Falling number test

A sample of wheat goes through a falling number test for starch damage at the USDA Agricultural Research Service laboratory in Pullman, Wash. The agency is advertising for a researcher to tackle the problem.

Northwest wheat farmers can check online to see how the different wheat varieties fared this year in falling number tests.

USDA Agricultural Research Service molecular geneticist Camille Steber posts the information gleaned from Washington State University cereal variety trials on her website. The tool compares falling number susceptibility and yield, two important factors for farmers deciding which varieties to plant next.

The website shows “which had high falling numbers, which ones also yield well,” Steber said.

Falling number is a test that measures starch damage in wheat that reduces the quality of baked goods and noodles. Grain inspectors measure the time it takes two pins on a falling number test machine to fall through a ground wheat-water slurry, measuring viscosity. The price of grain with a low falling number is discounted because end-use quality is compromised by starch damage.

Farmers were caught off-guard in 2016, when roughly 44 percent of soft white wheat samples and 42 percent of club wheat samples tested below 300, the industry standard. The industry estimates the damage that year cost farmers more than $30 million in lower prices.

Steber hopes the data will help wheat breeders avoid releasing varieties susceptible to falling number.

Scott Steinbacher, regional manager of the Washington State Department of Agriculture grain inspection program, said he’s seeing more samples with falling number above 300 in the Colfax and Spokane offices as harvest progresses.

“The difficult part now is all those (samples with) low falling numbers are being resubmitted to be double-checked. ... it’s hard to tell the difference between an original and a resubmit,” he said.

The harvest rush is winding down in the Spokane office, while the Colfax office has a steady flow of samples coming in.

Falling number this year has been consistent with Steber’s expectations. The enzyme late-maturity alpha amylase, or LMA, caused problems in areas where the wheat flowered earlier. Wheat was in a susceptible window during a cold snap in June, Steber said. Wide fluctuations in temperature can damage wheat during a certain stage of its maturity.

Farmers are having less trouble in areas where the wheat matured later, she said.

“We’re getting problems, but the falling numbers aren’t as extremely low as what we saw in 2016,” she said. Most were in the high 200s, she said.

Steber and Steinbacher are both concerned that recent rain could lead to sprouting on wheat still in the fields. Sprouting can also damage starch and lead to low falling number test results.

“At this point I’m just hoping we don’t get a pre-harvest sprouting problem on top of an LMA problem,” Steber said.



Recommended for you