Discovering Soybean Plants Resistant to Aphids

Insect resistance breeding is always a race against time before the currently resistant variety loses its efficacy against new insect biotypes. This is what researchers at the University of Illinois experienced. After the initial discovery of soybean aphids in the summer of 2000, the researchers screened 18,000 different accessions and came up with two soybean lines Dowling and Jackson having the same resistance genes, and PI200538 with a different resistance gene against the aphid. Soybean varieties adapted to the Midwest were recipients of resistance genes from Dowling and were able to control the prevailing aphid biotype.

However, a new aphid biotype was found to be resistant to the Dowling resistance genes. It was fortunate that the third soybean line PI200538 can overcome the new aphid biotype. Breeding strategies are now geared towards stacking the two insect resistance genes into one soybean variety. "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." UI scientist Brian Diers said. He further added that, "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." 

For details see the press release at: http://www.aces.uiuc.edu/news/stories/news4863.html