Summer Pruning Severity Affected Vegetative and Reproductive Traits in the Rabbiteye Blueberry (Vaccinium virgatum Ait.)

Abstract

Moderately vigorous shoots of mature rabbiteye blueberry 'Tifblue' bushes were pruned in summer to clarify the effects on vegetative and reproductive traits. Treatments included un-pruned, 25% pruned (removing 25% of the shoot length), 50% pruned (removing 50% of the shoot length) and 75% pruned (removing 75% of the shoot length). Vegetative and flower bud number per shoot decreased with increasing pruning severity. Consequently, the number of laterals per shoot dropped. However, lateral length increased with increasing pruning severity. Shoots pruned at 75% produced a small number of laterals, but they were the most vigorous. Pruning severity induced the transition of vegetative buds to reproductive buds in areas lower than the cut position. The flower bud number per shoot decreased with increasing pruning severity. However, yield per shoot was not affected due to a compensatory increase in berry weight. Total soluble solids content and titratable acidity of the berry juice, as well as, the number of berries per flower bud were not affected. Hence, to reduce the unproductive parts of the plant, and to produce bigger berries, September removal of either 50% or 75% of the length of mature rabbiteye blueberry shoots under conditions similar to the Kanto region of Japan is recommended.