Rotate SCN-resistant seed varieties for optimal protection

By The SCN Coalition™

Understanding the difference between soybean cyst nematode-resistant varieties may help soybean growers understand the importance of rotating sources of resistance, which is one of the “active SCN management” strategies advised by The SCN Coalition. For combating SCN during the 2022 growing season, The SCN Coalition encourages growers to work with their advisors to select the appropriate SCN-resistant varieties.

“Most soybean growers are familiar with PI 88788 and Peking, the two most widely used sources of resistance to soybean cyst nematode,” says Melissa Mitchum, University of Georgia molecular nematologist. “What might be news to growers is these different sources of SCN resistance have different resistance genes — also known as different modes of action.”

Simply speaking, resistance from the PI 88788 line contains one gene, Rhg1. Resistance from Peking contains two resistance genes, Rhg1 and Rhg4. “There are also different flavors — aka alleles — of the Rhg1 genes, which is where the A and B designations come into play,” Mitchum adds.… Continue reading