Sustainable Pest Management Strategies for Arid-land Crops
Location: Pest Management and Biocontrol Research
Title: Gene Flow in Seed Alfalfa: A Summary of Recent Research
Submitted to: California Alfalfa Symposium Proceedings
Publication Type: Proceedings
Publication Acceptance Date: March 30, 2011
Publication Date: March 30, 2011
Citation: Mueller, S.C., Teuber, L.R., Hagler, J.R. 2011. Gene Flow in Seed Alfalfa: A Summary of Recent Research. California Alfalfa Symposium Proceedings. 43-45.
Interpretive Summary: Alfalfa seed is grown in the Western United States where the climate is suited to the production of high yields of a high quality product. Major producing states include California, Idaho, Nevada, Oregon, and Washington. Public and proprietary alfalfa varieties are produced for markets throughout the US and for export worldwide. California is one of the largest producers of alfalfa seed in the United States. It is unique from other Western seed-producing states in that the majority of the production is of non-dormant varieties and 80% of the seed is destined for export markets. Export markets have long valued the consistently high quality of California seed, but the introduction of the first biotech alfalfa in 2005 raised concerns about production and marketing of both forage and seed in markets sensitive to the presence of biotech traits.
Alfalfa wasn’t the first biotech crop to be produced in California, but it was the first perennial crop and seed production required the use of pollinators, which led to concerns that gene flow would impact other alfalfa hay or seed production fields in the area. Gene flow is not a new phenomenon; it is well documented that genes move between alfalfa varieties grown in close proximity. It is the sensitivity to the biotech origin of the genes controlling the trait that has brought such attention to gene flow. Gene flow issues resulted in a rocky introduction of Roundup Ready® alfalfa into US production systems. Less than one year after its release in June 2005, a lawsuit was filed questioning the lack of a thorough review of its environmental impact. Roundup Ready alfalfa deregulation was reversed in February 2007 and USDA-APHIS was ordered to conduct an Environmental Impact Study (EIS). Although new alfalfa fields could not be established after March 30, 2007, production continued on existing hay and seed fields planted to Roundup Ready alfalfa varieties. In December 2010, the final EIS was issued and in January 2011 Roundup Ready alfalfa was deregulated once again. Although it was deregulated without conditions, the industry recognized the need to protect production of conventional varieties in order to maintain existing domestic and export markets with sensitivity to biotech traits while allowing production of Roundup Ready varieties for markets that desired it.
Development of coexistence strategies began prior to the controversy over deregulation of Roundup Ready alfalfa. The industry recognized the importance of implementing stewardship programs because, in the future, other traits will become available through advances in
Gene flow is the mechanism by which a gene from one population becomes established in another population. There are two types of gene flow: pollen-mediated gene flow and seed-mediated gene flow. Pollen-mediated gene flow results from the movement of pollen from one location to another resulting in fertilization and production of a viable seed that contributes to the gene pool of the population to which it moved. Seed-mediated gene flow results from contamination from contaminated seed lots, contaminated harvest or processing equipment, and movement of seed with soil, wind, water or by animals.
Pollen flow is not equivalent to gene flow, although the terms are often used interchangeably. Pollen flow is the movement of pollen from one location to another, but pollen flow does not necessarily result in the transfer of genetic material (gene flow). It is important to note that the potential for either gene flow or pollen flow from a biotech field is no different from the potential for gene flow or pollen flow from a field producing a conventional alfalfa variety.