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GMO Alfalfa

In January 2011, the USDA deregulated the planting of genetically modified alfalfa. The current trait of interest is for tolerance to glyphosate also known as Roundup Ready (RR). It is expected that Roundup Ready alfalfa will be planted in the USA in 2011. In Canada this trait was approved for use in 2005 but has not yet been commercialized for use on farms. Currently there are no registered varieties of alfalfa and glyphosate is not registered for this use on alfalfa in Canada. In time however it will likely be planted here. To understand the potential risks we need to understand how alfalfa is currently grown and how GMO alfalfa may potentially spread.

In the Ontario situation most alfalfa fields are planted with 10-30% perennial grasses. Grasses are planted to improve feed value, harvestability, and palatability for the livestock. RR alfalfa would only be appropriate for use in pure alfalfa fields which has not been the general preference of producers in Ontario. Spraying a typical hay field with glyphosate would kill all perennial grasses. The use of a herbicide like Roundup is useful to reduce weeds but current practices of using underseeding with grains for establishment and short rotations of less than 3-4 years for the hay crop reduces the need for this type of herbicide.

A primary concern of GMO alfalfa is for pollen drift and the pollination of non-GMO alfalfa plants. RR alfalfa will likely see its greatest utility in intensively managed alfalfa fields that are harvested in a 3-5 cuts/yr system before the crop flowers. This early cutting would eliminate pollen spread. For seed to be produced the hay would have to remain standing for another 4-6 weeks after flowering. This could happen if the pollen spreads to feral alfalfa plants that are growing outside the field boundaries. Feral alfalfa should be eliminated near seed fields where this is a risk. Care also needs to be taken at seeding to avoid seed spills of GMO seed and allowing seed to be spread into non-harvested areas.

Another trait of alfalfa plants is that they are autotoxic - if an alfalfa plant produces seed and that seeds falls to the ground it will not be able to produce a healthy plant within about 15 cm of an existing mature alfalfa plant. Adjacent grass plants in the stand also outcompete these new alfalfa seedlings. This reduces the chance of pollen from another field creating GMO plants within a non-GMO field.

Most of our alfalfa seed is produced in western Canada or USA. The main concern will be to ensure the purity of the non-GMO seed. Isolation distance guidelines for alfalfa seed production will need to take this into account as will other seed handling practices. Most alfalfa pollination is by leaf cutter bees that do not travel as far as honey bees.

In the future we will likely see more types of GMO alfalfa that will increase yields or improve the digestibility and other feed traits of alfalfa and these may see greater usefulness in Ontario.

Organic prohibits GMO and organic farmers must manage their farms to reduce the chances of GMO in their organic products. Like pesticides, GMO's are part of the farm environment, and we must learn how to manage any potential issues arising from their use.

Another article discussing this issue is Understanding Roundup Ready Alfalfa by Dr. Dan Undersander, Univ of Wisconsin .

Links to other articles on biotech alfalfa and coexistence of GE are available.