Washington State University’s screening continues to find no evidence of glyphosate herbicide resistance in Pacific Northwest wheat varieties

June 2016

Washington State University glyphosate screening activities

  • In each year since the 2013 discovery of glyphosate resistant wheat in Oregon, the WSU Cereal Breeding and Variety Testing Programs implemented routine- annual phenotype screening for resistance. This is undertaken by using glyphosate herbicide to control over-planted and volunteer wheat in alleyways of field plots. Alleys are then inspected for wheat surviving the spray treatment. This is similar to the Phase I screening effort undertaken in 2013.
  • In each of the last three years (2014, 2015 and 2016), the field screening process has involved over 80 varieties, 2,000 advanced breeding lines and more than 35,000 individual plots from WSU cereal breeding and variety evaluation programs. Collectively, varieties included in these trials represent over 95 percent of the wheat acreage planted in Washington.
  • Testing to date has revealed no glyphosate resistant wheat in these trials.

2013 glyphosate-resistance screening efforts undertaken by Washington State University

  • At the time of the May 2013 discovery of glyphosate resistant wheat Washington State University launched a comprehensive effort to screen all wheat germplasm in its programs. In Phase I of this effort, we screened public and private varieties representing 90 percent Washington’s soft white winter wheat crop. We also screened nearly 75 percent of the less heavily planted spring wheat varieties with similar results. The Phase I 2013 screening process involved 60 varieties, 1,900 advanced breeding lines and more than 20,000 individual plots from WSU cereal breeding and variety evaluation programs. Testing completed in June, 2013 found no glyphosate-resistant wheat plants in any of the screening trials.
  • In Phase II testing in 2013, WSU initiated a new program to focus on foundation seed lots held by the Washington State Crop Improvement Association. Crop Improvement is the seed certification entity in Washington and their Foundation seed stocks represent the parent seed for all of the certified seed sold in Washington and the vast majority of all wheat seed planted in Washington. Importantly, we expanded the scope of the project to include Foundation seed of varieties from Oregon State University, the University of Idaho and varieties from two of the three largest private cereal seed companies in the Pacific Northwest (Limagrain Cereal Seeds and Monsanto/WestBred).
    • The trial occurred at the WSU Spillman Agronomy farm located outside of Pullman. In brief, 92 seed lots were involved in the final test. We planted over 100,000 seeds of each of the lots by growing them in the field and treating them with the glyphosate herbicide. Treating such a large number of seeds is important and would enable us to detect a very low frequency of contaminated plants, if they exist. None of the plants survived the spray, indicating there is no presence of the GM glyphosate resistance trait in any of the seed lots tested.
    • Together with the first round of testing, we evaluated varieties representing 97 percent of the winter wheat acreage and 93 percent of the spring wheat acreage in Washington, as well as a large majority of the acres in Oregon (88 percent) and Idaho (74 percent).
  • In summary, in 2013 we found no evidence of the GM trait in any of our testing. This includes pre-released germplasm at all stages of development in the breeding programs, parent (foundation) seed stocks, and commercially available certified seed. In a sense, this is wheat at all stages of the breeding, certified seed increase, and commercial sale/distribution process. This supported the belief that the 2013 incident in Oregon was an isolated case and that wheat with the GM trait is not present in Pacific Northwest commercial wheat seed.