Field Efficacy Assessment of Transgenic Roundup Ready Wheat

Herbicide tolerant crops provide farmers access to a new weed control option of nonselective herbicide such as Roundup 1 A wheat transgenic event 33391 was produced via Agrobacterium ‐mediated transformation of a donor cultivar Bobwhite wheat ( Triticum aestivum L.) and was identified as a commercial candidate to develop Roundup Ready wheat 2 The objective of this study was to assess field efficacy of the transgenic event in spring wheat production regions in North America. Transgenic event 33391 was tested in field trials at 14 locations in 1999, 13 locations in 2000, and 14 locations in 2001. All trials were split‐plot designs with multiple rates of Roundup treatment. No vegetative or reproductive damage was observed with the application of 4 L ha −1 Roundup at the 3‐ to 5‐leaf stages. No yield reduction was observed with Roundup treatment. The transgenic event with or without Roundup application yielded as high as the nontransgenic Bobwhite. These results indicate that the wheat transgenic event 33391 has at least 2× tolerance to the nonselective herbicide Roundup.