Long-day treatments were applied to everbearing strawberry (Fragaria × ananassa Duch.) 'Natsuakari' before planting to accelerate flower initiation for the autumn harvest. Twenty-four-hour day length treatment for one month promoted the flower initiation of runner plants potted on May 30, June 17, July 1, and in the previous July. The yields of the first-year runner plants that were subjected to 24-h treatment were not lower than those of the plants potted in the previous July. An increase in day length led to a corresponding increase in flower initiation. Two weeks of treatment was sufficient for flower initiation in all the plants that underwent 24-h day length treatment or 4-h night interruption treatment. In the case of plants that underwent 16-h day length treatment, anthesis was observed in all of these plants after treatment for a total of one month. Three different planting dates after 24-h continuous or cyclic lighting (15 min・h −1 , overnight) treatments were investigated. As a result of 24-h continuous lighting for 3 weeks, harvesting could be initiated from early September for plants that were planted on July 28, but the yield in October was higher for the plants that were planted on August 10. Not all of the plants that were planted on September 2 could be harvested by December. Cyclic lighting was markedly less effective for flowering than continuous lighting.

Fluctuations of flowering time and cut flower quality due to meteorological changes in temperature in the Tohoku region were investigated in summer-to-autumn flowering-type 'Iwa-no-hakusen' and autumn flowering-type 'Jinba' chrysanthemum. After long day treatment, plants were grown under natural day length and high and low temperature conditions in a temperature gradient chamber (TGC), in which the air temperature followed the natural outside temperature fluctuation. The experiments were carried out twice in different seasons; the dates of transfer to TGC were 8 July and 10 August for 'Iwa-no-hakusen', and 22 September and 13 October for 'Jinba'. In 'Iwa-no-hakusen', the temperature greatly varied during transfer on 8 July, and the anthesis was delayed by the high temperature after flower budding. The days to anthesis in transfer on 10 August was decreased by the shorter photoperiod than that at transfer on 8 July. In 'Jinba', anthesis was delayed by low temperature in both experiments. The days to anthesis following transfer on 13 October were increased by the lower temperature before flower budding than that of transfer on 22 September. The percentages of disk florets in 'Iwa-no-hakusen' were increased by low temperature and short photoperiod, and the number of florets in 'Jinba' were decreased by low temperature. In conclusion, the fluctuation of August flowering time of 'Iwa-no-hakusen' is induced by fluctuation of temperature, and the low temperature induces the delay in autumn flowering-type 'Jinba' in the Tohoku region.