Effect of supplemental lighting from different light sources on growth and yield of strawberry

Although supplemental lighting has been successfully used to boost greenhouse vegetable production, it has not found wide application in forced strawberry cultivation. In this study, we examined the effect of supplemental lighting from two different light sources on strawberry growth and yield. Strawberry plants were exposed to LED or fluorescent lamp illumination for 12 h (6:00-18:00) daily from January to April. Under LED illumination, PPFD values greater than 400-mol m·2 s·1 were recorded at leaf heights of 10-30 cm, and leaf photosynthetic rates in plants exposed to LED supplemental lighting were much higher than in controls and plants exposed to fluorescent light. This accelerated photosynthesis promoted plant growth, as manifested by increases in leaf dry matter production, leaf area, and specific leaf weight, leading in turn to significant increases in average fruit weight, number of fruits, and marketable yield. The higher yields observed in LEDexposed plants compared with those under fluorescent lamp illumination were due to comparatively higher LED light intensities. Fruit soluble solids content, an index of sweetness, also increased under LED lighting. These results suggest that supplemental lighting using higher irradiance LED is an effective method for high yield production during forced strawberry cultivation.