The major strawberry cultivars cultivated in Japan today are June-bearing strawberry cultivars. Because June-bearing strawberry cultivars are qualitative short-day plants, they cannot differentiate flower buds under high temperature and long-day condition during the summer. However, since there is a demand for domestic strawberries for fresh eating such as cakes during the summer, attempts are being made to introduce everbearing strawberry cultivars that can differentiate flowers even under high temperature and long day conditions during the summer. However, there are some problems in cultivation under high temperature conditions, and we are trying to solve them.

Traditionally, incandescent light bulbs have been used as the light source for illuminated culture of horticultural crops, but from the viewpoint of energy conservation, LEDs are being replaced. However, while incandescent bulbs contain light with a wide range of wavelengths, LEDs emit light with shorter wavelengths. Since different wavelengths of light affect the growth of plants, we are investigating the effects of different colors of LEDs on growth and flower bud differentiation in everbearing strawberry cultivars and ornamental plants.