Abstract
The effects of environmental conditions during winter on the development of flowers and shoots were studied from 1943 to 1956. The results were as follows:
1. Drought from December to late January or early February increased the number of flowers in the next spring, but that in later season, on the contrary, decreased the number.
2. The higher the temperature in winter, the greater was the number of flowers in the next spring. The warm temperature from December to the beginning of March was especially effective for Satsuma orange and that of December to late January was effective for lemon. This effect was much more remarkable on lemon than on Satsuma orange.
3. Blooming was promoted by high temperatures during winter. High temperatures after March were highly effective for Satsuma orange, and those dur ing February and March were effective for lemon.
4. Generally speaking, the high temperature in winter promoted shoot growth. When it remarkably increased the number of flowers, the number of shoots decreased.
5. Covering trees with straw mats in winter was effective in protecting them from the cold wind, but it interrupted sunlight. Consequently in an ordinary year it decreased the number of flowers and shoots because of a shortage of sunlight. When the winter climate was very cold the covered trees bore many more flowers than the uncovered ones.
