Ames, Iowa, USA
January 23, 2012

Source: Integrated Crop Management News
By Greg Tylka, Department of Plant Pathology and Microbiology

The soybean cyst nematode (SCN) is one of the most damaging pests of soybean in Iowa and throughout the Midwest. The amount of yield loss that occurs is directly related to the SCN egg population densities (numbers) in the soil. Keeping SCN egg population densities from increasing to high levels is needed to maintain profitable soybean production in SCN-infested fields. An effective way to produce high soybean yields and keep SCN egg population densities in check is to grow SCN-resistant soybean varieties.

Iowa farmers can choose from more than 800 soybean varieties described as resistant to SCN (recently discussed in ICM News). SCN resistance is never 100 percent effective, but varieties that allow less than 10 percent SCN reproduction meet the scientific definition of SCN resistance.

Soybean varieties vary greatly in yield and in ability to control the nematode. Differences in nematode control among resistant varieties is because there are at least four different genes involved in conferring resistance to SCN in soybean, and not every SCN-resistant soybean variety has all of the genes in the same combination. Soybean varieties with fewer SCN resistance genes will allow more SCN reproduction than varieties with the full complement of resistance genes. The amount of SCN reproduction that a variety allows is not provided in the description of the variety.

Full article

Website: http://crops.extension.iastate.edu

Published: January 23, 2012