Avaliação de variedades de videira resistentes ao míldio e ao oídio cultivadas no sudoeste da França

Abstract

With genetic improvement, it is possible to obtain grapevines that are resistant to multiple diseases of economic importance in France and worldwide, such as downy mildew, powdery mildew, and black rot, which must be tested before being made available to winegrowers. The aim of this work was to evaluate the behavior of grapevine varieties, from the Resdur and Bouquet genetic improvement programs, resistant to downy mildew and powdery mildew, grown in southwest France. To this end, a test plot was set up on the Anglars-Juillac departmental farm in southwest France and has been monitored since 2018, with evaluations being carried out throughout the crop's development, from the phenology of the crop, the durability of the resistance to downy mildew and powdery mildew, to the analysis of the wines produced from these varieties. For the 2023 analyzes, it was observed that the red Resdur varieties, Artaban and Vidoc, proved to be earlier than the white varieties, Floreal and Voltis, while the Bouquet G9B and 3179-90-7N varieties stand out from the other white varieties for their earliness, which is more pronounced when the buds open, while all the red varieties have comparable earliness. The resistance to downy mildew would be classified as partial tolerance, because with high parasite pressures, due to the climatic conditions conducive to the development of the disease in 2023, all the varieties showed symptoms, but these did not cause any significant damage, with attack intensities decreasing after the rainiest months. As for powdery mildew, the resistance is total, at least in the conditions of the study environment, and it is important to analyze the other regions where the varieties are planted to confirm this resistance. When the other pests and diseases common to grapevines were analyzed, black rot proved to be extremely destructive, causing significant damage to all the varieties, meaning that the absence of the other fungi favored the development of this secondary disease. Finally, the results of the sensory analysis show that the white wines produced have interesting characteristics, producing good quality wines, while for the red wines there is a flaw in the oenological profile of the wines produced, which would jeopardize market acceptance, and it is necessary to work on hybrids to improve the visual, olfactory and taste quality of the red wines produced.