“Sweet and Very Delicious” – Japanese Scientists Create New Variety of Grape

Scitech Daily ^ | October 15, 2025 | Okayama University of Science

[Red Badger]

The newly developed Muscat Shiragai grape offers a sweet, smooth flavor with a subtle Muscat aroma. Credit: Okayama University of Science

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A team from Okayama University of Science has developed a new wine grape variety, “Muscat Shiragai.” A team of researchers led by Professor Emeritus Takuji Hoshino at Okayama University of Science (OUS) has developed a new wine grape variety called “Muscat Shiragai.” The grape was produced by crossing the wild Shiraga grape, which naturally grows only along the Takahashi River basin in Okayama Prefecture, with the well-known Muscat of Alexandria.

The group has submitted the new variety for official registration with Japan’s Ministry of Agriculture, Forestry and Fisheries (MAFF), and the application has been formally accepted.

During a press conference at OUS, Professor Hoshino explained, “I wanted to create a wine grape that incorporates wild genetic traits. If this grape becomes widely cultivated and its wine contributes to regional revitalization and tourism, that would be the best outcome.”

Professor Hoshino, an expert in plant systematics, became the founding director of OUS’s Institute of Viticulture and Enology in April 2017. Working in collaboration with Funao Winery in Kurashiki City, he began studying the Shiraga grape, a rare and endangered native species found only in small parts of Okayama Prefecture.

This partnership inspired the vision of developing a distinctively “Okayama-born” wine grape through a cross with Muscat of Alexandria.

Launching the Project

In February 2018, OUS signed a comprehensive cooperation agreement with Kurashiki City and Funao Winery, launching the project as part of a national government–recognized regional revitalization initiative to promote “branding of local resources.”

Presentation of the Newly Developed Wine Grape Muscat Shiragai

The fruit and wine of the newly developed grape “Muscat Shiragai,” presented at a press conference by Professor Emeritus Takuji Hoshino (right). From left to right above: Kurashiki Deputy Mayor Kenji Komatsu, OUS President Hiroyuki Hirano, and Funao Winery CEO Kenichiro Miyake. Credit: Okayama University of Science

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By fiscal year 2022, wines were being brewed from different breeding lines and evaluated for sugar content, acidity, pH, and taste, leading to the selection of promising strains. Drawing on these trial results, the new “Muscat Shiragai” variety was finalized in 2024.

The official application for new variety registration was jointly filed by Kake Educational Institution and Kurashiki City in December 2024 and was publicly announced in June 2025. The official registration is expected within four to five years.

Presentation and Tasting Event

The press conference, held at the Presentation Room in OUS Building A1, was attended by Kurashiki Deputy Mayor Kenji Komatsu, Funao Winery CEO Kenichiro Miyake, and OUS President Hiroyuki Hirano. Participants sampled the Muscat Shiragai grapes and wine, which were well received—described as “sweet and very delicious” for the fruit, and “with a subtle Muscat aroma and smooth drinking quality” for the wine.

Deputy Mayor Komatsu commented: “We are very much looking forward to offering a wine filled with the unique charm that can only be produced in Kurashiki. We also anticipate further research results to refine Muscat Shiragai into an even more sophisticated grape.”

CEO Miyake added: “With Muscat Shiragai as a branded grape, we hope to create a new high-value red wine identified with Kurashiki as its place of origin. Please look forward to the day when we can bring this to market.”

President Hirano noted: “Collaboration among industry, academia, and government is essential for building innovative local communities. OUS will continue integrating education and research, returning the results to the community, and contributing to solving regional and social issues.”

Currently, 20 vines are cultivated at Funao Winery and the OUS vineyard, yielding 41.6 kilograms in 2024. An additional 300 grafted vines were planted at the end of fiscal year 2023, with a goal of harvesting more than 500 kilograms by 2028–2029. The team also plans to optimize practices such as leaf removal, fertilization, and irrigation to further improve quality.

[Larry Lucido]

I accidentally bought sickenly-sweet “cotton candy” grapes because they look like regular (tart) green grapes. I couldn’t eat more than a few of them.

So yesterday I order green grapes from Kroger and get cotton candy grapes delivered. Complained and got my money back and bought the right ones later on.

/rant over

[Twotone]

Yum! Where can I go to taste? :-)

[Red Badger]

Japan...................

[hinckley buzzard]

Isn’t science great!

[Red Badger]

Now cross them with watermelons..................

[dfwgator]

Isn’t science great!

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Shouldn’t they focus on more important things, like conquering hair loss and prolonging erections?

[Twotone]

I would like to go to Japan. One of these days... ;-)

[Miami Rebel]

You’ll love it! I am not one to go exotic for the sake of exotic (i.e., Egypt and India are not on my list,) but Japan is SUPER-exotic while still being comfortable and safe for tourists.