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Yosakoibijin

Parents: Fusaotome (seed parent) and Koshihikari (pollen parent). Crossed in 2003. Bred by Kochi Agricultural Research Center.

高育76号

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 Koshihikari → Hitomebore Hatsuboshi → Hitomebore Koshihikari → Hatsuboshi 40-11 → Hatsuboshi Hitomebore → Fusaotome Fusaotome → Yosakoibijin Koshihikari → Yosakoibijin Yosakoibijin 高育76号 Fusaotome Chiba No.6 Koshihikari Etsunan No.17 ・ 32.6% 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 Hitomebore Tohoku No.143 ・ 8.4% Hatsuboshi Aichi No.26 40-11
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

Cross combination: ふさおとめ/コシヒカリ

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.

The source uses the words "mother" and "father"

With the aim of breeding a variety strong under high temperature, of good grain quality, and of eating quality equal to or better than Koshihikari's, in 2003 the Kochi Agricultural Research Center made an artificial cross using Fusaotome — a high-temperature-tolerant variety bred in Chiba Prefecture — as the mother, and the good-eating variety Koshihikari as the father.

This site distinguishes seed parent from pollen parent only where the source states it in words. This source uses the words "mother" and "father". So Fusaotome is recorded as the seed parent and Koshihikari as the pollen parent.

Fusaotome is a Chiba variety, and its own mother is Hitomebore. Kochi chose a heat-tolerant Chiba variety as the mother and put Koshihikari on it as the father. A combination that crosses prefectures.

The purpose comes first

The passage does not begin by describing the variety. It begins with why it was made. In Kochi, summer heat was producing large numbers of chalky immature grains in non-glutinous brown rice, and the share graded first class was falling. The cross was made against that problem.

Harvested in July

Maturity falls around 26 July: very early, inside the month. At 23.4 g per 1,000 grains it is on the heavy side, and it yields more than the existing very early varieties.

The source also lists the weaknesses. Very weak to leaf blast, weak to panicle blast, only medium for lodging resistance — with the risk of lodging under heavy fertiliser written out as well. This is not a document that records only the strong points.

The breeding line, selected from Kokei 344 and Kokei 345, was named Koiku No.76 in 2013, entered the recommended-variety trials in 2014, and was adopted.

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.

Which parent of Hitomebore was the seed parent

The NARO pedigree field reads Koshihikari/Hatsuboshi, and by convention the name before the slash is the seed parent. The breeding report from Furukawa Agricultural Experiment Station, which raised the variety, states the reverse. The same disagreement appears for Koshihikari's own parents (D001), so this kind of discrepancy is not unusual. The diagram follows the NARO notation and both readings are recorded here.

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「越南17号を親とする品種一覧」（全607行） — 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34号（水稲農林22号）」 — Institute of Crop Science, NARO ・ primary source ・ accessed 2026-10-01
  8. 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
  9. 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
  10. 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
  11. 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
  12. 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
  13. 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
  14. 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
  15. イネ品種データベース検索システム 交配系譜図「東北143号（ひとめぼれ）」 — Institute of Crop Science, NARO ・ primary source ・ accessed 2026-09-10
  16. 令和6年産 水稲の品種別作付割合 — Rice Stable Supply Support Organization ・ primary source ・ accessed 2026-09-10
  17. イネ品種データベース検索システム「東北143号（ひとめぼれ）を親とする品種一覧」 — Institute of Crop Science, NARO ・ primary source ・ accessed 2026-09-10
  18. 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
  19. 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
  20. 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
  21. 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
  22. コシヒカリBLの導入のねらい — Niigata Prefectural Government ・ primary source ・ accessed 2026-09-10
  23. 水稲新品種「ひとめぼれ」について（宮城県古川農業試験場研究報告） — Furukawa Agricultural Experiment Station, Miyagi Prefecture ・ primary source ・ accessed 2026-09-10
  24. 平成5年冷害における水稲品種「ひとめぼれ」の耐冷性（日本作物学会東北支部会報 第37号, 1994年） — Tohoku Branch, Crop Science Society of Japan ・ primary source ・ accessed 2026-09-10
  25. 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
  26. 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
  27. 品種登録データベース 品種名検索（品種名のよみ） — Ministry of Agriculture, Forestry and Fisheries ・ primary source ・ accessed 2026-10-01
  28. 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
  29. 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
  30. イネ品種データベース検索システム「中部17号（ミネアサヒ）」品種来歴文書 — Institute of Crop Science, NARO ・ primary source ・ accessed 2026-10-01
  31. 水稲極早生新品種‘よさ恋美人’の概要／‘よさ恋美人’の特性一覧 — Kochi Agricultural Research Center ・ primary source ・ accessed 2026-10-02