Discovering soybean plants resistant to aphids and a...(sistant germplasm and marker technology ...)

The first aphid-resistant variety developed and released by the University of Illinois is Round-up Ready, and the second is a conventional, non-Round-up Ready variety. Diers says "we believe that the aphid resistance in a conventional background will be especially helpful to organic soybean producers because currently if they have aphids in their fields, they don't have any practical method of control because they cannot spray insecticides. I've been contacted by some organic growers in northern Iowa and southern Minnesota who are ready to give up growing organic soybeans because aphids have caused such large losses."

Diers said that resistant varieties can save farmers money and help the environment. "Farmers have been controlling soybean aphids by spraying insecticides. If we can deploy resistance, this could reduce the use of these insecticides, which will have many environmental benefits."

The message to farmers is that there are going to be varieties with soybean aphid resistance available. "The tests we've done have shown that we have less aphid reproduction on these resistant lines than on susceptible lines," Diers said. "But so far the resistance isn't a magic bullet. You can't grow these aphid-resistant varieties and not scout for aphids because there may be aphids in your fields that can defeat the resistance."

The other unknown is how adaptable aphids will be to these new varieties. "Our hope is that we can combine these two genes and get more durable resistance," Diers said. "We hope that we can develop a plant with a number of resistance genes so that if any one of them breaks down, the plant would still be resistant."

This work was supported by funding from the United Soybean Board and the Illinois Soybean Association. "Without funding from these organizations, our research on aphid r
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