In the United States (U.S.), strawberries (Fragaria ×ananassa) are the most popular berry fruit with a value of $2.8B. To meet consumer demand for flavorful, fresh, local, and year-round strawberries, the industry is expanding into controlled environment (CE) production of day-neutral (everbearing) cultivars in greenhouses and indoor farms. Within CEs, growers can potentially improve flavor through the manipulation of environmental parameters such as temperature, light, vapor pressure deficit, and carbon dioxide concentration. The objectives of this study were to 1) quantify flavor related compounds of day-neutral cultivars in greenhouses; 2) determine how day and night temperatures influence fruit quality; and 3) develop a model to predict the cardinal temperatures of yield and flavor for each cultivar. Four cultivars, ‘Albion’, ‘Mara Des Bois’, ‘San Andreas’, and ‘Seascape’ were grown at day/night temperatures (12 h/12 h) of 15/7, 18/10, 21/13, 24/16, or 27/19 °C, under a 16-h photoperiod, and a target daily light integral of 15 mol·m–2·d–1. Berries were harvested twice weekly for three months and at harvest, yield, marketable yield, berry mass, and diameter. Berries were then cut into quarters, with ¼ being saved in a –80 °C freezer, and the other ¾ being used for destructive chemistry measurements. This included titratable acidity (TA), total soluble solids (TSS) content, pH, total anthocyanins, and the concentration and composition of flavor-related volatile organic compounds (VOCs). After 12 weeks of harvest, the highest TA was measured from berries harvested at 27/19 °C. ‘Albion’, and ‘Seascape’ harvested at 18/10 °C had the highest TSS, whereas the TSS of ‘Mara Des Bois’ and ‘San Andreas’ harvested at 15/7 °C was highest. The TSS/TA ratio was found to be correlated with day and night temperatures and a good indicator of consumer preference. Differences were also observed among cultivars and temperature treatments for anthocyanin and flavor-related VOCs. Our results collectively show that day and night temperatures influence the yield and flavor of strawberries.
