Effects of UV-B, water deficit, abscisic acid sprays, and its interactions on grapes and wines of Vitis vinifera L. cv. Malbec

ALONSO R.; BERLI F.; FONTANA A.; BUSCEMA F.; PICCOLI P.; BOTTINI R.

Mendoza

Congreso; XX GIESCO International Meeting, Group of International Experts for Cooperation on Vitivinicultural Systems; 2017

Organización Internacional de la Viña y del Vino (OIV)

Malbec is the most important grape variety cultivated in Argentina. In Mendoza, at 1450 m asl, the intensity of natural ultraviolet-B (UV-B) radiation is high and causes a significant increase on polyphenol content in berries. Water deficit is a cultural practice known for increasing grape phenolic content in berries as well. Stressing conditions and/or environmental signals, including water deficit and UV-B, cause an increase of the natural plant regulator abscisic acid (ABA). The aim of the present work was to study the effect of UV-B, water deficit, ABA sprays, and their interactions, on high altitude Malbec vines, grapes and wines. Morphological, physiological and biochemical parameters were evaluated during three seasons. The results show that UV-B, given independently, increased low molecular weight polyphenols (LMWP) in grape skins and wines. Water deficit alone did not modify the LMWP or anthocyanin profile of grape skins and wine. ABA sprays increased terpenes in leaves and LMWP and anthocyanins in berries. Finally, the results indicate that the effect of natural UV-B light cannot be replaced by ABA sprays or water deficit.