Studies on the cyclic setting of fruit in egg-plant

Abstract

1. To study the occurence and the cause of the cyclic fruit setting in egg-plant, the amount of fertilizer, picking size of fruits, and the number of leaves were varied from May to August. “Shinkuro, No. 1” was used in this case. 2. The cyclic variation of fruit setting appeared rather remarkably. After heavy fruit setting period, the light setting period occurred, and three cycles were observed until the end of August. 3. The appearance of cycle varied according to the amount of fertilizer. The hills of wave con-tinued long, the valleys appeared later and the cycle was rather weak by heavy fertilization. By light fertilization, the valley continued long period, the cycle came out distinctly, and the number of fruits and the yield decreased. 4. By the restriction of the number of leaves. the hill of fruit setting appeared later, and which was rather small. When the fruits were picked off in small size, the fruits set continuously and there appeared no significant valley of clycle. The num-ber of fruits set and the yield increased distinctly. 5. The cyclic phenomenon was observed even in the yield day by day. When the cycle of fruit set-ting was large, the periodical variation of yield became large accordingly, and yield- decreased. But the yielding cycles did not appear so distinctly as with the fruit setting cycles, because the growth of the fruits was delayed by heavy fruit bearing and accelerated by light fruit bearing on the plant. 6. The fruit setting cycle was caused by the periodical variation of the number of flowers and the per-cent of fruit setting directly, but they were under the influence of the number of leaves and fruits on the plant secondarily. When the bearing number of fruits increased and the burden became too large compared with leaf area, dropping of flowers occurred first, and the number of flowers decreased in the next period. The leaf area and number of fruits bearing on the plant were influenced by the amount of ferti-lizer and fruit picking size were the indirect causes of the occurrence of the cycle of fruit setting in egg-plant.