After 1953, when Japan created a tea cultivar registration system under the Ministry of Agriculture, Forestry and Fisheries (MAFF), farmers began cataloging and systematizing the creation and development of tea cultivars, members of the camellia sinensis family that are bred to contain specific characteristics. Today, Japan—and most tea-growing regions—have established centers to research and develop new varietals and strains. Carefully bred cultivars enable farmers to grow tea plants that do well in the given climate (for example, certain cultivars resist frost better), but this also translates to aroma and flavor profile. Arguably green teas exhibit their cultivars better than any other type of tea, because there is little processing done to the plant post-harvest.
Here is the list of tea cultivars developed and registered in Japan—because cultivar registration is not required, there are others not on this list:
Common roots refer to the type of tea or harvest time; for example: "beni" refers to red and is used for red teas (synonymous in Western culture to black teas; black teas refer to fermented teas in Japan as well as other parts of Asia); "midori" means green; "oku" denotes cultivars that are harvested after the yabukita cultivar, which is a frequently used point of reference for cultivar comparison.
Of Japanese tea cultivars, yabukita is the most popular, making up over 75% of all tea grown in Japan. Many cultivars are cross-bred with yabukita in order to incorporate yabukita's resistance to frost, high yield, and strong umami flavor.