Speed is a relative term. For plant breeders, the process to find, isolate, incorporate and commercialize a new trait for soybeans or corn usually takes a minimum of 10 years or more.

But sometimes, everything clicks and years are lopped off the development interval. For soybean growers vulnerable to aphid attack, the good news is that progress on aphid-resistant soybean varieties is moving along at breakneck speed.

Six years ago, we were blissfully unaware of soybean aphids. Then, in 2001 this pest attacked North American soybean fields with a vengeance and decimated the crop. Extension workers and agronomists scrambled to develop spraying programs to counter exploding populations of aphids. It soon became obvious this new pest represented an ongoing challenge to profitable soybean production.

Plant breeders were confused too. Farmers were telling them they’d discovered an aphid-resistant variety because one field was devastated while an adjoining field planted to a different variety was left unscathed and healthy. Little did the farmer know that one road over, aphids had hammered that variety. Without genetic resistance, farmers have had to rely on insecticide treatments, which require regimented scouting, aphid counting and pinpoint timing to be successful.

But soybean breeders have been on the case — working to find genetic solutions to battle aphids. In one of the greatest examples of efficient teamwork between private and public breeding programs, farmers should have access to the first aphid-resistant commercial soybean varieties within 2 years.

The quest for aphid resistance started in the USDA’s massive soybean seed bank at the University of Illinois. It’s one of the biggest soybean seed banks in the world, second only to a similar facility in Beijing, China.

The seed bank in Illinois houses 16,000 soybean germplasm lines. Seeds of wild soybean plants from China are stored beside long-forgotten commercial varieties. It’s like a museum for soybeans except at any moment, any one of the seeds could hold the genetic key to solve a new threat to the soybean crop.

And that’s just what happened in this case. Researchers started working their way through the various varieties. They grew plants and exposed them to aphids. It took 3 years, but eventually 2 old-timey varieties grown 30 years ago in the southern U.S. called Dowling and Jackson were found to not only repel aphids, but also to be toxic to aphids that fed on these plants. This breakthrough discovery occurred 2 years ago. Since then researchers have been crossing these 2 old lines into modern commercial varieties.

“We were able to get Dowling into varieties with good agronomic backgrounds,” says Brian Diers, professor of soybean breeding and genetics at the University of Illinois. “It appears that the resistance doesn’t have any adverse agronomic effect.”

The University of Illinois has licensed the gene to private seed companies. Most of the breeding is being done using traditional, non-biotech methods.

“With transgenics the first difficulty is to clone the gene, which is not an option until you have identified the sequence of DNA that provides resistance,” says Diers. “We’ve mapped it but it still includes millions of DNA, so we don’t know where the gene is in that huge sequence of DNA.”

Often, plant breeders find that when they take a desired gene and insert it into a new variety, there’s a risk that you’ll drag along other undesirable traits — like lodging or yield loss — along with the genes that produce the resistance. The other problem is a transgenic plant will take millions of dollars to get through the approval process. For these reasons, the first aphid-resistant soybean varieties will not be biotech or GMOs.

In the rush to provide hope against the next flush of aphids, the researchers have chosen to avoid one important part of the research. “We don’t know exactly how the resistance works,” says Diers. “What we do know is that when we put the aphids on the plants they don’t reproduce at as high a rate. Feeding on these resistant varieties is actually causing the aphids to die.”

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