Leaf canopy structure and vine performance

Abstract

Leaf canopy structure of mature Pinot noir grapevines was manipulated during two consecutive seasons: shoot tipping at full bloom (yes or no), lateral shoot length (no laterals, laterals cut back to four leaves at full bloom, laterals allowed to grow undisturbed), and cluster zone leaf removal (leaf removal in the cluster zone or no leaf removal). Treatments were carried out in factorial combinations. Shoot tipping at bloom increased percent fruit set, berries per cluster, cluster weight, yield per shoot, and yield to pruning ratio. Shoot tip removal also increased main and lateral leaf size and the contribution of lateral leaves to total leaf area. Tipping decreased total yield per vine, juice pH, leaf area per vine, pruning weight, and cane weight and sugars in the trunk during dormancy. Increasing lateral shoot length increased juice soluble solids, juice pH, skin anthocyanin content, cane weight, and sugar and total non-structural carbohydrates in the trunk during dormancy. Percent fruit set increased in the absence of vegetative growing tips, on either the main or lateral shoots. Leaf removal in the cluster zone four weeks after bloom had no impact on yield components but reduced juice soluble solids.