Local CO2 Application within Strawberry Plant Canopy Increased Dry Matter Production and Fruit Yield in Summer and Autumn Culture

ABSTRACT June-bearing strawberry cultivars have been widely grown in Japan. Since they are harvested in winter and spring, little produce is available in summer and autumn. To achieve stable year-round supply, we need to expand the production area of ever-bearing cultivars. Here, we examined whether it is possible to increase dry matter (DM) production and fruit yield by increasing the CO2 concentration within the plant canopy through local application to promote photosynthesis in summer and autumn protected culture. We investigated the CO2 concentration in the plant canopy, DM production characteristics, yield characteristics, fruit quality, projected leaf area, cumulative light interception, and light use efficiency. We confirmed that the CO2 concentration within the plant canopy could be increased in summer and autumn (Control; 398 ppm, CO2; 1280 ppm), significantly increasing DM production and total yield (Control; 349 g, CO2; 447.5 g). We consider that local application of CO2 increased the projected leaf area and thus cumulative light interception. This method may help to increase fruit yield in summer and autumn protected culture.