Temperature Affects Yield and Flavor of ‘Seascape' Strawberry

Strawberry (Fragaria x ananassa L.) grown in controlled environments is a candidate small-fruit crop for space life-support systems. A range of environmental conditions is being tested for effects on fruit yield and quality over long durations. Day-neutral ‘Seascape' strawberry plants were grown under 10-hr photoperiods in three reach-in growth chambers set to day/night temperatures (°C) of 16˚/8˚, 18˚/10˚, or 20˚/12˚. Plants were grown for 282 days with fruit collection beginning 65 days after planting. Fruit were collected, weighed, and counted, and pH, Brix, and titratable acidity assays were performed. Overall, the warmest two temperature regimes produced the largest number of fruit, but the middle temperatures, 18˚ days/10˚ nights, produced the highest fruit fresh weight. Individual berry weights decreased with increasing temperature. Yields oscillated over time, with plants grown under warmer conditions fruiting earlier than those under cooler conditions. Brix averaged 10 for the first half of the harvest period but dropped to 8.4 during the latter half, indicating fruit may become less sweet as plants age. Titratable acidity averaged 0.6 but increased slightly during the middle of the harvest period. The highest-yielding group (18˚/10˚) had the lowest Brix and highest tritatable acidity, indicating that as the duration of production progressed, fruits were slightly more tart and less sweet. Fruit from the coolest treatment had the highest Brix and lowest titratable acidity and were slightly higher in pH than fruit of the other temperature treatments. Interestingly, in a previous experiment when human organoleptic evaluations were performed with fruit developed under the same environmental conditions, human tasters preferred fruit from the coolest temperature treatment, and fruit from the intermediate conditions (18˚/10˚) were highest yielding but least liked. This research was supported by NASA: NAG5-12686.