Rubidoux Trifoliate

Rubidoux is a trifoliate orange selection, and UCR records its original parentage as unknown. UCR says its parent tree was planted at the old Rubidoux site of the University of California Citrus Research Center in Riverside about 1907, from R. M. Teague Nursery Company in San Dimas; Rubidoux seed was received from the Rubidoux Experiment Station in 1916. These dates refer to the parent-tree planting and seed receipt, not the selection date. Citrus ID cites Cottin (2002) for the spellings Robidoux and Rubideaux.^⁠[1]⁠[2]

The historical description places Rubidoux in the small-flowered trifoliate group with medium vigor; UCR lists December–January ripening at Riverside.^⁠[1]

Rootstock studies report one Minneola tree on a zygotic Rubidoux-derived rootstock as smaller than nucellar Rubidoux trees, with 20% higher yield per canopy volume. The authors described possible dwarfing use conditionally, if this performance continued. A publisher-indexed abstract for an evaluation of 10 Poncirus trifoliata strains and 6 hybrids reports Rubidoux among those with a high degree of resistance to Phytophthora nicotianae var. parasitica. UCR separately distinguishes a parent tree susceptible to brown rot gummosis from resistant seedlings. These are study-specific progeny/rootstock and disease-screen results, not general clone performance or fruit-quality evidence.^{⁠[3]⁠[4]⁠[1]}