Grenache behavior influenced by climate variability in the Mediterranean vineyards

Abstract

In Spain, Grenache is the second most planted red wine grape variety. In warm years with high temperatures during ripening grape composition could be modified, thus phenolic synthesis damaged. In order to evaluate the behavior of Grenache, two vineyards were chosen in Tarragona (T) and Priorat (P) AOC. Grapevines in (P) are cultivated in a density of 3500 vines/ha; vines in (T) have a density of 3780 vines/ha. Both vineyards are pruned as bilateral cordon and VSP trellising with 2 wires with 70cm height in (P) and 90cm in (T). During 2011 and 2012, temperature, rainfall, VPD and GDD were collected in each parcel. Leaf water potential (ΨL) was measured at veraison (V) and ripeness (RP) at 5hr and 12hr (solar time). Berry composition and phenolic maturity was monitored from V to the RP. Yield and water use efficiency (WUE) were evaluated. Measurements and analyses were done from triplicated field plots. ANOVA statistics and Tukey test was applied for post-hoc analysis (SPSS, version 21.0) between treatments. During the growing season, rainfall is much higher in (T) than in (P); about 50% and 75% for 2011 and 2012 respectively. In 2012 vintage, ΨL at V (12:00) reaches a lower value in (T) (-1.65) than (P) (-1.44). The kinetic of sugar pulp accumulation it is not related to wine region, neither the vintage. Berry size was smaller in 2012 where the temperatures increased at the end of the ripeness; nevertheless, the phenol content did not differ between vintages in each location. Concerning wine phenolics, Priorat showed more concentration than Tarragona regardless of the vintage. Only in Priorat, the vine yield was notably reduced in the drought year. Rainfall in spring led to a low WUE in T.