Pedro Balda

Variations of soil properties affect the vegetative growth and yield components of “Tempranillo” grapevines

To obtain the best must quality, winegrowers must harvest uniform batches of grapes, thus they might define sub-units of the vineyard and treat them as separate management units for cultivation and harvest. The objectives of this work were to determine if there were variations of soil properties that could be arranged into different units of relative uniformity and separated from each other by discrete boundaries, and if there was a significant relationship between those units and the vegetative development and yield components of the grapevines. A soil index that is a linear combination of four soil characteristics was constructed and an interpolation method allowed the definition of soil areas with relative uniformity. These areas were significantly correlated with the vine growth that, in turn, had a significant correlation with the yield components of the vines. This methodology might prove useful to define areas within vineyards where the vegetative development and yields warrant a differentiated management within the vineyard.

Reducing the sugar and pH of the grape (vitis vinifera l. Cvs. 'Grenache' and 'tempranillo') through a single shoot trimming

Many vineyards all over the world can easily produce high potential alcohol levels, but the importance of the sugar content in berries has been changing over the past few years. The objective of this work was to reduce the sugar and pH of the grapes, delay berry ripening by decreasing the ratio between the leaf area and yield, perform an intense trimming treatment after berry set and establish the consequences for grapevine productivity in the following year. Severe shoot trimming was done over a three-year period (2010 to 2012). Phenological, vegetative and productive parameters were examined. The date of veraison was delayed by about 20 days. On the same harvesting date, the trim treatment had lower soluble solids (12% to 15 % reduction), lower pH (0.1 to 0.3) and a lower total anthocyanin content (10% reduction). The trim effect was also reflected in berry weight; as a consequence, bunch size and yield were also reduced by around 10%. If the trim treatment does not reduce the leaf area to fruit ratio below 0.50 m2/kg, there is no negative impact on vine capacity in the next year.

Use of Minimal Pruning to Delay Fruit Maturity and Improve Berry Composition under Climate Change

Minimal pruning (MP) is a technique used to reduce labor costs and produce high-quality winegrapes. To evaluate the effects of MP on grapes cultivated in warm-climate regions, a long-term study on Tempranillo (Vitis vinifera L.) was conducted in Badarán, La Rioja, Spain. For each vintage between 1999 and 2013, yield and total soluble solids (TSS) were evaluated in grapes from MP vines and from conventionally hand-pruned (CHP) vines. In 2014 and 2015, grapes were analyzed at 22 Brix to assess the effects of MP on fruit maturation and quality. The long-term study showed that MP increased yield by 56% and reduced TSS by 9% compared to CHP. Results from 2014 and 2015 demonstrated that MP delayed fruit maturity (22 Brix) by ~17 days. At the same TSS level (22 Brix), MP vines had 24% lower berry weight, 57% lower cluster weight, and 51% greater yield. Must from MP fruit had greater total anthocyanin concentrations compared to must from CHP fruit (+17% in 2014 and +21% in 2015); however, potential improvements in wine color were more likely due to smaller berry size than to greater anthocyanin synthesis per unit area of berry skin. These results indicate that MP can delay berry ripening and may help to improve wine color.

Study of Chardonnay and Sauvignon blanc wines from D.O.Ca Rioja (Spain) aged in different French oak wood barrels: Chemical and aroma quality aspects

This study discusses chemical data corresponding to the analysis of twenty-one wood-extractable aromatic compounds in twenty-four different barrels varying in the toasting level at three sampling times: at the end of the alcoholic fermentation and after 5 and 12months of aging. Twelve barrels contained monovarietal Chardonnay wine while the other twelve barrels contained Sauvignon blanc wine. The levels of nearly all the analyzed compounds increased with the aging time, with the exception of vinylphenols and methyl vanillate, which decreased. These latter compounds had significantly higher levels in the Chardonnay wines than in the Sauvignon blanc. Furfural, guaiacol and vanillin derivatives increased with the toasting level. ANOVA study showed significant interactions between the toasting level and aging time as well as between the variety and aging time, which revealed significant differences in the levels of the compounds studied in the wines dependent on the toasting level, variety and aging time. Quality perception based exclusively on orthonasal aroma stimuli was evaluated by a panel of Spanish wine professionals in 12-month aged wines belonging to both grape varieties. Experts from D.O.Ca Rioja aroma did not share a common aroma quality concept for aged Chardonnay and Sauvignon blanc wines. Considering the cluster formed by the majority of experts (76%) for the Chardonnay and cluster 1 (56%) for Sauvignon blanc, quality scores were negatively correlated with the concentration level of 4-vinylphenol and positively with the concentration level of (E)-isoeugenol. The opposite was observed for cluster 2 (44%) identified for Sauvignon blanc wines.

Characterization and Identification of Minority Red Grape Varieties Recovered in Rioja, Spain

A research project to recover the minority varieties of Rioja was started in 1988 as grapevine biodiversity accumulated during the past centuries was diminishing. The selected vines were preserved within a germplasm bank. Ampelographic description according to 44 Internationale Organisation de la Vigne et du Vin (OIV) characters and genetic characterization using 11 nuclear microsatellites markers were performed on each of the 45 red accessions at the germplasm bank in Logroño, Spain. In total, 26 different varieties were found by the ampelographic and genetic analysis and 24 of them were identified. The remaining two varieties did not match any other genetic profile in the Spanish or European microsatellite databases. The origin of the identified varieties is very diverse, indicating the importance of grape variety exchange that occurred during the last centuries. Minority varieties could play an important role in the future, considering their capacity to adapt to new climatic conditions and their specific wine profiles.

Does full exposure of clusters have any negative effects on Tempranillo (Vitis vinifera L.) Grape Quality in La Rioja, Spain? The use of severe Cluster-zone Leaf Removal after Berry Set

A three-year experiment comprising severe leaf removal (LR) was carried out on Tempranillo grapes in Logrono, North-central Spain. For the LR treatment, six basal leaves, along with the basal lateral shoots, were removed two weeks after fruit set. Berry total soluble solids (TSS) were examined when the colour began to appear. Grapes from both the LR and control (C) vines were analysed at the same TSS level (≈ 22°Brix). LR advanced the onset of anthocyanin synthesis slightly but significantly. Yield components were not affected by LR and no symptoms of sunburn were observed. Both treatments showed similar juice pH and titratable acidity, although tartaric acid increased with LR while malic acid decreased with it. In spite of failing to increase the final anthocyanin concentration of the grape juice, LR enhanced the colour and body of the wine. These results indicate that a relatively early LR could be a viable way to improve the quality of grapes and wine under the climatic conditions of the Rioja wine region.