Minimal pruning (MP) is considered a viable technique to reduce labor costs and produce high quality wine grapes. To evaluate its effects on grapes cultivated in warm areas, a long-term study on Tempranillo (Vitis vinifera L.) was conducted in Badarán (La Rioja, Spain). For each vintage between 1999 and 2013, grapes from MP vines and those conventionally hand pruned (CHP) were evaluated for yield and total soluble solids (TSS). On this basis, from 2014, a further study was initiated in which grapes were analyzed at the same TSS to verify the effects of MP on fruit maturation and to determine the effects of MP on fruit quality. The long-term study showed that MP increased yield by 56% and reduced TSS by 9% compared to CHP. Results from 2014 and 2015 demonstrated that MP delayed fruit maturity (22 Brix) by ≈ 17 days. At the same TSS level (22 Brix), MP had lower berry weight by 24% and cluster weight by 57%, and increased yield by 51%. Must from MP fruit had higher total anthocyanin concentration (+17% in 2014 and +21% in 2015). However, this improvement in potential wine color was more likely due to smaller berry size rather than higher anthocyanin synthesis per unit area of berry skin. The study indicates that MP can effectively delay berry ripening and help to improve potential wine color.
- ©2016 by the American Society for Enology and Viticulture