Macrowine 2021
IVES 9 IVES Conference Series 9 Macrowine 9 Macrowine 2021 9 Grapevine diversity and viticultural practices for sustainable grape growing 9 Application of treatments to delay the ripening of grape varieties cultivated in valpolicella

Application of treatments to delay the ripening of grape varieties cultivated in valpolicella

Abstract

AIM: Winegrape cultivars are particularly sensitive to temperature and recent changes in climate have advanced the onset of berry ripening, resulting in unbalanced fruit composition at harvest. High temperatures during ripening result in berries with increased sugar concentration, reduced acidity and colour and unwanted or underdeveloped aroma compounds. To reduce the negative effects of climate change, several adaptation strategies, represented especially by viticultural practices, have been proposed. In this work we tested and compared the effect of two different treatments aimed to delay ripening of the most important grape varieties cultivated in Valpolicella (Verona, Italy).

METHODS: Clusters of Corvina and Corvinone, cultivated in Valpolicella, cordon trained, cane pruned, were treated one week before veraison with 1-Naphthaleneacetic acid (NAA), a synthetic auxin. On another block of vines of the same cultivars in the same vineyard, a postveraison defoliation treatment was applied, with the effect of removing about 30-40% of the leaves thus creating a vertical window without leaves above the bunch area. The dynamic of the main ripening parameters was monitored over the course of maturation and yield and yield components were determined at harvest.

RESULTS:Leaf removal had a very limited effect on delaying the accumulation of sugars in berries, which was the main scope of the trial, compared to berries from untreated vines. On the other hand, the NAA treatment greatly impacted the ripening dynamic of both varieties, postponing the accumulation of sugars and anthocyanins and the decrease in acidity. The effect was more pronounced in Corvinone than in Corvina.

CONCLUSIONS

The results evidenced that a relevant delay of ripening time can be obtained by treating clusters of the main grape varieties cultivated in Valpolicella with auxin-based products. On the contrary, the leaf defoliation treatment only weakly affected the ripening dynamics, possibly due to the remobilization of reserves from the perennial organs of the plant.

DOI:

Publication date: September 2, 2021

Issue: Macrowine 2021

Type: Article

Authors

Giovanni Battista Tornielli 

University of Verona, Ron SHMULEVIZ, University of Verona

Contact the author

Keywords

climate change, valpolicella, ripening, auxin, defoliation

Citation

Related articles…

NEAR INFRARED SPECTROSCOPY FOR THE ESTIMATION OF TEMPRANILLO BLANCO VOLATILE COMPOSITION ALONG GRAPE MATURATION

Grape volatile compounds are mainly responsible for wine aroma, so it is important to know the va-rietal aromatic composition throughout ripening process. Currently, there are no tools that allow mea-suring the aromatic composition of grapes, in intact berries and periodically, throughout ripening, in the vineyard or in the winery. For this reason, this work evaluated the use of near infrared spectroscopy (NIR) to estimate the aromatic composition and total soluble solids (TSS) of Tempranillo Blanco berries during ripening. For this purpose, NIR spectra (1100-2100 nm) were acquired from 240 samples of in-tact berries, collected at different dates, from veraison to overripening.

Impact of non-fruity compounds on red wines fruity aromatic expression: the role of higher alcohols

A part, at least, of the fruity aroma of red wines is the consequence of perceptive interactions between various aromatic compounds, particularly ethyl esters and acetates, which may contribute to the perception of fruity aromas, specifically thanks to synergistic effects.1,2 The question of the indirect impact of non-fruity compounds on this particular aromatic expression has not yet been widely investigated. Among these compounds higher alcohols (HA) represent the main group, from a quantitative standpoint, of volatiles in many alcoholic beverages. Moreover, some bibliographic data suggested their contribution to the aromatic complexity by either increasing or masking flavors of wine, depending of their concentrations.

Soil electrical resistivity measurement: from terroir characterization to within-field crop inputs management

Soil Electrical Resistivity measurement is a zoning tool used by soil scientists and agronomists in viticulture. Indeed, the measure enables to optimize pedological surveys

IMPACT OF RHIZOPUS AND BOTRYTIS ON WINE FOAMING PROPERTIES

A lot of work has been done on the impact of Botrytis on the foam of sparkling wines. This work often concerns wines produced in cool regions, where Botrytis is the dominant fungal pathogen. However, in southern countries such as Spain, in particularly hot years such as 2022, the majority fungal pathogen is sometimes Rhizopus. Like Botrytis, Rhizopus is a fungus that produces an aspartic protease.

Reduced berry skin epi-cuticular wax and cutin accumulation associates with a genomic deletion and increased polyphenols extractability in a clone of Tempranillo Tinto 

Tempranillo Tinto (TT) is the third-most planted red wine variety in the world, and it is mostly grown in the Iberian Peninsula. Spontaneous somatic variation appearing during vegetative propagation can be exploited to improve elite varieties as Tempranillo Tinto, including the selection of new phenotypes enhancing berry quality. We described previously that a somatic variant of TT with darker fruit color, the clone VN21, exhibits increased extractability of polyphenols during the winemaking process. To unravel the molecular mechanism underlying this phenomenon, we performed whole-genome resequencing to compare VN21 to other TT clones, revealing a 10 Mb deletion in chromosome 11 that likely affected only the L1 meristem cell layer of VN21 and tissues derived from it, such as external cell layers of berry skin.