Pre-Harvest Night-Interruption on Everbearing Cultivars in Out-of-Soil Strawberry Cultivation in Belgium

Trials were conducted in 2009 and 2010 to examine the relationship between photoperiod and temperature in commercial production of two everbearing strawberry cultivars. Specifically, two experiments were conducted to determine: 1) the extent of flowering and runnering in the everbearing strawberry cultivar Charlotte as influenced by night-interruption using incandescent lights, or no night-interruption; and 2) the influence of temperature and night-interruption on flowering and runnering of the everbearing cultivar Portola in 2010. The 2009 trial was conducted in a glasshouse, while the 2010 trial was conducted on a table-top system. In both trials, the influence of pre-harvest night-interruption lighting or night-interruption lighting + temperature on fruit yield, cropping pattern, and runnering were investigated. The results demonstrate that use of night-interruption can result in increased fruit production and earlier fruit production of the second fruit cycle and a reduced stolon development for both cultivars. Both cultivars were sensitive to long-day treatments. It appears that an appropriate lighting strategy is required for optimizing yields of everbearing cultivars in Northern European environments.