Highlights of the University of Florida, Citrus Research and Education Center’s comprehensive citrus

A comprehensive citrus breeding and genetics program was established at the UF/CREC during the mid-1980'scombining conventional breeding with tools provided by tissue culture, emerging biotechnologies, moleculargenetics and genomics. Scion Improvement: The Florida citrus industry is 90% processing sweet oranges. Amajor goal has been to develop new cultivars for Not From Concentrate juice production with emphasis onincreasing juice quality and expanding seasonal availability. Improved clones from seedling introductions,budwood irradiation and somaclonal variation will be discussed. The fresh fruit industry in Florida is dominatedby grapefruit and seedy mandarins. Primary objectives for fresh fruit improvement include expandingseasonal availability, development of Canker tolerant and low furanocoumarin grapefruit, and developmentof seedless, easy-peeling mandarins. The focus of our program has been on parent development, andseedless triploid production via interploid crosses; strategies and successes will be discussed. RootstockImprovement: Initial focus was on improving soil adaptation, tree-size control to facilitate harvesting andcold-protection, and disease resistance, especially to blight, CTV induced quick decline and Phytophthora. Breeding objectives have since been expanded to include tolerance of the Diaprepes/Phytophthora complexand HLB, and development of rootstocks that facilitate advanced citrus production systems (ACPS). Progressfrom conventional breeding (both 2x and 4x) and somatic hybridization will be discussed. Genetic Engineeringand Genomics: Due to the HLB and Canker epidemics, focus has been on disease resistance gene discovery,transformation, and evaluation of transgenic plants; progress will be discussed.