By Andi Anderson
The Iowa State University (ISU) Extension has updated its list of soybean cyst nematode (SCN)-resistant soybean varieties for 2025. This year’s compilation, published as ISU Extension document CROP1649, includes 920 soybean varieties resistant to SCN across four maturity groups.
This total is up by 54 varieties from last year and provides an extensive selection to help Iowa farmers manage nematode infestations in their fields.
The publication highlights 200 varieties with Peking resistance, which is a notable increase compared to previous years. SCN has long been a challenge in Iowa, affecting over 70 percent of the fields in the state.
Since the 1990s, PI 88788 resistance has been the primary SCN-resistant option, but reliance on PI 88788 has allowed SCN populations to adapt, leading to yield reductions.
Varieties with Peking resistance are now proving to be highly effective, yielding up to 20 bushels more per acre in fields with high SCN presence.
The addition of Peking-resistant varieties gives farmers a diverse set of tools to improve their crop health and yield. ISU cautions against relying solely on Peking-resistant varieties to prevent SCN populations from adapting quickly, as happened with PI 88788.
Instead, farmers are encouraged to rotate between Peking-resistant and PI 88788-resistant varieties to maintain sustainable and effective SCN control over time.
ISU's SCN-resistant soybean variety evaluation program continues to conduct research across Iowa, supported by soybean checkoff funds from the Iowa Soybean Association.
These evaluations help ensure that local farmers have access to the latest and most effective SCN-resistant varieties each season. For detailed information, CROP1649 also provides each variety’s herbicide resistance, relative maturity, and iron deficiency tolerance, making it a valuable resource for farmers.
Farmers who know of SCN-resistant varieties not listed in CROP1649 can contact Greg Tylka at ISU to include them in future editions. By offering updated, research-based options, ISU is committed to helping Iowa’s agricultural community effectively manage SCN infestations and improve soybean production.
Photo Credit: iowa-state-university
Categories: Iowa, Crops, Soybeans