Effect of Some Rootstocks on Vegetative Growth, Nutrient Content, Yield and Quality of Thompson Seedless Grapevines and H4 Strain under Conditions of Egyptian Delta Region

Abstract

T HE GENERAL trend of expanding in the cultivation of grapes in the Delta region de-pends on the cultivation of grafted cultivars on different rootstocks, with a preference for the cultivation of H4 strain grafted over the Thomson Seedless grafted. The aim of this study was to evaluate grafting Thomson Seedless and H4 strain cultivars on three different rootstocks (Freedom, Salt Creek, and SO4) compared with non-grafted (own rooted) to select the most suitable rootstock under clay soil conditions and surface irrigation system of the Delta region, Egypt. This experiment was conducted over four consecutive seasons (2019, 2020, 2021, and 2022), and the data were taken during the 2021 and 2022 seasons. Results showed that grafting Thomson Seedless and H4 strain cultivars on Freedom, Salt Creek and SO4 rootstocks was better than non-grafted(own rooted) on improving all studied parameters. The best results for all studied parameters were obtained when the vines were grafted on Freedom followed by Salt Creek followed by SO4. In addition, the obtained results showed that the H4 strain grafted on Freedom rootstock recorded the significant highest values as compared with Thomson Seedless grafted on Freedom in most studied parameters. Therefore, it is recommended to graft Thomson Seedless and H4 strain cultivars on Freedom rootstock under the conditions of clay soil and surface irrigation system in the Delta region, with preference planting of the H4 strain due toits good vegetative growth, high cluster weight, and yield. However, further studies to reduce the compactness coefficient of clusters are essential in this strain.