1. With four varieties of grapes grown at different altitudes of Shimane prefecture (high altitude; Tonbara 450m, and low altitude; Taisha, Izumo and Yasugi 10 to 20 m above the sea level), fruits were analyzed to observe their quality in 1964. Average air temperature and duration of sun-shine were measured from July 21 to September 10. They were 3.4℃ lower and 104 hours less respectively at the high altitude than at the low altitude.
2. When fruits were harvested at their proper ripening time based on a certain level of the soluble solids content of juice (19% in Delaware and 16% in other varieties), they reached the maturity 12 days later on Delaware and DK 151, and 4 to 5 days later on Super Hamburg and Muscat Bailey A at the high altitude than at the low altitude. Through all of varieties, the fruits at the high altitude were somewhat inferior to those at the low altitude in both bunch size and berry weight. Besides, the former contained more free acid than the latter.
3. In red grapes (Delaware and DK 151) fruits at the high altitude colored better containing more abundant anthocyanins in the skin than fruits at the low altitude. On the other hand, in black grapes (Super Hamburg and Muscat Bailey A) no such trend was observed.