Why is it necessary that farmers limit the use of farm-saved seed to one generation past Certified Seed?
The varietal blend will change over time, especially under heavy insect pressure. For example, under extremely heavy midge infestation, the susceptible refuge variety could sustain up to 50 percent yield loss. To keep the refuge at the desired level of 10 percent of the plant population, the use of farm-saved seed beyond one year will be prohibited. At present, the test to measure the level of the refuge variety has not been validated to the point where it is commercially available. It is currently being used by seed growers to measure the level of refuge varieties in high generation pedigreed seed. This test should become more widely available in the future. Based on what we know today, the best way to preserve the midge tolerance is to not use farm-saved seed beyond one generation from certified and to purchase certified seed at least every two years.
