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Citrus ID

 

Thomson

 

Synonyms

 

Curlwaa, de Nice, Dungan, Garroway, Navel de Nice, Nice, Rocky Hill, Sheldon, Thomson Improved, Zimmerman (sec. Cottin 2002)

Cultivar or taxon

 

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

Origin

 

Hodgson (1967) noted that: "The Thomson variety originated as a limb sport of Washington in Duarte, California, and was named and introduced by the owner, A. C. Thomson, about 1891. Because of the earliness and attractive appearance of the fruit, it was extensively planted for some years and introduced to other navel orange-producing countries such as Algeria, Morocco, Chile, and Australia. Within a few years, however, its faults became so evident that planting was discontinued and most of the California acreage was converted or removed. So far as can be determined, this has been its history elsewhere, with the possible exception of Chile. Except for earliness of maturity, it is inferior to the parent variety in all respects."

Description

 

Crown compact or dense, not weeping. First-year twig surface glabrous; second- or third-year twig surface striate; thorns absent or not persistent; prickles absent or not persistent. Petiole glabrous, length medium; wings narrow or medium, adjoining the blade. Leaflets one, margin crenate/crenulate or 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 yellow-orange (11), orange (12), or red-orange (13); rind texture slightly rough (4-5); firmness leathery; navel present; flesh orange; taste acidic-sweet.

Hodgson (1967) provided the following additional notes on the cultivar:

"Fruit medium-large, globose to slightly obovate or ellipsoid; occasionally with collar and commonly with two or three relatively deep and long radial basal furrows; apex usually protruded or broadly nippled or with large open navel; seedless. Less well-colored than Washington. Rind medium-thin and surface smooth and glossy though finely pitted. Flesh well-colored with firm texture; medium juice content; flavor good. Holds on the tree poorly with rapid loss in quality. Very early in maturity (10 days or more in advance of Washington).

Tree less vigorous and more compact than Washington and commonly semi-dwarfed; also less cold- and heat-resistant. Clone unstable, very likely chimeric in constitution, and exhibits tendency toward reversion."

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 (2)

 

Citrus ID Edition 2
October, 2011
idtools.org