Influence of rootstock,irrigation level and recycled water on growth and yield of Soultanina grapevines

Recent studies have revealed complex interactions among grapevine rootstocks, soil water status, and water quality in terms of yield and growth. Understanding these interactions is essential to optimise yield and its quality, especially in regions with limited or degraded water resources. Thus, a study was conducted to investigate the effect of rootstock (41B, 1103P, and 110R), irrigation level (0.50, 0.75 and 1.00 of ET, evapotranspiration), and water quality (fresh and recycled water) on vegetative characteristics and on yield quantitative and qualitative components of potted Soultanina vines for a 3-year-period. Vine growth was inhibited by irrigation with recycled water and that inhibition became more severe by increasing the irrigation level and from one season to the next season. Furthermore, recycled water reduced yield by 50% and grape juice from these vines exhibited higher pH and titratable acidity values and lower total soluble solids. Rootstock significantly affected shoot growth, an effect which varied with age and within the growing season. Vines grafted on 41B developed more leaf area and produced higher yield than vines grafted on the other two rootstocks. Decreasing in the irrigation level dramatically reduced all vegetative parameters without affecting fruit quality and yield components. A significant interaction was detected between rootstock and irrigation level in terms of yield. Vines on 41B produced the highest yield of vines irrigated at 1.00 ET, and produced higher yields than vines grafted on 110R when irrigated at 0.75 ET, but the differences in yield among rootstocks disappeared at the 0.50 ET level.