Abstract
Fresh weight of strawberry fruit is known to be greater when plants are grown under relatively cool temperature because the enlargement of receptacle is partly influenced by temperature. However, fruit weight also depends on the number of achenes per fruit. Therefore, the effect of temperature during the period of flower bud formation on the number of achenes was investigated. 1. Strawberry plants 'Nyoho' grown under controlled conditions, were subjected to 32/27°C, 28/23°C, 24/19°C, 20/15°C and 16/11°C (day/night) under a 12-h photoperiod after stamens differentiation of apical flowers. The number of achenes per fruit increased proportionately as the temperature was lowered. 2. When 'Nyoho' and 'Toyonoka' plants were subjected to the same treatments as above but during the flower bud differentiation, respectively, the number of days from anthesis to ripening and the fresh weight/achene ratio did not differ among the treatments. The number of achenes correlated negatively with temperature as in Exp. 1. Consequently, fruit fresh weight also correlated negatively with temperature. 3. When 'Nyoho' plants were subjected to the same treatments as in Exp. 1, but during the pistil differentiation period, the number of achenes per fruit decreased because the plants were exposed to 5 days of high temperature early.
