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World of CitrusWorld of CitrusUFR-4
FFSP · 2014-05
https://www.ffsp.net/wp-content/uploads/2014/05/Citrus-Rootstock-Overview.pdf (opens in a new tab)
FFSP 2014 rootstock overview, UFR-4 page: Orange 19; tetraploid; medium–high yield; low–medium HLB rating; medium tree; high fruit quality; blight and Diaprepes/Phytophthora tolerance listed by FFSP. Ratings are source-specific, not immunity claims; comparative data were limited.
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UF/IFAS Extension
https://ask.ifas.ufl.edu/publication/HS1260 (opens in a new tab)
UF/IFAS HS1260 5th-edition rootstock table: first commercial availability 2015; germination 80–90%; UFR-4 tree size intermediate and freeze tolerance intermediate. This guide entry is a source-specific selection aid, not an immunity claim.
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United States plant patent · Google Patents
https://patents.google.com/patent/USPP27745P3/en (opens in a new tab)
Patent source for UFR-4 breeding background. The patent source describes UFR-4 as a sexual cross between the somatic-fusion parent [Nova + H.B. pummelo] and the somatic-fusion parent [Cleopatra + Argentine trifoliate orange]. Parentage notation is preserved as source-reported; no legal-status claim is recorded.
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West Coast Agroforestry
Profile quotes group guidance attributed to an Albrecht et al. Florida 2024–25 rootstock guide: named rootstocks including UFR-4 produced good yields and lower-than-average fruit drop under high HLB pressure. Secondary group guidance only; no individual measurement, scion, trial setup, or disease-resistance rating. No verified byline or publication date.
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Ksenija Gasic; John E. Preece; David Karp · HortScience · 2020
https://doi.org/10.21273/HORTSCI50register-20 (opens in a new tab)
The UFR-4 description reports a tetraploid allotetraploid zygotic hybrid produced by crossing two prior somatic hybrids. The USPP 27,745 selection had 18–23 seeds per fruit and was described as polyembryonic. These are selection-specific observations; no embryo-count denominator or zygotic rate is reported.
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