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United States Department of Agriculture

Agricultural Research Service

Research Project: Acquisition, Evaluation and Conversation of Temperate Forage Legume Genetic Resources Title: Tracking the Roundup Ready® gene: implications for coexistence

Author
item Greene, Stephanie

Submitted to: Meeting Abstract
Publication Type: Proceedings
Publication Acceptance Date: January 10, 2012
Publication Date: January 15, 2012
Citation: Greene, S.L. 2012. Tracking the Roundup Ready® gene: implications for coexistence. Proceedings for the 2012 Winter Seed School, Western Alfalfa Seed Growers Conference, January 15-17, Las Vegas, NV. pp53-55.

Interpretive Summary: With the deregulation of genetically engineered alfalfa in 2011, the alfalfa industry has been concerned about the coexistence of genetically engineered and non-GE alfalfa seed production. The USDA is committed to conducting research to address these concerns. In 2011 we conducted a survey to obtain a baseline estimate of the presence of transgenic roadside alfalfa plants. We surveyed alfalfa seed production areas in Fresno County, CA, Canyon Co., Idaho, and Walla Walla Co., Washington. At each location we sampled 700-800 survey sites. Leaf and seed were collected from alfalfa plants growing at the site. Back in the lab, dried leaves were tested for the Roundup ready alfalfa (RRA) gene with test strips. Based on our preliminary analysis, we detected feral-RRA populations at each of our study locations. These plants were detected 4 years after the 2007 injunction against planting RRA, which suggested that the RRA transgene can persist in the environment. In Fresno and Canyon County, 24% of the sites we visited had roadside populations, and 29% (Fresno) and 26% (Canyon) of the populations tested positive for the transgene. Only 13% of the sites in Walla Walla County had roadside populations, and 8% tested positive for the transgene. Seed-mediated gene flow may be significant since feral populations were more frequent on some main arterial roads. Although seed production locations had RRA-feral sites, sites were also located elsewhere, suggesting hay production may be a source of feral and feral-RRA escapes. Our team is gearing up to launch a 4 year study that will assess relative levels of RR gene flow along commercial-scale GE alfalfa hay and seed production pathways taking into account different landscape factors and pollinators. The final output of the project will be to develop a production-level gene flow model that industry can use to guide the selection of specific co-existence strategies based on location, production environment and type of pollinator used.

Technical Abstract: The USDA has been conducting research to address concerns voiced by the alfalfa industry regarding the coexistence of genetically engineered and non-GE alfalfa seed production. In 2011 a survey was conducted to get a baseline estimate of the presence of transgenic roadside alfalfa plants. We surveyed alfalfa seed production areas in Fresno County, CA, Canyon Co., Idaho, and Walla Walla Co., Washington. Survey sites were randomly selected along rural roads using the Spatially Balanced Sample Design tool from ARC GIS 10. At each location we sampled 700-800 survey sites. We also stopped to sample feral alfalfa which we encountered along our routes. Leaf and seed were collected from alfalfa plants growing at the site. Back in the lab, dried leaves were tested for the RRA gene with RUR test strips. At each site we also collected data on topography, wind, agricultural, ecological, and population factors to help us better explain the presence of the RRA transgene. Based on our preliminary analysis, we detected feral-RRA populations at each of our study locations. These plants were detected 4 years after the 2007 injunction against planting RRA, which suggested that the RRA transgene can persist in the environment. In Fresno and Canyon County, 24% of the sites we visited had roadside populations, and 29% (Fresno) and 26% (Canyon) of the populations tested positive for the transgene. Only 13% of the sites in Walla Walla County had roadside populations, and 8% tested positive for the transgene. Seed-mediated gene flow may be significant since feral populations were more frequent on some main arterial roads. Although seed production locations had RRA-feral sites, sites were also located elsewhere, suggesting hay production may be a source of feral and feral-RRA escapes. Our team is gearing up to launch a 4 year study that will assess relative levels of RR gene flow along commercial-scale GE alfalfa hay and seed production pathways taking into account different landscape factors and pollinators. We will continue to focus on seed production areas in the following counties: Fresno, CA; Canyon, ID; Walla Walla and Grant, WA. The final output of the project will be to develop a production-level gene flow model that industry can use to guide the selection of specific co-existence strategies based on location, production environment and type of pollinator used.

Last Modified: 12/22/2014
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