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)
Citrus decumana var. racemosa M. Roem; C. decumana var. patoniana Riccob.; C. maxima var. uvacarpa Merr. (sec. Swingle and Reece 1967)
Hodgson (1967) noted that:
"While pigmented pummelos have been known for centuries in the Orient and were early brought to the West Indies, it was not until 1907 that the first-recognized, pink-fleshed grapefruit, the seedy Foster variety, was found. Shortly thereafter (1913), a seedless pink-fleshed limb sport of Marsh was discovered which in 1924 was propagated as the Thompson variety. Only five years later a seedless red-fleshed fruit, Redblush (Ruby), was found as a limb sport of Thompson in the Lower Rio Grande Valley of Texas.
Though of attractive appearance and excellent quality, because of its seediness the Foster variety never achieved commercial importance. Thompson became available just as the Texas industry began its phenomenal development and was therefore planted extensively. The favorable reception accorded it in the markets caused it to be planted somewhat extensively in Florida. When Redblush became available in the markets, however, the deeper color of the flesh and the attractive pink blush on the rind, which is lacking in Thompson, made it an immediate favorite. As a consequence, the Thompson variety rapidly lost favor and for years past Redblush has been the only pigmented variety widely planted. Redblush is now grown extensively in Florida and Texas and to a limited but increasing extent in Arizona and California."
"Of particular interest in respect to the mode of origin of pigmented grapefruit varieties is a recent report (Cameron, Soost, and Olson 1964) showing that nucellar seedling clones of the Thompson and Foster varieties do not exhibit the same degree of pigmentation as do the parent varieties. Pigmentation is lost in the nucellar Thompson and increased in the nucellar Foster. The degree of pigmentation remains unchanged, however, in the Redblush (Ruby) and Shambar varieties. Convincing evidence is presented that chimeric constitution of the parent clones is the cause of this interesting behavior. It is postulated that both clones are periclinical chimeras that carry a color factor in germ layers 1 and 11. A somewhat similar situation is reported to exist in the true sweet lemon (Chapot 1963)."
Crown compact or dense, not weeping. First year twig surface glabrous or pubescent; second or third year twig surface striate; thorns absent or not persistent or straight; prickles absent or not persistent. Petiole glabrous or pubescent, length short, medium or long, wings narrow, medium or wide, adjoining the blade or tucking beneath blade. Leaflets one, margin entire, crenate/crenulate or bluntly toothed, shade leaflet blades flat, weakly or strongly conduplicate, sun leaflet blades weakly or strongly conduplicate. Leaflets sweetly orange-like when crushed. Fruit broader than long or as broad as long or longer than broad, rind green-yellow (6), yellow (7-10), yellow-orange (11), orange (12) or red-orange (13), rind texture smooth (1-3) or slightly rough (4-5), firmness leathery, navel absent, flesh orange, red/purplish-tinged or yellow, taste grapefruit-like.
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.
Cameron, J. W., R. K. Soost, and F. O. Olson. 1964. Chimeral basis for color in pink and red grapefruit. Journal of Heredity 55(1):23–28.
Chapot, H. 1963. Citrons doux…ou acides? Cahiers de la Recherche Agronomique. [Rabat] 18:105–12.
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: The Citrus industry. Ed. 2. Vol. I. W. Reuther, H. J. Webber, and L. D. Batchelor, eds. Riverside: University of California. 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.
Search for this cultivar in NPGS/GRIN1
1GRIN: Germplasm Resources Information Network; NPGS: National Plant Germplasm System
2NCBI: National Center for Biotechnology Information