Protection from lepidopteran insect feeding is unlikely to significantly alter the weediness potential of Glycine soja

Environmental risk assessment of a genetically modified (GM) crop is an integral part of the process to gain approval for the import or cultivation of these crops.  One specific aspect of an environmental risk assessment for GM soybean is an assessment of the potential for increased weediness of Glycine soja if it crossed with soybean with a GM trait. To provide information and data for a potential weediness assessment of G. soja should it cross with soybean with a lepidopteran protection trait, two studies were conducted: 1) a survey of natural G. soja populations to determine what herbivores fed upon G. soja and what level of defoliation they caused, and 2) an experiment to assess the impact of defoliation on G. soja seed production. The results from these studies showed that the defoliation by lepidopteran observed is very low (averaging less than 2% across locations) compared to that caused by other taxa, and defoliation levels were very low relative to those that would likely cause reductions in pod and seed production, it is reasonable to conclude that there would likely be little to no impact to the reproductive ability of G. soja should outcrossing to G. soja with a lepidopteran protection trait occur.  Thus, acquiring the lepidopteran protection trait alone would likely have little impact on G. soja weediness potential.  Considering these results and the very low level of outcrossing between G. max and G. soja, it is highly unlikely that introgression of a GM trait conferring lepidopteran tolerance into G. soja would impact its weediness potential.