‘Malbec’ grapevines commonly have high yield, thus intermittently negatively affecting wine quality parameters. Here, we describe the use of late shoot pruning (LSP) practice applied for wine quality improvement. We examined the effect of timing of LSP on ‘Malbec’ vines grown in Mediterranean conditions during three consecutive seasons (2016–2018) in Israel. The timing of LSP treatment applications (applied one, two and three weeks after bud break) were compared with cluster-thinned, winter-pruned vines (WP + T) and standard winter pruning (WP). The LSP practice postponed bud break of target buds but did not have a temporal effect on the onset of veraison. Midday stem water potential was less negative and stomatal conductance and net CO₂ assimilation rate were higher in the LSP vines. This practice led to a substantial reduction in the number of clusters and crop yield. Finally, wine quality was positively affected by applying LSP treatment. Performing the inexpensive LSP treatment at the precise timing after bud burst was found to save labor, decrease crop yield and improve grape and wine parameters. LSP application should be considered in adequate varieties as a significant tool for the enhanced effectiveness of vine growing in warm regions.

In semi-arid areas, vineyards grown for winemaking are usually mildly irrigated by drip irrigation systems in a manner maintaining drought stress. This practice ensures the proper development of vegetative and reproductive organs on the one hand, and on the other, the development of high-quality grapes which can be hampered by overly abundant water application. In previous work, we have developed and demonstrated an irrigation model suitable for high-quality grape production in semi-arid areas. Here, we tackle the question of proper irrigation initiation dates—should one wait for vines to develop drought stress before the initiation of irrigation, or rather commence irrigation earlier? Our results show that vines which undergo initial irrigation late in the growing season tend to develop a lower midday stem water potential even after irrigation initiation. In addition, these vines tend to produce a lower number of bunches per vine and smaller berry size, leading to lower yields. The wine produced from the late-irrigated treatments had a higher phenolic content, primarily due to higher levels of catechin and epicatechin. Their levels increased as irrigation initiation dates were delayed, while caffeic acid levels showed an opposite trend. Late irrigation also led to higher color intensities compared to those of irrigation at earlier stages, due to higher levels of most anthocyanins. Finally, we show that the overall wine sensory score, representing its overall quality, was approximately five points higher for wines made from delayed irrigation treatments compared to wines made from early season irrigation treatments.