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Yamabiko
Parents: Chukyoasahi (seed parent) and Norin No.22 (pollen parent). Crossed in 1945. Bred by Tokai Branch, National Agricultural Experiment Station (cross) → Anjo → Tokai-Kinki Agricultural Experiment Station.
Tokai No.7 TOU0000070
Pedigree
Skip the diagram and read the listParents
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Chukyoasahi seed parent
Sources: イネ品種データベース検索システム「東海7号（ヤマビコ）」品種来歴文書 / イネ品種データベース検索システム「東海6号（チヨヒカリ）」品種来歴文書
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Norin No.22 pollen parent
Kinki No.34 ・ Resistant to rice blast
Sources: イネ品種データベース検索システム「東海7号（ヤマビコ）」品種来歴文書 / イネ品種データベース検索システム「東海6号（チヨヒカリ）」品種来歴文書
Siblings
- Chiyohikari Tokai No.6
Descendants
Relations are counted along the shortest line of descent. The rows in the diagram follow the order of crosses, so a variety with more than one path down can sit lower in the diagram than its relation here suggests.
It writes Norin No.22 as the father
At the Tokai Branch of the Ministry of Agriculture and Forestry Agricultural Experiment Station, an artificial cross was made in 1945 taking "Chukyoasahi" as the mother and "Paddy Rice Norin No.22" as the father
Norin No.22 is the father.
Norin No.22 appears on this site mostly on the mother's side. Koshihikari, Yamakogane and Tarehonami all take Norin No.22 as the mother.
In Yamabiko it is the other way round. The document says "as the father" in words, so that is what we record.
The cross-combination field alone reads "Chukyoasahi / Norin No.22", which agrees with the convention that what precedes the slash is the mother. But we only know the convention held because a document states it in words.
The mother's habit, made short
It shows the habit of Norin No.22 made short-culmed, but with more panicles than that variety.
The shape of Norin No.22, lowered, with more panicles. Lodging was Norin No.22's weakness; shortening it makes it stand.
Non-glutinous, with large brown rice. Glossy and of excellent quality.
Strong against blast, with outstanding panicle blast resistance as its distinguishing feature.
Strong against panicle blast — another trait Norin No.22 did not have.
It is not universal, though.
Resistance to brown spot and bacterial leaf blight are both moderate, not strong. Its adaptability on autumn-declining land is low.
It is strong against rice stem maggot, but the question of stem borer damage is doubtful: one trial site reported damage in the first generation.
It says "doubtful." One trial site out of several reported damage, so it declines to assert.
To Gifu's double-cropping belt
Its yield differs little from Norin No.29's and, autumn-declining fields aside, it has excellent traits as an early variety for fertile flat land; it is thought to have great scope to spread in place of Norin No.22 and Higashiyama No.38 in the double-cropping belt
The variety it replaces is its own mother, Norin No.22. The expected area is 4,000 cho; the comparison varieties listed are Norin No.22, Higashiyama No.38, Norin No.29, Wakaba and Homarenishiki.
A child replaces its parent. The pedigrees on this site are mostly that shape.
Sources disagree
On naming
Variety names are proper nouns. We use a name in this language only where a published source for it can be cited; otherwise the Japanese name stands.
What we have not yet confirmed
We have not looked below the top twenty
The site covers the twenty most widely planted varieties of the 2024 crop and the varieties that connect them back to Koshihikari. Many descendants exist below that line; we have not yet verified them against primary sources.
The year Masshigura was crossed
Neither Aomori Prefecture's table of recommended-variety characteristics nor the NARO database gives the year Masshigura (Aokei No.138) was crossed. The cross itself, Ou No.341 / Yamagata No.40, and its adoption as a recommended variety in fiscal 2004 are confirmed from primary sources; the year of the cross is not. For the same reason we do not say which parent was the seed parent. On 8 October 2026 we went back to the breeder's own side. The Masshigura page in the variety database of the Aomori Prefectural Industrial Technology Research Center's Agriculture and Forestry Research Institute carries a heading reading “The origin of Masshigura” — with nothing under it. Of the institute's bulletins, only No.42 (2015) onward are online, and the issue that would hold the breeding report for Masshigura is not among them. So the year of the cross is absent from the breeder's own published material as well.
Sources
The source document is in Japanese.
- イネ品種データベース検索システム 交配系譜図「越南17号」 — Institute of Crop Science, NARO ・ primary source ・ accessed 2026-09-10
- イネ品種データベース検索システム 交配系譜図「近畿34号（水稲農林22号）」 — Institute of Crop Science, NARO ・ primary source ・ accessed 2026-10-01
- イネ品種データベース検索システム 交配系譜図「近畿15号（水稲農林8号）」 — Institute of Crop Science, NARO ・ primary source ・ accessed 2026-09-10
- イネ品種データベース検索システム 交配系譜図「近畿9号（水稲農林6号）」 — Institute of Crop Science, NARO ・ primary source ・ accessed 2026-09-10
- コシヒカリのエピソード1 〜交配から系統の育成まで〜 — Niigata Prefectural Government ・ primary source ・ accessed 2026-09-10
- 戦後日本のイノベーション100選「コシヒカリ」経緯 — Japan Institute of Invention and Innovation ・ accessed 2026-09-10
- イネ品種データベース検索システム「近畿15号（水稲農林8号）」品種来歴文書 — Institute of Crop Science, NARO ・ primary source ・ accessed 2026-09-16
- イネ品種データベース検索システム「近畿9号（水稲農林6号）」品種来歴文書 — Institute of Crop Science, NARO ・ primary source ・ accessed 2026-09-16
- イネ品種データベース検索システム「越南12号（ヤマコガネ）」品種来歴文書 — Institute of Crop Science, NARO ・ primary source ・ accessed 2026-10-01
- イネ品種データベース検索システム「東海7号（ヤマビコ）」品種来歴文書 — Institute of Crop Science, NARO ・ primary source ・ accessed 2026-10-01
- イネ品種データベース検索システム「山陰47号（ヤエホ）」品種来歴文書 — Institute of Crop Science, NARO ・ primary source ・ accessed 2026-10-01
- イネ品種データベース検索システム「東海6号（チヨヒカリ）」品種来歴文書 — Institute of Crop Science, NARO ・ primary source ・ accessed 2026-10-01