** AWARDS ISSUED PRIOR TO JANUARY 20, 2025, WERE FUNDED UNDER PREVIOUS ADMINISTRATIONS AND MAY NOT REFLECT THE PRIORITIES AND POLICIES OF THE CURRENT ADMINISTRATION.** GROWING POPULATION AND SHRINKING AGRICULTURAL RESOURCES ARE ONE OF THE MOST IMPORTANT CHALLENGES FACING FOOD PRODUCTION. IN ORDER TO MEET THE PROJECTED INCREASE OF GLOBAL DEMAND FOR FOOD, FEED, AND FIBER (100% BY 2050), THE LINEAR PROGRESS WILL NEED TO BE INCREASED BY ACCELERATING THE EFFICIENCY, RELIABILITY, AND SPEED OF GENETIC IMPROVEMENT. DOUBLED HAPLOID (DH) TECHNOLOGY CAN SPEED UP INBRED LINE DEVELOPMENT BY REDUCING THE NUMBER OF GENERATIONS FROM SEVEN IN TRADITIONAL BREEDING TO TWO GENERATIONS IN DH BREEDING. THERE ARE TWO MAIN STEPS IN DH TECHNOLOGY. THE FIRST STEP IN A DH BREEDING PROGRAM IS TO PRODUCE HAPLOIDS FOR A DONOR GENOTYPE BY POLLINATING THE DONOR USING A MATERNAL HAPLOID INDUCER AS MALE. THE SECOND STEP IS TO PRODUCE DHS BY SELF-POLLINATING THE HAPLOIDS. HAPLOID MAIZE HAS A DECENT AMOUNT OF HAPLOID FEMALE FERTILITY, BUT LACK OF HAPLOID MALE FERTILITY (HMF) IS THE BOTTLENECK TO DEVELOP DH LINES EFFICIENTLY. TO OVERCOME THE HMF LIMITATION, HAPLOID SEEDLINGS ARE CHEMICALLY TREATED WITH COLCHICINE TO MEDIATE GENOME DOUBLING, WHICH IS LABOR- AND RESOURCE- INTENSIVE AND IT IS AN INEFFICIENT METHOD. THE ALTERNATIVE IS TO FIND GENETIC MECHANISM(S) TO RESTORE HMF.OUR PREVIOUS RESEARCH IN ARABIDOPSIS INFORMED US THAT MUTATIONS IN PARALLEL SPINDLE (PS) GENES ARE SUFFICIENT TO RESTORE HMF IN ARABIDOPSISAND THE DHS OBTAINED USING PS MUTATIONS HAVE NO CHROMOSOMAL ABNORMALITIES. THE GOAL OF THIS RESEARCH IS TO IDENTIFY MAIZE PS GENES WITH SEQUENCE SIMILARITY TO ARABIDOPSIS PS GENES. MUTATIONS BY TRANSPOSON INSERTION IN MAIZE PS GENES WILL BE IDENTIFIED FROM PUBLIC COLLECTION AND NEW MUTATION WILL BE CREATED BY GENOME EDITING EXPERIMENTS. HAPLOIDS WILL BE PRODUCED FOR THESE MUTANT PLANTS AND THEIR MALE FERTILITY WILL BE EVALUATED BY SCORING FOR THE PRESENCE OF ANTHERS AND POLLEN. ULTIMATELY, THIS PROJECT WILL IDENTIFY GENETIC MECHANISM(S) TO RESTORE HMF WITHOUT THE USE OF LABOR- AND RESOURCE- INTENSIVE AND TOXIC CHEMICAL METHODS. IN OTHER WORDS, HAPLOID SEEDS CAN BE DIRECTLY SOWN IN THE FIELD. GENETIC MECHANISM(S) TO RESTORE HMF HAS THE POTENTIAL TO MAKE DH TECHNOLOGY IN MAIZE BROADLY AVAILABLE, WHICH IS STILL MOSTLY CONFINED TO MAJOR CROP BREEDING PROGRAMS. FURTHER, THESE GENES ARE CONSERVED IN OTHER PLANT SPECIES OPENING THE POSSIBILITY FOR THE APPLICATION OF THIS TECHNOLOGY TO OTHER CROPS WHERE IT IS NOT AVAILABLE SO FAR.