Advances made in eyespot resistance screening

Advances made in eyespot resistance screening

News
INFECTION ISSUES: Lodged wheat plants lying in layers like a blanket as a result of eyespot infection, at Cleve Hills in 2016. Photo: MARGARET EVANS, SARDI

INFECTION ISSUES: Lodged wheat plants lying in layers like a blanket as a result of eyespot infection, at Cleve Hills in 2016. Photo: MARGARET EVANS, SARDI

Aa

Eyespot can literally flatten cereal crops, significantly reducing yields.

Aa

EYESPOT can literally flatten cereal crops in the southern growing region, significantly reducing yields.

But SA researchers are perfecting techniques to screen new germplasm for eyespot resistance in a controlled environment - which should help plant breeders advance the delivery of resistance traits.

This research has been a focus of a strategic partnership between the GRDC and SARDI, in collaboration with the University of Adelaide.

SARDI senior research scientist Margaret Evans says screening for eyespot resistance is not simple.

"Sites with a problem aren't likely to be included in the National Variety Trials and it is not straightforward to apply inoculum to a trial site and get even and reliable results," she said.

"Even on an infected site, seasonal conditions have to be conducive to eyespot developing on the plants."

To address these problems, Dr Evans has been researching methods for screening based on artificially applied eyespot inoculum.

With no established eyespot pathogen artificial inoculation method, a system had to be developed where consistent numbers of infected field-collected stems could be used to inoculate plants growing in pots.

Eyespot screenings: Wheat cultivars being grown for eyespot screening by SARDI researchers. The 'stars' of brown stems are infected field samples used as the disease source. Photo: MARG EVANS, SARDI

Eyespot screenings: Wheat cultivars being grown for eyespot screening by SARDI researchers. The 'stars' of brown stems are infected field samples used as the disease source. Photo: MARG EVANS, SARDI

At present, researchers collect infected stems from paddocks and position three of them into each of the groups of 25 plants being grown for screening.

Overhead irrigation is used to simulate rain that splashes spores onto the plant stems, followed by days of misting to maintain humidity required for spore germination and plant infection.

"While developing this screening system, we have also developed methods for identifying and producing eyespot spores on field-collected stems, so we can now generate single spore isolates," Dr Evans said.

"We are aiming to artificially infect sterilised stems with the single spore isolates and to use these stems as an inoculum source, which will make the screening program more efficient."

Once we can prove the effectiveness of our program, we'll be ready to offer eyespot screening to more plant breeders. - MARGARET EVANS

This season will be the first where the research team uses its techniques to evaluate retentions in the GRDC's NVT program as well as commercial bread wheat varieties.

The priority is to demonstrate that controlled screening results accurately reflect eyespot resistance in the field.

For this reason, 'check' varieties with known resistance responses will be included in the screening trials.

"Once we can prove the effectiveness of our program, we'll be ready to offer eyespot screening to more plant breeders and potentially help deliver more resistant varieties to growers," Dr Evans said.

  • Start the day with all the big news in agriculture. Sign up here to receive our daily Stock Journal newsletter.
Aa

From the front page

Sponsored by