Yield and Quality Response of Concord Grapes (Vitis labruscaL.) to Mechanized Vine Pruning

Yield, vine size, and juice quality were determined from Concord grapes after 6 consecutive years of hand pruning to a 30+10 pruning schedule or mechanical pruning followed by no node adjustment or node limitation to 60 or 90 per vine. Hand pruning to limit the number of nodes per vine to 60 following mechanical pruning maintained vine size, produced fruit yield, and juice quality comparable to vines balanced pruned to a 30+10 schedule. Retaining 90 or more nodes per vine following mechanical pruning reduced per vine and per node fruit yields after the 6th year and resulted in unacceptable objective and sensory quality. These treatments resulted in uneven ripening of the grapes which contributed to the problem of low soluble solids and poor juice color. Continuous use of mechanical pruning of Concord grapevines would only be feasible in relatively uniform vineyards that have been shoot positioned and followed by cane selection and node limitation.