Evaluation of the potential of the Johanniter grape variety for high-quality winemaking in the Lower Don region

The article provides a detailed analysis of the agrobiological, economically valuable traits and properties of white wine grape variety Johanniter, a complex interspecific hybrid obtained at the State Institute of Viticulture (Freiburg, Germany). The study was conducted at the All-Russian Research Ya. I. Potapenko Institute for Viticulture and Winemaking (branch of the Federal State Budget Scientific Institution “Federal Rostov Agricultural Research Center,” Novocherkassk, Rostov Oblast, Russia) in 2021–2023 using the methods generally accepted in viticulture and winemaking. The vineyards were uncovered, non-irrigated, with plants grafted onto Kober 5BB rootstock. The planting pattern was 3.0x1.5 m. The vines were pruned to form two cordons (arms) and a trunk with an average height of 80 cm. The study aims to assess the prospects of using this variety for the grape industry in Rostov Oblast conditions. The Johanniter grape variety shows considerable potential in the context of sustainable viticulture. It is resistant to fungal diseases (mildew and oidium) at the level of 2.5 points, which enables a remarkable reduction in the amount of chemical plant protection products used. The data of agronomic surveys confirmed the high potential yield (10.0 t/ha) and high winter hardiness of the variety, which is sufficient for cultivating vines without covering them in zones with mild winters (the percentage of blossoming buds was 79.6, of which 85.7% were fruit-bearing shoots). The wines produced from the Johanniter variety demonstrated floral aromas and a fruity profile, with citrus and stone fruit notes similarly to Sauvignon Blanc. The tasting score of the dry wine material equaled 8.6 points. The chemical composition of the berries was characterized by an optimal ratio of sugars (21.7 g/100 cm3) and titratable acids (8.5 g/dm3), a high juice yield (66.9-68.2 %), and a rich aromatic profile. Thus, the variety is suitable for high-quality wine production. The research results confirm the promising potential of the Johanniter variety from an agronomic and winemaking standpoint, which creates new opportunities for its introduction into industrial production. The variety can enhance the development of new approaches in organic winemaking and sustainable viticulture, which is especially relevant in the context of climate change and stricter requirements for the environmental safety of food products.