�Objective 1. Create hybrid rootstocks which 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.�During Oct-Dec 2018, six new replicated rootstock trials were field planted, including three on the East coast region, two in the Central ridge region, and one in the Southwest region.� Replicated randomized experimental designs were used and included several commercial standard rootstocks for comparison.Multiple trees of about 120 selected new rootstock hybrids were budded and grown in the nursery, in preparation for field planting new rootstock field trials.� These nursery trees included many of the most promising SuperSour hybrids identified in ongoing trials established in previous years, as well as several commercial standard rootstocks.� These nursery trees also include several new and different hybrids chosen because of newly available information about parentage and characteristics best associated with outstanding traits.� Three new field trials with sweet orange scion will be planted from these trees in 2019, including one trial in the East coast region, one in the Central ridge region, and one in the Southwest region.� A rootstock trial with grapefruit scion is also planned for planting during spring 2019 in the East coast region.�Objective 2. Collect field performance data from early-stage replicated rootstock field trials and release new rootstock cultivars as justified by superior performance in multiyear field trials.�Seventeen rootstock trials planted prior to summer 2018 (as described in the Proposal Appendix ii) were monitored and used for data collection on field performance, as appropriate during this quarter for the scion involved.� Yield and fruit quality data was collected from four Hamlin and one pummelo field trial.Three new USDA rootstocks were released on 2 November 2018, identified as US SuperSour 1 (SS1), US SuperSour 2 (SS2), and US SuperSour 3 (SS3), and are freely available without restriction.� An informational sheet with performance data on the three rootstocks was prepared and distributed widely to industry, and provided to CRDF.� All three new rootstocks demonstrated good fruit quality with sweet orange and superior fruit yield in trials, compared with Sour orange, Swingle, and Cleopatra rootstocks.� Seed source trees have been planted with all three new rootstocks, although initially propagation will be limited to cuttings and micropropagation from FDACS clean source material.����