In response to climate change, agricultural laboratories nationwide are conducting research to see whether crops can be cultivated farther north than their usual growing regions.

Experimental farms in 11 prefectures have been conducting the studies, including Yamagata, which is trying to cultivate "yuzu" (citron), a fruit commonly grown in warmer areas to the south.

Saitama Prefecture is meanwhile attempting to grow mango, a tropical fruit domestically grown mainly in the southwest.

The Environment Ministry predicts the nation's average temperature could rise by 2.1 to 4.0 degrees by around 2100 if climate change continues at the current pace.

Some experts also say the Kanto region could become a suitable production area for tropical crops.

The Yamagata Integrated Agricultural Research Center, one of the farm stations, began this year to cultivate yuzu and "sudachi," a small, sour, green citrus also currently produced mainly in the western part of the country.

The Saitama Prefectural Agriculture and Forestry Research Center has cultivated mango and sugar cane on a test basis since fiscal 2008.

Chiba Prefecture has been successful in cultivating passion fruit, while Shizuoka is trying to produce dragon fruit.

Miyazaki, known for mangoes, aims to adopt star fruit and litchi as specialty products.

Other prefectures conducting similar research are Miyagi, Gunma, Mie, Shiga, Hyogo and Ehime.

Farm stations in several more prefectures, including Iwate and Shimane, are considering similar moves.