In the forcing production of strawberry Fragaria × ananassa Duch., the use of tray plants grown from cuttings of runner tips is becoming popular with the increase in strawberry production with substrate culture systems, due to their lower cost and ease of plant management compared to conventional pot-grown plants. Effects of the date of runner cutting and the duration of nutrient starvation on flower bud differentiation and flowering of tray grown plants of strawberry 'Nyoho' were investigated. Plants cut on mid or late July and rooted on cell trays performed early and uniform flower bud differentiation and flowering compared to June or August cut plants. When the plants were supplied nutrient solution containing ca. 6 mg-N/plant/week, nutrient starvation from the end of August led to the early and uniform flowering of tray plants, outperforming the earlier or later starvation.イチゴでは，根域容量130mL程度のセルトレイを利用した挿し苗育苗が省力育苗技術として急速に普及している．そこで，‘女峰’を用いて挿し苗時期と施肥中断時期が花芽分化と開花に及ぼす影響について検討した．挿し苗は7月中下旬が適期であり，6月や8月挿し苗区より花芽分化と開花が早く，極端に遅れる株が少なかった．液肥を用いて約6㎎-N/株・週の割合で与えた場合，施肥中断時期は8月末が最も優れ，週間早いと定植前の肥料不足によって極端に開花の遅れる株が増加し，1週間遅れると高窒素による花芽分化抑制が認められた
