ChileanJAR

Two trials with different gibberellin sources (GA₃ or GAs) were carried out to evaluate the effects of cluster thinning and addition of N-(2-chlor-4-piridyl)-N'-phenylurea (CPPU), a synthetic cytokinin, on production and quality of table grapes (Vitis vinifera L.) cv. ‘Sultanina’. In each trial, factors considered were whether CPPU (5 mg L^-1) was added or not and whether additional berry thinning (30% elimination) was performed or not, leading to four treatments. The addition of CPPU to GA₃ caused increases in berry size(20%), cluster weight (20%) and total yield per plant (22%), with a delay in fruit maturity. CPPU-addition induced greener berries, thicker pedicels, and improved rachis appearance. Additional berry thinning resulted in advanced fruit maturity (11 to 18 days) and less berry drop. The mixture of gibberellins (GAs), as compared with GA₃, caused a delay in fruit harvest (5 to 12 days), increased berry size (9 to 20%), greener berries, increased pedicel length and thickness, and improved rachis appearance. Furthermore, berry drop increased with application of gibberellin mixture, as compared with GA₃, probably due to reduced pedicel flexibility.