Responses of growth, yield and fruit quality of strawberry to elevated CO2, LED supplemental light, and their combination in autumn through spring greenhouse production

During the whole growth cycle growth, yield and fruit quality of strawberry are often strongly affected by insufficient CO2 and low light in greenhouse production. However, it is still not clear what extent growth, yield and fruit quality of strawberry can be improved by elevated CO2 and supplementary light combination. We measured growth, yield and fruit quality of strawberries under four combinations of two levels of CO2, and two levels of light. Our results showed that yield enhancement throughout the growing season was 23.4% by elevated CO2, 21.46% by LED supplemental light, and 51.3% by their combination. Both elevated CO2 and LED supplemental light significantly increased soluble sugar content, but significantly decreased titratable acidity. LED supplemental light could partly or fully compensate for the negative impacts of elevated CO2 on soluble protein content, total phenol content, total flavonoid content, anthocyanin content, and total antioxidant capacity. Yield under four CO2 and light treatments was positively correlated with soluble sugar content, but negatively correlated with titratable acidity. Taken together, the combination of elevated CO2 and LED supplemental light largely improved both fruit yield and sweetness of strawberry during the autumn through spring in greenhouse. Optimal both CO2 and light is a worthwhile practice for improving strawberry production.