Effect of Shoot Density and Crop Control on Growth, Yield, Fruit Composition, and Wine Quality of ‘Seyval blanc’ Grapes

Abstract

A factorialized thinning level/shoot density experiment which was started in 1980 demonstrated that ‘Seyval blanc’ grapes benefits from cluster thinning in terms of vine size maintenance, cane ripening, berry weight, and Brix. Reducing shoot density led to increased cane ripening. Concomitant increases in cluster exposure improved fruit composition and led to higher berry weights. However, maintaining reasonably high shoot densities (4 shoots/30 cm of row or more) also was essential to maintain yield and vine size, even when crop was controlled by thinning. Levels of 4 shoots/30 cm of row and 17 clusters/500 g cane prunings are recommended to maximize yield and maintain reasonable fruit quality and vine size. Postbloom cluster thinning was found to reduce the incidence of bunch rot and to reduce the production of 2nd crop in 1982, without affecting any parameters of yield or fruit composition.