**AWARDS ISSUED PRIOR TO JANUARY 20, 2025, WERE FUNDED UNDER PREVIOUS ADMINISTRATIONS AND MAY NOT REFLECT THE PRIORITIES AND POLICIES OF THE CURRENT ADMINISTRATION.** FUSIFORM RUST DISEASE, CAUSED BY THE FUNGAL PATHOGEN CRONARTIUM QUERCUUM F.SP. FUSIFORME (CQF), IS DESTRUCTIVE AND COSTLY IN LOBLOLLY PINE (PINUS TAEDA). QUALITATIVE RESISTANCE TO FUSIFORM RUST, NOTED BY PRESENCE (SUSCEPTIBLE) OR ABSENCE (RESISTANT) OF GALLS ON STEMS AND BRANCHES IS THE FOCUS OF CURRENT PINE BREEDING PROGRAMS THAT USE THIS GALL / NO-GALL TRAIT TO SELECT RUST RESISTANT PINES. HOWEVER, CROP LITERATURE SHOWS THAT BECAUSE QUALITATIVE RESISTANCE INVOLVES ONE OR FEW GENES, IT CAN BE RAPIDLY OVERCOME BY THE PATHOGEN. HERE WE WILL DIRECTLY ASSESS THE DURABILITY OF QUALITATIVE RESISTANCE TO FUSIFORM RUST. LOBLOLLY PINE HAS SEVERAL RUST RESISTANCE GENES OF MAJOR EFFECT; WE WILL TRACK THOSE GENES AND MONITOR THEIR EFFECTIVENESS WITH DNA MARKERS. QUANTITATIVE RESISTANCE, (VARIATION IN GALL SIZE), IS LESS EXPLORED AND IS AN ALTERNATIVE BREEDING TARGET IF QUALITATIVE RESISTANCE IS OVERCOME AND NOT DURABLE. SEQUENCING OF THE CQF GENOME IDENTIFIED EFFECTORS THAT INTERACT WITH RESISTANCE GENE PRODUCTS IN THE HOST, PROVIDING MARKERS FOR GENOTYPING THE PATHOGEN AND GUIDING SEEDLING DEPLOYMENT. WE PROPOSE AN INTEGRATIVE BREEDING APPROACH TO DEVELOP DURABLE RESISTANCE THROUGH THREE AIMS: 1) HOST-PATHOGEN MARKER DEVELOPMENT OF RESISTANT AND SUSCEPTIBLE PINE SEEDLINGS AND WHOLE-GENOME SEQUENCING OF CQF ISOLATES; INTEGRATING HOST AND PATHOGEN MARKERS IN GENOMIC PREDICTION MODELS, 2) INTEGRATING DATA FROM PAST AND PRESENT GENETIC EVALUATION TRIALS, USING GENOMIC CONNECTIVITY AMONG DIVERSE POPULATIONS, AND 3) EXPANDING THE RANGE OF HOST X PATHOGEN COMBINATIONS FOR MODEL VALIDATION, RESULTING IN THE FIRST COMPREHENSIVE MODEL OF THE LOBLOLLY PINE-FUSIFORM RUST PATHOSYSTEM FOR IMPROVING PINE BREEDING PROGRAMS.