A healthy wheat head (left) stands in contrast to one inoculated with Fusarium graminearum showing severe symptoms of Fusarium head blight disease (right). Click the image for more information about it.

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New Durum Wheat Line Resists Scab Disease

By Jan Suszkiw
March 20, 2007

A new germplasm line of durum wheat, dubbed DGE-1, is now available for geneticists and researchers to use in the fight against the fungus Fusarium graminearum, which causes scab disease.

Scab, also known as Fusarium head blight, can substantially diminish the grain yield and quality of durum, or "macaroni wheat," which is used to make pasta and semolina. U.S. durum growers produced 101 million bushels of the cereal crop in 2006.

Unchecked, the Fusarium fungus infects wheat heads, causing the kernels to shrivel up and turn chalky white. It can also produce toxins which reduce the market value and quality of the kernels.

Today's durum cultivars contain little or no scab resistance. However, the wheatgrass Lophopyrum elongatum is almost immune to scab, notes Prem Jauhar, a research geneticist in the Red River Valley Agricultural Research Center, operated by the Agricultural Research Service (ARS) in Fargo, N.D.

DGE-1 has a pair of chromosomes from this wild grass that makes the new wheat germplasm line scab-resistant.

Jauhar's studies have shown that the pair of grass chromosomes carrying scab resistance became a stable part of DGE-1's genome, meaning that the trait won't be lost when propagated from seed. Screening under greenhouse and field conditions has shown an average 21 percent infection in DGE-1 heads, compared to 80 percent in the durum cultivar Langdon. In field tests, DGE-1 plants grew to nearly 30 inches tall and matured one to two weeks later than Langdon. Its seed was also slightly smaller but showed 100 percent germination.

Released in January, DGE-1 isn't meant for direct use by farmers, but rather by scientists conducting basic and applied research aimed at developing new, scab-resistant durum cultivars. Plant geneticists, breeders and other researchers engaged in similar work will find DGE-1 useful.

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