Seasonal Patterns of Carbohydrate and Nitrogen Accumulation and Depletion in Strawberry are Affected by Fruiting but Not Day Neutrality

Abstract

The seasonal patterns of carbohydrate and nitrogen (N) accumulation and depletion have been studied in June-bearing strawberries, but little information is available for day neutral cultivars beyond a single growing season. Non-photoperiodic (day neutral/repeat fruiting) and photoperiodic (short day/June bearing) plants were grown for two years in pots under field conditions. Day neutral plants were either allowed to crop during the first and second growing season or just during the second growing season. Short day plants followed the regular cropping cycle for the perennial system in which plants were deflowered the first year and allowed to crop in the second. Stolons were removed regularly from all plants. Plants were sequentially and destructively harvested and separated into leaves, crowns and roots at several intervals from Sept. 2001 to July 2002. Both photoperiodic types exhibited similar seasonal patterns of carbohydrate and N accumulation and depletion in whole plants and plant parts when they had a similar fruiting status. However, fruiting during the first year in 'Seascape' (day neutral) plants resulted in reduced biomass, second-year yields, starch, and N levels, compared to 'Seascape' and 'Jewel' plants that fruited only in the second year. Day neutral and June bearing cultivars respond similarly to environmental cues regarding carbohydrate and N accumulation, even though the flowering response differs, while first year fruiting in 'Seascape' can negatively impact production capacity in the second year.