Guna

Main Characteristics

Guna is a multi-purpose grapevine cultivar characterized by an extremely early ripening period. It is a product of amateur selection by the Latvian breeder P. Sukatnieks, obtained by crossing the parental forms Madeleine Angevine and Dvietes zila. The time interval from budburst to the harvest maturity of the crop spans a mere 95–100 days. Under the Baltic agroclimatic conditions, the berries ripen in late July, which distinguishes the Guna grapevine cultivar as one of the earliest crops in the region.

By the standards of northern viticulture, the cultivar demonstrates decent yield and commercial quality parameters. The cluster weight is relatively small, ranging from 100 to 150 g; the clusters exhibit a cylindrical shape with a distinct wing and are characterized by medium density. Large dark pink berries weighing 4.5–5.0 g display a roundish or slightly oval shape. The dense skin covers a moderately mucilaginous pulp. The cultivar features a specific labrusca flavor with a pronounced fox (izabella) aroma. The expressed juice is transparent and slightly colored. The harvest withstands transport operations without sustaining damage and retains its commercial appearance perfectly.

Agrotechnical Features

Guna possesses a functionally female flower type, which necessitates the presence of a pollinator cultivar that flowers during the same time frame. Productivity indices remain consistently high: the proportion of fruitful shoots on the vine is 80–85%, and the fruitfulness coefficient equals 1.5–1.8 clusters per developed shoot. Short pruning of fruitful canes to 3–4 buds is recommended, with an optimal total bud load per vine restricted to 30–40 buds.

The vines exhibit winter hardiness down to -25 °C, which enables their cultivation in cool climate zones. The cultivar possesses complex resistance to major fungal diseases affecting the vine, demonstrating a reliable immunity against downy mildew, powdery mildew, and grey mold berry rot. The cultivar displays good compatibility with rootstocks, although in northern territories it is more frequently cultivated as own-rooted vines. It is well suited for training on un-covered arbor systems.

Winemaking and Finished Product Characteristics

Due to its multi-purpose utility, the harvest is suitable for both fresh consumption and processing. The berries yield light, ordinary wines with a distinctive cultivar-specific aroma. The initial parameters of the must provide an optimal balance: the natural sugar accumulation of the juice reaches 16–20%, while the titratable acidity index is maintained within the boundaries of 4.0–5.0 g/L.