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United States Department of Agriculture

Agricultural Research Service

2012 Annual Report

1a.Objectives (from AD-416):
The primary objective will be to fill information gaps regarding pollen flow dynamics. That new information will directly inform management practices to help ensure hay and seed production for both genetically engineered (GE) sensitive and non-sensitive markets continue to prosper in the United States.

1b.Approach (from AD-416):
Feral alfalfa populations will be surveyed for RRA transgene. Feral alfalfa plants will be systematically sampled in an 8 km radius around six RRA fields. Leaf tissue will be tested for the presence of the RRA transgene using QuickStix™ tests at the collection site. Seed will be harvested from previously tested feral plants and tested for transgene presence. All positive plants will be confirmed for the RRA transgene using event specific PCR primers. At each collection site and RRA source field, information on variables influencing pollen-mediated transmission will be collected including topography, prevailing wind, farmer practices/history, surrounding crops/vegetation, and feral plant density. Spatial maps of RRA gene flow will be generated. Results from our study of transgene transmission from RRA hay and seed fields to feral alfalfa will help us better understand the extent of insect-mediated pollen flow across different environments, and the role feral alfalfa plays in transgene flow.

3.Progress Report:

Since 2007, the alfalfa industry has been working to develop coexistence strategies for genetically engineered (GE) Roundup®-Ready alfalfa (RRA) spearheaded by the National Alfalfa and Forage Alliance (NAFA). The USDA Office of secretary has also been supporting research efforts to help address the concerns of industry with science-based information. In 2011 the USDA supported a baseline assessment of the RRA transgene in feral roadside alfalfa. In July, August and September of 2011, and May 2012, 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. Positive tests will be confirmed by comparing to DNA sequence data obtained from Monsanto. 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. Preliminary results suggested that Fresno and Canyon county had similar levels of transgenic roadside plants. Twenty four percent of the sites visited had roadside/feral populations, and the RRA transgene was detected in 29 % (Fresno) and 26 % (Canyon) of these plants. In Walla Walla county, WA, 13% of the sites visited has roadside populations, and 8 % of these plants carried the RRA gene. These plants were detected 4 years after the 2007 injunction against planting RRA, which suggests that the RRA transgene can persist in the environment. Seed-mediated gene flow may also be significant since feral populations were more frequent on some main arterial roads. Although seed production locations had RRA-feral sites, these sites were also located elsewhere, suggesting hay production may be a source of feral and feral-RRA escapes. This fall we will complete our analysis which will give us a better understanding of how environmental factors influence the occurrence of feral alfalfa and the movement of the RRA transgene into feral populations.

Last Modified: 8/26/2016
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