Variability and Clonal Selection of Muscats in the Valais
Photo: Agroscope
Safeguarding the clonal diversity of Muscats in the Valais has enabled the characterisation of 42 Muscat à petits grains and 36 Moscato Giallo clones. The characteristics of the two are quite distinct, particularly their aromatic potential. The best clones will be included in the Swiss certification scheme.
Not one but two Muscats
Muscats have been cultivated since a long time in Valais. A survey carried out in 2006 in old vineyards revealed that in Valais, the term ‘Muscat’ encompasses two distinct grape varieties: Muscat à petits grains and Moscato Giallo. Conducted in a collaboration between Agroscope, the Office of Vine and Wine of the Canton of Valais and the Society of Vineyard Nurserymen of Valais, this operation for safeguarding the genetic diversity of the two grape varieties has allowed the inclusion of 42 clones of Muscat à petits grains and 36 clones of Moscato Giallo in collection.
Muscat à petits grains vs. Moscato Giallo
The agronomic and aromatic potential of the selected Muscat clones was characterised between 2018 and 2021 on Agroscope’s Experimental Farm in Leytron (Canton of Valais). The observations revealed inter alia that Moscato Giallo ripens later than Muscat à petits grains by around ten days. Slightly more productive, Moscato Giallo produces less-compact bunches that are much less sensitive to grey mould. In terms of the musts, it exhibits lower levels of tartaric acid and higher levels of malic acid. Moreover, Moscato Giallo has higher levels of aromatic terpene compounds (except for geraniol) than small-berried Muscat.
Clonal selection
Based on agronomic and analytical observations carried out from 2018 to 2021, a choice of 14 Muscat à petits grains clones and six Moscato Giallo clones was established. These candidate clones are the subject of tests set up on Agroscope’s Experimental Farm in Leytron in order to precisely define their agronomic and oenological potential with a view to including the most worthwhile accessions in the Swiss certification system.
Conclusions
- Safeguarding the clonal diversity of the Muscats de Valais has enabled the inclusion of 42 clones of Muscat à petits grains and 36 clones of Moscato Giallo in collection of Agroscope’s Experimental Farm in Leytron (Canton of Valais).
- The agronomic and analytical observations conducted from 2018 to 2021 showed that the Moscato Giallo grape variety ripens some ten days later than Muscat à petits grains. It also produces musts of a higher malic acid content and a lower tartaric acid content and with a distinctly greater concentration of aromatic terpene compounds (except for geraniol).
- In general, phenotypic variability is much greater in Muscat à petits grains.
- These observations have allowed the preselection of 14 Muscat à petits grains clones and six Moscato Giallo clones that will be tested inter alia oenologically with a view to including the most worthwhile accessions in the Swiss certification system.
Bibliographical reference
Variability and Clonal Selection of Muscats in the Valais
