Will Roundup Ready wheat benefit you?
(July 9, 2002 -- CropChoice news)
by Andrea Geary
You might be one of the thousands of farmers who now use the herbicide Roundup to control weeds, or you might grow Roundup Ready
canola. But what is the value of growing Roundup Ready wheat if its developer, Monsanto, is granted the government approval needed to
put in on the market in Canada?
The question of whether or not to introduce Roundup Ready wheat, a genetically modified, herbicide-tolerant variety, into your fields requires
careful deliberation. Agronomic management questions are as important as the market impact questions that have been widely discussed
among farmers and others in the grain industry. For example, any problems with control of volunteer Roundup Ready wheat could affect our
ability to guarantee wheat shipments free of any genetically modified varieties. Many customers for western Canadian wheat have said that
they want to be assured that the wheat they buy is not co-mingled with genetically modified wheat.
The CWB believes that a thorough understanding of the agronomic issues related to Roundup Ready wheat is necessary in order to make
wise decisions on future use of this genetically modified variety. CWB agronomist, Mike Grenier wrote a discussion paper entitled,
ĎAgronomic Assessment of Roundup Ready Wheatí to provide farmers with more information. This paper brings together information and
professional opinions about the agronomic benefits and risks associated with the potential introduction of Roundup Ready wheat, and identifies
the main issues, information gaps and points of disagreement within this information. The paper's purpose is to disseminate information and
Grenierís paper identifies three main concerns about the potential impact of RRW. The first concern pertains to control of volunteer Roundup
Ready wheat. The cost and availability of control options for managing herbicide tolerant wheat would result in increasing complexity and risk
in managing crop rotations. Studies show that any potential returns that herbicide tolerant wheat offers farmers are highly sensitive to individual
management practices and cropping systems. Including more than one Roundup Ready crop in rotation would require careful management of
volunteers and could lead to increased herbicide costs, especially under conservation tillage systems.
The second concern involves gene spread. Field surveys demonstrate that volunteer wheat may persist in rotations for up to five years. Given
the frequency of wheat in crop rotations, and the length of volunteer persistence, gene spread by contamination through mixing of seed or
through pollen flow should be of primary concern for anyone who chooses not to adopt the technology. It appears that more research is
required on the risk of gene spread if Roundup Ready wheat is granted environmental release and grown on commercial scale.
The final main concern relates to herbicide resistance. While Roundup Ready wheat offers a new control option for resistant weed
management, there is worry that the in-crop use of Roundup will increase the selection pressure and risk of developing weed resistance to
glyphosate. Conservation tillage systems are highly reliant on the use of glyphosate for pre-seed weed control, and any increase in herbicide
costs due to glyphosate-resistant weeds could put conservation cropping systems at risk.
To read the complete discussion paper, please visit the CWBís Web site at http://www.cwb.ca or call 1-800-275-4292. Farmersí opinions are
essential to a complete discussion of this issue, so please send in your comments.
To reach the CWB, please call our toll-free phone line at 1-800-275-4292. This column is written on a regular basis by CWB communications
consultant Andrea Geary.