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Yumepirika

Parents: Sakkei 96118 (seed parent) and Hoshitaro (pollen parent). Crossed in 1997.

Joiku No.453 JYI0004530

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 → Akitakomachi Ou No.292 → Akitakomachi Akitakomachi → Hoshinoyume Hoshinoyume → Hoshitaro Hoshitaro → Yumepirika Sakkei 96118 → Yumepirika Akiho → Hoshitaro Yumepirika Joiku No.453 ・ 1.8% Hoshitaro Joiku No.427 Sakkei 96118 Hoshinoyume Joiku No.418 Akiho 空育150号 Akitakomachi Akita No.31 ・ 6.7% Koshihikari Etsunan No.17 ・ 32.6% Ou No.292 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
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: 札系96118/上育427号

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 objective was "extremely good eating quality"

One sentence in the historical document sets out what this variety is:

In 1997, at the Hokkaido Prefectural Kamikawa Agricultural Experiment Station, with the aim of breeding a variety of extremely good eating quality, the low-amylose, good-eating line "Sakkei 96118" (later "Hokkai No.287") was used as the seed parent and the high-yielding, good-eating line "Joiku No.427" (later "Hoshitaro") as the pollen parent.

1997. The objective is not "good eating quality" but "extremely good eating quality." Hokkaido rice had long been treated as unable to reach the level of Honshu rice. This cross was designed without accepting that premise.

Choosing a low-amylose line as the mother makes the intent explicit. The lower the amylose, the stickier the cooked grain.

How far down they went

The document places the composition precisely:

Amylose content is about 2–3% higher than "Oborozuki" and about 5–6% lower than "Hoshinoyume"

Not as low as Oborozuki, a dedicated low-amylose variety, but far below Hoshinoyume, the mainstay it was to replace. The target sits deliberately between the two, and the numbers say so.

On eating quality:

The eating quality of the cooked rice is clearly superior to "Hoshinoyume", and equal to or slightly better than "Oborozuki"

But not everything was gained.

Cold tolerance is somewhat inferior to the check varieties, though grain thickness and grain weight are superior

In Hokkaido, giving up a step of cold tolerance is not normally permitted. They did it anyway, for eating quality. That is what an objective of "extremely good eating quality" means in practice.

Five generations to get here

Share of paddy rice area in the 2024 crop: 1.8%, eighth nationally (tied with Kinumusume).

Follow the diagram up through Hoshitaro, Hoshinoyume and Akitakomachi and it returns to Koshihikari. Yumepirika is a great-great-grandchild of Koshihikari.

Akitakomachi was bred in Akita, Hoshinoyume at Kamikawa. Hokkaido took in a line from Honshu and then spent four generations developing it within Hokkaido.

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. イネ品種データベース検索システム 交配系譜図「秋田31号（あきたこまち）」 — Institute of Crop Science, NARO ・ primary source ・ accessed 2026-09-10
  15. 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
  16. イネ品種データベース検索システム 交配系譜図「上育418号（ほしのゆめ）」 — Institute of Crop Science, NARO ・ primary source ・ accessed 2026-09-10
  17. イネ品種データベース検索システム 交配系譜図「上育427号」 — Institute of Crop Science, NARO ・ primary source ・ accessed 2026-09-10
  18. イネ品種データベース検索システム 交配系譜図「上育453号（ゆめぴりか）」 — Institute of Crop Science, NARO ・ primary source ・ accessed 2026-09-10
  19. 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
  20. 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
  21. 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
  22. 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
  23. コシヒカリBLの導入のねらい — Niigata Prefectural Government ・ primary source ・ accessed 2026-09-10
  24. イネ品種データベース検索システム「秋田31号（あきたこまち）」品種来歴文書 — Institute of Crop Science, NARO ・ primary source ・ accessed 2026-09-10
  25. あきたこまち（美の国あきたネット） — Akita Prefectural Government ・ primary source ・ accessed 2026-09-10
  26. 水稲新品種「あきたこまち」の育成について（秋田県農業試験場研究報告 第29号, 1989年, 65-88頁） — Akita Agricultural Experiment Station ・ primary source ・ accessed 2026-09-10
  27. 水稲新品種「ななつぼし」の育成（北海道立農試集報 83, 1-10, 2002年） — Hokkaido Central Agricultural Experiment Station ・ primary source ・ accessed 2026-09-11
  28. イネ品種データベース検索システム「空育150号」交配組合せ — Institute of Crop Science, NARO ・ primary source ・ accessed 2026-09-11
  29. イネ品種データベース検索システム「上育453号（ゆめぴりか）」品種来歴文書 — Institute of Crop Science, NARO ・ primary source ・ accessed 2026-09-11
  30. イネ品種データベース検索システム「上育427号（ほしたろう）を親とする品種一覧」 — Institute of Crop Science, NARO ・ primary source ・ accessed 2026-09-11
  31. 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
  32. 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
  33. 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
  34. 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