Dekopon (デコポン) is a seedless and very sweet citrus fruit, a hybrid between Kiyomi and ponkan (Nakano no.3), developed in Japan in 1972. Originally a brand name, Dekopon has become a genericized trademark and it is used to refer to all brands of the fruit; the generic name is shiranuhi or shiranui (不知火). Dekopon is distinctive due to its sweet taste, large size and the large protruding bump on the top of the fruit.
The name is most likely a portmanteau between the word deko (凸, デコ; meaning convex) as a reference to its bump, and the pon in ponkan (ポンカン; one of the fruits that it is derived from) to create dekopon (デコポン).
There were many market names for dekopon during the time dekopon was a trademark of the product from Kumamoto. For instance, himepon was the market name for the fruits originating from Ehime prefecture. The ones grown in Hiroshima prefecture were marketed as hiropon. However after an agreement whereby anyone can use the name dekopon if they pay a fee and meet certain quality standards, the name “dekopon” is used for products from anywhere in Japan.
Dekopon does not have an agricultural variety registration number (Nōrin Bangō) because of its bump, which at the time of its development was considered to be unsightly, and failure to reduce acidity in the fruit.
Outside of Japan
In Brazil, dekopon is marketed under the brand name of Kinsei which derived from the Japanese word for Venus. Brazilian farmers have succeeded in adapting the variety to tropical to temperate climate in the highlands of Sao Paulo state. The work is done by Unkichi Taniwaki, a farmer of Japanese origin. Kinsei is easily harvested from May to September. In the high season for kinsei, each fruit costs around 0.50 USD at the Brazilian street market and supermarkets.
The fruit was brought into the United States in 1998 by a California citrus grower, Brad Stark. The rights to the cleaned up budwood were purchased in 2005 by the Griffith family. It was released as a commercial product under the name “Sumo” in early 2011.
In commemoration of the 15th anniversary of the first shipment of dekopon, Japan Fruit Growers Cooperative Association designated March 1 “Dekopon day” in 2006.