Shiranui

The Japanese created this hybrid in the 1970s. In their quest for absolute sweetness, they crossed a Tangor Kyomi with a Ponkan mandarin tree. The resulting fruits are called Dekopon (a protected trademark), but only for the sweetest, with no trace of acidity. These fruits are large with a typical protrusion, sweet and aromatic with melting pulp. They can be harvested from March onwards, and by keeping them in a cool place for a few weeks, they gain even more sugar. The adult tree remains compact and is fairly cold-resistant. It is also suitable for greenhouse cultivation, which enables harvesting to be brought forward to the end of December… References
https://idtools.org/tools/1076/index.cfmhttps://citrusvariety.ucr.edu/crc4249