Battling Budworms

battling budworms

New genomic tools hold promise for economic boon in forest industry

Last revised: December 2015

White spruce represents 26 per cent of Canada’s softwood growing stock, offering the spruce budworm immense opportunity to turn lush green conifer stands from coast to coast into scorched-looking landscapes. Among the many reasons to stop the defoliating larvae: the white spruce harvest annually injects billions of dollars into the country’s economy.

The announcement in 2013 that Canadian scientists had sequenced the entire genome of the white spruce, accelerating future applications for the discovery of a gene with natural resistance to the spruce budworm was, therefore, welcome news.

“It wasn’t cost effective until recently,” says Dr. MacKay. As soon as it was, the team built on a decade’s work in spruce genomics to produce the sequence in just a year and a half. “We’re now improving that draft,” he says, “extracting all the information.”

They have found, for instance, that the budworm-resistant gene is active in the foliage where and when the larvae feeds, but activity levels vary considerably in the same gene from tree to tree. Ongoing studies will determine how efficiently scientists can select the highly active genes.

The researchers are also investigating genes affecting yield and quality in the white spruce. Wood stiffness and durability, for example, are important traits in building construction.

The genomic tools that result from their research will allow breeders to evaluate spruce trees after a couple of years, rather than waiting 15 years for the trees to mature in a demonstration plot. “The impacts could be rapid,” says Dr. MacKay.

If 50 percent of saw-logs came from trees selected for traits related to wood stiffness, for example, the average grade of lumber for the typical Canadian sawmill would improve by 15 percent, adding $1.5 million a year to its product value. Across Canada, that’s an increase of $300 million.

"In two to three years, nurseries will be able to select spruce seedlings that are resistant to the budworm."
— Dr. John MacKay, co-leader of SMarTForests

In Canada, some 500 million trees are planted annually. Forest sector revenues are valued at $58 billion. But the sector faces changing environments, pressure to conserve forest lands and demands for sustainable forest management. Genes have already been identified for quicker growth, pest resistance and wood durability. Tools are in development that will allow tree-breeding programs to choose seedlings with these traits, which is improving productivity while maintaining healthy forests.

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