The influence of two methods of crop removal at different leaf areas on maturation of Sauvignon blanc (<em>Vitis vinifera</em> L.)

Abstract

Aim: The research aims to determine if removing all bunches from alternate shoots had the same effect on berry maturity parameters of Sauvignon blanc as removing alternating bunches – apical versus basal – from each shoot. Methods and results: Shortly after fruit set, 50% crop was removed from four-cane vertical shoot positioned (VSP) pruned vines using the two different methods. At the same time, all the shoots were trimmed to six or 12 main leaves. Soluble solids (°Brix), pH, titratable acidity and berry weight were measured weekly from pre-veraison to harvest. Leaf area and yield were also measured at harvest. There were no differences in fruit composition between the two methods of crop removal. However, reducing leaf number per shoot from 12 to six leaves delayed veraison, reduced soluble solids accumulation and reduced berry weight with no additional effect from the thinning treatments. Conclusions: The thinning methods produced no differences in berry maturity parameters of Sauvignon blanc, indicating that carbohydrates can be readily translocated from shoots with no bunches to those with bunches. Significance and impact of the study: Carbohydrate translocation can occur at the whole-vine level where shoots behave as an integrated system and not as individual shoot units, especially under source-limited conditions.

Keywords

• carbohydrates
• crop removal
• maturation
• Sauvignon blanc
• translocation