EFFECTS OF LIGHT CONDITIONS AND AIR TEMPERATURE ON THE GROWTH OF EVERBEARING STRAWBERRY DURING THE VEGETATIVE STAGE

We studied the effects of light conditions and air temperature on the growth of the everbearing strawberry (Fragaria × ananassa Duch. cv. ‘HS138’) during the vegetative stage in order to optimize the environmental conditions required for plant growth. We conducted 4 treatments with continuous lighting at 2 light intensities (225 and 337.5 μmol•m^-2•s^-1) and 2 air temperatures (25 or 20°C) and 2 treatments with a 16-h light period and a light intensity of 337.5 μmol•m^-2•s^-1 (light/dark, 25/25 or 25/20°C, respectively). The daily light integrals (DLIs) of these 6 treatments were classified into 19.4 (low) or 29.2 (high) mol•m^-2•d^-1. All plants were cultivated hydroponically for 20 days after transplanting. Under the same DLI condition, variations in the light period were not observed to have any effect, and dry matter accumulation in the plants without roots was higher at 25°C than at 20°C. Under the same air temperature condition, dry matter accumulation in the plants was 1.4-1.5 times greater at a high DLI than at a low DLI. In conclusion, within the range of this experiment, the optimum growth condition for the everbearing strawberry during the vegetative stage was a DLI of 29.2 mol•m^-2•d^-1 and a temperature of 25°C.