Barley and other cereal grains would be more nutritious if they contained less phytate.

Adjusting Fertilizer to Create Low-Phytate Crops

By Don Comis
November 29, 2006

Giving too much phosphorus to wheat and barley plants has been shown to raise the amount stored as phytate, rather than as more digestible forms of phosphorus. This finding is important for two reasons: Livestock that are fed high-phytate grains excrete more phosphorus in their manure, which can pollute water. Also, phosphorus is a finite resource that could be irreplaceable once it has been thoroughly mined—which could happen in the next 25 years.

Agricultural Research Service (ARS) geneticist Edward J. Souza and colleagues at the University of Idaho Research and Extension Center in Aberdeen—David Bowen, Mary J. Guttieri and Karen M. Peterson—made the discovery. Souza, formerly at the University of Idaho, is now research leader of the ARS Soft Wheat Quality Research Unit in Wooster, Ohio. Guttieri is now with the Ohio Agricultural Research and Development Center in Wooster, and Bowen is now with Pioneer Hi-Bred International, Inc., Johnston, Iowa.

The researchers found that soil phosphorus levels may affect grain phytate levels as much as plant breeding can, offering two complementary solutions to the nutritional and environmental problems caused by high phytate levels in grains. Besides being more environmentally sound, getting the application rate for phosphorus fertilizers just right might improve the nutrients delivered by grain crops such as wheat and barley.

Not only is the phosphorus in low-phytate grain crops more digestible by people, but low-phytate grains free up minerals essential to human nutrition: zinc, manganese and iron.

ARS plant geneticist Victor Raboy, in Aberdeen, is a co-author of a paper on phosphorus development in barley seeds—one of four papers by Souza, Guttieri and Peterson in the November-December 2006 issue of Crop Science Journal. Raboy pioneered development of low-phytate corn, rice and barley. His patented work also led to low-phytate soybeans.

A summary paper is available online.

ARS is the U.S. Department of Agriculture's chief scientific research agency.