Summer Pruning Differentiates Vegetative Buds to Flower Buds in the Rabbiteye Blueberry (Vaccinium virgatum Ait.)

Abstract

Pruning is a recommended cultural practice in blueberries (Vaccinium spp.) to maintain the balance between vegetative growth and reproductive development. Winter pruning is common and well-documented practice. Summer pruning, however, has been less studied. In this study, 5 primaryshoots (PSs) were selected per treatment (pruning date) on 5 different bushes (replications) of the rabbiteye blueberry (Vaccinium virgatum Ait.) 'Tifblue' and half-length headed back during its active growth period from June through Nov. The hypothesis tested in this study was that summer pruning induces flower buds at the basal area of PSs, controls the plant canopy and makes it possible to harvest fruits in the next summer season from the same shoots. In this study, there were no significant differences observed among any treatments with respect to yield and fruit quality. Early summer pruning (June) stimulated secondaryshoots (SSs) and later in autumn, terminal flower buds of these SSs produced fruits in the following year. However, no SSs were produced after summer pruning in Sept., and only vegetative buds that were at the basal area of PSs differentiated to flower buds and produced fruits in the following year. In conclusion, summer pruning can be practiced to complement or replace winter pruning and growers could decide the date of summer pruning in accordance with the size of plants' canopies. Plants with smaller canopies can be pruned in June and those with bigger canopies can be pruned in Sept.