Farmers across the Midwest could soon have high-yielding commercial varieties with effective resistance to soybean aphids as the result of a major breakthrough at the University of Illinois. After nearly three years of effort, a team of researchers at the U of I has identified a single-gene source of aphid resistance that can be easily crossed into elite commercial varieties.
"Growers could have resistant varieties fairly quickly, especially if industry adopts this technology," says Glen Hartman, plant pathologist with the USDA's Agricultural Research Service at the U of I. "I think three to four years would be a reasonable time frame for that to happen."
The aphids were first discovered in large numbers in fields near the end of the 2000 growing season. After careful scientific investigation, they were identified as Aphis glycines, which had previously been reported only in Asia, Australia, and some Pacific islands. By 2003, this pest had emerged as a major problem for growers throughout the Midwest. Insecticides cost as much as $20 to $25 per acre, resulting in substantial savings for producers if a resistant line is found.
Researchers began screening about 100 cultivars that had been identified as the major genetic contributors to modern soybean varieties. Those ancestral lines account for more than 90% of the genetic variation in our current soybeans. "Luckily we found resistance in two different cultivars," says University of Illinois Senior Research Associate Curtis Hill." One is called Jackson, which is an old southern cultivar. Another was Dowling, which also is an old variety grown in the south."
"Even with a large numbers of aphids present, we found virtually no difference in yield and agronomic traits whether these resistant lines were treated with an insecticide or not," Hartman says. "At the same time, the commercial varieties were severely damaged when they were not treated with an insecticide, with many of the plants actually dying."
Brian Diers from the U of I's Department of Crops Sciences, says the research confirmed that the resistance is conferred by a single major gene. "We are now using that marker information to breed the resistance gene into adapted soybean varieties and testing whether there is any associated yield or agronomic drag associated with the gene. We hope to have resistant varieties available to farmers by 2008," he says.
With assistance from the Office of Technology Management at the U of I, they have also applied for a patent and will soon be licensing this new technology to both university and industry breeders.
"The idea of licensing is to make it a fair playing field for everyone," Hartman said. "Otherwise an individual company could take this research and patent the gene for itself. By licensing the technology to a large number of companies and public breeders, we can ensure that the benefits will reach growers across the Midwest as quickly and cheaply as possible."
Additional details on this technology are available on the Internet by clicking HERE.