Effect of some Pre-Harvest Treatments on Quality of ʺCrimson Seedlessʺ Grapes During Cold Storage and Shelf Life

This work was carried out during two successive seasons (2017 and 2018) to examine the response of ʺCrimson Seedlessʺ grapes to some pre-harvest treatments i.e. jasmonic acid (JA) at (4 and 8) mM/L and grapefruit seed extract (GSE) at (0.5 and 1) mM/L on some berries quality parameters under cold storage and shelf-life conditions. Vines were sprayed in two application times at (25^th and 30^th August) during 2017 and 2018, respectively. The non-ionic surfactant Tween-20 at 0.05% (v/v) was added to all treatments to reduce the surface tension and increase the contact angle of sprayed droplets. Results showed that both jasmonic acid and grapefruit seed extract treatments at different concentrations were significantly effective in reducing weight loss, berry decay, berry shatter, and total loss in cluster weight percentages during the cold storage period and shelf life as compared to the control. Also, the previous treatments significantly increased berry firmness, soluble solid content (SSC%), SSC/acid ratio, and total anthocyanin contents, where it was caused a significant decrease in total acidity percentage during the cold storage period and shelf life in comparison with control.
Furthermore, the lowest values of weight loss, berry shatter, berry decay and total loss in cluster weight were founded by JA at 8 mM and GSE at 1 mM at the end of shelf life in comparison with other treatments. It could be concluded that JA at 8 mM and GSE at 1 mM as preharvest treatments are applicable for improving the storability of ʺCrimson Seedlessʺ grapes and maintaining their quality during cold storage and shelf life.