Climate change – variety change?

Esca, one of the main grapevine trunk diseases, is a complex and poorly understood disease. Phaeoacremonium minimum and Phaeomoniella chlamydospora, two of the main pathogens associated to this disease, are thought to be responsible for the first trunk infections. Little is known concerning grapevine trunk defenses during pathogen infection.

In Tuscany region the Rufina is a district of Chianti D.O.C.G. positioned in Val di Sieve, 20 km north east from Florence.

Grapevine is a plant that holds significant socioeconomic importance due to its production of grapes for fresh consumption, wines, and juices. However, climate changes and susceptibility to diseases pose a threat to the quality and yield of these products. The breeding of new genotypes that are resistant/tolerant to biotic and abiotic stresses is essential to overcome the impact of climate changes. In this regard, Marker-assisted selection (MAS), which uses DNA markers, is a crucial tool in breeding programs. The efficiency and economy of this method depend on finding rapid DNA isolation methods.

Malbec is Argentina’s flagship variety, and it is internationally recognized for producing high-quality red wines. Fruit set rate is a major component in grapevine yield determination, and it is the outcome of multiple genetic and environmental interacting variables. Here, we characterized the reproductive performance of 25 Malbec clones grown under homogeneous conditions in a 23-years old experimental plot. We measured traits near flowering (like the number of flowers per inflorescence) and at harvest (including the number of berries per cluster and berry weight), during two consecutive seasons (2022 and 2023).

Climate has a significant impact in the success of any agricultural system, with a direct influence on the crops suitability to a given region, interfering on yield and quality and also with the economic sustainability of the productive activity. In the Douro Demarcated Region (RDD), as in most regions of the Mediterranean climate, the scarce precipitation (33% has less than 600 mm per year), and your high variability, associated with high rates of evapotranspiration during the summer, is usually one of the fundamental factors that limit the grapevine development, as well as the production and quality of the harvest. Thus, facing the scenario in temperature changes for the next decades (1.5-2.5°C) and confirming the predictions of precipitation decreases and/or great variability in the occurrence of heat waves and intense rainfall, the consequences for slope stability in mountain viticulture and sustainability of all operations involved, are risks to be taken into account. In this way, a deepest and sustained knowledge regarding the adaptation measures to adverse environmental conditions is of a crucial importance, enabling a more efficient adaptation of plant growth conditions and the optimization of production and quality of the grapevines. The development of this work, carried out in two commercial vineyards, one located in Soutelo do Douro, São João da Pesqueira, Cima Corgo sub-region, and another located in Numão, Vila Nova de Foz Côa, Douro Superior sub-region, it seeks to establish a relationship between climatic elements and physiological, productive and qualitative parameters, as well as to evaluate the effectiveness of adaptation measures, including different types of deficit irrigation (2002-2019) and the application of shading nets (2019-2020) in the physiological, viticultural and oenological behavior in the Touriga Nacional and Moscatel Galego Branco varieties, respectively. The results showed that the application of deficit irrigation allowed to significantly reduce the impact of the adverse weather conditions at key moments in the development of the grapevine, particularly in the period immediately before veráison and maturation, reducing the negative effects on the physiological processes and productivity, without compromise the must quality parameters. On the other hand, the application of shading nets significantly reduced de leaves temperature, allowing to increase the water potential, stomatal conductance and photosynthetic rate of grapes, which was reflected in the yield increase in the 2nd year of the study. For the maturation indicators, higher levels of total acidity, malic acid and assimilable nitrogen were obtained. The last measure presents a huge potential, being essential to carry out more years of trials to obtain stronger conclusions in terms of production parameters, but also in characteristics as important as the grape ripening components and the organoleptic characteristics of wines.