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Norin No.21
Parents: Kyoasahi (seed parent) and Norin No.1 (pollen parent). Crossed in 1931. Bred by Niigata Prefectural Agricultural Experiment Station.
Hokuriku No.23 HOK0000230
Pedigree
Skip the diagram and read the listParents
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Kyoasahi seed parent
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Norin No.1 pollen parent
Hokuriku No.4 ・ High yielding with good grain quality and eating quality; susceptible to rice blast
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.
Children 1
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Hatsuminori Hokuriku No.45
Sources: イネ品種データベース検索システム「北陸45号（ハツミノリ）」品種来歴文書
Crossed in the very year Norin No.1 was named
"Paddy Rice Norin No.21" was produced in the Ministry's designated paddy rice breeding trial at the Niigata Prefectural Agricultural Experiment Station, where in 1931 "Kyoasahi" was taken as the mother and "Paddy Rice Norin No.1" as the father in an artificial cross, and selection and fixing were pursued thereafter. In March 1939 its seed was distributed to the relevant prefectures and others under the line name "Hokuriku No.23" to confirm regional suitability, and in May 1942 it received the variety name "Paddy Rice Norin No.21".
The cross was made in 1931 — the same year, in March, that Norin No.1 was renamed "Paddy Rice Norin No.1".
Two months after it got its name, it was already in the next cross. With Norin No.20 (Hokkaido, crossed 1932), one of the earliest uses of it.
The names: Hokuriku No.23 (1939) → Paddy Rice Norin No.21 (1942). Eleven years from cross to variety name.
Many panicles, and a very high yield
Paddy Rice Norin No.21 is an early non-glutinous variety of the Hokuriku region, heading and ripening between "Norin No.1" and "Ginbozu Chusei", with medium culm length, many panicles, and a very high yield. Its blast resistance is strong, but the culm is somewhat weak.
"A very high yield." Strong against blast as well. But the culm is somewhat weak.
Norin No.1 had two weaknesses: susceptible to blast, and prone to lodging. One was fixed, the other remained.
The eating quality is "not inferior"
The quality survey is as shown in the following table, and Paddy Rice Norin No.21 is found to be good, broadly not inferior to "Paddy Rice Norin No.1" or "Ginbozu Chusei".
Not "superior" — "not inferior."
Ahead on yield and disease resistance, with quality not falling. The order of those words shows what the breeding of the time put first.
Ten years later it became a mother
The mother of Hatsuminori (Hokuriku No.45) is this variety. The partner was Norin No.1 again.
taking "Hokuriku No.23" (the line that later became Paddy Rice Norin No.21) as the mother and "Paddy Rice Norin No.1" as the father
Norin No.1 crossed once more onto its own child.
Sources disagree
How the seed parent of Norin No.1 is written
- Moritawase, written 森多早生 — イネ品種データベース検索システム 交配系譜図「北陸4号」
- Moritawase, written 森田早稲 — イネ品種データベース検索システム「北陸4号（水稲農林1号）」品種来歴文書
The two spellings appear in the same NARO database, in the pedigree field and in the historical document respectively. We use the pedigree field's spelling and list the other.
How Kamenoo No.4 is written
- 亀の尾4号 — イネ品種データベース検索システム 交配系譜図「陸羽132号」
- 亀ノ尾4号 (the common spelling)
We follow the NARO database. The commonly seen spelling uses a katakana no; we prefer the spelling we can cite.
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「北陸4号（水稲農林1号）」品種来歴文書 — 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「北陸4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「北陸4号を親とする品種一覧」（全263行） — 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「陸羽132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「陸羽20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
- イネ品種データベース検索システム「北陸23号（水稲農林21号）」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「北陸45号（ハツミノリ）」品種来歴文書 — Institute of Crop Science, NARO ・ primary source ・ accessed 2026-10-01