Hoshinomidori

Hoshinomidori is a sencha cultivar selected from indigenous (zairai) tea seedlings in Hoshino village, in the mountains of Yame County, Fukuoka, and registered in 1981. Hoshino is one of Japan’s most celebrated gyokuro districts — its own Wikipedia entry credits the morning mist off the Hoshino river and the local soil for that reputation — and the cultivar takes its name directly from the village where its breeder lived, not from any tea-producing intent tied to gyokuro. What sets it apart botanically is its young leaf: strikingly yellowish-white rather than green, a trait now studied as one of a small handful of naturally occurring white-leaf tea cultivars in Japan. Despite the address it shares with a premier gyokuro region, no source found documents Hoshinomidori being grown under shade; it was registered, and remains classified, as a plain sencha cultivar.

Lineage

• Fukuoka zairai seedling — an individual selection from indigenous, seed-grown tea gardens in Hoshino village, Yame County, not a controlled cross.

Hoshinomidori has no recorded pollen parent, and the registration record gives no crossing combination at all — consistent with an individual plant picked out of a seed-grown population for a trait (its pale new-leaf colour) rather than assembled by hand from two named cultivars. It is not documented as the seed or pollen parent of any later registered cultivar, and — unlike Yabukita or Himemidori — it was never carried through a research station’s breeding programme at all: it was found, propagated and registered by a single named grower.

History

The breeder of record is an Inoue (井上十二生; the given name’s reading is not confirmed in any source consulted), a private tea grower resident at Hoshino village, Yame County, Fukuoka — the address on the registration is given as 16901 Hoshino-mura. That detail matters more than it might for other cultivars: almost every other cultivar in this collection was bred at a national or prefectural experiment station, under a named research team, over a multi-year trial programme. Hoshinomidori was not. It was selected, propagated and registered by an individual grower working alone, and the registration record accordingly lists no crossing history, no strain-code lineage of the kind institutional programmes generate (compare Himemidori’s Fuku-15 or Kirari 31’s Mi99-23), and no trial-station data.

Registration followed a different legal route as well. Japan’s older tea cultivars — Yabukita, Himemidori, and the rest of the Cha Norin series — were registered directly by the Ministry of Agriculture and Forestry under its own tea-cultivar numbering system (茶農林). Hoshinomidori is absent from that registry entirely. Instead, Inoue applied on 23 July 1979 (application No. 35) under the Plant Variety Protection and Seed Act (種苗法), a general-purpose breeders’-rights law that had only come into force a few years earlier and covered all crops, not tea specifically. The application was granted on 4 February 1981 as Registration No. 71, filed under the “Industrial Crops” category (工芸作物第2号) rather than any tea-specific one. Breeder’s rights ran for the standard 18 years and lapsed on 5 February 1999, so the cultivar has been free of any propagation restriction for over two decades.

The only contemporary publication found is a general roundup, not a dedicated tea paper: Akihama Tomoya’s “Introduction to Varieties Registered under the Plant Variety Protection Law (4),” in the Japanese Journal of Breeding (育種学雑誌), volume 31, 1981. It is a digest of that round’s 34 new Plant Variety Protection registrations across vegetables, fruit, ornamentals and mushrooms as well as tea — Hoshinomidori is simply the first of the 34, given a paragraph — rather than the kind of dedicated release paper with trial tables and named co-researchers that Himemidori received in 1961 from the Kyushu Agricultural Experiment Station. Beyond the official registration record and this one-paragraph digest, no dedicated release paper, selection history, or named trial programme for Hoshinomidori has been found.

Hoshinomidori resurfaces three decades later in a different context. A 2011 paper in 茶業研究報告 (Tea Research Report), by researchers at Shizuoka University and the Shizuoka Prefecture Tea Research Center, surveyed the chemistry of Japan’s white-leaf tea cultivars — a small group whose new growth is pale rather than green — and used Hoshinomidori as reference material alongside the strain Moroko-zawa (諸子沢) and the cultivar Kiraka (きら香, a 2006-registered Yabukita sport). That is the clearest evidence that Hoshinomidori still exists as propagated material somewhere in Japan’s germplasm collections, even though it is absent from every commercial cultivar list and vendor catalogue checked for this record, and does not appear in Yamecha’s own breakdown of cultivars grown in Yame today.

Characteristics

Hoshinomidori’s growth habit is upright, with vigour rated medium — slightly weaker than Yabukita’s. Its picking period is medium-to-late, later than Yabukita, though no day-count figure against the Yabukita benchmark has been sourced. Yield runs at roughly 90% of Yabukita’s. Only first-flush (ichibancha) tea was reported as processed at the breeding site; there is no record of a second-flush harvest being taken.

The defining trait is leaf colour. New leaves are long-oval, medium-sized, slightly thin and soft in texture, and — per the registration record — “strongly yellowish-white, clearly distinguishable from Yabukita,” gradually deepening to ordinary green as the picking window passes. Mature leaves are long-oval, medium in size and thickness, and green. The 2011 chemistry survey puts numbers to this: Hoshinomidori’s new-shoot leaf-colour index measured 0.6–8.1 against Yabukita’s 32.7 — effectively chlorophyll-poor by comparison — with catechin content around three-quarters of Yabukita’s and free amino acids at 1.8 times Yabukita’s or higher. That is the same broad chemical signature — low astringency compounds, elevated umami-linked amino acids — that defines white-leaf teas generally, and it lines up with the registration record’s own tasting note: a first-flush liquor that is deep yellow, with sweetness and astringency “in harmony” for a mild, gentle impression, and an aroma described as brisk and clean, though the dry leaf itself was noted to lack lustre.

No source consulted reports disease resistance, cold hardiness, or rooting behaviour for Hoshinomidori, and none records it being grown under shade. That last point is worth stating plainly against the brief for this record: Hoshino village is one of Japan’s most celebrated gyokuro districts, and Himemidori — Fukuoka’s other landrace selection, bred one prefecture-wide research programme over and registered two decades earlier — was purpose-built at a national research station specifically to give Yame growers a dedicated gyokuro cultivar. Hoshinomidori, despite carrying the village’s name, was registered as an ordinary sencha cultivar with no shading component reported, selected by a private individual rather than an institution, and — so far as the sources for this record show — was never taken up as a gyokuro cultivar or as a recommended cultivar of any kind. It survives today less as a commercial tea than as a curiosity: an obscure, privately registered landrace selection whose most concrete modern use is as one of a handful of reference points in the study of what makes a tea leaf turn white instead of green.