Create new candidate hybrids. During this quarter, seed from last year’s crosses were grown-out in the greenhouse in preparation for propagation, testing, and establishment of seed trees. Emphasis of hybridization in the USDA rootstock program is among parents with superior tolerance to HLB, CTV, and Phytophthora. Propagate and plant new field trials. Budwood increase trees of selected scions were propagated in our nursery, in preparation for budding trees for new rootstock trials in the fall and spring. Plantings of new field trials this quarter were delayed because of institutional Coronavirus shutdown. Nursery trees for rootstock trials with Valencia, Star Ruby grapefruit, Eureka lemon, and Navel orange are being prepared in the greenhouse for field planting sometime later in 2020.Collect data from field trials. Information on tree performance is collected from established field trials, and includes measurement of tree size, fruit crop, fruit quality, and pathogen titer, HLB symptoms, and assessments of tree health. Cropping data is collected during the time of scion harvest, and this quarter is not usually used for harvest of any citrus crops in Florida. Assessments of tree health and measurements of tree size were completed on 2 trials during this quarter, which was reduced from the normal because of the institutional Coronavirus shutdown.Evaluate effectiveness for seed propagation of new rootstocks and develop seed sources. Some of the newest hybrid rootstocks can be uniformly propagated by seed, but others cannot. As the best rootstocks are identified through testing, seed sources are established and used to determine trueness-to-type from seed. Studies were continued this quarter to evaluate seed propagation for 25 of the most promising SuperSour hybrid rootstocks. SSR analysis of progeny was delayed because of institutional Coronavirus shutdown.Posting field trial results for grower access. The USDA rootstock trials produce large amounts of information that is useful to identify the most promising of the new hybrids, as well as comparative information on the relative performance of many commercially available rootstocks. During this quarter, the website https://www.citrusrootstocks.org/ was updated with new summaries of performance information from the USDA rootstock trials. Release of superior new rootstocks for commercial use. Several of the 300 advanced Supersour rootstock hybrids in field trials are exhibiting good performance in comparison with the commercial standard rootstocks. Performance data continues to be collected, but it is anticipated that 2-3 of the most outstanding of these will be officially released in 2021-22.