Relationship between the number of delayed flowers and the nutrient status of Japanese persimmon (Diospyros kaki Thunb.) 'Maekawa Jiro'

The relationship between the nutrient status of Japanese persimmon trees cv 'Maekawa Jiro' and the number of delayed flowers and yield was studied. 1. The number of delayed flowers was about 150 per tree, about 20% of the number of total flowers, and the coefficient of fluctuation was about 90. A positive correlation existed between the number of delayed flowers and the number of normal flowers. 2. A negative correlation was found between the number of delayed flowers in spring and the leaf soluble sugar contents in July of the previous year. A positive correlation was, however, found between the number of delayed flowers and the leaf starch contents in August and September of the previous year. The causal relationships between the number of delayed flowers and the leaf carbohydrate contents in the previous year were left for open question. 3. The correlation between the number of delayed flowers and yield of the previous year was not precisely determined. A weakly positive correlation was detected between the number of delayed flowers and starch content in the dormant 1-year-old woods when analyses were made throughout the two year experiments. When examined the experiments separately, a positive correlation was found in one year, whereas a weakly positive correlation in another year between starch content of woods and the number of delayed flowers that eliminated the influence of the number of normal flowers. A weakly positive correlation existed between nitrogen contents of dormant 1-year-old woods and the number of delayed flowers when analyzed throughout the two-year experiments. When analyzed them separately, a weakly positive con-elation was observed in one year, but no apparent correlation in another year. 4. From these results, I conclude that the starch and nitrogen of dormant 1-year-old woods are important factors in the determination of the number of delayed flowers.