The effect of chilling temperature on flower bud expansion of rabbiteye blueberry

Abstract

Shoots containing terminal flower buds of rabbiteye blueberry ( Vaccinium ashei, Reade), cultivars ‘Bluebelle’, ‘Bluegem’, ‘Briteblue’, ‘Climax’, ‘Delite’, ‘Southland’, ‘Tifblue’ and ‘Woodard’, were collected at selected chilling hours ranging from 0 to 700 for 2 years to determine a rapid method of estimating chilling requirements of rabbiteye cultivars. Chilling hours in this study were defined as hours of cold temperatures below 7.2°C (45°F). Growth of flower buds as influenced by chilling hours varied with cultivar, the duration of chilling (400–700 h or 0–700 h), when measurements were made after treatment, and the type of measurement. Chilling requirements for the bud break of the 8 cultivars ranged from 250 to 650 h. Measurement of flower buds 2 weeks after exposure to chilling hours appears to be a reliable system to determine chilling requirements of rabbiteye blueberry plants.