Gene flow from transgenic canola ( Brassica napus) to weedy relatives is an extant risk in implementing biotechnology in agricultural systems. Wild relatives, such as Brassica rapa and Raphanus raphanistrum, have been shown to hybridize with transgenic canola, and future research must characterize the possible ramifications of transgenic phenotypes contained within introgressed weed populations. We have developed a system to track the movement of an insecticidal Bt transgene from genetically modified canola into relatives by a visual marker, green fluorescent protein (GFP). Whole plant fluorescence has been used to track gene flow into B. rapa, and future studies will use these transgenic hybrid lines to test the impact of an insecticidal transgene on agricultural crops through competition studies.