Feb. 21, 2011

Soybean producers and farm managers have a new resource to help with soybean variety selection for SCN-infested fields. In 2010, the Nebraska Soybean Board funded a project to provide a standard evaluation platform for the most common soybean varieties grown in Nebraska in SCN-infested fields. The goal of this project is to help producers identify soybean varieties that yield well, yet do not allow significant reproduction of SCN. That’s right – even though a soybean variety is marketed as resistant, they can vary in their effects on SCN populations by influencing reproduction differently.

The most common source of SCN-resistance -- PI88788 -- is the largest group in the trials. Most varieties in this group were similar; however, a few allowed more reproduction. Another parameter that can influence this interaction with the SCN resistance type is the HG type or biotype of the SCN population at the field site. We have observed some fields in Nebraska where more than 10% of the SCN population can effectively reproduce on the PI88788 resistance.

What can you do? At this time we do not recommend producers test their fields to determine SCN HG type (biotype), but we do recommend follow-up soil sampling every five or six years to make sure your rotation is working correctly. If your population has adapted to the source of resistance in the varieties you are growing, you will see an increase in population. If you observe this, we can look into identifying the HG type in the problem field.

The SCN Variety Trial summaries are at pdc.unl.edu/agriculturecrops/soybean/soybeancystnematode. This is our first year for this program and summaries will be posted earlier in future years. This site also includes summaries of the Soybean Cyst Nematode Management Field Day demonstration plots for each year.

If you are a seedsman and would like to have your top SCN-resistant soybean varieties entered into this trial, e-mail lgiesler1@unl.edu. The cost for testing is covered by the Nebraska Soybean Board.

Loren Giesler Extension Plant Pathologist, Lincoln
John Wilson, Extension Educator, Burt County