**AWARDS ISSUED PRIOR TO JANUARY 20, 2025, WERE FUNDED UNDER PREVIOUS ADMINISTRATIONS AND MAY NOT REFLECT THE PRIORITIES AND POLICIES OF THE CURRENT ADMINISTRATION.** WHEAT STREAK MOSAIC (WSM) IS ONE OF THE MOST ECONOMICALLY IMPORTANT VIRAL DISEASES OF WHEAT WITH AN ESTIMATED ANNUAL LOSS OF 1.5-5.6% OF THE U.S. WHEAT CROP. WHILE CULTURAL CONTROL CAN MITIGATE THE DISEASE, RESISTANT VARIETIES ARE SORELY NEEDED TO REDUCE THE LOSSES AND ENSURE FOOD SECURITY AND FARM PROFITABILITY INTO THE FUTURE. THE WSM COMPLEX IS ASSOCIATED WITH SEVERAL DOCUMENTED VIRUSES WITHWHEAT STREAK MOSAIC VIRUS(WSMV) AS THE PREDOMINANT FOLLOWED BY MIXED INFECTIONS WITHTRITICUM MOSAIC VIRUS(TRIMV). TO DATE, ONLY THREE RESISTANT GENES HAVE BEEN IDENTIFIED AGAINST WSM. ALTHOUGH THE USE OF CURRENT RESISTANT VARIETIES IS PROMISING, RESISTANCE-BREAKING VIRUS ISOLATES HAVE BEEN RECENTLY REPORTED. HENCE, IT IS CRUCIAL FOR BREEDING PROGRAMS TO CONTINUE SEARCHING FOR ALTERNATIVE RESISTANCE FROM DIFFERENT SOURCES INCLUDING WHEAT WILD RELATIVES.AEGILOPS TAUSCHII, WHICH IS THE DIPLOID DONOR OF THE D GENOME OF CULTIVATED BREAD WHEAT, HAS KNOWN RESISTANCE TO MANY PESTS AND DISEASES. DESPITE THE SIGNIFICANT DAMAGE OF WHEAT VIRAL DISEASES, THIS SPECIES HAS NOT BEEN EXPLORED AS A SOURCE OF RESISTANCE FOR VIRUSES. TO ADDRESS THIS KNOWLEDGE GAP, THIS PROJECT WILL EXPLORE A LARGE PANELAE. TAUSCHIIACCESSIONS FOR RESISTANCE/TOLERANCE TO WSMV USING ASSOCIATION MAPPING WITH WHOLE-GENOME SEQUENCING DATA TO IDENTIFY RESISTANCE LOCI WHICH CAN BE SUBSEQUENTLY USED FOR WHEAT IMPROVEMENT. TO BETTER UNDERSTAND THE DYNAMICS AND BIOLOGY OF THE WSM, WE WILL EVALUATE RESISTANCE/TOLERANCE THROUGH PHENOTYPIC ASSESSMENT OF DISEASE SYMPTOMS COMBINED WITH THE VIRUS ACCUMULATION QUANTIFICATION. TO DISENTANGLE THE SYNERGISTIC IMPACT, IDENTIFIED RESISTANT ACCESSIONS WILL BE ASSESSED FOR WSMV IN SINGLE AND MIXED INFECTIONS WITH TRIMV. THE IDENTIFICATION OF RESISTANCE SOURCES AND SPECIFIC RESISTANCE GENE LOCI ALONG WITH THE DETAILED UNDERSTANDING OF RESISTANCE/TOLERANCE TO WSM GENERATED FROM THIS STUDY WILL HELP TO IMPROVE WHEAT GERMPLASM FOR VIRAL RESISTANCE.