Repeated runner removal after harvest and floating row cover during fall affect carbohydrate status and yield potential of strawberry cvs. Polka and Wendy in the Northern climate

We investigated the impact of repeated runner removal after harvest and row cover during fall on strawberry (Fragaria × ananassa) cvs. Polka and Wendy cropping potential in the joint project of the University of Helsinki and the Rural Advisory Services Finland. Field trials were carried out in 2017 to 2019 on strawberry farms in Southern Ostrobothnia, Finland, at 62°49′N. The treatment effects on the crown carbohydrate reserves, flowering, and yield were recorded. Runner removal three times in three-week intervals after harvest decreased the crown starch reserves but increased the length of the apical inflorescence initials as observed through flower mapping in November, and the numbers of inflorescences and flowers in cv. Polka. Floating row cover after flower induction in September to October hastened floral development in the fall and increased the numbers of inflorescences, flowers, and fruit in cv. Wendy. Although the effects may depend on a cultivar and weather conditions during fall, repeated removal of runners after harvest and covering plants with a floating row cover after flower induction are recommended to increase strawberry yield potential in the Northern climate.