Field evaluation of SCN-resistant soybean varieties

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Investigators: Gregory L. Tylka, Gregory D. Gebhart, Christopher C. Marett
Funding: Iowa Soybean Association, seed company fees

An effective and affordable way to manage SCN is to grow resistant soybean varieties. SCN-resistant soybean varieties suppress SCN reproduction, reducing the yield loss caused by damage from nematode feeding. SCN resistance preserves the yield of soybean varieties growing in SCN-infested fields.

There are hundreds of SCN-resistant soybean varieties available. The SCN resistance genes come from breeding lines or “sources of resistance.” Not all SCN-resistant soybean varieties possess genes from the same source of resistance (although all but 2% of SCN-resistant varieties available to Iowa growers in 2008 have resistance from PI 88788). And different varieties with the same source of resistance (PI 88788 for example) may not have all of the SCN resistance genes from the source of resistance. Bottom line: all SCN-resistant soybean varieties do not yield the same nor do they control SCN the same.

For more than 15 years, the Iowa State University SCN-resistant Soybean Variety Trial program has assessed the yield and nematode control provided by hundreds of SCN-resistant soybean varieties at multiple locations throughout Iowa. Yield and the amount of SCN reproduction that occurs on the resistant varieties are measured under field conditions throughout the state.

Key findings from the research include:

  • SCN-resistant soybean varieties, even the top-yielding SCN-resistant varieties, provide different levels of SCN control.
  • The HG type (formerly called race) test system provides information about what sources of SCN resistance are effective for management SCN populations. But the HG type of an SCN population does not always predict what SCN-resistant soybean varieties will be the highest yielding.

This research is conducted annually. Results are published each year in an Iowa State University Extension bulletin (Evaluation of Soybean Varieties Resistant to Soybean Cyst Nematode in Iowa - IPM-52) and are also posted on http://www.plantpath.iastate.edu/tylkalab/iowa-state-university-scn-resistant-soybean-variety-trials.

Photograph of farmers planting a test plot One range of 4-row variety trial plots Planting the plots Aerial image of the ISU SCN-resistant Soybean Variety Trial Program

Graph of soybean yields

Yield (left graph) and end-of-season SCN population densities (right graph) from the three top-yielding SCN-resistant soybean varieties at a variety trial location in north central Iowa

Preview of information sheet

View a one-page information sheet (mini- poster) about the research in pdf format»