Early Season Yield Responses of Selected Strawberry Cultivars to Photoperiod and Chilling in a Florida Winter Production System

Abstract

Abstract ‘Douglas’, ‘Tufts’, and ‘Pajaro’ strawberry (Fragaria × ananassa Duch.) plants were sampled for 3 consecutive years (1982–1984), and ‘Chandler’ plants were sampled for one year (1984) from September through October from a North Carolina nursery. Plants were subjected to short days (12-hr photoperiod) at day/night temperatures of 15.5°/4.4°C in 1982–1983 and to short days (9-hr photoperiod) and long days (9-hr photoperiod with a 3-hr night interruption) with or without chilling [15.5°/4.4° (day/night) or 22.0718.0° (day/night), respectively] in 1984 for 0, 1, 6, or 12 days in the NCSU phytotron. After treatment, plants were shipped to Florida for planting in the winter planting system for evaluation of early season yield (1 Dec. -15 Jan.). Optimum digging dates for all cultivars were observed to be a photoperiod response. Chilling enhanced early yield for ‘Douglas’ and ‘Pajaro’ when plants were dug prior to or at the optimum date. Plants dug later than the optimum date had much lower yields, even with substantial chilling. In ‘Chandler’, slight chilling (<125 hr from 1 Sept. until digging date) suppressed early yield, while increased chilling (>125 hr) enhanced early yield when plants were dug at or prior to the optimum date. Chilling decreased early yield in ‘Tufts’ regardless of digging date. Significant yield increases were only obtained with chilling much greater than that which naturally occurs in North Carolina.