HIGHLIGHTS OF THE UNIVERSITY OF FLORIDA, CITRUS RESEARCH AND EDUCATION CENTER'S COMPREHENSIVE CITRUS BREEDING AND GENETICS PROGRAM

Abstract

A comprehensive citrus breeding and genetics program was established at the UF/CREC during the mid-1980s combining conventional breeding with tools provided by tissue culture, emerging biotechnologies, molecular genetics and genomics. Scion Improvement: The Florida citrus industry is 90% processing sweet oranges. A major goal has been to develop new cultivars for Not From Concentrate (NFC) juice production with emphasis on increasing 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 dominated by grapefruit and seedy mandarins. Primary objectives for fresh fruit improvement include expanding seasonal availability, development of canker tolerant and low furanocoumarin grapefruit, and development of seedless, easy-peel mandarins. The focus of our program has been on parent development, and seedless triploid production via interploid crosses; strategies and successes will be discussed. Rootstock Improvement: Initial focus was on improving soil adaptation, tree-size control to facilitate harvesting and cold-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 complex and Huanglongbing HLB, and development of rootstocks that facilitate advanced citrus production systems (ACPS). Progress from conventional breeding (both 2x and 4x) and somatic hybridization will be discussed. Genetic Engineering: 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.