Amanatsu

Amanatsu (甘夏) or is a yellow citrus fruit, a cultivar that originated as a mutation of the  or. It was discovered in 1935 in Tsukumi, Oita Prefecture, Japan. The original natsu mikan that served as the basis for amanatsu was found in Yamaguchi Prefecture around 1700.

Names
Amanatsu means "sweet summer" in Japanese. In Japan, the fruit is known as kawano natsu daidai (カワノナツダイダイ（川野夏橙）), but also colloquially the amanatsu,, , and.

Description
Natsumikan is about the size of grapefruit and oblate in shape. The fruit contains 12 segments and about 30 seeds. The rough textured fruit is easy to peel and is commonly eaten fresh. It is also used for wide variety of products ranging from marmalades to alcoholic beverages.

Cultivation
Natsumikan is grown commercially in Japan, notably in Yamaguchi, Kumamoto and Ehime prefecture. The city of Hagi is famous for its natsumikans, particularly when used in natsumikan juice and ice cream.

Yamaguchi Prefecture takes such pride in their natsumikan industry that the typically white crash barriers of Japan were changed to a befitting orange.

Genetics
The natsumikan tree is believed to be genetically derived from the pomelo (Citrus grandis or Citrus maxima).

Medicine
Researchers found that immature natsumikan peel is beneficial for the treatment of chronic allergic dermatitis in mice.