Wheat harvest on the Palouse. Click the image for more information about it.

New "Waxy" Wheat Being Tested for Public Release

By Jan Suszkiw
May 25, 2005

Agricultural Research Service (ARS) scientists are field-testing a soft white spring wheat whose starch could open the door to novel food uses. That's the hope of Craig Morris, a cereal chemist who developed the new wheat, called Penawawa-X, at the ARS Western Wheat Quality Laboratory at Pullman, Wash.

In that and other Pacific Northwest states, soft white wheat is typically grown for making cookies, cakes, udon noodles, flatbreads and other Asian or Middle Eastern baked goods. The wheat's starch consists of two kinds of glucose polymer: a branched form called amylopectin, and a straight-chain form called amylose.

According to Morris, who directs the ARS lab, Penawawa-X would be one of the first commercial, soft white spring wheats with 100-percent amylopectin starch, a trait known as "full-waxy." As such, it forms a paste at lower temperatures and swells with more water than regular or partially waxy wheat starches (those containing less than 25 percent amylose).

Waxy starch gels also do not lose water upon exposure to freezing and thawing. Food-bodying agents, shelf-life extenders and shortening replacement are some potential uses envisioned for full-waxy starches, including those from rice, corn and barley.

Morris developed Penawawa-X using conventional plant breeding techniques that enabled him to combine three deficient forms of the gene for granule-bound starch synthase (GBSS), the enzyme responsible for making amylose. Since the deficient forms can't make GBSS, no amylose is made either. Besides novel food uses, the full-waxy starch may have industrial applications, perhaps in adhesives.

To identify possible uses, Morris' lab sent dozens of samples of Penawawa-X wheat to bakers, millers, food companies and others. Under an ARS cooperative research and development agreement, one company is exploring commercial use of the wheat's starch, flour, bran and other components.

Multistate field trials are now under way to generate yield and other data necessary to register Penawawa-X in the journal Crop Science and to publicly release it.

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