Strawberry (Fragaria × ananassa Duchesn.) cultivars differ in response to removal date of row covers when they are used for winter protection and to accelerate fruit development and production. In 1986-87 and 1987-88, eight cultivars were overwintered under either spun-bonded polypropylene row cover or under straw. The straw was removed from control plots in late March. Row covers were removed on four dates beginning in late March and separated by about 2-week intervals. The time of flowering, fruit set, and fruit ripening was advanced in direct relation to the time that row covers remained over plants in spring. The differences in time of fruit ripening were less than those of time of flowering, however. The mid-harvest date was advanced as much as 8 days for `Earlidawn' and `Midway', but only 4 days for `Redchief' and `Scott'. Weight per fruit and percentage of marketable fruit were reduced when plants remained under row cover until mid-May. This effect was most noticeable for `Earlidawn', `Guardian', and `Redchief'. The fruit quality of `Midway' and `Jerseybelle' was not significantly affected by date of row cover removal. These cultivar-specific responses were probably not related to the stage of fruit development when row covers were removed, as both early and late-flowering cultivars were sensitive (and insensitive) to the date of row cover removal.
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