Tolerance and yield of ‘H8001 RR’ soybean to single and sequential glyphosate applications made during vegetative and reproductive stages were examined in field trials in 2000 and 2001. In addition, germination and seedling characteristics from harvested seed were assessed. Glyphosate-resistant soybean tolerated single and sequential applications of 1.7 kg ae/ha glyphosate with minimal injury (≤5%), except for an R2 application in 2000 that caused 20% injury. All observed injury was transient and did not adversely affect soybean density, height, seed weight, or seed yield. Germination and seedling growth of harvested seed were similar to those of a nontreated control. These results suggest that glyphosate-resistant soybean can withstand sequential applications of glyphosate during vegetative and reproductive stages without prolonged adverse effects.

Nomenclature: Glyphosate; soybean, Glycine max (L.) Merr ‘H8001 RR’.

Additional index words: Injury, transgenic soybean, yield.