Flower initiation in June-bearing strawberry as affected by crown depth, age, and size of tray plants

The use of tray grown transplants is becoming popular for substrate strawberry production. Although tray plant production with hanging runner cuttings is a laborsaving propagation procedure for forcing of June-bearing strawberries, the tray grown plants are inferior to pot grown plants in terms of earliness and uniformity of flowering. The crowns of rooted tray plants are often deeply drawn into medium by their own roots. The effect of crown depth, age, and size of tray plants on flowering of June-bearing strawberry (Fragaria × ananassa Duch. 'Nyoho') were investigated. Tissue temperature around the apical meristem was lower, and earlier and more uniform flower bud differentiation was obtained in the crown stripped or shallow-grown plants compared to deeply embedded plants. Flowering was later in young and small tray plants compared to aged large plants. By applying crown stripping, early and uniform flowering could be obtained even in the young and small tray plants. The variation in the depth of crown was clarified to be a cause of poor flowering performance of the tray grown strawberry plants. To obtain productive tray grown transplants, crown stripping would be an efficient procedure in practice. JSHS