Fernando Martínez de Toda

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.

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.

Variability of Tempranillo grape composition in the Rioja DOCa (Spain) related to soil and climatic characteristics: Tempranillo grape composition in Rioja related to soil and climate

BACKGROUND Soil and climate are terroir elements that condition vine response. This research was intended to evaluate the variability of grape composition of the Vitis vinifera L. cv. Tempranillo in the Qualified Designation of Origin Rioja (DOCa) (Spain) in La Rioja (Spain), and its relationships with soil and climate characteristics. RESULTS The relationships between grape composition (sugar content, acidity, phenolic compounds, and berry weight) and climate characteristics were analyzed for the period 2008-2017 in 20 plots scattered throughout Rioja Alta and Rioja Baja, using multiple-regression analysis. The spatial variability of grape composition and the effect of soil properties were evaluated using cluster analysis. Despite the high variability in climate characteristics from year to year, it was possible to define the soil and plot characteristics that affect grape composition at ripening. CONCLUSION Acidity and anthocyanin concentrations were affected by temperature and by precipitation recorded in different time periods throughout the growing cycle. The increase in temperature in earlier stages reduced the total acidity and increased the total polyphenols, while an increase in temperature during the ripening period produced a decrease in total acidity, malic acid, and anthocyanin concentration, and a lower ratio between anthocyanins and sugars. The plots located in soils with higher soil water availability presented higher acidity and lower anthocyanin concentrations.