ROOT GROWTH AND DEVELOPMENT IS REGULATED BY MANY FACTORS INCLUDING PLANT HORMONES SUCH AS AUXIN. RECENT REPORTS HAVE DEMONSTRATED THAT ROOT ARCHITECTURE CAN DIRECTLY IMPACT YIELD AND DROUGHT RESISTANCE IN MAIZE, BUT LITTLE IS KNOWN REGARDING GENETIC FACTORS THAT DETERMINE MAIZE ROOT DEVELOPMENT. WE HAVE RECENTLY IDENTIFIED THREE NOVEL MAIZE ROOT MUTANTS WHICH ARE AFFECTED IN AUXIN PATHWAYS AND THUS PROVIDE AN INROADS INTO FILLING THESE KNOWLEDGE GAPS. IN THIS STUDY WE PLAN TO USE GENETIC AND MOLECULAR APPROACHES TO DEFINE ROLES FOR THESE PROTEINS IN ROOT DEVELOPMENT. ADDITIONALLY, WE WILL TEST THE ABILITY OF THESE GENES TO INFLUENCE YIELD IN FIELD GROWN MAIZE. THESE STUDIES WILL FILL CURRENT KNOWLEDGE GAPS REGARDING HOW AUXIN PATHWAY PROTEINS CONTROL ROOT DEVELOPMENT IN MAIZE AND TEST THE HYPOTHESIS THAT ALTERED ROOT ARCHITECTURE IMPACTS YIELD IN MAIZE. ALTOGETHER THESE STUDIES FIT WITH THE NIFA STRATEGIC GOAL TO ADVANCE OUR NATION'S ABILITY TO ACHIEVE GLOBAL FOOD SECURITY AND FIGHT HUNGER (NIFA STRATEGIC PLAN FY2014-2018). UPON COMPLETION OF THIS PROJECT WE WILL HAVE DEFINED THREE NEW GROWTH REGULATORS IN MAIZE AND IDENTIFIED HOW ROOT DEVELOPMENT CAN IMPACT YIELD. BECAUSE MAIZE IS A KEY CROP FOR FOOD AND FUEL IN THE UNITED STATES WE ANTICIPATE THESE FINDINGS COULD IMPROVE STRATEGIES FOR ENHANCING CROP YIELD.