By CELESTE BAUMGARTNER
Ohio Correspondent

COLUMBUS, Ohio — Researchers at The University of Illinois and The Ohio State University are making progress in finding aphid resistant soybean genes, but as soon as they do, the critters find ways to overcome those genes – and what works in one state may not work in another.

UoI researchers found the first aphid resistant soybean gene in 2004. It came from two soybean germplasm lines that were grown in the South but have not been commercially available for 30-40 years, according to an Associated Press article. That soybean will be on the market next year and will be available to farmers in the upper Midwest.

The researchers are not sure, however, if it will work in Ohio. “It already seems like the aphid in Ohio can overcome them,” said Rouf Mian, a molecular geneticist who works with the USDA Agricultural Research Service and OSU. “The gene will be effective against some aphids, but the aphids are continually mutating to overcome that new gene.

“Once we found that the aphids had overcome that gene, we found a new source that is still effective in Ohio and several other states. I don’t know how long it will take the aphids to overtake that one. We come up with one gene and the aphid overcomes it, and then we come up with another gene. That’s how it goes.”
Although the process is slow, the researchers are gaining ground. Starting with a new gene, it takes five to six years for a cultivar to be developed incorporating that gene, Mian said. But it is a continuous process.

“Now that I have one gene, I am already working on other sources of genes so that they will be ready in the pipeline if one goes down,” he said. “It doesn’t take that long because we are already making progress. There will be another one coming down the line.”
With DNA markers, researchers can also “pyramid” genes – that is, combining a series of target genes into a single genotype. If the aphids overcome one gene there is still another one in the soybean to thwart them.

“You put two or three genes in the same place and probably get more durable and broad-based resistance,” Mian said.
Soybean aphids, probably from eastern Asia, were first found in the United States in the Chicago area in 1999. They moved into Ohio in 2001.

“It’s the biggest insect problem for soybeans in the United States,” Mian said. “Nearly 80 percent of U.S. soybeans are grown in the North Central region, where the soybean aphids thrive.”

The aphids suck the nutrients out of the plants and stunt their production. They give birth to live babies continually, Mian said, comparing the situation to an alien movie. They can also transmit viruses among soybeans and vegetable plants.

The pest is even more of a problem for food-type soybeans because the aphids discolor the seeds and make them unattractive for eating.

“They (food-type soybeans) are exported to Japan and the Oriental markets are very picky,” Mian said. “So even though the farm may have a good yield, they can’t sell it because it doesn’t look good anymore.”

The producers of conventional food type and organic soybeans will benefit the most from aphid resistant soybean cultivars. Aphid resistant soybean fields should not require insecticides for aphid control.