Relation Between the Temperature Characteristics of Tea Growing Districts Along the Oi River and the Growth and Quality of New Shoots of Tea Plants

In order to know the relation among the productivity, quality of new shoots of tea plants and temperature characteristics of the cultivated districts, the growth of new shoots, their chemical analysis and the meteorological observation had been carried out at seven tea fields along the Oi river for 15 years.<BR>1. Annual mean air temperature in the flat region around the lower reaches of the river was higher than that in the mountainous region around the middle reaches of the river. The temperature difference between the two regions was remarkable in the minimum temperature, and not in the maximum temperature.<BR>Although the diurnal range of air temperature was generally large in the mountainous region, it was much affected by the geographical features of the mountainons region, Mine district, situated 400m above sea level, showed a small range as being close to that in the flat region. On the other hand, Shiomoto district, a basin at an elevation of 220m, showed a large range.<BR>2. The bud opening time of the first flush was influenced by the temperature characteristics winter season and highly correlated with the accumulated air temperature from December to February. The bud opning in the flat region was early, and that in the mountainous region was further delayed by frequent frost damages. The tendency in the mountainous region was unequivocally revealed in Shiomoto district, but small in Mine district.<BR>3. Although the bud opening and the shoot growth in the mountainous region were delayed, the length of new shoots in the mountainous region was large as compared with that in the flat region at the time of shoot plucking. Accord-ingly the internode of a new shoot became long in the mountainous region. Furthermore, it was an-other feature of mountainous region that a lateral bud grew well similarly to an apical bud and that the uniform growth of new shoots was expected.<BR>4. The contents of chlorophyll, total nitrogen and amino acids of new shoots were high in the mountainous region as compared with those in the flat region. The catechin content did not show any significant difference between the two regions.<BR>5. From the results of these investigations, the growth and quality of new shoots were influenced by air temperature of each region. Since the influence of meteorological characteristics other than air temperature was not elucidated, analysis on the effect of other meteorological characteristics, humidity, radiation, etc., is thought to be neccesary.