Successful clonal selection of grapevine (Vitis vinifera L.) in Slovenia – 40 years of research, observations and measurements

Grapevine selection in Slovenia has started more than 40 years ago, during all this time selectionists, researchers, grape and wine producers have collaborated and been actively involved in selecting and preserving grapevine cultivars. Furthermore, Slovenia has a rich viticultural heritage with indigenous and local (domestic) grapevine cultivars, more than 130 different cultivars and their biotypes are kept in the genebank vineyard in Pouzelce (STS Vrhpolje). These indigenous cultivars are highly valued for their unique characteristics and contribution to the diversity of Slovenian wines. Grapevine selection in Slovenia takes into account various factors such as grape quality, disease resistance, adaptability to local conditions, and the potential for producing high-quality wines and till nowadays has given 47 certified clones of 18 cultivars (Vitis vinifera L.). The annual production of certified scions is around 3.6-4.8 million, of which 2.0-2.8 million of Slovenian grapevine clones, while an annual production of grafts reached 3.4-5.0 million, 1.0-1.6 million grafts with Slovenian clones. The largest share of produced grafted vines of Slovenian clones is the ‘Welschriesling’, followed by the ‘Sauvignon blanc’ and ‘Riesling’, while the smallest share is the ‘Radgonska ranina’, ‘Barbera’ and ‘Kraljevina’ cultivars. The Slovenian Winegrowers' Association, Public Service for Viticulture and regional winegrowers' associations actively promote the preservation and cultivation of indigenous grapevine cultivars. They organize tastings, events, and educational programs to raise awareness about Slovenian grapevine diversity and the importance of preserving local wine traditions.