Commercialization & Co-existance

Gene Flow in Alfalfa
California, with a large export market, grows approximately 30% of the alfalfa seed produced in the United States. A clear understanding of gene flow is essential to produce high purity seed, especially with the pending re-introduction of Roundup Ready® alfalfa in 2010. The SBC is continuing to work with Larry Teuber (UC Davis), Shannon Mueller (UC Cooperative Extension), James Hagler (USDA/ARS, Maricopa, AZ) and Forage Genetics International to determine gene flow between commercial-scale seed fields of alfalfa. In 2009, data were collected and processed to trace bee movement among fields using fluorescent “glow dust” and antibodies. The results indicate a high correlation between bee foraging and gene flow. The results of this study are being prepared for several publications and have already helped growers and seed certification agencies refine isolation distances and practices for seed production in alfalfa. Funding for this research is from the USDA National Research Initiative.

For more information see:
Roundup Ready Alfalfa: An Emerging Technology ANR Publicaton 8153.

Van Deynze, A.E., Fitzpatrick, S., Hammon, R., McCaslin, M.H., Putnam, D.H., Teuber, L.R., and Undersander, D.J. 2008. Gene Flow in Alfalfa: Biology, Mitigation, and Potential Impact on Production. Council for Agricultural Science and Technology.
         See Alfalfa Gene Flow in Alfalfa – CAST Press Release

2007 workshop on Gene Flow in Alfalfa: Biology, Mitigation and Potential Impact on Production

Gene Flow Studies in Cotton
California grew 275,000 acres of cotton in 2008, 155,000 acres (56%) of which was Pima. We previously conducted studies of gene flow in Acala cotton, and understanding gene flow in Pima cotton is critical to maintaining genetic purity for specific seed markets. In collaboration with Robert Hutmacher (UC Cooperative Extension), the SBC is studying gene flow in Pima cotton and between Pima and Acala cotton. In 2008, the SBC completed a two-year study by conducting herbicide bioassays on seed samples collected in
2006 and 2007 from commercial, conventional Pima cotton fields at distances from 10 feet to 1 mile from herbicide-resistant fields. Seed samples were also assayed from a small-scale field experiment conducted at the Kearney Research and Extension Center to supplement commercial field samplings. The positive seed samples were confirmed using test strips specific for the herbicide resistance protein. The proportion of seeds with herbicide resistance is a direct measure of gene flow. Gene flow in Pima cotton is 1/10 to 1/5 that of Acala cotton (published in 2005 by the SBC) at a given distance. This work was funded by the California Crop Improvement Association and Cotton Incorporated.

See publicaion in Crop Science, Volume 45, July-August 2005
Pollen-Mediated Gene Flow in California Cotton Depends on Pollinator Activity