**AWARDS ISSUED PRIOR TO JANUARY 20, 2025, WERE FUNDED UNDER PREVIOUS ADMINISTRATIONS AND MAY NOT REFLECT THE PRIORITIES AND POLICIES OF THE CURRENT ADMINISTRATION.** THE DEMAND FOR ORGANIC TOMATOES IN THE SOUTHEAST IS HIGH, BUT PRODUCTION IS LIMITED DUE TO THE LACK OF REGIONALLY ADAPTED HIGH-YIELDING VARIETIES. ORGANIC GROWERS HAVE REQUESTED RESEARCH ON DISEASE MANAGEMENT PRACTICES INCLUDING IMPROVED VARIETIES WITH SUPERIOR FRUIT QUALITY SO THAT THEY CAN TAKE ADVANTAGE OF THE EVER-INCREASING MARKET DEMAND. OUR LONG-TERM GOAL IS TO DEVELOP SUSTAINABLE APPROACHES IN DISEASE MANAGEMENT FOR ORGANIC PRODUCTION BY INTEGRATING RESISTANCE BREEDING AND GRAFTING METHODS WELL-ADAPTED TO ORGANIC GROWING CONDITIONS IN THE SOUTHEAST. THE PROPOSED PROJECT WILL BENEFIT FARMERS IN THE U.S. IN GENERAL, AND IN THE SOUTHEAST IN PARTICULAR, WHO NEED HIGH-VALUE CROPS THAT CAN BE GROWN ON SMALL ACREAGES. THIS PROPOSAL WAS DEVELOPED THROUGH DIRECT INTERACTION WITH THE ORGANIC GROWERS. THE OBJECTIVES OF THIS PROPOSAL ARE:(1) DETERMINE GENOTYPIC DIFFERENCES FOR FOLIAR AND SOILBORNE FUNGAL DISEASE RESISTANCE, AND FRUIT QUALITY IN HEIRLOOM TOMATO VARIETIES GROWN UNDER ORGANIC CONDITIONS. (2) IDENTIFICATION OF SUITABLE TOMATO VARIETIES AND ROOTSTOCKS FOR ORGANIC PRODUCTION THROUGH PARTICIPATORY VARIETY SELECTION FOR HIGH YIELD, DISEASE RESISTANCE, AND FRUIT QUALITY. (3A) GENETIC ANALYSIS OF HOST RESISTANCE TO EARLY BLIGHT (EB), SEPTORIA LEAF SPOT (SLS), AND SOUTHERN STEM BLIGHT (SSB). (3B) ASSESSMENT OF RESISTANCE TO PATHOTYPES OF ALTENARIA LINARIAE AND SEPTORIA LYCOPERSICI USING MOLECULAR MARKERS COMPLEMENTED BY VIRULENCE TESTING. (4) DISSEMINATE KNOWLEDGE GAINED ON TOMATO VARIETIES AND PRODUCTION SYSTEMS GROWN IN ORGANIC CONDITIONS TO FARMERS, EXTENSION AGENTS, INDUSTRY, AND THE GENERAL PUBLIC. THE PROPOSED RESEARCH IS RELEVANT TO THE ORG PROGRAM AND WILL FACILITATE THE DEVELOPMENT OF ORGANIC AGRICULTURE PRODUCTION (ESPECIALLY TRANSITIONING SYSTEMS), BIODIVERSITY, MANAGEMENT OF PRIORITY DISEASES, AND INTEGRATING NOVEL TECHNOLOGY INTO ORGANIC SYSTEMS.