To improve tea varieties suitable for southwestern Japan, a tea breeding project has been carried out at the Tea Breeding Section, Tea Division, Miyazaki Agricultural Experiment Station. In April 1970, the station released the new variety "Unkai" suitable for Kamairicha, which was registered with M. A. F. as a superior variety.
"Unkai" was selected from the F1 hybrids between "Takachiho" and "F1 9-4-48" which was an F1 hybrid of MA 23 (the Assam var.) × MC 3 (the Caucasia var.). This variety was tested for local adaptability at several experimental locations in southern Kyushu and Tokai districts as a clone No. A 15 before it was registered. The results of the tests showed that the variety was excellent in growth, yield, coldresistance, disease-resistance, marketing quality and table quality. Therefore, it was adopted as a recommended variety in Kumamoto and Miyazaki prefectures.
The characteristics of this variety are as follows:
1. This variety, like "Yabukita", is a few days earlier than "Takachiho" in plucking time. On the other hand, the sprouting time is a few days later than that of "Takachiho" and "Yabukita".
2. This variety is an intermediate type with respect to shape of plant, and it shows vigorous growth and high yield from early stages to mature stages.
3. This variety has higher resistance than that of "Takachiho" and "Yabukita" to net blister blight and anthracnose, and it also has high resistance to winter injury in natural and artificial conditions.
4. The vegetative propagation of this variety is as easy as it is with " Takachiho " and " Yabukita " varieties using the usual cutting method.
5. This variety has superior marketing and table qualties equal to those of "Takachiho".
6. From the results of the experiments testing the local adaptability of " Unkai" variety in different environments, it is concluded that it is a suitable variety in south-western Japan.
