A new mildew-resistant wheat breeding stock has surprised U.S. Department of Agriculture plant pathologists by warding off every strain of powdery mildew in their laboratory gauntlet. Previously, eight strains out of ten was the best any wheat could do.

Bakery-bought cookies and cakes get their delicate texture from flour made with soft red winter wheat, which grows east of the Mississippi. But powdery mildew hits soft wheat types the hardest. This fungal disease costs wheat growers between $2 million and $3 million annually, said plant pathologist Steve Leath with USDA’s Agricultural Research Service in Raleigh, N.C. ARS is the chief research agency of USDA.

Enter NC 97BGTAB-10. It’s the new breeding stock developed by Leath--with the ARS Plant Science Research Unit--and his colleagues at North Carolina State University and the University of Georgia.

To breed this “perfect 10," the research team made traditional breeding crosses with wheat’s hardy wild ancestors found in the Middle East.

“Farmers wouldn’t want to plant this new breeding stock, since it doesn’t yield as well as their favorite varieties and its flour is not as soft,” said Leath. “But as a hybrid-parent in breeding programs, it could make the wheat they favor stronger against powdery mildew.”

ARS scientists have long known about soft wheat farmers’ mildew problem. That’s why they have been crossing U.S. varieties with tough, mildew-resistant wild wheat from Eastern Europe and the Middle East to find this winning genetic combination, Leath said.

The idea is to breed a hybrid with just enough of both the wild genes and the U.S. softness and yield traits. Commercial seed companies can use the breeding lines to build mildew resistance into their farmer-favored, bakery-bound soft red wheat varieties.

Leath’s university cooperators on NC 97BGTAB-10 are Jerry Johnson at the University of Georgia, Athens; and J. Paul Murphy at North Carolina State University, Raleigh.

Scientific contact: Steven Leath, plant pathologist, ARS Plant Science Research Unit, Agricultural Research Service, USDA, Raleigh, N.C., phone (919) 515-6819, fax (919) 515-7716, Steven_leath@ncsu.edu .

By Jill Lee

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