Tomatoes and strawberries have become common vegetables for Japanese people. Tomatoes originated in the Andes plateau in South America, and strawberries were created in the Netherlands in the 1700s by crossing wild strawberries from North and South America, so each of them has grown in an environment different from Japan. Tomatoes and strawberries have become common in Japan around the time of rapid economic growth, and consumption increased as food became more diversified and westernized. As in Japan at that time, demand for fruits and vegetable such as tomatoes and strawberries has recently increased in Southeast Asia, where economic growth has been remarkable. Therefore, we are conducting research at the Tropical Agriculture Research Front (TARF) on Ishigaki Island in Okinawa Prefecture to develop cultivation techniques for tomatoes and strawberries that are as delicious in tropical and subtropical regions as in Japan.
 
The average temperature of Ishigaki Island, which belongs to the subtropical zone, is 18.9°C in January, the lowest, and 29.6°C in July, the highest. The temperature suitable for growing tomatoes and strawberries is said to be 15-25℃. Therefore, Ishigaki Island in summer is too hot for growing tomatoes and strawberries. In order to grow tomatoes and strawberries in such an environment, we are conducting research by developing the ‘Asian Monsoon Plant Factory System’. In this plant factory, sensors are used to monitor temperature, humidity, amount of light, and carbon dioxide (CO₂) concentration in the air, which are important environmental factors for plant growth. Control devices such as opening and closing, ventilation fans, and air conditioning are adjusted to create an environment suitable for plant growth.
 
In order to harvest a lot of delicious tomatoes and strawberries, it is necessary to have the plants perform a lot of photosynthesis and produce a lot of sugar. This requires moderate temperatures, sufficient light, and CO₂ in the atmosphere. By skillfully combining ventilation fans, fine mist cooling, shading curtains, and CO₂ gas application to bring in light and CO₂ while controlling the temperature in the greenhouse in a hot environment, delicious tomatoes and strawberries can be produced even in subtropical regions such as Ishigaki Island.
 
We organized on-site visits for tomato farmers in Ishigaki to let various people know about our research activities. We also introduce our research results to stakeholders in Thailand, Indonesia, and other countries who are interested in the ‘Asian Monsoon Plant Factory System’. We would like to conduct more studies so that delicious tomatoes and strawberries can be grown in Southeast Asia and other countries based on the results obtained in Ishigaki Island.

Please see the article in our Japanese publication 広報 JIRCAS. https://www.jircas.go.jp/ja/publication/jircas/10

The JIRCAS Tropical Agriculture Research Front (TARF) on Ishigaki Island, where the plant factory is located, will open its doors to the public for a limited one-week online open house starting today. The TARF Open House will feature videos of mini lectures on sugarcane and tropical fruit tree research, as well as photos of agriculture, nature, lifestyle, and culture of Ishigaki Island taken with a 360° camera, and will be enjoyable for both children and adults. Hope you’ll enjoy these events as well.

The 16th TARF Open House
Date : October 31 (Mon) - November 6 (Sunday), 2022
Format : Online (JIRCAS Open House Special Site) https://www.jircas.go.jp/en/event/2022/tarfopenhouse

Contributor: NAKAYAMA Masakazu (Tropical Agriculture Research Front)