NDSU Releases Soybean IDC Scores for 2027 Planning

By Scout Nelson

North Dakota State University (NDSU) has released its 2026 soybean iron deficiency chlorosis (IDC) ratings. The information helps producers select soybean varieties for the 2027 growing season and improve crop performance in fields with a history of IDC.

Although drought conditions are a major concern for many growers today, cool and wet weather earlier in the 2026 season created favorable conditions for IDC across parts of North Dakota. In some areas, flooded and saturated soils increased the severity of chlorosis symptoms in soybean fields.

“This information is crucial for farmers who deal with IDC in their fields annually,” says Ana Carcedo, NDSU Extension broadleaf crops agronomist. “Choosing soybean varieties that are less susceptible to IDC is the first step in addressing this issue.”

NDSU conducts annual research to evaluate soybean varieties for IDC tolerance. Soybean varieties show genetic differences in how well they handle chlorosis, making variety selection, and important management decisions for producers.

“Selecting a soybean variety with IDC tolerance is an important management decision that can help producers minimize the negative impact of chlorosis on yield,” says Carcedo.

During the summer of 2026, NDSU's soybean breeding program evaluated 90 soybean varieties. The study included Enlist, GT27, Roundup Ready, Xtend, and conventional soybean varieties.

Iron deficiency chlorosis is a common problem in some soybean-growing areas. Symptoms often include yellow leaves with green veins, yellowing, browning, and stunted plant growth. These symptoms commonly appear early in the growing season and can reduce yield potential.

The research was conducted through replicated field trials at a location with a history of IDC. Researchers visually rated plants using a scale from 1 to 5. A rating of 1 indicated no chlorosis, while a rating of 5 represented the most severe symptoms.

Ratings were recorded at three different soybean growth stages to provide a detailed assessment of each variety's tolerance level. The results help producers compare varieties and identify those better suited for fields affected by IDC.

While IDC tolerance is important, producers are encouraged to consider additional traits when selecting soybean varieties. Yield potential, agronomic performance, and other characteristics should also be part of the decision-making process.

Varieties with similar IDC ratings can still differ significantly in yield performance. For this reason, growers are advised to review all available information before making final planting decisions.

The IDC ratings and soybean variety trial information are available at https://vt.ag.ndsu.edu/list/soy.

Photo Credit: istock-oticki