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Yamahonami

Parents: Norin No.22 (seed parent) and Norin No.14 (pollen parent). Crossed in 1946. Bred by Konosu Testing Site, National Agricultural Experiment Station (cross) → MAF Izumo → MAF Fukui → Fukui Prefectural Agricultural Experiment Station.

Etsunan No.18 ETU0000180

Norin No.8 → Norin No.22 Norin No.6 → Norin No.22 Ginbozu → Norin No.8 Asahi → Norin No.8 Joshu → Norin No.6 Sen'ichi → Norin No.6 Norin No.22 → Wakasa Norin No.14 → Wakasa Norin No.22 → Yamahonami Norin No.14 → Yamahonami Yamahonami Etsunan No.18 Norin No.22 Kinki No.34 Norin No.14 Norin No.8 Kinki No.15 Norin No.6 Kinki No.9 Joshu Sen'ichi Ginbozu Asahi Wakasa Etsunan No.15
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

  • Wakasa Etsunan No.15

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.

Leaves that droop, then stand up

Tillering after transplanting is medium; the leaves are pale, broad and long, and through the vegetative period the plant droops its blades and looks slender and weak, but as it enters the reproductive phase the blades gradually stand, and after heading the flag leaves emerge in points above the wave of panicles.

A historical document's character section usually describes the finished plant. This one describes the passage of time.

After transplanting it droops its leaves and looks feeble. Once it starts making panicles the leaves stand up. After heading, the flag leaves show in points above the panicle wave.

Look at it at the wrong moment and it reads as a weak variety.

Out of the same cross as Wakasa

At the Konosu Testing Site of the Ministry of Agriculture and Forestry Agricultural Experiment Station, in 1946, taking "Paddy Rice Norin No.22" as the mother and "Paddy Rice Norin No.14" as the father, an artificial cross was made

Year, place, mother, father and route of distribution all match Wakasa's document (Etsunan No.15). Two lines out of one cross, both selected in Fukui.

The maturity split: Wakasa early, Yamahonami late-mid.

The heading and ripening of "Etsunan No.18" are slightly earlier than "Koganenami"'s and about level with "Norin No.22"'s

Koganenami appears among the comparisons — and Koganenami's mother is Koshihikari's mother too, so half siblings are being dated against one another.

Far harder to lodge than its mother

The culm is slightly shorter even than "Koganenami"'s, which is nearly a tenth shorter than "Norin No.22"'s, and the culm is somewhat thinner than these varieties' but tough in quality.

Its resistance to lodging is far stronger than "Norin No.22"'s, and the difference is conspicuous particularly under heavy fertiliser.

Thinner, and yet stronger. Norin No.22 lodged easily. This one was made shorter, thinner, and tougher in the culm.

"Far stronger" is strong language for a breeding report. And it says the gap opens up precisely when more fertiliser is applied.

Oita Prefecture adopted it as a recommended variety from fiscal 1958. Selected in Fukui, used in Oita.

An intermediate type, strong against lodging, strong in disease resistance, with yields not much different from Norin No.22's. Quality good. To replace Hozakae and Norin No.22 in the mid-mountain cold-upland districts.

"To replace." It was brought in to displace Norin No.22.

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.

  1. 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
  2. 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
  3. 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
  4. 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
  5. 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
  6. 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
  7. 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
  8. 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
  9. 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
  10. 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
  11. イネ品種データベース検索システム「越南15号(ワカサ)」品種来歴文書 — Institute of Crop Science, NARO ・ primary source ・ accessed 2026-10-01
  12. イネ品種データベース検索システム「越南18号(ヤマホナミ)」品種来歴文書 — Institute of Crop Science, NARO ・ primary source ・ accessed 2026-10-01