Effect of increased irrigation and additional nitrogen fertilisation on the concentration of green aroma compounds in Vitis vinifera L. Merlot fruit and wine
Version of Record online: 9 JAN 2014
© 2014 Australian Society of Viticulture and Oenology Inc.
Australian Journal of Grape and Wine Research
Volume 20, Issue 1, pages 80–90, February 2014
How to Cite
Mendez-Costabel, M.P., Wilkinson, K.L., Bastian, S.E.P., Jordans, C., McCarthy, M., Ford, C.M. and Dokoozlian, N.K. (2014), Effect of increased irrigation and additional nitrogen fertilisation on the concentration of green aroma compounds in Vitis vinifera L. Merlot fruit and wine. Australian Journal of Grape and Wine Research, 20: 80–90. doi: 10.1111/ajgw.12062
- Issue online: 26 JAN 2014
- Version of Record online: 9 JAN 2014
- Manuscript Accepted: 28 JUL 2013
- Manuscript Revised: 3 JUL 2013
- Manuscript Received: 13 AUG 2012
- C6 compound;
Background and Aims
Green aroma compounds are considered undesirable when present at a high concentration in red wines. This study aimed to understand the effect of two irrigation levels and a higher than standard nitrogen fertilisation on the concentration of both 3-isobutyl-2-methoxypyrazine (IBMP) and six C6 compounds during fruit development.
Methods and Results
Fruit samples were collected biweekly during the 2009 and 2010 seasons in a commercial Vitis vinifera L. Merlot vineyard in California, USA, where two irrigation levels (70 and 100% of crop evapotranspiration) and a higher than standard nitrogen fertilisation dose were implemented. The higher irrigation level and additional nitrogen promoted canopy growth and decreased fruit exposure, resulting in increased concentration of IBMP during fruit maturation. The concentration of the six measured C6 compounds, however, was not affected. Deficit irrigation increased fruit colour, quercetin glycosides and phenol-free glucose glycosides (i.e. aroma precursors), and decreased vine yield. The two irrigation levels did not differ on the sensory vegetal perception of the wines, but the additional application of nitrogen fertiliser at fruitset enhanced it.
Significance of the Study
These findings confirm previous work showing that vineyard management practices influence fruit and wine concentration of IBMP, and demonstrate for the first time that the same practices have no significant impact on the concentration of six C6 compounds in grapes or on the concentration of hexanol in wines. Grapegrowers aiming to minimise IBMP concentration in fruit at harvest would probably benefit from a reduced application of water and nitrogen to the vineyard.