Post-harvest conservation of Rubi grapes treated with abscisic acid

Loss of mass, shatter and decay are undesirable for fresh grapes, as they decrease the cluster quality during post-harvest conservation. The objective of this study was to assess the effect of abscisic acid (S-ABA) application on ‘Rubi’ grapes’ loss of mass, shatter, decay incidence and conservation periods. ‘Rubi’ grapes’ clusters used in the experiment were gotten from a commercial vineyard located in the town of Sao Miguel Arcanjo, SP, Brazil (23° 31’ S, 47° 35’ W and 660 m above sea level). The experimental design was completely randomized with subdivided plots and six replicates; the plots represented the concentration levels of S-ABA and the subplots represented the assessment days, starting on the day of harvest, extending up to 18 days after harvest. The concentrations of the isomer (S)-cis-abscisic acid (S-ABA) used were: Control (0 mg L-1); 400 mg L-1 of S-ABA at the beginning of maturation (BM); 400 mg L-1 in the BM + 200 mg L-1 at 25 days after the first application (25 DAFA); and 400 mg L-1 in the BM + 400 mg L-1 at 25 DAFA. The clusters were placed in expanded polystyrene trays and stored at room temperature (25.0 ± 5°C and 50 to 85% relative humidity (RH)). The loss of mass, berry shatter and decay incidence were assessed over the post-harvest conservation periods. The S-ABA influenced the evaluated characteristics. One application of S-ABA reduced shatter and decay incidence, while two applications (400 mg L-1 in the BM + 400 mg L-1 at 25 DAFA) reduced the loss of mass.   Key words: Post-harvest conservation, grapes, abscisic acid, shatter, decay incidence, cluster quality.