Effect of salicylic acid on storage life and postharvest quality of grape (Vitis vinifera L. cv. Bidaneh Sefid)

Postharvest life of table grapes is usually shortened by berry softening, berry drop, stem browning and its desiccation, and also by fungal decay. In the present study, effects of salicylic acid (SA) treatment on grape postharvest storage life and its quality were studied. Harvested clusters of 'Thompson Seedless', or 'Bidaneh Sefid' in Iran, were treated by SA at four concentrations, 0, 1, 2 and 4 mM, stored for 45 days at 0 °C and then exposed for two days at 20 °C to estimate as their shelf life. The SA treatment significantly increased the storage life of the clusters. All of the three SA concentrations were effective to reduce water loss, fungal decay and the softened berry rate. SA used at a concentration of 4 mM effectively inhibited development of decay infection. SA applied at concentrations of 2 and 4 mM significantly delayed rachis browning. The lowest berry shatter was observed in all of the SA-treated clusters. SA used at the high concentration of 4mM obviously maintained berry appearance. In addition, SA treatment also enhanced the increase of total phenolic content of berry skin after the shelf life period. The highest contents of phenolic components were detected in the berries treated by 4 mM SA. The concentrations of quercetin and catechin were higher in SA-treated berries. These results demonstrate that the postharvest treatment of grape berries by SA has potential for increasing storage life of table grapes and maintaining their quality.