Vol 120 (2007): Proceedings of the Florida State Horticultural Society
Handling & Processing

Update on the USDA, ARS citrus scion improvement project

T. Gregory McCollum
Published December 1, 2007
  • citrus breeding,
  • irradiation,
  • new varieties


Citrus breeding 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; ease of peeling is still an important objective of the program. Swingle hybridized 'Duncan' grapefruit (Citrus paradisi) with pollen from 'Dancy' tangerine (Citrus reticulata), which resulted in the new citrus type known as tangelos, of which 'Orlando' and 'Minneola' are the most important comercially. Frank Gardner used 'Orlando' tangelo pollen in crosses with 'Clementine' mandarin and created the hybrids 'Osceola', 'Lee', 'Nova', and 'Robinson'. Gardner pollinated 'Minneola' tangelo with 'Clementine' pollen, 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 identi?ed 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. Recently, research to determine the components of fruit quality important to consumers, as well as to how new cultivars hold up in marketing channels, have been 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.