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World of CitrusWorld of CitrusAmanatsu Sour Orange
University of California, Riverside — Citrus Variety Collection
https://citrusvariety.ucr.edu/crc3235 (opens in a new tab)
The UCR CRC 3235 page records an open-pollinated seedling received as seed in 1957, with parents unknown, and is titled “Kawano natsudaidai sour orange hybrid.” Its 1988 note says the accession is not Natsumikan and recommends sour-orange-hybrid placement; the 2008 note questions that classification. The page's tree, fruit, and season descriptions apply to CRC 3235, not to the historical Kawano/Amanatsu selection unless identity is independently established. The parenthetical “this accession” appears in a reproduced 1986 passage about the named 1–2%-acid Kawano, but does not authenticate CRC 3235 as that cultivar or show that its acidity was measured on CRC 3235; no method is supplied.
Accessed
Robert Willard Hodgson · University of California, Division of Agricultural Sciences, Berkeley · 1967
Hodgson reports Kawano originated as a limb sport in an Oita Prefecture orchard about 1905, was named and registered in 1950, and differed from common Natsudaidai by maturing earlier; he says its fruit loses quality if left on the tree after maturity. This historical account does not establish that Kawano is genetically identical to UCR accession CRC 3235.
Accessed
Skandiberg · Tropical Fruit Forum · 2026-03-09
https://www.tropicalfruitforum.com/index.php?topic=60062.msg577550#msg577550 (opens in a new tab)
Post 96 labels the received fruit Amanatsu. Skandiberg reports Brix 11 and at least one seed per segment, describes a citrus/orange-like rind fragrance, easy peeling, juicy flesh, and tough membranes. The catalog record is Amanatsu Sour Orange, also listed under Kawano Natsudaidai Sour Orange; the post gives no accession or orchard provenance, so this source supports only the fruit report under that label.
Accessed
Skandiberg · Tropical Fruit Forum · Cold Hardy Citrus · 2026-03-15
https://www.tropicalfruitforum.com/index.php?msg=578064 (opens in a new tab)
Post #99 reports juice from one additional Amanatsu fruit, separate from the earlier tasting in post #96. The poster says it yielded over 2 dL when squeezed mostly by hand and describes it as very juicy. One-fruit grower report; no cultivar-wide yield or composition claim.
Accessed
Ryusei Hosono · RyuKoch · 2025-06-07
https://ryukoch.com/en/basics/amanatsu-citrus-fruit-japan (opens in a new tab)
Secondary article describing Amanatsu appearance, flavor, seed count, uses, and growing regions. Published June 7, 2025 and updated July 11, 2025. Its identity and naming discussion cites Wikipedia; it does not identify an accession or establish that the sampled or generalized fruit is the historical Kawano clone. Treat its approximate fruit dimensions and sensory descriptions as article-level claims, not measurements from a traceable tree.
Accessed
Kankitsu Labo
https://kankitsulabo.com/blogs/our-kankitsu/amanatsu (opens in a new tab)
Undated commerce-page profile with general fruit appearance, flesh, acidity, bitterness, and culinary uses. The page gives no author, accession, sample, or observation method; it does not establish identity with a particular Amanatsu clone or a controlled comparison.
Accessed
Skandiberg · Tropical Fruit Forum · 2026-03-16
https://www.tropicalfruitforum.com/index.php?msg=578143 (opens in a new tab)
Forum follow-up comparing juiced Shunkokan with Amanatsu. The author says Amanatsu membranes had nearly disappeared during juicing; no accession, specimen identity, or measurement is supplied, and the statement is not an independent sample count. Preserve separately from source #3's report of tough membranes in a received fruit.
Accessed
Murai, Yuda, Matsui, and Nakagawa · Journal of the Japanese Society for Horticultural Science · 1989
https://doi.org/10.2503/jjshs.58.69 (opens in a new tab)
Study of leaf and bark protein and amino-acid contents in relation to flower-bud formation in cultivar-named ‘Kawano natsudaidai.’ The abstract reports seasonal flower-bud formation and treatment findings; detailed methods are in Japanese and are not summarized here. The paper names the cultivar but does not identify an accession or establish that any catalog sample is the studied material.
Accessed
Akikazu Sakudo and Yoshihito Yagyu · AMB Express · 2021-01-09
https://doi.org/10.1186/s13568-020-01177-2 (opens in a new tab)
Laboratory postharvest surface-treatment study using fungus-inoculated ‘Kawano-natsudaidai’ pericarp. The article reports a 1.88-minute D value for P. venetum under plasma treatment; this describes viable-cell reduction on the tested fruit surface, not cultivar disease resistance. The paper gives no cultivar accession, lot, orchard, or fruit-maturity identity.
Accessed
Science & Technology Inst., Co. (Flower Database)
https://www.flower-db.com/en/flowers/citrus-natsudaidai-hayata (opens in a new tab)
Undated secondary page labels ‘Kawano Natsudaidai’ the official name for Citrus natsudaidai ‘Hayata’ and describes Amanatsu as a bud mutation of Natsumikan. It also gives general tree, flower, rind, and flesh descriptions without an identified specimen, accession, or method. The page supplies no cited basis for its naming account and does not authenticate CRC 3235 or any catalog sample.
Accessed
Masao Iwamasa · HortScience · 1988-08
https://doi.org/10.21273/HORTSCI.23.4.687 (opens in a new tab)
Table 1 (printed pp. 688–689) summarizes 1983 area, production, region, and shipping season. It lists Kawano Natsudaidai separately from common Natsudaidai at 11,100 ha and 316,400 t, with March–June shipping in southern Honshu, Kyushu, and Shikoku. These are historical national totals, not individual-fruit measurements, and do not establish that UCR CRC 3235 is the named Kawano selection or that it is Kawano Wase.
Accessed