GENE FLOW BETWEEN GENETICALLY ENGINEERED (GE) AND ORGANIC AND CONVENTIONAL ALFALFA FIELDS IS STILL OCCURRING DESPITE THE DIVERSE MEASURES IMPLEMENTED TO CONTROL IT. THE GLYPHOSATE RESISTANCE (GR) GENE IS A GE GENE THAT IS SPREADING AMONG ALFALFA FIELDS AND TO FERAL ALFALFA POPULATIONS. FERAL ALFALFA REPRESENTS PLANTS OF CULTIVATED ALFALFA THAT HAVE ESCAPED FROM THE FIELD AND HAVE ESTABLISHED IN THE WILD. FERAL ALFALFA CAN SERVE AS REFUGE FOR GE GENES AND CAN ACT AS A BRIDGE BETWEEN ALFALFA FIELDS AND THEREFORE IMPACTS THE SPREAD OF GE GENES IN ALFALFA. ALTHOUGH THE GR GENE HAS BEEN DETECTED IN MANY FERAL ALFALFA POPULATIONS WE KNOW LITTLE ABOUT ITS FREQUENCY IN FERAL ALFALFA POPULATIONS AND ABOUT ITS IMPACT OM THE POLLINATORS PESTS AND DISEASES OF FERAL ALFALFA. MOREOVER WE MUST DETERMINE WHETHER THIS GENE ALTERS THE REPRODUCTIVE CHARACTERISTICS OF FERAL ALFALFA AND ITS POTENTIAL FOR INVASIVENESS. FILLING THESE KNOWLEDGE GAPS IS THE OVERALL GOAL OF THIS PROPOSAL. WE PROPOSE TO (1) EXPAND THE GEOGRAPHICAL SURVEY OF FERAL ALFALFA POPULATIONS AND ESTIMATE THE FREQUENCY OF THE GR GENE IN THESE POPULATIONS; (2) QUANTIFY THE IMPACT OF THE GR GENE ON POLLINATORS PESTS AND DISEASE AND ON LIFE HISTORY PARAMETERS OF FERAL ALFALFA ACROSS REGIONS AND (3) PARAMETERIZE POPULATION MATRIX MODELS FOR GR AND NON-GR ALFALFA TO DETERMINE THE GROWTH RATE OF GR AND NON-GR ALFALFA ACROSS REGIONS. TO REACH THESE GOALS WE WILL REVISIT PREVIOUSLY VISITED FERAL POPULATIONS (CA ID WA) AND EXPAND THE SEARCH FOR FERAL POPULATIONS IN THESE AND OTHER STATES (WY MT KS AND WI). IN EACH POPULATION WE WILL TEST FOR THE PRESENCE OF THE GR GENE AND CALCULATE ITS FREQUENCY. WE WILL QUANTIFY THE IMPACT OF THE GR GENE ON POLLINATORS PESTS AND DISEASE AND LIFE HISTORY PARAMETERS OF FERAL ALFALFA BY CONTRASTING THESE CHARACTERISTICS BETWEEN GR AND NON-GR FERAL ALFALFA ACROSS REGIONS. FINALLY USING THE LIFE HISTORY PARAMETERS WE WILL BUILD POPULATION MATRIX MODELS TO QUANTIFY THE POTENTIAL FOR INVASIVENESS BETWEEN GR STATUS AND ACROSS REGIONS. INFORMATION GATHERED IN THIS PROPOSAL WILL IMPROVE OUR UNDERSTANDING OF THE ROLE OF FERAL POPULATIONS IN MAINTAINING AND SPREADING THE GR GENE WITH THE AIM OF GUIDING THE DEVELOPMENT OF STRONGER RULES FOR COEXISTENCE.