Practical Screening Method from USDA to Speed Up Scab-Resistant Wheat Breeding

Individual kernels of wheat and barley can be quickly evaluated for resistance to a damaging scab disease by using near infrared light (NIR) technology, according to a U.S. Department of Agriculture (USDA) study conducted in support of a program to safeguard these valuable grain crops.

NIR light is partially absorbed by the kernels, creating a type of "fingerprint" scientists can use to detect fusarium head blight, also known as "scab," or its related mycotoxin, called deoxynivalenol, in single kernels of wheat or barley, according to engineer Floyd Dowell, with USDA's Agricultural Research Service (ARS). ARS is USDA's chief intramural scientific research agency, and Dowell works at the agency's Center for Grain and Animal Health Research in Manhattan, Kan.

Scab is a fungus that causes yield losses in wheat and barley. The ability to detect—in single kernels of wheat—the fungus or the toxin it produces will help breeders rapidly and objectively evaluate new wheat lines and select for resistance to the fungus or its toxin.

Dowell and colleagues measured NIR absorption values of pure deoxynivalenol and kernels with and without the toxin or fungus. This information was used to improve near-infrared calibrations used to sort single kernels based on scab infection or deoxynivalenol levels.

This research was published in the Journal of Near Infrared Spectroscopy, and was partially funded by the U.S. Wheat and Barley Scab Initiative (USWBSI) managed by ARS.

USWBSI has also developed several online tools to keep growers apprised of the latest scab threats. A website known as "Scab Smart" provides a quick guide to help growers predict disease risk throughout the growing season, select the right fungicides, and choose resistant varieties of wheat and barley to minimize the threat of an outbreak. Growers, millers and suppliers can also sign up to receive cell phone or e-mail alerts that provide weekly updates on the likelihood of scab in their areas.

This research supports the USDA priority of promoting international food security and food safety.