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Background and Aims: Deficit irrigation techniques have been used to improve water use efficiency and control vigour in grapevines, but the consequences of using saline water with these techniques have been little investigated. Here, we investigate the effect of deficit irrigation with moderately saline water on within-vine ion allocation. Methods and Results: Drip-irrigated own-rooted Shiraz and Grenache vines grown in pots were subjected to control, reduced control and partial root-zone drying (both approximately 50% less than control) irrigation treatments utilising moderately saline irrigation (mean of 2.46 dS/m) over two seasons. Plant water status and stomatal conductance were measured during the growing seasons, and at the end of the second season, the vines were destructively sampled to determine plant growth and concentration of ions of various vine structures. When compared against the control, partial root-zone drying had a higher total concentration of Cl À , Na + , K + and Ca ++ present on a whole vine basis. Although Cl À concentration was elevated in leaves for the partial root-zone drying treatment, it was partitioned away from leaves on a total content basis relative to both control and reduced control treatments. The partial root-zone drying treatment also resulted in significantly lower midday leaf water potential. Conclusion: Ion partitioning within grapevines depends on the type of deficit applied. Significance of the Study: Utilising deficit irrigation techniques in combination with saline irrigation water will alter the allocation of ions within a grapevine highlighting the importance of monitoring during the growing season for both fruit composition and long-term vine health.

Background and Aims:This study investigated the response of field-grown Shiraz vines to saline irrigation involving water-deficit irrigation techniques. Methods and Results: Drip-irrigated Shiraz vines were subjected to control (1.0-2.3 ML/ha), reduced control and partial root zone drying (both approximately 50% less than control) irrigation treatments utilising moderately saline irrigation over three seasons. Grape juice chloride (Cl − ) and sodium (Na + ) concentration was not affected significantly by irrigation treatment, although it did vary greatly between seasons. Seasonal influence of rainfall was shown to have more of an effect on Na + concentration in grape juice, while irrigation applied and hence overall salt load impacted more heavily on grape juice Cl − . Partial root zone drying when compared against the controls had reduced stomatal conductance, leaf water potential, berry mass, and yield and pruning mass, while there was no significant effect on TSS (°Brix), pH and titratable acidity. Conclusion: In this study, the seasonal variation of rainfall and total irrigation applied played a greater role in altering the concentration of grape juice Cl − and Na + than the application of irrigation water with the same moderate salinity but with the differing irrigation strategies. Significance of the Study: Regions, where water allocation has been reduced and which are relying on a saline irrigation source, have the ability to manage the Cl − and Na + concentration present in grape juice by having a better understanding of the role season can play and the variability within that season, thereby making more informed decisions on when to apply irrigation. 468Impact of salinity and water deficit on Shiraz