10/23/2026
🌱 What’s Causing the Discoloration in Enlist E3 Soybeans?
If you’ve noticed brown or gray discoloration on soybeans this harvest, there’s some interesting science behind it!
Researchers have linked this discoloration to the AAD-12 enzyme expressed by the Enlist E3 herbicide-tolerance trait.
Here’s the simple explanation:
Soybeans naturally contain compounds called isoflavones. Research found that one of these compounds can interact with iron and pectin (a natural part of the seed coat), creating brown discoloration.
🌦️ Why is it worse some years?
That’s where growing conditions may come into play.
Temperature, moisture, and conditions during seed development may influence how noticeable the discoloration becomes. Some varieties may also be more susceptible than others.
A few important points:
* This is associated with the genetic trait, not necessarily an Enlist herbicide application.
* Soil pH and iron availability affect plant health, but we don’t have evidence that soil pH directly causes this discoloration.
* The discoloration alone doesn’t necessarily mean the soybean is damaged or has poor quality.
The takeaway: Research supports a connection between the Enlist E3 trait and seed-coat discoloration. The environment appears to influence how strongly it shows up, but scientists are still working to understand exactly why.
Have you noticed differences between fields or varieties this year?
🌱 Let’s walk the field with Andrea.
Source: Identification of iron-chelating phenolics contributing to seed coat coloration in soybeans (2020).
