Quality of ‘Isabel’ grape treated pre-harvest with CaCl2 and citrus biomass-based elicitor

The high rate of fruit decay and berry drop reduces quality and increases postharvest losses in 'Isabel' grapes, requiring pre-harvest and postharvest management practices available to the small-scale farmer, which maintain quality and extend postharvest life of the clusters. The objective of this study was to evaluate the effect of the pre-harvest application of CaCl2 and Citrus Biomass-based elicitor in 'Isabel' grapes, in the maintenance of quality during storage at room conditions under ambient and modified atmospheres. The experiment was conducted in a randomized block design with 8 replicates, in the field located at the municipality of Sao Vicente Ferrer-PE, Brazil. 'Isabel' vines were treated 28 days before harvest with: Citrus Biomass-based elicitor (CB), Citrus Biomass-based elicitor + CaCl2 (CB + C), CaCl2 (C) and Control (T) - without application. Grapes harvested in the commercial maturity were stored in a 4 × 2 × 7 factorial arrangement, with 4 treatments (applied in the field), 2 storage conditions, ambient (AA) and modified (AM) atmospheres, under room conditions (25 ± 2 °C and 75 ± 2% RH) and 7 evaluation periods in four replicates. The application of CaCl2 and CB-based elicitor reduced the berry drop index (55 and 75%, respectively), the decay and weight loss of 'Isabel' grape clusters. These treatments, associated or not, increased MA efficiency in maintaining cluster quality. The 'Isabel' grape berry drop index was directly influenced by the SS/TA ratio, pH and fruit decay index.