Cluster-thinning ‘de Chaunac’ French Hybrid Grapes Improves Vine Vigor and Fruit Quality in Ontario1

Abstract

Abstract Cluster-thinning of the French hybrid grape cultivar ‘de Chaunac’ ( Vitis sp.) resulted in superior fruit quality and an increase in vigor of the vines in comparison to the unthinned vines in a similar pruning and management regime. The higher sugar levels associated with thinning are consistently desirable for wine making under Ontario conditions. The favorable test site used limited the expression of vine decline and winter injury usually associated with over-cropping of this cultivar in the Niagara Peninsula of Ontario.