Response of Okanagan Riesling Vines to Training System and Simulated Mechanical Pruning

Abstract

Ten-year-old Okanagan Riesling vines were subjected over three growing seasons to two pruning strategies (18 nodes/m row and simulated mechanical pruning; SMP) within each of three training systems (midwire bilateral cordon, MBC; Hudson River Umbrella, HRU; and Lenz Moser, LM). SMP reduced vine size, cluster weight, berries/cluster, and berry weight but led to substantial increases in shoots/vine and yield. Titratable acidity (TA), °Brix, and Botrytis-infected fruit were also reduced by SMP. Shoots/vine, yield, and vine size were maximized by MBC training; however, °Brix was reduced, TA and pH were elevated, and Botrytis-infected fruit increased when combined with SMP. Point quadrat analysis indicated MBC to have the densest canopy containing the greatest number of leaf contacts, while this technique combined with photometric measurements revealed MBC to possess minimal cluster exposure. SMP vines tended to have fewer canopy contacts than their manually pruned counterparts. Wine quality and aroma intensity were best in wines from manually pruned HRU-trained fruit. SMP tended to reduce wine quality compared to manual pruning.