The grapefruit is believed to be a Barbadian invention, not having existed prior to the 18th Century. A large citrus fruit known as a shaddock was brought to the Caribbean from Polynesia. This shaddock was then crossed with the orange (or a citrus!) to produce what we now call a "grapefruit".

With a slightly acidic and bitter taste, the "white" grapefruit takes its name from the color of its flesh. There are also pink or ruby grapefruits and the blood pummelo, which are sweeter. 

Variety

Pomelo