Responses of growth, yield and fruit quality of strawberry to elevated CO 2 , 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 CO 2 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 CO 2 and supplementary light combination. We measured growth, yield and fruit quality of strawberries under four combinations of two levels of CO 2 , and two levels of light. Our results showed that yield enhancement throughout the growing season was 23.4% by elevated CO 2 , 21.46% by LED supplemental light, and 51.3% by their combination. Both elevated CO 2 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 CO 2 on soluble protein content, total phenol content, total flavonoid content, anthocyanin content, and total antioxidant capacity. Yield under four CO 2 and light treatments was positively correlated with soluble sugar content, but negatively correlated with titratable acidity. Taken together, the combination of elevated CO 2 and LED supplemental light largely improved both fruit yield and sweetness of strawberry during the autumn through spring in greenhouse. Optimal both CO 2 and light is a worthwhile practice for improving strawberry production.