Wheat evaluated for cereal cyst nematode resistance
By John O’Connell
ST. ANTHONY, Idaho — Researchers involved in a long-running evaluation of Pacific Northwest wheat varieties have made recommendations for growers coping with cereal cyst nematode infestations.
The project — funded by the Idaho Wheat Commission, Oregon Wheat Commission and Washington Grain Commission — also aims to provide its first comprehensive data on resistant barley varieties from this summer’s trials.
UI Extension cereals pathologist Juliet Marshall, co-director of the project, has witnessed up to 30 percent yield losses due to cereal cyst nematode in fields planted in susceptible varieties in the Rexburg and Sugar City areas. She explained roots of symptomatic plants resemble a “witch’s broom.” Infestations are also common in Eastern Washington and Eastern Oregon.
“I do think it’s an under-recognized problem. I have gone to several fields where it’s been a mystery as far as why fields aren’t healthy,” Marshall said.
Oregon State University plant pathology professor and project co-director Richard Smiley said the top performing soft white wheat variety in the trials, both in yields and suppressing nematode reproduction, was the numbered line 08SB0658-B, which is being evaluated for release. He said WB Rockland, popular in southeast Idaho, has been the top performing hard red wheat variety, and WB 9576 has also tested well.
The hard red spring wheat Kelse is a good choice for Washington and Oregon farmers, Smiley said. UI Stone, a soft white, maintained favorable yields but didn’t curtail nematode reproduction.
Smiley has been evaluating wheat varieties for resistance and tolerance to both root lesion nematode and cereal cyst nematode since 1999, and has worked on the current project with UI since 2010. Initially, trials were also conducted in Oregon and Washington, but starting last season, they were done exclusively in St. Anthony, where sandy soils facilitate root evaluations.
Smiley and OSU have also developed wheat crosses with cereal cyst and root lesion nematode in mind, sharing the resistant germplasm with about nine public and private breeding programs. Some of the resulting breeding lines are in the seventh field generation, and USDA’s Pullman, Wash., Agricultural Research Service is working to identify genetic markers responsible for their nematode resistance. Genetic markers should dramatically expedite breeding efforts and wheat line evaluations.
The researchers conducted their first evaluations of barley lines exposed to cereal cyst nematode last season in St. Anthony. Several feed barley and 6-row malting barley varieties and the 2-row European malting barley Odyssey proved to be effective at suppressing cereal cyst nematode reproduction. Smiley explained yield results from last season were inconclusive because the nematicide application method resulted in the stunting of crops. This season, he hopes to obtain a full picture of barley varieties.
Though Odyssey appears promising thus far, Marshall explained Limagrain introduced it to the U.S., and it must obtain approval through the American Malting Barley Association to be accepted by malting companies.
In addition to planting tolerant and resistant varieties, Marshall said growers can reduce cereal cyst nematode populations by breaking up cereal crop rotations with potatoes, alfalfa and other broadleaf crops. A webinar detailing the research is available for viewing at www.idahowheat.org.