Chill unit models for blackcurrant (Ribes nigrum L.) cultivars 'Ben Gairn', 'Ben Hope' and 'Ben Tirran'

摘要

Temperate-zone crops require a period of winter chilling to terminate dormancy and ensure adequate bud break the following spring. The exact chilling requirement of blackcurrant (Ribes nigrum), a commercially important crop in northern Europe, is relatively unknown. Chill unit models have been successfully utilized to determine the optimum chilling temperature of a range of crops, with one chill unit equating to 1h exposure to the optimum temperature for chill satisfaction. Two-year-old R. nigrum plants of the cultivars 'Ben Gairn', 'Ben Hope' and 'Ben Tirran' were exposed to temperatures of -10.1pC, -3.4pC, 0.1pC, 1.5pC, 2.1pC, 3.4pC or 8.9pC (pl0.7pC) for durations of 0, 2, 4, 6, 8 or 10 weeks and multiple regression analyses used to determine the optimum temperature for chill satisfaction.