Pre-anthesis CPPU Treatment Modifies Quality and Susceptibility to Post-harvest Berry Cracking of Vitis vinifera cv. 'Thompson Seedless'

Plant growth regulators (PGRs), especially gibberellic acid (GA), are often used in table grape (Vitis vinifera) production to increase berry size. However, overuse of this PGR (for example, more than 200 g.ha(-1) . season(-1) of GA) may result in problems with berry condition at the post-harvest stage. A synthetic cytokinin, florchlorfenuron (CPPU), could be considered an alternative to GA. Thus, our objective was to study the effects of pre-anthesis CPPU treatment on berry quality and susceptibility to post-harvest cracking of table grapes. CPPU applied to 'Thompson Seedless' inflorescences 48 or 36 days prior to anthesis increased ovary size, number of cells in the ovary peri-carp at bloom and berry size at harvest. It also increased the amount of soluble solids and decreased titratable acidity of the fruit, thus allowing an earlier harvest. Finally, if GA was applied during berry growth, CPPU at pre-anthesis improved berry potential tolerance to post-harvest cracking and spoilage. This work demonstrates that application of CPPU at the pre-anthesis stage modifies grape development, improving berry size and potential post-harvest fruit performance facilitating also an early harvest.