URBAN AGRICULTURE IN THE U.S. AND GLOBALLY IS OFTEN TOUTED AS HAVING THE POTENTIAL FOR MEETING URBAN COMMUNITIES NEEDS IN LOCALLY-GROWN FRESH AND HEALTHY VEGETABLES PRODUCE. HOWEVER, ABIOTIC AND BIOTIC STRESSES STILL SIGNIFICANTLY LIMIT YIELD POTENTIAL AND PROFIT MARGINS ACHIEVED IN GROWING THESE VEGETABLES IN THE CURRENT SMALL-SCALE URBAN FARMING OPERATIONS. THESE CHALLENGES CALL ON AGRICULTURE-RELATED RESEARCHERS ACROSS UNIVERSITIES IN THE U.S. AMONG OTHER KEY PLAYERS IN DEVELOPING EFFICIENT AND SUSTAINABLE MANAGEMENT PRACTICES TO IMPROVE PERFORMANCE OF THESE URBAN FARMING OPERATIONS. THIS SEED GRANT IS PROPOSED TO EXPAND OUR INITIAL RESEARCH WORK FOR GENERATING REGION-SPECIFIC, SCIENCE-BASED PRODUCTION PRACTICES FOR ENHANCING PRODUCTIVITY, PROFITABILITY, AND SUSTAINABILITY OF HIGH-VALUE VEGETABLE CROPPING SYSTEMS IN URBAN ENVIRONMENTS IN TEXAS AND BEYOND. SPECIFICALLY, WE WILL PURSUE TWO KEY RESEARCH OBJECTIVES AIMED AT GENERATING DATA TO OPTIMIZE CONTROLLED ENVIRONMENT HYDROPONIC PRODUCTION SYSTEMS OF VEGETABLE CROPS THROUGH CULTIVAR SELECTION, NUTRIENT SOLUTION CONCENTRATION, SUPPLEMENTAL LIGHTING, AND VEGETABLE GRAFTING TECHNIQUE IN HIGH TUNNEL AND GREENHOUSE. OBJECTIVE 1 WILL EVALUATE THE INTERACTION EFFECTS OF SUPPLEMENTAL LIGHTING AND NUTRIENT CONCENTRATIONS ON PHYSIOLOGICAL TRAITS, GROWTH, NUTRIENT ACCUMULATION, AND YIELDS OF LETTUCE IN THESE SEMI-CONTROLLED PRODUCTION ENVIRONMENTS. IN OBJECTIVE 2, WE WILL EVALUATE THE INTEGRATED USE OF VEGETABLE GRAFTING TECHNIQUE FOR EFFICIENT HYDROPONIC TOMATO PRODUCTION UNDER HIGH TUNNEL ENVIRONMENT. THESE STUDIES WILL GENERATE PRACTICAL GUIDELINES FOR SUSTAINABLE HYDROPONIC PRODUCTION OF VEGETABLE CROPS TO ADVANCE URBAN AGRICULTURE IN TEXAS AND BEYOND. THIS RESEARCH THEREFORE WILL ADDRESS THE AFRI PROGRAM AREA PRIORITIES FOUNDATIONAL KNOWLEDGE OF AGRICULTURAL PRODUCTION SYSTEMS RELATED TO DEVELOPING INNOVATIVE PRODUCTION SYSTEMS TO OPTIMIZE PRODUCTIVITY AND PROFITABILITY.