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Koshijiwase

Parents: Norin No.22 (seed parent) and Norin No.1 (pollen parent). Crossed in 1944. Bred by Niigata Prefectural Agricultural Experiment Station (cross).

Sei 40 SEI0000400

Pedigree

Skip the diagram and read the list
Norin No.22 → Koshihikari Norin No.1 → Koshihikari Norin No.8 → Norin No.22 Norin No.6 → Norin No.22 Moritawase → Norin No.1 Rikuu No.132 → Norin No.1 Ginbozu → Norin No.8 Asahi → Norin No.8 Joshu → Norin No.6 Sen'ichi → Norin No.6 Rikuu No.20 → Rikuu No.132 Kamenoo No.4 → Rikuu No.132 Aikoku → Rikuu No.20 Norin No.22 → Honenwase Norin No.1 → Honenwase Norin No.22 → Hatsunishiki Norin No.1 → Hatsunishiki Norin No.22 → Yamasenishiki Norin No.1 → Yamasenishiki Norin No.22 → Koshijiwase Norin No.1 → Koshijiwase Norin No.22 → Yo 44 Norin No.1 → Yo 44 Norin No.22 → Yo 45 Norin No.1 → Yo 45 Norin No.22 → Yo 46 Norin No.1 → Yo 46 Norin No.22 → Yo 47 Norin No.1 → Yo 47 Norin No.22 → Yo 48 Norin No.1 → Yo 48 Norin No.22 → Yo 49 Norin No.1 → Yo 49 Koshijiwase Sei 40 Norin No.22 Kinki No.34 Norin No.1 Hokuriku No.4 Moritawase Rikuu No.132 Rikuu No.20 Kamenoo No.4 Aikoku Norin No.8 Kinki No.15 Norin No.6 Kinki No.9 Joshu Sen'ichi Ginbozu Asahi Koshihikari Etsunan No.17 ・ 32.6% Honenwase Etsunan No.14 Hatsunishiki Ou No.224 Yamasenishiki Ou No.225 Yo 44 Yo 45 Yo 46 Yo 47 Yo 48 Yo 49
The diagram shows this variety's own parents and the line that connects it to Koshihikari. Among the descendants only the main varieties are drawn; the other parent of each cross, and every descendant not drawn here, are listed in full below. Faint boxes are unnamed breeding lines.

Parents

Siblings

  • Koshihikari Etsunan No.17
  • Honenwase Etsunan No.14
  • Hatsunishiki Ou No.224
  • Yamasenishiki Ou No.225
  • Yo 44 Yo 44
  • Yo 45 Yo 45
  • Yo 46 Yo 46
  • Yo 47 Yo 47
  • Yo 48 Yo 48
  • Yo 49 Yo 49

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.

No historical document of its own

The cross-combination record exists.

Cross combination: Norin No.22 / Norin No.1

A line from the same cross as Koshihikari, line number Sei 40. But the variety's historical document returns no text. No report on this variety has been digitised.

Nor does this page state which parent was mother and which father.

The mother and father come from its siblings' documents

Three lines from the same cross do have historical documents, and each of them says:

in 1945 an artificial cross was made taking "Norin No.22" as the mother and "Norin No.1" as the father

It is one and the same cross. So Koshijiwase's mother is Norin No.22 and its father is Norin No.1.

This is not an inference from convention. It is an assertion grounded in three documents written about the same cross. That is set down here so the basis is visible.

Its character is written in Yamasenishiki's document

The Ishikawa section of Yamasenishiki's historical document gives the reason Koshijiwase was adopted.

"Koshijiwase" has stronger resistance than Norin No.1 to leaf and panicle blast, sclerotial disease and root rot, and has been adopted as a recommended variety for the wet and semi-wet paddies throughout the prefecture, and for the lagoon-shore districts, where Norin No.1 cannot secure panicle number, replacing Norin No.1 and Shin No.6 there.

A variety for wet paddies. Where there is too much water, Norin No.1 cannot put up enough panicles. This replaces it there.

Ishikawa sorted four lines from one cross by the type of field: Honenwase for the dry fertile flats, Hatsunishiki along the hills, Koshijiwase for wet paddies and the lagoon shore. About 3,000 ha were expected.

A variety that survives in someone else's document

It has no report of its own. Yet its name, its character and the land it suits are written in its sibling's report.

A source is not written only for the variety it is about. Some varieties cannot be known without reading the document of another.

Sources disagree

Which parent of Koshihikari was the seed parent

The NARO historical document states in words that Norin No.22 was the seed parent and Norin No.1 the pollen parent. Niigata Prefecture, which bred the variety, states the reverse. The diagram follows the historical document; Niigata's account is recorded here. We call neither wrong.

The year of the cross

The NARO documents appear to reproduce the prefectures' original applications for recommended-variety status and give 1945 — and the documents for Honenwase, Hatsunishiki and Yamasenishiki, all from the same cross, give 1945 as well, four in agreement. Niigata's own account says the cross was made in 1944 and that the 1945 planting was skipped for lack of hands. We use 1944 and note the discrepancy.

How the seed parent of Norin No.1 is written

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

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.

  1. イネ品種データベース検索システム「越南17号（コシヒカリ）」品種来歴文書 — Institute of Crop Science, NARO ・ primary source ・ accessed 2026-09-10
  2. 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
  3. 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
  4. 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
  5. 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
  6. 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
  7. 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
  8. 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
  9. 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
  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
  11. 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
  12. 新潟コシヒカリの軌跡 〜誕生から定着に至るまで〜 — Niigata Prefectural Government ・ primary source ・ accessed 2026-09-10
  13. 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
  14. あきさかりの良さを引き出す栽培法 — Fukui Prefectural Government ・ primary source ・ accessed 2026-09-10
  15. ぎふクリーン農業／県産品種 ハツシモ — Gifu Prefectural Government ・ primary source ・ accessed 2026-09-11
  16. 水稲「あさひの夢」の奨励品種採用（研究成果情報） — National Agricultural Research Center, NARO ・ primary source ・ accessed 2026-09-11
  17. コシヒカリのエピソード2 〜奨励品種への採用から〜 — Niigata Prefectural Government ・ primary source ・ accessed 2026-09-10
  18. コシヒカリBLの導入のねらい — Niigata Prefectural Government ・ primary source ・ accessed 2026-09-10
  19. 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
  20. 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
  21. イネ品種データベース検索システム「越南14号（ホウネンワセ）」品種来歴文書 — Institute of Crop Science, NARO ・ primary source ・ accessed 2026-10-01
  22. イネ品種データベース検索システム「奥羽224号（ハツニシキ）」品種来歴文書 — Institute of Crop Science, NARO ・ primary source ・ accessed 2026-10-01
  23. イネ品種データベース検索システム「奥羽225号（ヤマセニシキ）」品種来歴文書 — Institute of Crop Science, NARO ・ primary source ・ accessed 2026-10-01
  24. イネ品種データベース検索システム「近畿34号を親とする品種一覧」（全167行） — Institute of Crop Science, NARO ・ primary source ・ accessed 2026-10-01
  25. イネ品種データベース検索システム 交配系譜図「生40（越路早生）」 — Institute of Crop Science, NARO ・ primary source ・ accessed 2026-10-01
  26. 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
  27. 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