Irrigation and Leaf Removal Effects on Polyphenolic Content of Grapes and Wines Produced from cv. ‘Agiorgitiko’ (&lt;i&gt;Vitis vinifera&lt;/i&gt; L.)

Evangelia Horti,Stefanos Koundouras,Manolis Pavlidis,Stamatina Kallithraka,Maria Kyraleou,Yorgos Kotseridis

doi:10.15835/nbha.44.1.10254

Irrigation and Leaf Removal Effects on Polyphenolic Content of Grapes and Wines Produced from cv. ‘Agiorgitiko’ (<i>Vitis vinifera</i> L.)

Evangelia Horti, Stefanos Koundouras + Show 4 more

Open Access

https://doi.org/10.15835/nbha.44.1.10254

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Abstract

Vitis vinifera L. cv. ‘Agiorgitiko’ is one of the most important red grape varieties of Greece, cultivated almost exclusively in the region of Nemea in north-eastern Peloponnese. This work aimed to study the influence of some commonly applied viticultural practices on the polyphenolic composition of ‘Agiorgitiko’. Leaf removal at veraison, irrigation, and a combination of both, were applied and the phenolic content of the grapes and of the produced wines was compared. The results showed that leaf removal decreased berry size, enhanced total anthocyanin, total phenol and malvidin 3- O -monoglucoside accumulation in skins and increased the amount of extractable anthocyanins in the juice. The combination of irrigation and leaf removal caused a significant increase in total phenols in the skin and in the amount of extractable anthocyanins in juice. As far as the produced wines were concerned, color intensity, tannin content and total polyphenols were increased due to leaf removal. Both irrigation and leaf removal resulted in wines with the highest concentration of malvidin 3- O -monoglucoside, although neither practice resulted in any significant difference in anthocyanin concentration of the wines. Vines where only irrigation was applied produced berries with reduced extractable anthocyanins, increased seed total phenols and lower wine total tannins. The study showed that increasing cluster sun exposure of ‘Agiorgitiko’ vines may be, overall, beneficial to the quality of the produced wine.

Highlights

Several strategies have been applied in order to increase the content of phenolic compounds in wine during the process of grape growing and wine making
Growth components Berries from leaf removal (LR) were smaller (Fig. 1), there was no difference among treatments in seed and skin weight which leads to conclude that they had lower pulp mass compared to the other treatments
According to Kotseridis et al (2012) when leaf removal was applied before bloom, it had no effect on berry size in the case of ‘Merlot’ and ‘Sangiovese’ grapes, but reduced it in the case of ‘Cabernet Sauvignon’ grapes, leading to conclude that the effect may be cultivar-related

Summary

Introduction

Several strategies have been applied in order to increase the content of phenolic compounds in wine during the process of grape growing and wine making. The positive effect of pre-bloom leaf removal on grape composition has been often attributed to lower cluster and berry size at harvest. At the whole vine level, pre-bloom defoliation was reported to increase leaf area-to-fruit ratio due to reduced fruit set and/or berry size and to leaf area recovery after veraison (Intrieri et al, 2008). Fruit zone defoliation at berry set was found to reduce whole vine photosynthesis at an early stage (Petrie et al, 2003). Post-bloom defoliation was reported to be ineffective in lowering cluster weight and berry number per cluster in ‘Graciano’ and ‘Carignan’, whereas final total leaf area per shoot was reduced, with no evident compensation for lateral leaf area (Tardaguila et al, 2010)

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