The white grape variety is a new variety between Saperavi Severny x (Foster's White Seedling x Prachttraube). Snonyms are Ambros Weiß, Geisenheim 6495-3 and Sibera Blanca. Genes from Vitis amurensis and Vitis vinifera are included. The hybrid was crossed in 1964 by Vilém Kraus (1924-2103) in Lednice in the former Czechoslovakia. The breeding and selection of the seedlings was then carried out at the Research Institute Geisenheim (Rheingau) under Dr. Helmut Becker (1927-1990). Incidentally, the same parents also produced the variety Serena. Sibera was a crossing partner in the new Calastra variety. The early-ripening vine is resistant to both types of powdery mildew and frost, and due to its loose grapes it is only slightly susceptible to botrytis. No stocks were reported in 2016 (Kym Anderson).
For me, Lexicon from wein.plus is the most comprehensive and best source of information about wine currently available.Egon Mark
Diplom-Sommelier, Weinakademiker und Weinberater, Volders (Österreich)