Effects of exogenous 24-epibrassinolide to control grey mould and maintain postharvest quality of table grapes

The potential of various concentrations of 24-epibrassinolide (EBR) treatments on the control of grey mould in artificial Botrytis cinerea inoculation test and on the maintenance of postharvest quality of table grapes without inoculation in cold storage were researched. In the cold storage, clusters of grapes with exogenous EBR application (EBR1, 0.1mgL(-1) EBR; EBR2, 0.4mgL(-1) EBR; EBR3, 0.8mgL(-1) EBR) were stored at 0 +/- 1 degrees C. Fruits' quality attributes including berry firmness, weight loss, berry drop, decay berry percentages, total sugar and titratable acidity were measured at 15, 30 and 60days. The results showed that EBR treatments exhibited a higher berry firmness and a lower percentage of weight loss, berry drop and decay berry. In the artificial inoculation trial, single berries were immersed in EBR1, EBR2 and EBR3, then inoculated by spraying with a B.cinerea spore suspension and stored at 25 +/- 2 degrees C and 95% relative humidity. Disease severity (DS), lipid peroxidation and defence-related enzymes of these berries were analysed every 2days. EBR-treated berries resulted in an increase in activities of defence-related enzymes including superoxide dismutase, peroxidase, catalase and phenylalanine ammonia-lyase compared with control berries inoculated by B.cinerea. Simultaneously, significant decreases in DS and production of superoxide anion radical and malondialdehyde were observed. These results suggested that exogenous application of EBR could play a protective role in controlling the grey mould of postharvest grapes and maintaining the postharvest quality during cold storage.