During the second quarter of 2019, we continued our horticultural field trial evaluations as outlined in the proposal. Trees in all three trials are composed of Valencia scion on eight different rootstocks (US-802, US-812, US-897, US-942, US-1516, X-639, Swingle, Cleopatra). The SWFREC trial (Collier County) was established in October 2017. The two commercial trials were established in April 2018 on a typical Ridge site in Polk County and on a flatwoods type-site in southwest FL (Hendry County). Rhizotron root growth measurements at the SWFREC location were continued in monthly intervals. Results showed some differences in root growth among propagation methods within a rootstock cultivar during the first year of growth in the field. But, when averaged across all rootstock cultivars, no differences associated with propagation method were observed. Statistical analyses are still ongoing. After one year of growth, significant differences in tree height were found among trees on different rootstocks independent of the propagation method. The largest tree size was measured for US-1516 and the lowest for US-897. No statistically significant differences in tree size were attributed to the method by which rootstocks were propagated. Other horticultural parameters such as trunk diameter and the ratio of rootstock to scion trunk diameter were significantly influenced by rootstock and by propagation method. Nutrient analysis of leaves showed no significant differences associated with the propagation method, but differences were found among trees on different rootstocks for all nutrients except nitrogen and potassium. The SWFREC trial was demonstrated during a field day in April 2019.During the first year of growth in the commercial locations, no dieback of trees was observed for trees at the Polk County location. A small percentage of trees died within several weeks after transplant at the Hendry County location, but dieback was not related to the propagation method or rootstock cultivar. After one year of growth, no significant differences in tree height, canopy spread, and trunk diameter among trees were observed based on the method by which rootstocks were propagated in both trials. In contrast, significant differences were observed for trees on different rootstocks independent of the propagation method. Data analysis is still ongoing. Rhizotrons for root observations were installed during the previous quarter, and the first measurements were conducted.Tree propagations for the additional field trial to be conducted in Indian River County were completed and trees are maintained at the US Horticultural Research Lab in Ft. Pierce until ready for planting. Trees have Valencia scion and are grafted on four different rootstocks (US-812, US-897, US-942, and US-1516) propagated by seed, cuttings, and tissue culture.