Objective 1. Collect field performance data from replicated rootstock field trials and release new rootstock cultivars as justified by superior performance in multiyear field trials.Collect field performance data. Thirty-two USDA replicated rootstock trials are active. For the current quarter, canopy health was collected from all trials. Cropping and fruit quality data was collected from two early mandarin rootstock trials, and two lemon rootstock trials. Juice analysis of frozen samples continued from trials for the 2022-23 season. A new auto-titrator and spectrophotometer for use in fruit quality analysis were purchased from base USDA funds, and will greatly accelerate and improve the evaluation of fruit quality in rootstock trials.During this quarter, SSR assessment of trueness-to-type from seed was completed for the SuperSour rootstocks that are available now and will be released this year. This information on trueness-to-type from seed will be published shortly after the official release of the two new rootstocks. Additional work on trueness-to-type assessment and salinity tolerance of new rootstocks was continued.Release of new rootstocks. New rootstocks will be officially released by USDA for commercial use when justified by superior performance in multi-year replicated field trials. The most promising USDA rootstock selections are provided to the FDACS-DPI program for shoot tip grafting and disease testing in advance of potential release. The two new USDA rootstocks, US SuperSour 4 and US SuperSour 5 were released by USDA on September 5th, 2023, and are already clean and available in the DPI program to commercial nurseries. Four other promising new USDA rootstocks were provided to DPI for STG and testing this quarter, in preparation for possible release in future years.Objective 2. Create hybrid rootstocks that combine germplasm from parental material with good rootstock traits and HLB tolerance, propagate the most promising of these hybrids, and establish replicated field trials with commercial scions.Create hybrids. Selected new crosses were completed in spring 2023, and seed extracted this quarter. About 230 hybrid seedlings from high priority crosses will be grown in the spring for preliminary evaluation and further testing.Propagate hybrids. Trees for two new stage 2 rootstock trials with 33 advanced selection SuperSour rootstocks with Valencia scion continue growing in the nursery, with a plan for field planting in summer 2024.Establish replicated field trials. One new replicated field trial with a new high quality mandarin scion on 17 rootstocks was established this quarter at the Whitmore farm in Lake County.Tree care in trials. Periodic care was applied in the 32 field trials to maintain tree health and productivity, and manage weeds. Two young rootstock trials are being grown with IPCs. One rootstock trial is being used for a comparison of tree performance of different rootstocks with and without OTC injection.2. Please state what work is anticipated for next quarter:For the coming quarter, work will focus on collection of 2023-24 season yield and fruit quality data from trials with Hamlin scion, continuing propagation of trees for future trials, and care of existing trees in trials. Data analysis of tree performance in the 32 trials is underway, to evaluate SuperSour candidates for official release in 2025-26, and compare performance of those commercially available. Cooperative work continues to evaluate USDA rootstocks for tolerance/resistance to sting nematode, citrus nematode, salinity, cold hardiness, and other traits.3. Please state budget status (underspend or overspend, and why):The budget is on schedule for spending all funds by the end of the currently funded year. One employee left the program, and a recruitment is underway to take on those duties. Work is progressing as planned.