Trifeola

Trifeola is a Minneola tangelo × Poncirus trifoliata hybrid selected by Dr. McClean at Buffelspoort Research Station in the late 1950s or early 1960s, according to UCR’s retrospective account. UCR received budwood from South Africa in 1985 (CRC 3954 / PI 539846 / VI 468).^⁠[1]

UCR reproduces information received in February 1986 about a Malelane Nursery account describing 10-year-old trees of grapefruit, navel, Ortanique, lemon, and Valencia on Trifeola. It reports vigorous field growth, easy budding, and no incompatibility observed at that stage; it also says Phytophthora susceptibility had not been seen yet. These are historical trial observations, not universal immunity.^⁠[1]

Citrus ID describes a compact or dense, non-weeping crown and fruit as broad as long or longer than broad, with a slightly rough, leathery rind and orange flesh. A separate 2019 grower report describes one shaded fruit of about 90 g as juicy and seedless when cut, with little sweetness and acidity; that single fruit does not establish typical taste or seedlessness. The grower also described peel oils as unpleasant, while the flesh lacked the expected Poncirus oil flavor.^⁠[3]⁠[4]

UCR lists Riverside ripening in October–November, while a grower reported a late-February fruit; these are observations from different settings, not a single cultivar-wide season. Two video accounts describe young plants flowering and setting fruitlets that were not yet ripe or tasted. A forum poster repeats a −15 °C nursery frost rating without firsthand testing, while a separate winter video reports local injury; these sources do not establish a reliable minimum temperature for Trifeola.^{⁠[1]⁠[4]⁠[7]⁠[8]⁠[9]⁠[2]}

Hall and colleagues included seedlings from Trifeola CRC 3954 in a March 2014 free-choice Asian citrus psyllid assay. Egg-density ratings did not differ significantly from the susceptible sweet-orange control. The seedlings could include nucellar clones and sexual offspring; the study did not test HLB resistance.^⁠[6]

Another grower near Aachen reports Trifeola fruit dropping somewhat unripe in autumn under glass in zone 7b; he describes it as juicy and “way too bitter.” He also reports abundant pollen and pollination with Batumi Citrumelo, producing germinated monoembryonic seeds and visibly different seedlings, but offspring identities were not confirmed. These observations contrast with the separate 2019 shaded-fruit account and do not establish typical flavor or ripening.^⁠[10]