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MSU develops aphid-resistant soybeans

For Andy Welden and other soybean growers in Michigan, aphids are little insects that cause big headaches. Welden planted 800 acres of soybeans on his 1,500-acre farm in Hillsdale County this year.

“Aphids are never not a problem,” Welden says. “I try to get an idea of what the aphid population is going to look like by doing things like counting eggs in the fall and scouting fields. Even when I do that, aphids are still hard to control.”

The problem of soybean aphids, a pest for growers around the world, may soon be reduced thanks to a new aphid-resistant soybean plant developed by researchers at Michigan State University.

Key Points

• Most effective way to control aphids is the use of broad-spectrum insecticides.

• MSU developed soybean germplasm to breed plants resistant to soybean aphids.

• New technology, called Sparta, expected to be available commercially in 2012.

Dechun Wang, associate professor in the Department of Crop and Soil Sciences at MSU, has developed germplasm that can be used to breed soybean plants resistant to aphids. The technology, known by the trade name Sparta, is based on four recessive genes that result in resistance. While many resistance traits are controlled by only one gene, the fact that Sparta is controlled by multiple recessive genes creates two interesting dynamics: the genetics were more challenging to discover, but aphids have a harder time figuring it out.

Both soybeans and soybean aphids originated in Asia, but the soybean aphid wasn’t discovered in the United States until 2000. Soybean aphids affect plants by sucking sap and transmitting viruses from plant to plant.

Costly pests

Michigan growers produce more than 75 million bushels of soybeans on nearly 2 million acres of farmland annually. If not managed, aphids can cause significant yield losses. In outbreak years, conventional growers spend at least $15 per acre to control aphids using insecticides. And that’s just for one application — some growers spray multiple times to control the pest. Prior to 2000, few, if any, soybean acres were treated with insecticides in the Midwest. In 2003, aphids caused an estimated $120 million in losses for U.S. soybean growers. In 2005, 42% of Michigan’s soybean acreage was treated with insecticide to control the pest, increasing production costs statewide by nearly $6.7 million.

“Even in the best situation, you’re out the cost of application and product,” MSU Extension educator Mike Staton says of chemical pest control methods.

Insecticides have an effect on more than just aphids. Applicators must consider effects on human health, the environment, bees and other pollinators, as well as the cost of chemical control methods.

“Everybody knows aphid control is a problem, but no one has an answer,” says John Gerard, president of Access Plant Technology.

That is, until now.

MSU and the Michigan Soybean Promotion Committee, which funded the project along with the Michigan Agricultural Experiment Station, hold the licensing rights to Sparta. Licensing lets MSU and MSPC get the product to producers as quickly and as cheaply as possible, and allow commercial seed companies access to the trait. MSPC and MSU are working with Gerard and his company to move the Sparta technology from academia to commercial seed production. Most major seed companies are using the aphid-resistant germplasm to develop aphid-resistant varieties.

“The benefit to producers is less to no spray with Sparta,” says Keith Reinholt, field operations director for MSPC.

Estimates have 2012 as the earliest Sparta will be available commercially.

Sollman, a senior at Michigan State University, works for ANR Communications at MSU.

Some added benefits of Sparta

According to MSU Extension educator Mike Staton, a decrease or elimination in insecticide use for aphids won’t be the only benefit Sparta will provide. Growers will be able to proceed through the growing season without having to reconfigure their sprayer, run over their plants, spend money on insecticides or struggle with the perfect timing of an insecticide application.

“To me, variety selection is the most important step to profitable soybean production,” Staton says. “Genetic resistance has been the best way to manage nematodes and disease. In the future, the genetic resistance conferred by the Sparta technology will be the best way to manage soybean aphids.”

Sparta is in research and development at major seed companies, which are incorporating the aphid-resistant trait with their genetics.


designer GENES: Dechun Wang (left), associate professor in the Department of Crop and Soil Sciences at Michigan State University, talks with Hillsdale County soybean grower Andy Welden about the Sparta technology. Wang is the primary researcher for Sparta. He screened more than 2,000 soybean lines to select for genes that make plants resistant to soybean aphids. Michigan Soybean Promotion Committee, MSU and the Michigan Agricultural Experiment Station funded his research. Photo: Emily Walker, ANR Communications

This article published in the September, 2010 edition of MICHIGAN FARMER.

All rights reserved. Copyright Farm Progress Cos. 2010.