2025-12-18

Japan International Research Center for Agricultural Sciences (JIRCAS) 
National Agriculture and Food Research Organization (NARO)

The Japan International Research Center for Agricultural Sciences (JIRCAS), in collaboration with the National Agriculture and Food Research Organization (NARO), has successfully developed a next-generation rice variety, Hokuriku 193-MP3, which exhibits higher yields even under high-temperature and low-fertilizer conditions.

In this study, researchers introduced the MP3 gene, which increases panicle number in indica-type rice originally derived from “Koshihikari,” into Hokuriku 193 (Japan's highest-yielding rice variety) through backcrossing and verified its effects. The results showed that Hokuriku 193-MP3 had a 21–28% increase in panicle number compared to the parent variety Hokuriku 193. Even in extreme summer conditions where the maximum temperature exceeds 35℃, the new variety achieved a 7–9% increase in brown rice yield. Moreover, higher yields were also confirmed even without nitrogen fertilizer application.

Previous studies had reported that an increase in the number of spikelets often leads to a decrease in grain-filling efficiency. However, in “Hokuriku 193-MP3,” the greater panicle number resulted in more spikelets overall, and these additional spikelets ripened sufficiently, successfully translating into a yield increase.

Because of its superior performance under high-temperature and nutrient-limited conditions, “Hokuriku 193-MP3” holds great promise for adaptation to climate change and for promoting sustainable agriculture. It is expected to contribute to stable rice supply despite challenges such as soaring fertilizer prices and global warming. Future research will evaluate the regional adaptability, grain quality, and palatability of this line, followed by improvements suitable for various applications.

This achievement marks an important step toward breeding next-generation rice varieties adapted to a changing global environment.

The results of this research have been published as an open-access article in the online edition of Field Crops Research (September 7, 2024, Japan time).
 

Related Information

Funding

Japan Society for the Promotion of Science (JSPS) Grant-in-Aid for Scientific Research “Cloning and utilization of sink-source related genes toward increasing rice yield potential” (20H02972)

Authors 

TAKAI Toshiyuki, Aung Zaw Oo, OKAMOTO Takanori, NAKANO Hiroshi

Paper Title

MP3, a quantitative trait locus for increased panicle number, improves rice yield potential in Japan by connecting with high source and translocation traits

Journal Title

Field Crops Research
DOI: https://doi.org/10.1016/j.fcr.2024.109566

JIRCAS President: KOYAMA Osamu

Program Director:

FUJITA Yasunari

Research Staff:

TAKAI Toshiyuki (Crop, Livestock and Environment) 
Aung Zaw Oo (Crop, Livestock and Environment) 

Press Coordinator:

OMORI Keisuke (Head, Information and Public Relations Office)
Press e-mail: koho-jircas@ml.affrc.go.jp

National Agriculture and Food Research Organization (NARO)

Research Staff:

NAKANO Hiroshi (Central Region Agricultural Research Center) 

Press Coordinator:

TAGUCHI Kazuyo (Public Relations Team Leader, Research Promotion Office, Central Region Agricultural Research Center)
Contact Form: https://www.naro.go.jp/laboratory/carc/inquiry/index.htm