Ames, Iowa, USA
November 1, 2010
The soybean cyst nematode (SCN) continues to be a serious threat to soybean production in all soybean-producing areas of Iowa and the Midwest. But there are hundreds of SCN-resistant soybean varieties available for growers to use to manage the pest. It’s important for growers to know what resistant soybean varieties are available, as well as what sources of resistance the varieties possess.
This information is important because university scientists recommend rotating different sources of resistance and different SCN-resistant varieties. This prevents the buildup of SCN populations with increased reproduction on resistant soybean varieties. Increased SCN reproduction can lead to increased yield loss in future years. Iowa State University nematologist Greg Tylka says “The key to profitable long-term soybean production in SCN-infested fields is keeping the nematode numbers in check. With SCN, it’s much easier to keep low numbers low than to drive high numbers back down.”
To help soybean growers, Iowa State University Extension annually publishes a list of SCN-resistant soybean varieties in maturity groups 0, 1, 2 and 3. The 2010 version of the publication, developed with soybean checkoff funds from the Iowa Soybean Association, has been recently released and is available to download at ISU Extension Online Store as publication PM 1649 at www.extension.iastate.edu/store. Print copies of the publication will be available in late 2010 or early 2011.
"Resistant soybean varieties pay dividends twice; they produce profitable yields in SCN-infested fields and they help prevent the buildup of SCN numbers, which will ensure profitable soybean production in future years,” says Tylka, who is an author of the list.
The 813 SCN-resistant varieties listed in the updated publication are the most ever. But Tylka points out that almost all of the SCN-resistant varieties in the publication have the same source of resistance, from a breeding line called PI88788. Only 15 of the 813 varieties in the publication have a source of resistance that is not PI88788.
“There are 21 SCN-resistant soybean varieties in the list that were developed by Iowa State University scientists with soybean checkoff funding from the Iowa Soybean Association” Tylka points out. “Two of the varieties, IAR2101 SCN and IAR3001 Phyto SCN, have sources of SCN resistance that have not been used in varieties in the list before.”
In addition to compiling the list of resistant varieties annually, Iowa State also assesses the yields and nematode control of hundreds of SCN-resistant soybean varieties in experiments conducted in SCN-infested fields throughout the state each year. This work also is supported by the soybean checkoff through funds from the Iowa Soybean Association. The results of the 2010 SCN-resistant variety evaluations soon will be posted at www.isuscntrials.info and a printed report of the results will be available in early 2011.
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