The most damaging pathogen of soybeans in the US and Canada is the soybean cyst nematode (SCN). The nematode is likely present in up to 75% of Iowa corn-soybean fields. A critical tactic for managing SCN is growing SCN-resistant soybean varieties.
To help Iowa farmers know what their options are, Iowa State University annually compiles information about SCN-resistant soybean varieties for Iowa. The list has recently been updated, and a preliminary version is available online.
For next year’s cropping season, Iowa farmers can choose from 908 SCN-resistant varieties. The varieties for 2026 are from 35 different brands sold by 25 seed companies. The numbers of varieties with the different genetic sources of SCN resistance among the maturity groups are indicated in the table below. Most of the varieties have one or more herbicide resistance/tolerance technologies, but 90 varieties (10%) do not.
| Maturity group | PI 88788 | Peking | PI 88788 + Peking* | Total |
|---|---|---|---|---|
| 0–1 | 188 | 56 | 2 | 246 |
| 2 | 262 | 100 | 3 | 365 |
| 3 | 255 | 40 | 2 | 297 |
| Total | 705 | 196 | 7 | 908 |
* blends of varieties with PI 88788 and Peking resistance.
Performance of SCN-resistant soybean varieties
Each year, more than 200 resistant varieties are evaluated for yield and SCN control in field experiments conducted in all nine crop-reporting districts in the state. The work is funded by the soybean checkoff through the Iowa Soybean Association. See the ISU Extension publication IPM52 for yield and SCN control results from last year’s field evaluations.
Links to this article are strongly encouraged, and this article may be republished without further permission if published as written and if credit is given to the author, Integrated Crop Management News, and Iowa State University Extension and Outreach. If this article is to be used in any other manner, permission from the author is required. This article was originally published on October 6, 2025. The information contained within may not be the most current and accurate depending on when it is accessed.
- Morrill Professor
- Nematologist
- Director of the Iowa Soybean Research Center
- Research Scientist