Effects of post-veraison irrigation dose on Cabernet-Sauvignon vines in a dry and warm season in Valencia, Spain

Among the Vitis vinifera L. cv. Moscato, Moscato Bianco is the oldest and most cultivated one in Europe (1). According to the OIV Focus 2015, Italy is the country with the largest cultivated area of Moscato Bianco with about 12500 hectares (2), that is used to produce well-known wines (i.e., Moscato Passito in Piedmont, Moscato di Trani in Puglia, and Moscatello di Montalcino in Tuscany), mainly obtained from partially dehydrated grapes (1). Different dehydration techniques can strongly modify the chemical compounds of oenological interest, among which Volatile Organic Compounds (VOCs) (1) that are the main responsible for the varietal sensory character of the final wine.

During alcoholic fermentation, nitrogen is an essential nutrient for yeast as it plays a key role in sugar transport and biosynthesis of wine aromatic compounds (thiols, esters, higher alcohols). The main issue of a lack in yeast assimilable nitrogen (yan) in winemaking is sluggish or stuck fermentations promoting the growth of alteration species which may lead to economic losses. However, correcting this nitrogen deficiency is sometimes not enough to restore proper fermentation performance. This suggests the existence of other nutritional shortages.

Merlot grapevine is the second wine cultivar most planted in the world and especially in the Bordeaux wine region. This cultivar has many advantages in producing high quality wine; however, in the last decade, climate change has increased the sugar concentration in berries at harvest and shortened the maturation cycle. If this has been up to now a great opportunity to improve wine quality profile, we are touching the tipping point. High sugar concentration at harvest induces high alcool content in wine which can negatively impact wine quality. There are many viticultural and oenological practices possible to limit this effect. In this study we focus on plant material through intra-varietal diversity of Merlot cultivar.

Climate change has a strong impact on the earlier onset of important phenological stages and plant development in viticulture.

Rootstocks are used in vineyards worldwide and have been the focus of many studies. However, rootstock performance varies based on regional climates and soil types. As Oregon experiences warmer seasons and variable precipitation patterns, growers are interested in rootstocks with more drought tolerance than the commonly planted rootstocks: 3309C, Riparia Gloire, and 101-14 Mgt. In Oregon’s Willamette Valley, annual precipitation is typically sufficient to make dry-farming possible and use of irrigation is limited.