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Citrus ID

 

Imperial Grapefruit

 

Synonyms

 

None

Cultivar or taxon

 

Citrus x aurantium L., pro sp. [Grapefruit Group] (sensu Mabberley 1997, Bayer et al. 2009); Citrus paradisi Macfad. (sensu Swingle and Reece 1967; sensu Tanaka sec. Cottin 2002)

Origin

 

Hodgson (1967) noted that: "Of unknown origin, Imperial is presumed to be an introduction from Florida made about 1901 by the R. M. Teague Nurseries of San Dimas, California. It never attained commercial importance [but was used] in the early citrus breeding program at the University of California Citrus Research Center, Riverside."

Description

 

Crown compact or dense, not weeping. First-year twig surface pubescent; second- or third-year twig surface striate; thorns straight; prickles absent or not persistent. Petiole glabrous, length medium; wings medium, tucking beneath blade. Leaflets one, margin bluntly toothed, shade leaflet blades weakly conduplicate, sun leaflet blades weakly or strongly conduplicate. Scent of crushed leaflets sweetly orange-like. Fruit as broad as long or longer than broad; rind green-yellow (6), yellow (7-10), or yellow-orange (11); rind texture slightly rough (4-5); firmness leathery; navel absent; flesh yellow; taste grapefruit-like.

Hodgson (1967) provided the following additional notes on this cultivar: "This California variety produces a medium-small, very seedy fruit that lacks the typical grapefruit flavor and bitterness. In this respect, it closely resembles the Triumph, Mott (Aurantium) and Royal varieties."

References

 

Bayer, R.J., D.J. Mabberley, C. Morton, C.H. Miller, I.K. Sharma, B.E. Pfeil, S. Rich, R. Hitchcock, and S. Sykes. 2009. A molecular phylogeny of the orange subfamily (Rutaceae: Aurantioideae) using nine cpDNA sequences. American Journal of Botany 96: 668–685.

Cottin, R. 2002. Citrus of the World: A citrus directory. Version 2.0. France: SRA INRA-CIRAD.

Hodgson, R.W. 1967. Horticultural varieties of Citrus. In: Reuther, W., H.J. Webber, and L.D. Batchelor (eds.). The Citrus industry, rev. University of California Press. http://lib.ucr.edu/agnic/webber/Vol1/Chapter4.html.

Mabberley, D.J. 1997. A classification for edible Citrus (Rutaceae). Telopea 7: 167–172.

Swingle, W.T. and P.C. Reece. 1967. The botany of Citrus and its wild relatives. In: Reuther, W., H.J. Webber, and L.D. Batchelor (eds.). The Citrus industry. Ed. 2. Vol. I. University of California, Riverside. http://lib.ucr.edu/agnic/webber/Vol1/Chapter3.html.

Resources

 

Search for this cultivar in NCBI Entrez

Additional information on this cultivar at University of California: Riverside Citrus Variety Collection

 

Citrus ID Edition 2
October, 2011
idtools.org