**AWARDS ISSUED PRIOR TO JANUARY 20, 2025, WERE FUNDED UNDER PREVIOUS ADMINISTRATIONS AND MAY NOT REFLECT THE PRIORITIES AND POLICIES OF THE CURRENT ADMINISTRATION.** THIS PROJECT ADDRESSES REGIONAL AND NATIONAL AGRICULTURAL NEEDS AND OPPORTUNITIES BY DEVELOPING GERMPLASM AND GENOMIC RESOURCES IN SUPPORT OF MOLECULAR BREEDING INITIATIVES IN QUINOA (CHENOPODIUM QUINOA), A HIGHLY NUTRITIOUS, HIGH VALUE PSEUDOCEREAL CROP. CURRENTLY AVAILABLE QUINOA VARIETIES ARE NOT WELL-ADAPTED FOR PROFITABLE CULTIVATION IN MANY REGIONS OF THE UNITED STATES, INCLUDING BUT NOT LIMITED TO THE NORTHEAST AND OTHER REGIONS OF HIGH HUMIDITY. HOWEVER, THE EXISTENCE AND SUCCESS OF WILD, WEEDY RELATIVES OF QUINOA IN THESE SAME GEOGRAPHIC REGIONS INDICATES THE POTENTIAL OF QUINOA TO RESPOND TO MODERN BREEDING PRACTICES AIMED AT DEVELOPING LOCALLY ADAPTED COMMERCIAL VARIETIES. THE PROJECT APPROACH RECOGNIZES THE GENETIC COMPLEXITY OF QUINOA, WHICH STEMS FROM ITS HYBRID ORIGIN AND POLYPLOID GENOMIC CONSTITUTION. SPECIFICALLY, THE QUINOA GENOME CONSISTS OF FOUR SETS OF CHROMOSOMES (ALLOTETRAPLOIDY), RATHER THAN THE MORE USUAL TWO SETS (DIPLOIDY), WHEREBY TWO OF QUINOA'S CHROMOSOME SETS ARE EVOLUTIONARILY DESCENDED FROM ITS A GENOME DIPLOID ANCESTOR AND TWO SETS ARE DESCENDED FROM ITS B GENOME DIPLOID ANCESTOR. THUS, QUINOA'S ALLOTETRAPLOID CHROMOSOME COMBINATION, ALSO FOUND IN ITS IMMEDIATE WILD RELATIVE C. BERLANDIERI, ORIGINALLY AROSE VIA NATURAL HYBRIDIZATION BETWEEN THE TWO ANCESTRAL DIPLOIDS. THIS NATURAL HYBRIDIZATION EVENT PRODUCED THE WILD ALLOTETRAPLOID ANCESTOR C. BERLANDIERI, FROM WHICH ALLOTETRAPLOID QUINOA THEN EVOLVED UNDER DOMESTICATION PRIMARILY IN THE HIGH PLAINS REGION OF SOUTH AMERICA. OUR AIM IS TO DEVELOP THE ANCESTRAL B GENOME DIPLOID CHENOPODIUM FICIFOLIUM AS A SIMPLIFIED GENETIC MODEL SYSTEM IN WHICH TO IDENTIFY AND CHARACTERIZE GENES INFLUENCING ECONOMIC TRAITS, INCLUDING TRAITS OF INTEREST TO GROWERS (E.G., FAVORABLE PLANT ARCHITECTURE, REDUCED DAYS TO MATURITY, DISEASE RESISTANCE, AND OTHERS), AND TRAITS OF INTEREST TO CONSUMERS (SEED SIZE AND FLAVOR, NUTRITIONAL VALUE, COST, ETC). ONCE GENES OF INTEREST ARE IDENTIFIED, WE WILL SURVEY GENE-SPECIFIC DNA SEQUENCE DIVERSITY IN A DIVERSE SET OF GERMPLASM, INCLUDING REPRESENTATIVE QUINOA VARIETIES, GERMPLASM SAMPLES OF QUINOA'S WEEDY IMMEDIATE ANCESTOR, C. BERLANDIERI, AND IN REPRESENTATIVES OF THE ANCESTRAL A AND B GENOME DIPLOIDS. GENETIC CHARACTERIZATION OF THE MOST FAVORABLE GENE VARIANTS (ALLELES) WILL PROVIDE BREEDERS WITH INCREASED POWERS TO INCORPORATE FAVORABLE ALLELE COMBINATIONS INTO NEWLY BRED VARIETIES. FINALLY, WE WILL ASSESS THE EFFECTS OF TARGETED GENE MANIPULATION VIA GENE EDITING TECHNIQUES IN C. FICIFOLIUM, C. BERLANDIERI, AND IN QUINOA WITH THE ULTIMATE AIM OF FURTHER ACCELERATING BREEDING PROGRESS IN THIS PROMISING CROP. GENETIC, GERMPLASM, AND KNOWLEDGE RESOURCES GENERATED BY THIS PROJECT WILL BE WIDELY SHARED TO THE POTENTIAL BENEFIT OF QUINOA BREEDERS THROUGHOUT THE WORLD. THE ANTICIPATED OUTCOME OF THIS PROJECT IS THAT QUINOA BREEDERS IN DIFFERING ENVIRONMENTS WILL GAIN INCREASED POWERS TO ACHIEVE AND ACCELERATE THE DEVELOPMENT OF NEW QUINOA CULTIVARS THAT COMBINE ECONOMIC TRAITS WITH THE CHARACTERISTICS THAT IMPART ADAPTATION TO THE RESPECTIVE GEOGRAPHIC REGION AND ITS AGRONOMIC PRACTICES, THEREBY ENABLING MORE GROWERS AND CONSUMERS TO MORE WIDELY SHARE IN THE BENEFITS OF THIS NUTRITIOUS AND INCREASINGLY POPULAR FOOD CROP.