New blackleg resistance source found

Corteva Agriscience is incorporating a novel source of blackleg resistance into its canola varieties.

The new source of resistance is the result of a nine-year partnership with Agriculture Victoria, a state agriculture department in Australia.

“It was an opportunity to work with an organization that has a major issue with blackleg here in Australia,” said Steve Webb, head of external technology with Corteva.

The new source of resistance was discovered by using optimum haploid value (OHV) technology, an advanced breeding tool developed through the collaboration.

The tool helps accelerate breeding efforts by quickly finding desirable parental lines. Agriculture Victoria has a diverse collection of germplasm to mine for resistance traits.

The new trait was field tested in Australia, which has a serious problem with blackleg.

“It is performing extremely well in a very terrible environment with high disease pressure,” said Webb.

Corteva has licensed the technology and has incorporated it into its background breeding material.

The trait will soon be found in varieties sold under its Pioneer and Nexera brands once they have gone through the standard breeding program and variety registration process.

Clint Jurke, agronomy director with the Canola Council of Canada, welcomed the news of a new source of blackleg resistance developed in Australia, which is years ahead of Canada on working on that particular disease.

“Corteva pulling this from Australia is good news. We certainly welcome any new innovation in the blackleg space,” he said.

Blackleg was the number one disease in canola in the 1980s and 1990s but the introduction of resistance traits has knocked it down a couple of spots.

“It doesn’t cause widespread yield loss like sclerotinia, nor does it represent a huge threat to the canola industry like clubroot does,” said Jurke.

However, the disease has made a bit of a comeback over the last decade as it overcomes some of the existing resistance genes. It is now found in slightly less than 10 percent of canola plants on the Prairies.

“There is going to be some yield loss associated with that, but it’s not dramatic by any stretch,” said Jurke.

The industry wants to keep it that way by introducing new sources of resistance, such as the one Corteva has discovered.

He said the industry doesn’t want the disease to get out of control like it has in France and Australia.

On its website, Agriculture Victoria said blackleg is the most serious canola disease in the country. It temporarily wiped out Australia’s fledgling canola industry in the early 1970s.

Yield losses of 50 percent or more have been recorded some years in Australia. In some cases, losses have reached 90 percent when the fungus overcomes resistance in certain varieties.

Canadian canola growers have a new tool to help them keep the disease at bay. Labs are now able to identify what race of blackleg is present in a farmer’s field, which allows the grower to choose a line of canola resistant to that particular race.

The canola council’s top priority is to help growers protect their crops from succumbing to the disease, but there are also trade implications to keeping blackleg in check.

China has placed restrictions on imported Canadian canola over fears of introducing blackleg to its rapeseed crop.

“We do need to keep this disease down to a minimum just so that there are no threats to our external markets,” said Jurke.

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