Submitted to: Proceedings of Florida State Horticultural Society
Publication Type: Proceedings
Publication Acceptance Date: June 1, 2007
Publication Date: February 1, 2008
Citation: Mccollum, T.G. 2008. Update on the USDA, ARS Citrus Scion Improvement Project. Proceedings of Florida State Horticultural Society. 120:285-287.
Interpretive Summary: This paper provides a historical summary of the USDA citrus breeding program that has been ongoing in Florida since 1893. A number of commercially important citrus scions have been released from the program and many more are in various stages of evaluation. New citrus scions are important for producers to remain competitive.
A citrus breeding program has been conducted by the USDA in Florida since 1893 when W.T. Swingle made his first crosses at the USDA Subtropical Laboratory in Eustis, FL. The initial emphasis was to develop disease resistant cultivars. A second objective was to develop citrus fruit that were easy to peel; today ease of peeling is still an important objective of the program. Swingle hybridized ‘Duncan’ grapefruit (Citrus paradisi) with pollen from ‘Dancy’ tangerine (Citrus reticulata) and from those crosses resulted the new citrus type known as tangelos of which ‘Orlando’ and ‘Minneola’ are most important in commerce. Frank Gardner used ‘Orlando’ tangelo as the pollen parent in crosses with ‘Clementine’ mandarin and created the hybrids ‘Osceola’, ‘Lee’, ‘Nova’ and ‘Robinson’. Gardner pollinated ‘Minneola’ tangelo with pollen from ‘Clementine’ which led to ‘Page’. Jack Hearn began making citrus hybrids in the early 1960s and created ‘Sunburst’ (‘Robinson’ x ‘Osceola’) and ‘Fallglo’ (‘Bower’ x ‘Temple’). Several hybrids generated by Hearn have been identified as candidates for release and numerous additional hybrids are in the early stages of evaluation. Many seedy but otherwise high quality hybrids have been irradiated in an effort to reduce seed production and thereby increase consumer demand. Irradiation of ‘Fallglo’ has resulted in an essentially seedless version of that cultivar. A new emphasis on understanding the components of fruit quality important to consumers as well as how new cultivars hold up in marketing channels is being incorporated into the USDA scion improvement program. Continued development of new attractive, flavorful and convenient citrus cultivars available over a wide season will enable the US citrus industry to remain competitive in the global marketplace.