Changes coming to how frost and mildew are assessed in Western Canadian wheat


The way Western Canadian wheat is graded for frost/heat stress and mildew will be changing slightly on August 1, 2018.

Until now, if both grading factors were present in a sample of grain, they were assessed together based on standard samples that visually showed the effect of both factors.

The Canadian Grain Commission says recent research shows that frost/heat stress and mildew do not have a compounding negative effect on the end-use functionality of wheat, and so the CGC will be updating its guidelines for grading for the 2018-19 crop year to account for both factors independently.

Mildew in a CWRS wheat sample (courtesy CGC)

Individual standard samples for frost/heat stress and mildew will replace the current combined standard samples, preventing unnecessary downgrading of wheat in some cases, says the CGC.

“The Canadian Grain Commission is committed to science-based evaluation as the cornerstone of the grading system. As part of our broader grain grading modernization, this change will help to better meet the evolving needs of the grain industry while safeguarding the quality and reputation of Canadian wheat,” says Patti Miller, the CGC’s chief commissioner.

Frost/heat stress refers to kernels with blistered brans as a result of exposure to freezing temperatures or prolonged hot weather conditions.

Mildew kernels are affected by fungi that develop under conditions of excessive moisture affecting unthreshed kernels of wheat. Samples affected by mildew have an overall greyish discolouration with grey to black mildew spores typically attached to the brush end of the kernel.
(Source: Canadian Grain Commission)

The changes were recommended by the Western Standards Committee. They don’t apply to Eastern wheat classes, however the guides for mildew in Eastern classes will be renamed as “standards” effective July 1, 2018.

Mildew standards for milling wheat classes were loosened in 2016 after the CGC found mildew doesn’t impact the milling qualities of wheat as much as it affects appearance. Those changes were made after widespread downgrading due to mildew caused by wet conditions in 2014.


Mildew Standards Loosened for Western Canadian Milling Wheat

Mildew and Frost Could Result in Grading Differences Between Grain Buyers

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