Hudson Foster Grapefruit

Da Graça, Louzada & Sauls (2004) report that in 1930 a Foster Seedless tree—described there as derived from a Foster bud sport—produced very dark red fruit on post-freeze recovery growth; it was named Hudson but not commercially developed because of seediness. UCR gives a separate account for CRC 3638, describing it as a natural mutation on a Foster Pink tree found in the late 1950s. A 2020 review gives the less-specific parent label Foster, and US Citrus describes Hudson’s use in Hensz’s irradiation work leading to Star Ruby. These source-specific accounts do not resolve one origin or lineage; no freeze temperature or duration is reported.^{⁠[2]⁠[1]⁠[6]⁠[8]}

UCR’s CRC 3638 notes describe dark-pink flesh and very seedy fruit; the accession’s Riverside season is February–June. Separate general profiles describe Hudson fruit differently: Citrus ID calls its shape “as broad as long or longer than broad” and notes red or purplish-tinged flesh, while Garden Guides describes spherical fruit with yellow flesh tinged pink and red. Those general profiles are not tied to CRC 3638.^{⁠[1]⁠[4]⁠[5]}