Crop Load Adjustment in ‘Seyval Blanc’ Winegrape: Impacts on Yield Components, Fruit Composition, Consumer Wine Preferences, and Economics of Production

Abstract

Crop load management treatments were applied to ‘Seyval Blanc’ grapevines (Vitis hybrid) as a 2 × 2 factorial design: no shoot thinning (ST)/no cluster thinning (CL) (i.e., control), ST combined with CL (ST + CL), ST only, and CL only. All treatments reduced yield and crop load (yield/pruning weight) in 2009 and had a smaller impact in 2010 due to the carryover effect of previous year treatments on crop potential. Soluble solids were improved by up to 3.2% by the ST + CL treatment in 2009, but were not impacted by treatments in the second year when the range of yield was smaller and the ripening conditions more favorable. Rank sum analysis for the 2009 vintage indicated that wines produced from the CL treatment were preferred by the sensory panel compared with the control wine, but there were no differences in consumer preference for wines produced in the 2010 season. Grower preferred price in 2009 (required to compensate the grower for labor costs and lost yield) increased from $556/t in the control to $824/t in the CL treatment, an increase which could be justified by the demonstrated consumer preference for the CL wine. Grower preferred price was $1022/t in the ST + CL treatment in 2009, a price increase that was not justified by a demonstrated consumer preference for the wine. In 2010, grower preferred price ranged from $541/t for the control to $610/t for the ST + CL treatment, an unjustified increase based on the lack of demonstrated consumer preference for the wines.