A tale of two CEA-grown strawberries
Strawberry season will soon be upon us (if it isn’t already). It’s a popular crop – number three among fruits produced in the U.S. and constant consumer craving. That demand and the fruit’s adaptability for controlled environment agriculture (CEA) systems makes strawberry an attractive fruit crop for year-round production.
Optimal productivity means precise management of flowering for fruit yield as well as suppressing flowers for more runner production for nursery propagation. Understanding how different cultivars respond to environmental factors such as temperature and photoperiods is essential.
That’s why Mahadi Hasan Redoy, Ethan Darby and Tabibul Islam from the Department of Plant Sciences, University of Tennessee-Knoxville, released their findings on the interaction of photoperiod and temperature on the flowering of short- and long-day strawberry cultivars at the most recent American Society for Horticultural Science conference.
The UT-Knoxville team wanted to explore the flowering pattern of two cultivars – ‘Seascape’ (long-day, perpetual flowering) and ‘Earliglow’ (short-day, seasonal flowering) – under varying temperatures and photoperiod conditions.
The strawberry plants were grown in pots with Lambert LM-AP 10 (peat/bark-based) media under Growth Chamber (200 moles) in greenhouse conditions. They were fertilized weekly. They were also grown during different times of the year, first in mid-winter and then again in autumn.
The first experiment began with both cultivars being transplanted in January 2024, in a growth chamber from weeks 1 to 6 and with a photoperiod of 16 hours in weeks 6 to 9. They were harvested that August.
The second experiment began with both cultivars transplanted in September 2024, in the growth chamber with a 12-hour photoperiod from weeks 1 – 4 and then with natural greenhouse light conditions from weeks 4 through harvest that December. In both experiments, growth chamber temperatures were set to 53.6º, 68º or 82.4º F.
The researchers found that in Experiment 1, ‘Seascape’ did not flower under the conditions during the eight-week experiment. ‘Earliglow’ also did not initiate flowers due to its short-day requirements.
In Experiment 2, both cultivars previously exposed to 82.4º initiated flowering earlier compared to other treatments. ‘Earliglow’ plants exposed to 53.6º exhibited delayed flowering. However, they developed elongated inflorescences and produced significantly more flowers over time.
“Our findings demonstrate that ‘Seascape,’ despite its classification as a long-day cultivar, demonstrated clear dependency on the short-day induction period for flower initiation,” the research team wrote. “‘Earliglow,’ on the other hand, showed a strong dependency and response to both temperature and photoperiod for flower induction and production.”
The UT-Knoxville team are using their data to characterize the underlying regulatory mechanisms of the photoperiod and temperature interaction in strawberries. Growers interested in producing strawberries in CEA should keep these findings in mind regarding these cultivars, but as the work continues, remember to not take them as gospel.
by Courtney Llewellyn
