GiESCO 2019 banner
IVES 9 IVES Conference Series 9 GiESCO 9 Effects of severe shoot trimming at different phenological stages on the composition of Merlot grapes

Effects of severe shoot trimming at different phenological stages on the composition of Merlot grapes

Abstract

Context and purpose of the study – High concentration of sugars in grapes and alcohols in wines is one of the consequences of climate change on viticulture production in several wine regions. One of the options to alleviate this potential problem is to perform severe shoot trimming of the vines to limit the production of carbohydrates. Two different studies were performed in order to investigate the effects of severe shoot trimming on the composition of Merlot grapes; in a first study severe shoot trimming was performed at three different phenological stages (at berry set, at the beginning of veraison and at the end of veraison), while in a second study two trimming treatments (standard shoot trimming and severe shoot trimming performed at the end of veraison) were combined with two shoot densities in order to evaluate the relative impact of these treatments on Merlot grape composition.

Material and methods – In a study conducted during years 2013 and 2014 severe shoot trimming (65 cm shoot height) was performed at berry set (berries 2-4 mm in diameter), at the beginning of veraison (when <5% of berries had changed color), and at the end of veraison (when >80% of berries had changed color). These treatments were compared with a standard canopy treatment (125 cm shoot height). Another study was conducted during years 2015 and 2016, where standard canopy treatment (125 cm shoot height) and severe shoot trimming at the end of veraison (65 cm shoot height) were combined with two shoot densities per vine (obtained with 35% shoot thinning vs. untreated).

Results – Severe shoot trimming at all the three investigated stages reduced sugars in grapes, although this effect was the greatest in the two veraison treatments. Severe shoot trimming at berry set and at the beginning of veraison reduced also the concentration of total anthocyanins in grapes, while severe shoot trimming at the end of veraison obtained similar values of total anthocyanins to the standard canopy treatment. Photosynthetic active radiation in the cluster zone was greater in all treatments with severe shoot trimming because of greater light penetration from the upper part of the canopy. We hypothesize that greater light penetration around clusters in combination to the intensive accumulation of anthocyanins during the first weeks of berry ripening, enabled the treatment of severe shoot trimming at the end of veraison to obtain similar values of total anthocyanins to the standard canopy treatment. No effects on yield components, titratable acidity, pH and total phenolics in berries were observed in any of these treatments. In a study where standard and severe shoot trimming were combined with two shoot densities, a consistent effect on the reduction of grape sugar concentration was achieved only with late severe shoot trimming. Higher shoot density reduced sugars in grapes only in one season, while at the same time reduced the concentration of total anthocyanins in berries.

Download the PDF

DOI:

Publication date: September 29, 2023

Issue: GiESCO 2019

Type: Poster

Authors

Marijan BUBOLA1*, Sanja RADEKA1, Sara ROSSI1, Tomislav PLAVŠA1, Milan OPLANIĆ1, Ádám István HEGYI2, László LAKATOS2, Kálmán Zoltán VACZY2

1 Institute of Agriculture and Tourism, Karla Huguesa 8, HR-52440 Poreč, Croatia
2 Eszterházy Károly University, Food and Wine Research Institute, Leányka utca 6, H-3300 Eger, Hungary

Contact the author

Keywords

severe shoot trimming, shoot thinning, Brix, anthocyanins, phenolics

Tags

GiESCO | GiESCO 2019 | IVES Conference Series

Citation

Related articles…

Nutrient absorption in vines (Vitis vinifera L., cv. Tempranillo blanco) under two water management approaches in a semiarid region of the north of Spain

Two treatments were studied in vines of cv. Tempranillo blanco (Vitis vinifera L.) during the 2012-2018 period in an experimental plot located in Rincón de Soto (La Rioja, Spain). Rainfed treatment (R0) was compared with respect to an irrigation treatment (R2) equivalent to 30% of the crop evapotranspiration (ET0) from fruitset to harvest phenological stages. Pre-veraison irrigation ranged from 43 (2014) to 66 mm/m2 (2018) while post-veraison irrigation ranged from 37 (2017) to 115 mm/m2 (2012).The normalized difference vegetation index (NDVI) was assessed by measures of reflectance, nutrients were determined by analysis of petioles sampled at veraison, grape production was determined at harvest as well as renewable wood weight was assessed at pruning time.

Read More

IMPACT OF CLIMATIC ZONES ON THE AROMATIC PROFILE OF CORVINA WINES IN THE VALPOLICELLA REGION

In Italy, in the past two decades, the rate of temperature increases (0.0369 °C per year) was slightly higher compared to the world average (0.0313 °C per year). It has also been indicated that the number and intensity of heat waves have increased considerably in the last decades. (IEA, 2022). Viticultural zones can be classified with climatic indexes. Huglin’s index (HI) considers the temperature in a definite area and has been considered as reliable to evaluate the thermal suitability for winegrape production (Zhang et al., 2023).

Read More

Exploring between- and within-vineyard variability of “Malvasia di Candia aromatica” vineyards from Colli Piacentini

Several studies demonstrated how climate and soil may be key drivers of variability at different scales.

Read More

Evaluation of vineyards, fruit and wine affected by wild fire smoke

Wineries may randomly reject fruit from vineyards near wild fires exposed to smoke. It is difficult to determine if fruit has been compromised in quality when exposed to smoke

Read More

De novo Vitis champinii whole genome assembly allows rootstock-specific identification of potential candidate genes for drought and salt tolerance

Vitis champinii cultivars Ramsey and Dog-ridge are main choices for rootstocks to adapt viticulture in semi-arid and arid regions thanks to their distinctive tolerance to drought and salinity. However, genetic studies on non-vinifera rootstocks have heavily relied on the grapevine (Vitis vinifera) reference genome, which difficulted the assessment of the genetic variation between rootstock species and grapevines. In the present study, this limitation is addressed by introducing a novo phased genome assembly and annotation of Vitis champinii. This new Vitis champinii genome was employed as reference for mapping RNA-seq reads from the same species under drought and salt stresses, and for comparison the same reads were also mapped to the Vitis vinifera PN40024.V4 reference genome. A significant increase in alignment rate was gained when mapping Vitis champinii RNA-seq reads to its own genome, compared to the Vitis vinifera PN40024.V4 reference genome, thus revealing the expression levels of genes specific to Vitis champinii. Moreover, differences in coding sequences were observed in ortholog genes between Vitis champinii and Vitis vinifera, which therefore challenges previous differential expression analyses performed between contrasting Vitis genotypes on the same gene from the Vitis vinifera genome. Genes with possible implications in drought and salt tolerance have been identified across the genome of Vitis champinii, and the same genomic data can potentially guide the discovery of candidate genes specific from Vitis champinii for other traits of interest, therefore becoming a valuable resource for rootstock breeding designs, specially towards increased drought and salinity due to climate change.

Read More