GENE FLOW BETWEEN SORGHUM AND ITS WEEDY RELATIVES IN AGRICULTURAL LANDSCAPES REMAINS A TOPIC OF CONCERN FOR MANY STAKEHOLDERS. SORGHUM IS NATIVE TO EASTERN AFRICA, WHICH IS BELIEVED TO HAVE BEEN INTRODUCED TO THE US IN THE 19TH CENTURY. ALONG WITH GRAIN SORGHUM, ITS WILD RELATIVES WERE ALSO INTRODUCED INTO THE US FROM THEIR NATIVE REGION. JOHNSONGRASS, ONE OF THE WILD RELATIVES, IS WIDELY DISTRIBUTED AS A NOXIOUS WEED THROUGHOUT SORGHUM PRODUCTION AREAS IN THE SOUTHERN US. JOHNSONGRASS IS A PERENNIAL, TETRAPLOID SPECIES CAPABLE OF REPRODUCING BOTH BY SEEDS AND VEGETATIVE RHIZOMES AND THIS SPECIES CAN BE FOUND INFESTING CROP FIELDS AS WELL AS ROADSIDE AND OTHER NON-CULTIVATED AREAS. GIVEN THE EXCELLENT DROUGHT TOLERANCE AND AN ABILITY TO GROW UNDER MARGINAL ENVIRONMENTAL CONDITIONS, SORGHUM HAS BEEN CONSIDERED AS AN IMPORTANT FEEDSTOCK FOR BIOFUEL PRODUCTION. THE USE OF SORGHUM GRAIN AS HUMAN FOOD AND ANIMAL FEED IS ALSO IN THE RISE. SORGHUM INDUSTRY WILL BENEFIT FROM NEW AGRONOMIC (SUCH AS HERBICIDE RESISTANCE), BIOFUEL PRODUCTIVITY AND NUTRITIONAL QUALITY TRAITS INTRODUCED INTO THIS CROP.DESPITE THE IMPORTANCE OF GENETIC IMPROVEMENTS IN SORGHUM, THERE IS A LIKELIHOOD THAT GENE FLOW AND TRANSFER OF CERTAIN INTRODUCED TRAITS BETWEEN CULTIVATED SORGHUM AND ITS WEEDY RELATIVES, PARTICULARLY JOHNSONGRASS, MAY LEAD TO INCREASED WEEDINESS AND INVASIVENESS IN THE HYBRID PROGENIES. THE NATURE AND DYNAMICS OF GENE FLOW, HOWEVER, IS NOT FULLY UNDERSTOOD AND THERE EXIST SEVERAL KNOWLEDGE GAPS IN THIS REGARD. TO OUR KNOWLEDGE, THE VAST MAJORITY OF EXISTING RESEARCH ON GENE FLOW BETWEEN SORGHUM AND JOHNSONGRASS FOCUSES ON GENE FLOW ONLY IN ONE DIRECTION, I.E. USING JOHNSONGRASS AS THE MATERNAL PARENT. HOWEVER, GENE FLOW IN THE OPPOSITE DIRECTION (FROM JOHNSONGRASS TO SORGHUM) MAY ALSO BE IMPORTANT. A THOROUGH UNDERSTANDING IS REQUIRED ON THE FREQUENCY OF OUTCROSSING AS WELL AS PROGENY CHARACTERISTICS SUCH AS PLOIDY, LEVEL OF FERTILITY, RHIZOME PRODUCTION POTENTIAL, SEED PRODUCTION AND OVERALL FITNESS UNDER COMPETITION. FURTHER, FERAL SORGHUM IS COMMONLY FOUND ALONG ROADSIDES IN SOUTH TEXAS, OFTEN GROWING IN PROXIMITY TO JOHNSONGRASS, BUT THE ROLE OF FERAL SORGHUM IN GENE FLOW AND TRAIT TRANSFER TO THE BROADER ENVIRONMENT IS NOT CLEAR. THIS RESEARCH PROJECT IS AIMED AT ADDRESSING THESE VERY ASPECTS IN FILLING EXISTING CRITICAL KNOWLEDGE GAPS IN THIS AREA.IT IS EXPECTED THAT THE FINDINGS OF THIS RESEARCH WILL HELP DEVELOP A BETTER UNDERSTANDING OF THE NATURE AND CHARACTERISTICS OF GENE FLOW BETWEEN SORGHUM AND JOHNSONGRASS. THE FINDINGS WILL EVENTUALLY HELP IDENTIFY AVENUES FOR MINIMIZING AND MITIGATING GENE FLOW BETWEEN THE TWO SPECIES AND ASSIST THE DEVELOPMENT OF ROBUST STEWARDSHIP PRACTICES. THE FINDINGS WILL ALSO ASSIST THE FEDERAL AGENCIES APHIS AND EPA IN MAKING MORE INFORMED DECISIONS REGARDING THE REGULATION OF SORGHUM WITH NOVEL TRAITS. THE PROPOSAL IS MOST CLOSELY RELATED TO THE NIFA-BRAG PROGRAM AREA #3: CHARACTERISTICS, RATES, AND MECHANISMS OF GENE TRANSFER TO WILD RELATIVES.