The aim of this study was to evaluate the effects of silver nitrate (AgNO3) and nano-silver (Ag-NPs) on the physiological and biochemical characteristics, and quality of grape bunches during a cold storage period. For investigations, two varieties of grapes were used, Shine Muscat and Kyoho, with different concentrations of AgNO3 and Ag-NPs on post-harvest dipping. The data indicated that AgNO3 and Ag-NPs enhanced the fruits’ longevity and quality. Depending on the data analysis, it was found that the lowest weight loss value was obtained from Ag-NP treated grapes, followed by AgNO3 treated grapes, while the highest loss occurred in the control grapes. Immersion of grape bunches in Ag-NPs was the best application for maintenance of overall storage quality for both cultivars. In the same trend, treatment with Ag-NPs produced the best results for soluble solids content (SSC), titratable acidity (TA), malondialdehyde (MDA) content, polyphenol oxidase (PPO), pyrogallol peroxidase (POD), and pectin methylestraese activity (PME). It was concluded that Ag-NPs and AgNO3 were helpful in maintaining the quality of grape bunches up to 30 days, while grape bunches under control conditions were spoiled with 30 days of cold storage.

This study was carried out during the seasons of 2021-2022 to study the effect of GA3 plus urea each alone or with trunk girdling and bunches tipping on yield and bunch quality of Sultana 'H4 strain' grapevines. The data reveal that spraying vines with GA3 plus urea at the beginning of (15-20%) flowering significantly reduced the number of berries per bunch and the compactness coefficient of the bunch than the control. Furthermore, sprayed vines with GA3 plus urea with both trunk girdling and bunches tipping significantly produced a higher bunch weight, berry weight, and size. Despite this, treated bunches with GA3 plus urea gave no clear effect of SSC/acid ratio in berry juice than the control but increased the values of total chlorophyll a and b content in berry skin. Whereas, when girdling the trunk and tipping the bunch produced a higher SSC/acid ratio in berry juice and total carotenoid content in berry skin than the control.