Effect of Shoot and Cluster Thinning on Vine Performance, Fruit and Wine Quality of 'Blanc Du Bois'

Text - scientific article/review article


'Blanc Du Bois' exhibits resistance to Pierce's Disease (Xylella fastidiosa) (Wells et al. 1987) and is cultivated in the southeastern United States for wine production. Yet, little research has been conducted on horticultural practices to optimize yield and wine grape fruit quality in a subtropical climate. Shoot thinning (ST) and cluster thinning (CP) were used to optimize vine balance in five-year old 'Blanc Du Bois' vines. Shoot thinning (ST) or no shoot thinning (NST) in addition to cluster thinning (one cluster [CP1], two clusters [CP2] or three clusters [CP3] per shoot) were applied, with NST + CP3 serving as a grower control and industry standard. Vegetative measurements and fruit quality were measured in both years. In 2013 alone, vines with NST + CP1 showed higher photosynthetic rates compared to other treatments. In the other parameters measured no significant interaction was observed between shoot thinning and cluster thinning. Therefore significance was only observed when ST and CP were analyzed as main effects. Yield per vine increased in NST vine while shoot thinning significantly lowered juice pH. Cluster thinning increased soluble solids in CP1, but at the cost of total yield/vine, reducing overall yield. Neither shoot nor cluster thinning affected any vegetative measurements. Freeze damage in 2013 caused shoot damage and reduced fruit yield and quality, making treatment effects difficult to separate from vine damage. Thus, additional research needs to be conducted to understand the impact of these cultural practices on vine growth and fruit quality in 'Blanc Du Bois'.


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  • Xylella fastidiosa