years’ time.