Influence of Training System, Pruning Severity, and Thinning on Yield, Vine Size, and Fruit Quality of Vidal blanc Grapevines

Abstract

Vidal blanc grapevines were trained to four training systems: (1) High Cordon - a bilateral cordon at the top wire (1.7 m); (2) Low Cordon - bilateral cordon at the bottom wire (1.0 m); (3) High Head - a high head with the trunk maintained at or just below the top wire; and (4) Low Head - a low head with the trunk maintained at or just above the bottom wire. In addition, three pruning severities were applied (10 + 10, 15 + 15, and 20 + 20). Data were collected over a seven-year period from 1977 through 1983. The vines were evaluated for yield, vine size maintenance, fruit quality, and winter survival. Vines trained to the two cordon systems were superior to those trained to either head system. The labor savings associated with the High Cordon coupled with the reduced levels of crop loss due to winter damage resulted in that being the training system of choice. The large cluster status of the cultivar makes crop control problematic. Tentatively, we propose that crop may be controlled via a pruning severity of 15 + 10 when coupled with flower cluster thinning to one cluster per shoot.