Long-term Effects of Pruning Severity, Nodes per Bearing Unit, Training System, and Shoot Positioning on Yield and Quality of ‘Concord’ Grapes

Abstract

Abstract Yields on ‘Concord’ grape (Vitis labrusca L.) increased as pruning severity was decreased until the 6th and last year of this study, at which time the yields tended to equalize between the 30 + 10, 50 + 10, and 70 + 10 pruning treatments. By the last year, vines pruned to the 70 + 10 level produced fruit of unacceptable quality. When the 3-node spurs were shoot-positioned, their productivity was comparable to buds on the 6- and 9-node canes, indicating the need for exposure to sunlight. The length of the bearing unit has little or no effect on fruit quality attributes. In general, shoot positioning increased yield, node productivity, the percentage of soluble solids, and lowered vine size throughout the study. Geneva Double Curtain (GDC) trained vines produced more fruit than the bilateral cordon (BC) trained vines. Fruit from GDC trained vines had a reduced percentage of soluble solids in 2 of the last 3 years, and tended to have a low pH. The most productive vines producing fruit of acceptable quality for the 6-year mean were the GDC trained, 50 + 10 pruned to 6-node bearing units, and shoot positioned.