1918–1940
皇家费特亚斯卡与格雷芬贝格的无性系选育
在格雷芬贝格，小迈克尔为少女葡萄（Fetească）、Königsast 和意大利雷司令做无性系选育。皇家费特亚斯卡之名大概也在此时出现，而他选出的 Riparia × Berlandieri 藤苗，则以「Selecția Ambrosi」为名。
At Gräfenberg, Michael jun. makes clonal selections of Mädchentraube (Fetească), Königsast and Italian Riesling. The name Fetească Regală probably dates from the same years, and his selected Riparia × Berlandieri rootstocks are marketed as «Selecția Ambrosi».