Guidelines for the preparation of table grapes in SA for export 2025/2026_ND

The development of a grape berry

Grape berries develop according to a double sigmoidal curve (Figure 6). There is an initial steep increase in berry size from set to véraison, followed by a slight flattening in the curve. Then there is another steep increase until harvest. The cell division phase, which determines the number of cells per berry, occurs from set until approximately 21 days after set. Thereafter, the berry grows primarily through cell enlargement. The first growth phase is crucial for determining the final berry size. If berry size is below average during this phase, it is impossible to catch up and ultimately achieve the optimal berry size. Actions such as bunch thinning, girdling, enlargement using gibberellic acid, and bunch removal and shortening during the first phase influence the final product.

Figure 6. The development of a grape berry. Credit: Gawie van der Merwe.

SATI GUIDELINES FOR THE PREPARATION OF TABLE GRAPES IN SOUTH AFRICA FOR EXPORT 17