2019 ASHS Annual Conference

Strawberry cultivation in the United States has been increasing over the past two decades. In North America, challenges associated with field production (labor, water, and soil disease) have led to interest in soilless controlled environment agriculture (CEA) systems. To date, insufficient published research exists on the influence of supplemental light quantity/quality on commercially available cultivars. The objective of this research was to determine the effect of supplemental light from either high pressure sodium (HPS) or light emitting diode (LED) sources on strawberry yield and Brix content. The trial was conducted using strawberry cultivars ‘Albion’ and ‘Cabrillo’ in two glass greenhouses in Ithaca, NY. Data collection began with 5 month old plants on January 1, 2019 after an establishment period of 2 months under their respective treatment conditions. The experiment consisted of one LED supplemental light treatment (Philips GreenPower LED toplights DR₉₀/B₁₀-LB), one HPS supplemental light treatment (Gavita pro 6/750e DE Flex) and an ambient light treatment (control). For both light treatments, a target daily light integral (DLI) of 15 mol•m^-2•d^-1 with a maximum photoperiod of 20 hours was maintained using quantum sensors connected to microcontrollers running an algorithm to control light and shade. For the ambient light treatment, night interruption lighting was implemented with 2 µmol•m^-2•s^-1 incandescent lights from 2200 to 0200 to maintain flower initiation. A total of 30 replicates per cultivar per treatment were planted at a density of 10.76 plants•m^-2 with 3 plants per pot. ‘Cabrillo’ had the greatest total marketable fresh weight (TMFW) across all treatments, which was 0.9, 2.48, and 3.03 kg•m^-2 for the Ambient, LED and HPS treatments, respectively. The TMFW for ‘Albion’ was 0.55, 1.88, and 1.68 kg•m^-2 for the Ambient, LED and HPS treatments, respectively. Mean berry fresh weight was greatest under LED for both ‘Albion’ and ‘Cabrillo’ at 17 and 19 g, which was about 15% greater than the Ambient and HPS treatments for ‘Albion’ and about 20% greater for ‘Cabrillo’. ‘Albion’ had the highest Brix across all treatments at 7, 8 and 9 °Bx for Ambient, LED, and HPS, respectively. While for ‘Cabrillo’, brix content was 5, 7, and 7 °Bx for Ambient, LED, and HPS, respectively. Future research is underway to evaluate the effects of lighting on additional fruit quality and sensory attributes.