Relationship between the number of flowers and the nutrient status of Japanese persimmon (Diospyros Kaki L.) tree 'Maekawa Jiro'

The relationship between the nutrient status of Japanese persimmon trees cv Maekawa Jiro and the number of normal flowers and yield was studied. 1. The relationship between leaf soluble sugar in the June of the previous year and the number of normal flowers in the following spring was barely significant (r = 0.48). No significant relationship existed between leaf N, starch, and soluble sugars on all other sampling dates and the number of flowers the following season. 2. A positive correlation existed between nitrogen content in 1-year-old wood and the number of normal flowers; a coefficient of correlation, r = 0.57, was found between the number of normal flowers versus trunk cross-sectional area. Date for three years reveal that a small quantity of nitrogen is stored in the winter of the off-year. 3. A multiple regression equation reveal that the number of normal flowers is highly correlated with the nitrogen content in 1-year-old dormant wood and the leaf soluble sugar of the previous June. 4. Thus, we conclude that leaf carbohydrate content at the beginning of flower-bud initiation and the nitrogen level in 1-year-old wood about the time flowers are differentiating are important factors which determine the number and quality of flowers. 5. To obtain an optimum yield of good quality fruit annually in 'Maekawa Jiro', a leaf-fruit ratio of 40 is required, provided the nitrogen and carbohydrate levels are likewise optimum.