YIELD EVALUATION OF A GLYPHOSATE-TOLERANT SOYBEAN LINE AFTER TREATMENT WITH GLYPHOSATE

Transformation of soybean [Glycine max (L.) Merr.] with a gene encodin g a glyphosate-tolerance 5-enolpyruvylshikimate-3-phosphate synthase e nzyme from Agrobacterium sp. strain CP4 resulted in the development of glyphosate-tolerant line 40-3-2. Glyphosate (N-phosphonomethyl glycin e) is the active ingredient of Roundup herbicide. Line 40-3-2 was yiel d tested at 17 locations in 1992, 23 locations in 1993, and 18 locatio ns in 1994. At those locations, broadcast applications of glyphosate a t various rates were made over 40-3-2 or its derivatives from early ve getative growth to pod fill. No significant yield reduction was observ ed as a result of the glyphosate treatment at any of the locations. De velopment of glyphosate-tolerant soybean promises to provide the farme r with access to a new weed control system that should result in lower production costs and reliable weed control under a wide range of cond itions.