2022 Volume 21 Issue 1 Pages 65-71
Effects of daytime heating on yield, photosynthesis, translocation and distribution of photosynthetic assimilates of strawberry ‘Sagahonoka’ during the winter season in northern Kyushu were examined. Daytime heating at 18°C resulted in increases of the commercial fruit number and yield from December to February. The days from flowering to ripening of top fruits in the first and second inflorescences were shortened by about 5 days by daytime heating treatment. The photosynthetic rate was higher at 18°C than at 13°C when PPFD was 300 μmol・m–2・s–1 or higher. The translocation rate of 13C-photosynthetic assimilates under low light conditions was significantly higher at 18°C than at 13°C. On the other hand, the distribution patterns of 13C-photosynthetic assimilates were similar at 18°C and 13°C in the daytime. Since daytime heating increased the commercial fruit yield from December to February, it was indicated that daytime heating was effective for high productivity in winter strawberry forcing culture in northern Kyushu. Also, physiological factors promoting an increase in yield involved higher temperatures accelerating photosynthesis and translocation rates.
