SEMI-DWARF WHEAT MADE THE GREEN REVOLUTION A GREAT SUCCESS VIA RESISTANCE TO YIELD-REDUCING LODGING. HOWEVER, THE DWARF GENE ALSO REDUCED NUE, WHICH IS ALSO COMPROMISED DUE TO INCREASED CO2 LEVELS. AN INCREASE IN N FERTILIZER INPUT NOT ONLY INCREASES WHEAT PRODUCTION COSTS, BUT CAN ALSO DAMAGE OUR ENVIRONMENT DUE TO WATER POLLUTION. NEW SEMI-DWARF WHEAT VARIETIES COMBINING HIGH YIELD POTENTIAL AND HIGH NUE ARE URGENTLY NEEDED TO SUSTAINABLY MEET THE INCREASING DEMAND FOR WHEAT GRAINS.THIS PROJECT TAKES THE ADVANTAGE OF THE RECENTLY-DEVELOPED PRECISION GENOME EDITING TECHNOLOGY TO MODIFY THE N MODULATOR GRF4 TO INCREASE NUE AND GRAIN YIELD. THE PROJECT INCLUDES THREE SPECIFIC OBJECTIVES: 1) CREATE SYNONYMOUS MUTATIONS TO OVER-EXPRESS GRF4, 2) EVALUATE THE MUTATION EFFECT ON YIELD COMPONENTS AND NUE, AND 3) DEVELOP BREEDING-READY GERMPLASM. THE COMPLETION OF THIS PROJECT WILL DELIVER A SET OF EDITED MRE MUTATIONS IN THE GRF4 GENES, DETAILED INFORMATION OF THE MUTATION EFFECT ON GRF4 EXPRESSION AND PHENOTYPES, AND A PACKAGE OF COMPLETELY NEW GERMPLASM WITH ENHANCED NUE AND YIELD POTENTIAL. WITH THIS, THE PROJECT IS EXPECTED TO CONTRIBUTE TO A MORE PROFITABLE AND SUSTAINABLE US WHEAT INDUSTRY AND RURAL ECONOMY.