Nitrogen-Use Efficiency of Maize Natural Variation and Newly Created Mutants will pursue two primary objectives:  assess natural allelic variation for NUE under contrasting N conditions at the UNL Havelock Research Farm, and conduct a USDA-compliant field trial to evaluate the agronomic performance of newly created mutants using modern biotechnology. Although decades of breeding under nitrogen-sufficient conditions may have eliminated resilient alleles from modern U.S. germplasm, researchers will look to maize landraces from nutrient-poor regions—like highland Mexico and the Andes—that harbor untapped potential for nitrogen efficiency. The long-term goal is to generate genetic materials carrying these N-efficient alleles that are adapted to Nebraska environments and can be integrated into elite maize lines without sacrificing yield. Delivering maize hybrids with enhanced NUE will help reduce fertilizer inputs, increase profitability and strengthen the sustainability and resilience of Nebraska agriculture.