Influence of intensity of post-veraison defoliation or shoot trimming on vine physiology, yield components, berry and wine composition in Aglianico grapevines

Abstract

Background and Aims: Post-veraison trimming and defoliation have been proposed as strategies to decrease the concentration of berry carbohydrate at harvest and of wine alcohol, but it is unclear which of these two pruning techniques is more suitable and at what intensity they should be applied. The aimof this 3-year study was to compare the suitability of two intensities of post-veraison trimming or defoliation in controlling sugar accumulation in the berries of Aglianico grapevines.\ud Methods and Results: Five treatments were compared: two intensities of defoliation, two intensities of shoot trimming and a control. All pruning treatments decreased berry TSS at harvest and wine alcohol concentration. Defoliation and trimming of moderate intensity also improved wine sensory score, whereas intense defoliation and trimming can affect negatively this parameter.\ud Conclusions: Post-veraison defoliation and trimming of moderate intensity appear to be suitable strategies for decreasing berry TSS at harvest and wine alcohol concentration.\ud Significance of the Study: The selection of the correct intensity of leaf removal appears to be one of the critical factors in correctly designing a suitable strategy of post-veraison summer pruning that aims to decrease sugar accumulation in the berries, whereas the choice of the type of pruning appears to be less crucial

Effects of pre-harvest techniques in the control of berry ripening in grapevine cv. Sauvignon blanc

“…Berries from defoliated vines presented TA values no different from the control in 2015, whereas it was lower in 2017. Previous studies conducted on red grape cultivars (Sangiovese, Ciliegiolo, Barbera, Aglianico) in different cultivation environments, reported similar effect of pre and post-veraison sprays with antitranspirant on sugar accumulation in the berries [10,12,14,16]. Our findings therefore confirmed, for the first time, the efficacy of the antitranspirant compounds for the control of sugar accumulation in an early-ripening white cultivar such as Sauvignon blanc.…”

“…In this respect, the mechanisms underlying the effect of antitranspirant compounds on berry acidity should receive more targeted research, focusing also on the fate of the two main organic acids (malic and tartaric) in the grape berry. Finally, as in other studies [12,16] a postveraison reduction of the canopy area obtained by manually pulling the leaves close to the fruiting zone was found able to delay sugar accumulation in Sauvignon blanc berries with only minor modification of their final titratable acidity.…”

Low night temperature at veraison enhances the accumulation of anthocyanins in Corvina grapes (Vitis Vinifera L.)

“…42 showed that veraison is the most sensitive stage for anthocyanin accumulation in the berry skins of Aki Queen and that low average temperature treatment (20 vs 30 °C) during veraison significantly enhanced anthocyanin accumulation via an increase in mRNA levels of anthocyanin biosynthetic genes. Furthermore, exogenous treatments with abscisic acid 66 or agronomic practices, such as the application of different deficit irrigation regimes 67 , removal of apical leaves 68 , 69 or shoot trimming 70 don’t imply a variation in skin anthocyanin accumulation if conducted in post-veraison. According to our results, it appears clear that the possibility of influencing anthocyanin biosynthesis at transcriptional level by low night temperature is limited to the veraison stage and that subsequently no positive effects may arise.…”

Counteracting the Negative Effects of Copper Limitations Through the Biostimulatory Action of a Tropical Plant Extract in Grapevine Under Pedo-Climatic Constraints

“…Two-year-old shoots (holding the production of the year) per plant were selected to monitor growth by recording shoot length, number of leaves and leaf area. Leaf area was estimated by measuring the lamina width and applying the equations calculated based on the measurement of width and area of 25 leaves per treatment by means of a electronic leaf area meter (LI-3100 model, LI-COR Inc., Lincoln, Nebraska, United States), according to Caccavello et al (2017).…”