The white grape variety is a new breed between Riesling x Madeleine Royale. Some synonyms point to the parenthood of Riesling x Sylvaner, which was wrongly assumed for a long time. Within the EU those names are no longer permitted which refer to it, such as Riesling-Sylvaner. The most important are Müller-Thurgau Rebe, Müller Thurgau Weiß(Germany); Müller-Thurgau Blanc(France); Uva di Lauria(Italy); Riesling-Silvaner, Riesling x Silvaner, Riesling-Sylvaner(New Zealand, Switzerland); Rivaner(Austria, Luxembourg), Rizlingszilvani(Hungary), Rizvanac, Rizvanac Bijeli(Croatia); Rizanec, Rizvanec(Slovenia); Muller Thurgau White(USA).
Due to its characteristics, it is a popular crossing partner for new breeds. These are among others Albalonga, Arnsburger, Bacchus, Diana (1), Faberrebe, Floriánka, Fontanara, Gloria, Gold Riesling (2), Grando, Gutenborner, Helios (1), Hildegardistraube, Kanzler, Mariensteiner, Markant, Medea, Mília, Montagna, Muscabona, Muscat Bleu, Optima, Ortega, Pálava, Perle, Rabaner, Regner, Reichensteiner, Schantlrebe, Septimer, Tamara, Thekla, Thurling and Würzer. Two mutations are Findling (formerly ripening) and Red Müller-Thurgau (berry colour).
The determination of parenthood took decades, until in 1996 the paternity of the Silvaner, which was doubted again and again, proved to be wrong. The breeder was the Swiss Dr. Hermann Müller-Thurgau (1850-1927) from Tägerwilen in the canton of Thurgau. He worked at the Royal Institute for Fruit and Viticulture in Geisenheim (Rheingau) from 1867 to 1890. In issue no. 26 of the magazine "Der Weinbau" of 24 June 1882, he formulated the breeding objective of the crossbreeding experiments: "How important, for example, could a grape variety become for some wine-growing regions which combined the safe and earlier ripening time of the Sylvaner with the delicious properties of the Riesling grape" Until 1890, the preliminary testing of new varieties resulting from the breeding of the Riesling x Silvaner varieties was still carried out in Geisenheim.
In 1891, Hermann Müller-Thurgau was called to his home town of Wädenswil in the canton of Zurich to found and develop the Swiss Federal Institution based on the Geisenheim model. In the same year he had 150 of his seedlings, which had been tested in Geisenheim, brought to Wädenswil. There Heinrich Schellenberg (1868-1967) selected the best seedling No. 58 and propagated it in 1897 under the name "Riesling x Silvaner 1". The Bavarian Court Councillor August Dern (1858-1930), a former employee of Müller-Thurgau in Geisenheim, brought back 100 vines of this new breed to Germany in 1913 and named them "Müller-Thurgau-Rebe" (which Müller-Thurgau refused to do, by the way, he always named them after their supposed parents) in honour of the breeder.
Müller-Thurgau himself was sceptical about the parenthood Riesling x Silvaner at an early stage and expressed his concerns in a letter to August Dern, whom he accused of having "taken the wrong grape variety from Geisenheim". The thesis that the variety was not a Riesling x Silvaner cross was strengthened early on by the fact that not a single one of the later Geisenheim, Würzburg and Alzeyer Riesling x Silvaner crosses was in keeping with the character of "Müller-Thurgau" (one of the Geisenheim trials was Multaner). Already in 1950 Dr. Heinrich Birk (1898-1973) pointed out these connections for the first time. Also Dr. Hans Breider (1908-2000) came to the conclusion in 1952 that he could find too few characteristics of the alleged pollen donor "Silvaner". In 1957, Dr. Heinz-Martin Eichelsbacher (1924-2003) came to the conclusion in the course of extensive analyses that the variety "Müller-Thurgau" originated from the Riesling-Muscatel-Gutedel variety.
For a while, one also accepted a self-crossing Riesling x Riesling. Finally, in 1996, at the Klosterneuburger Weinbauinstitut in Lower Austria, biologist Dr. Ferdinand Regner identified Admirable de Courtiller (Chasselas de Courtiller) as the father variety by means of DNA analysis. However, subsequent analyses at the Institut Geilweilerhof (Pfalz-Germany) shortly afterwards verified that the father variety examined and correctly identified by Dr. Regner was Madeleine Royale (Regner was the first to determine the "correct" vine, but it was not correctly named). Both institutes therefore deserve credit for solving the mystery. Finally, in 2010 the Swiss Dr. Jose F. Vouillamoz completed the Müller-Thurgau family tree (ancestry of the Madeleine Royale).
The early maturing, high-yielding vine is susceptible to powdery and downy mildew, botrytis and red distillers. It prefers cool locations and is therefore very suitable for northern wine-growing regions. The variety produces fruity, fresh, rather low-acid white wines of light yellow colour with a subtle muscatite tone. Due to its special aromatic properties it is called a so-called bouquet variety. It is quite often used as a mass carrier, but also has quality potential with a corresponding reduction in yield and cultivation. Müller-Thurgau is not only in Germany, but worldwide one of the absolutely most successful new breeds, which has been widely cultivated in many countries since the middle of the 20th century.
In the 1920s and 1930s many experimental plants were created in Germany. But it was not until 1970 that the variety was classified as a recommended variety in all German growing regions. From 1975 to 1995 it was always at the top of the German grape variety index and only then was it replaced by Riesling. Since then the tendency has been constantly falling, but in 2009 it was still the second most common grape variety with 13,628 hectares of vineyards. It is particularly widespread in the Rhine-Hesse, Baden, Palatinate, Moselle and Franconia growing regions. In Austria, it is cultivated in all wine-growing regions on 2,102 hectares with a declining tendency.
Other stocks in Europe can be found in England (43 ha), France, Italy mainly in Trentino-Alto Adige, (1,312 ha), Croatia (60 ha), Luxembourg (184 ha), Moldavia (173 ha), Russia (106 ha), Switzerland (493 ha), Slovakia (932 ha), Slovenia (144 ha), Spain, Czech Republic (1,572 ha) and Hungary (2,098 ha). Overseas stocks are found in Japan (172 ha), Canada (7 ha) and New Zealand (79 ha), as well as in the US states of California, Oregon and Washington. In 2010, the variety occupied a total of 22,753 hectares of vineyards with a downward trend (ten years earlier it was 33,587 hectares). This puts it in 37th place in the worldwide grape variety ranking.
Sources: Main source regarding history and ancestry: Reader's forum of the magazine "Das Deutsche Weinmagazin" 1998, issue 22, pages 8-9, courtesy of Dr. Joachim Schmid, Department of Vine Breeding and Grafting, Geisenheim Research Institute. Helmut Becker, 1976, Genetic constitution, breeding and performance of the grape variety Müller-Thurgau, Die Weinwissenschaft, 31st ed., 26-37th ed. Heinrich Müller-Thurgau, F. Koblet: Crossing results in vines. Agricultural Yearbook Switzerland 1924, 499-562. Ferdinand Regner, 1996, Mitteilungen Klosterneuburg.
Pictures: Ursula Brühl, Doris Schneider, Julius Kühn Institute (JKI)