Loading variety overview…
World of CitrusWorld of CitrusRich 16-6 Trifoliate
Givaudan Citrus Variety Collection at UCR
https://citrusvariety.ucr.edu/crc3485 (opens in a new tab)
Accessed
Cecilia Parsons · Progressive Crop Consultant · 2022-07-13
Secondary recap of a Citrus Research Board webinar (article lines 29–36). Parsons reports that in a 2010–2020 Tango rootstock trial, Rich 16-6 and Pomeroy trifoliate had high tree losses, while Swingle, Carrizo, C-35, and Volkameriana showed few chlorosis symptoms. No underlying counts, site details, or Rich-only sample size are provided; this is trial-specific, not a general Rich 16-6 performance estimate.
Accessed
Hayat et al. · Plants · 2022
https://pmc.ncbi.nlm.nih.gov/articles/PMC9656899/ (opens in a new tab)
Secondary review, Plants 11(21), article 2876, DOI 10.3390/plants11212876. Table 2 summarizes Washington navel on Rich 16-6 in CDVd-related comparisons, including a row reporting greater than 20% canopy reduction in infected trees and a close-versus-standard spacing comparison. Viroid infection and spacing are part of the reported context; do not present the result as untreated Rich 16-6 dwarfing or an independent primary trial.
Accessed
Henry Schneider; John E. Pehrson Jr. · California Agriculture · September–October 1985
California Agriculture, pp. 13–16. Direct field report: Rich 16-6 rootstock with Frost nucellar navel scion. Rich-specific discussion is printed p.16 (PDF p.4), lines 289–297 and 352–372. Five Lindcove Rich trees were sampled 17 times from July 1982 to October 1984; none showed early tongue formation, with 15 samples rated excellent and two satisfactory. Limited shoulder development was beginning on all four Rich trees at Terra Bella. This is site- and combination-specific, not proof of universal immunity.
Accessed
Jake Price · UGA Citrus Blog · 2023-11-03
Nine-tree-per-rootstock Tango comparison assessed after the Christmas 2022 freeze. Rich 16-6 was among rootstocks with the most canopy removed; seven of nine Rich trees had been replaced a year after planting because they were smaller initially, and the two older unreplaced Rich trees had significant cold damage. The post gives no Rich-specific temperature, exposure duration, or canopy-loss percentage; this is a Tango trial, not a universal hardiness threshold.
Accessed
W. P. Bitters · Journal of Citrus Pathology (digital special topic) · 2021 (digital edition; manuscript circa 1986)
Unpublished manuscript compiled circa 1986; digital edition published as a Journal of Citrus Pathology special topic in April 2021. Rich passage is PDF p.71 (index 70), printed p.63, lines 2915–2923. It recounts the 1963 Lindcove Frost-navel planting: later unpublished examinations reportedly found Rich 16-6 also developing budunion creasing and that no selection appeared immune. This is qualified follow-up context, not a separately documented trial.
Accessed
Mateus Pereira Gonzatto; Sabrina Raquel Griebeler; Sergio Francisco Schwarz · IntechOpen · 2022-05-14
https://www.intechopen.com/chapters/81780 (opens in a new tab)
Review chapter, DOI 10.5772/intechopen.102851; submitted 2021-12-22, published 2022-05-14. Lines 150–151 report that CDVd used in trifoliate rootstock Rich 16-6 reduced canopy volume by up to 50%, with a long-lasting phenotype compared with Flying Dragon. This is a secondary summary of viroid-treated grafted citrus, not untreated Rich 16-6 stature or independent trial evidence.
Accessed
S. R. Cutler; M. L. Roose; C. Ramadugu · Citrus Research Board · 2020–2021
Annual report, Table 1 and progress summary, PDF pp.1–2. Rich 16-6 is listed as a trifoliate rootstock transformed with inducible flowering technology. Ten varieties were transformed; at least two independent lines per variety received mandipropamid and flowering was assessed the next month. Rich 16-6 did not flower after induction. This experimental transgenic material does not establish natural flowering behavior of ordinary trees.
Accessed
Curti-Diaz et al. · USDA Agricultural Research Service · 2004-02-15
https://www.ars.usda.gov/research/publications/publication/?seqNo115=163292 (opens in a new tab)
International Society of Citriculture Abstracts, p.145; USDA labels the record Abstract Only. Veracruz nursery study used 27 rootstocks, six single-plant replications, and normal watering or 15, 30, or 45 days without water. Rich 16-6 was assigned to Group 1, “Light drought symptoms.” No Rich-specific numeric result is given; do not generalize to mature orchard trees.
Accessed
José Luis Foguet · Estación Experimental Agroindustrial Obispo Colombres (EEAOC)
Presentation date is not visible. PDF p.11 (viewer index 10; slide label P10), table “A large list of rootstocks for lemon are used in Tucuman”: the Trifoliates row lists Rich 16/6 as yes for Lisbon and Genoa and no for Eureka. This is scion-compatibility guidance; no method, accession, trial year, or sample size is supplied.
Accessed
R. K. Sonkar; A. D. Huchche; Lallan Ram; Shyam Singh · Agricultural Reviews · 2002
https://arccarticles.s3.amazonaws.com/webArticle/articles/ar232002.pdf (opens in a new tab)
Agricultural Reviews 23(2):93–109, pp.12, viewer lines 689–703. Secondary review reports 321 fruits/tree for Lisbon Frost on Rich 16-6 at Monte Grande, Argentina, citing Foguet et al. (1997). This is yield of the named scion/rootstock combination, not Rich 16-6 fruit yield; trial methods, sample size, and year are absent from this passage.
Accessed
Cindy Fake · UC Cooperative Extension, Placer and Nevada Counties · 2020
https://ucanr.edu/sites/default/files/2020-10/63813.pdf (opens in a new tab)
Publication 31-018C, 2020 update, p.3 (viewer label P2), rootstock section. Extension guidance describes Rich 16-6 and Rubidoux as Poncirus rootstocks adapted to foothill conditions, semi-dwarfing, and providing cold hardiness. This is regional rootstock guidance for grafted citrus, not a measured Rich 16-6 standalone tree trial or numeric cold threshold.
Accessed
Rayane Barcelos Bisi; Ute Albrecht; Randall P. Niedz; Kim D. Bowman · PLOS ONE · 2026-04-30
https://doi.org/10.1371/journal.pone.0347764 (opens in a new tab)
PLOS ONE 21(4):e0347764, DOI 10.1371/journal.pone.0347764. Methods identify six-month Rich 16-6 and Carrizo rootstock seedlings budded with Washington Navel on 2025-11-21, grown in 2.54-L pots in a temperature-controlled greenhouse (21–27 °C) under winter LED treatments. Results lines 321–330 report modeled Rich-16-6-supported scion shoot diameter +41% under maximum LED settings and rootstock diameter +12% under specified light settings. These are treatment-specific nursery predictions, not orchard growth or fruit traits. A supplied ResearchGate figure page presents this same article and is not independent coverage.
Accessed
Simran Singh; Tanjeet Singh Chahal · Journal of Applied Horticulture · 2021
https://www.horticultureresearch.net/jah/2021_23_1_93_98.pdf (opens in a new tab)
Journal of Applied Horticulture 23(1):93–98, DOI 10.37855/jah.2021.v23i01.18. Full paper describes 2016–17 protected nursery study at Jallowal-Lesriwal, Jalandhar, with 15 rootstocks evaluated for growth/rooting and Kinnow bud take. Table 4 p.5 reports Rich 16-6 root length 15.3 cm and root thickness 3.75 mm; Table 5 p.5 reports 3.6 g plant dry weight and 46.4% Kinnow budtake. Rich seedlings took >390 days to buddable size. The related 2019 protected-nursery paper by Singh, Chahal, and Singh overlaps this program; do not count shared nursery metrics twice.
Accessed
Tanjeet Singh Chahal · African Journal of Agricultural Research
Article-in-press abstract, lines 72–86; received 2015-05-18 and accepted 2015-07-18. Abstract compares Midknight Valencia scions on Rich 16-6, Rubidoux, and Swingle; shortest Rich-supported trees are reported as 2.27 m, while rootstocks did not significantly affect fruit weight or size. Methods and publication date were not verified; abstract-level scion response only.
Accessed
Simran Singh; Tanjeet Singh Chahal; Harminder Singh · Agricultural Research Journal · December 2019
Agricultural Research Journal 56(4):757–761, DOI 10.5958/2395-146X.2019.00117.0. The supplied ResearchGate figure page belongs to this article; this citation links to the retrieved full-article page. Methods describe 15 rootstocks, three replicates of 100 seeds per stock, with seed from fruit of a single-tree source in protected Punjab nursery conditions. Table 1 reports 39.3 seeds/fruit for Rich 16-6 (fruit sample size unstated), plus germination and transplanting results. Table 2 overlaps the 2021 nursery report (#28); do not duplicate its 46.4% Kinnow budtake/root metrics.
Accessed