Effect of Intermittent Long-day Treatment on Flowering of Branch Crown and Yield in Everbearing Strawberry Cultivars

Abstract

In order to stabilize strawberry production in summer and autumn in the Tohoku region of northern Japan, we investigated the effect of intermittent long-day treatment on flower induction and vegetative growth in everbearing strawberries. The results showed that the number of leaves on flowering branches tended to increase when 24-hour daylength treatment was performed every two weeks compared with continuous treatment. We found that ‘Natsuakari’ plants flowered continuously and developed leaves on branches appropriately under a 16 or 20-hour daylength after long chilling. On the other hand, we found that ‘Tochihitomi’ plants did not require long-day treatment for flowering after chilling. ‘Natsuakari’ plants exposed to two weeks of a 24-hour daylength followed by two weeks of natural daylength did not differ in flower number or yield from plants treated with a continuous 24-hour daylength.