A series of tests on seed samples in Louisiana and Texas have shown that none contained the genetically modified material from a line of genetically modified LibertyLink rice, LLRICE601.

The findings included a second round of independent laboratory testing of five varieties grown by the LSU AgCenter foundation seed program. Tests on 28 rice seed samples at the USDA-ARS Rice Research Unit in Beaumont, Texas, also proved to be negative for the LLRICE601 material.

LSU AgCenter officials said the latest round of test results, obtained Sept. 7, concluded that LLRICE601 is undetectable in foundation seed of the five long-grain varieties, including Dellrose grown in 2005, and this year’s foundation seed of Cocodrie, Trenasse, Clearfield 131 and Clearfield 151.

Results from the first testing showed that only Cheniere foundation seed grown in 2003 contained trace amounts of LL601, but no trace of LL601 was detected in the Cheniere foundation seed from 2005.

David Boethel, LSU AgCenter vice chancellor for research, said this latest series of tests shows the problem appears to be limited to one variety grown in one year. “We are fairly comfortable that LL601 can be eliminated from seed stocks,” he said.

Anna McClung, Rice Varietal Improvement Program leader for the USDA-ARS Rice Research Unit, said Sept. 8 that the varietals that tested negative from Beaumont were Presidio, Jefferson, Dixiebelle, Sabine, Neches, Hidalgo, Sierra, Arborio, IAC600, Jasmine 85, Della, Dellmont, and Carolina Gold.

The following samples also tested negative: foundation rice seed samples for 2003, 2004, 2005, and 2006; commercial seed samples for 2005 and 2006; organic seed samples for 2006; and USDA-ARS head row seed samples for 2003, 2004, and 2005, she said.

The LSU AgCenter’s first round of tests, validated by the USDA’s Grain Inspection, Packers and Stockyards Administration, also indicated lots from 13 other varieties currently in the LSU AgCenter’s foundation seed program also appeared to be free of LL601. The other varieties involved in the initial testing included Cocodrie, Cypress, Trenasse, Pirogue, Bengal, Jupiter, Clearfield 131 and Clearfield 161.

LibertyLink lines of rice were developed by Bayer CropScience to allow the Liberty herbicide to be sprayed on weeds without killing the rice plants. The USDA and the Food and Drug Administration have approved two LibertyLink lines similar to LLRICE601, although those are not in commercial production, and federal authorities have concluded that LibertyLink rice poses no threat to food safety, human health or the environment.

Field research on LibertyLink was conducted in collaboration with Bayer CropScience at the LSU AgCenter’s Rice Research Station near Crowley, La., from 1999 through 2001.

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