ISU Seed Lab Certified to Test for Dicamba Tolerance and Other Biotech Traits

Mike Stahr
(Commentary by Seed lab Manager, Mike Stahr)

Individuals who submit seed samples to the Iowa State University (ISU) Seed Lab to be tested for the presence of biotech traits normally do so for two reasons. First, they want to ensure that one or more specific biotech traits are present in a sample so that it will provide protection from insects and/or tolerance to herbicides. Or secondly, they want to ensure that a biotech trait is not present in a sample because they plan to use the seed for organic production. Or, that the trait is present at a sufficiently low level so as to be acceptable.

One of the newest biotech traits tested at the ISU Seed Lab is tolerance to Dicamba. Dicamba is a growth-regulator herbicide that selectively kills broad-leafed weeds. Conventional soybeans are susceptible to this herbicide, but varieties with the Dicamba tolerance trait can tolerate the herbicide without visible damage. The ISU Seed Lab’s Trait Lab is certified to test for this trait, and to determine if seed is suitable for selling under the Dicamba tolerance trait label.

Seeds are tested using an herbicide bioassay test. This test exposes seed to Dicamba herbicide and only Dicamba-tolerant seed produce a normal seedling under these conditions. Control seedlings without the trait exhibit herbicide-toxicity symptoms. Similarly, when Dicamba-tolerant soybean plants are sprayed with Dicamba, broad-leafed weeds are killed, while the soybean plants remain healthy. Unfortunately, off-target movement of this herbicide can induce herbicide-toxicity symptoms even at very low doses. This drift could potentially affect yield, and in some cases the seed quality of susceptible plants. The ISU Seed Lab is uniquely positioned to test soybean seed for this and other biotech traits

For more information about biotech trait testing, contact

Iowa Seed & Biosafety News —10/01/17