The white grape variety originates from the USA. Synonyms are Delavar, Delavar Rozovii, Delavar Serii, Delawar, Delaware Piros, Fehér Delaware, French Grape, Gray Delaware, Heath Grape, Ladies Choice, Piros Delaware, Powell, Rose Colored Delaware, Ruff and Ruff Heath. The Swiss aristocrat Paul Henri Mallet-Prevost (1756-1833), who emigrated to the USA, bought a piece of land in New Jersey in 1794 and was engaged in vine breeding there, among other things. He is considered to be the breeder of the variety. According to DNA analyses carried out in 2015, the always assumed parentage was confirmed. The variety is a cross(Vitis aestivalis x Vitis labrusca) x Vitis vinifera. Mallet-Prevost gave cuttings to Benjamin Heath (hence one of the synonyms). Heath moved to Ohio in 1837 and took the vine with him. There he gave cuttings to his neighbour Abraham Thompson. Thompson was so enthusiastic that he sent cuttings to the Massachusetts Horticultural Society in 1855 and named them "Grape from Delaware City, Ohio". The vine spread to many states under the name Delaware.
The variety was subsequently a popular crossing partner for new varieties such as Beauty of Minnesota, Brilliant, Delago, Dutchess, Headlight, Ithaca, Monroe, Nectar and Reliance (2). Two open-pollinated seedlings are Heunis and Jewel. This early-maturing, low-yielding vine is relatively resistant to frost, very susceptible to downy mildew and black spot disease, and somewhat less so to powdery mildew, botrytis and black rot. It is also sensitive to phylloxera (which actually speaks for European genes). The variety yields white wines with a subtle foxtone.
The variety is widespread in the Northeast and Midwest of the USA, where it is used as a wine grape for still wines (also ice wines) and sparkling wines, but also as a table grape. These are mainly Delaware, Michigan, Minnesota, New York, Ohio and Pennsylvania. In total, it occupies 66 hectares of vineyards here. There are also other stocks in Brazil, Japan (254 ha) and South Korea (100 ha). In Austria, Delaware is one of the grape varieties for the local speciality Uhudler (not recorded). In 2016, a total of 421 hectares of vines were recorded with an increasing trend (Kym Anderson).
Source: Wine Grapes / J. Robinson, J. Harding, J. Vouillamoz / Penguin Books Ltd. 2012
Images: Ursula Brühl, Doris Schneider, Julius Kühn-Institut (JKI)
