This study was conducted during two growing seasons of 2016 and 2017 to evaluate the potential effects of different irrigation levels: 30, 50 and 70% depleted of available soil water (I1, I2 and I3, respectively) after fruit set as well as four foliar applications of Control, Silicon spray at 1.5 g/L, Calcium nitrate at 1 g/L and Amino acids at 2 ml/L (S1, S2, S3 and S4, respectively), which started at 15-20 cm of shoot length and the second one after fruit set, then these were continuous every two weeks till veraison stage on fruit quality and storability of "Thompson seedless" (Vitis vinifera L.) grapevines grown in clay soil under flow irrigation system in El-Mahalla region Gharbia Governorate.
The obtained results revealed that, vines irrigated at I1 and I2 recorded a significant increase in berry physical quality parameters in terms of firmness, removal force, berry shatter and chemicals as SSC%, acidity and SSC/acid ratio. However, irrigation at I3 recorded the lowest percent of cluster weight loss until the end of storage period. Calcium as well as silicon sprays, enhanced berry firmness, berry removal force and reduced berries shattering at picking date and during the cold storage period. Moreover, calcium application was more effective in increasing SSC/acid ratio, cluster quality index and marketable cluster percent and reducing physiological weight loss during storage. Foliar spray with amino acids recorded the highest significant values of SSC% and acidity and reduced the decayed berries% at the end of storage period.
The combination between I1 or I2 irrigation levels and calcium spray treatments were more effective in enhancing berry firmness, berry removal force, SSC/acid ratio, rachis browning index and marketable cluster percent and reduced shattered berries, decayed berries and cluster weight loss till 60 days of cold storage