Effect of Three-day Low-temperature Storage of Tray-grown Strawberry Plants on Emergence and Flowering of Primary Flower

Abstract

Climate change is expected to delay flower bud differentiation of strawberry nursery plants under natural conditions caused by high temperatures in autumn, which may destabilize early yields in forced cropping. In order to stabilize early yields, we investigated a simple method of flower induction: 3-day low-temperature storage (3D-LTS) treatment, using labor-saving tray plants and a vacant fruit pre-cooling refrigerator. First, we examined the quality of the tray plants to be used and found that large plants with three or four leaves at the time of runner cuttings showed accelerated flowering, whereas small plants with one or two leaves showed the same flowering date as the large tray plants under natural conditions, and flowering was not delayed. The effect of the start dates of 3D-LTS treatment on flower bud differentiation was examined, and the results suggested that the best time to start the treatment to promote flower bud differentiation varied among cultivars, and that it may be approximately 1 week before the time of flower bud differentiation under natural conditions at the cultivation site of each cultivar. The results suggest that 3D-LTS treatment for tray plants may be a low-cost and simple method to promote flower induction that avoids delays in flowering in the case of early planting.