Definition: diolle

José Vouillamoz, Doctor of Science at UNINE and expert on grapevine DNA, has just discovered that a few vines of this indigenous variety still exist.
As part of his research, he had published an announcement in the media asking vineyard owners to send samples of unusual or unknown grape varieties or vines. One sample, among some sixty received, led to an original and very interesting discovery.
The molecular biologist was able to establish that diolle is the result of a natural cross between Rèze and another unknown and extinct grape variety, with a morphology somewhat reminiscent of Chasselas. The diolle sample was sent to him by Germain Héritier, a winegrower from Savièse who, intrigued by uncultivated plants growing in a vineyard wall, submitted them to the researcher. This wall, rebuilt in 1946 or 1947, already enclosed these vines, which were intended to reinforce the structure. Uncultivated for decades, they were in poor condition due to cryptogamic diseases.
However, in recent years, the use of helicopter treatments, which are less precise than manual labour, has enabled the two Diolle vines to produce a few white grapes that no one recognised until José Vouillamoz established the family tree of the berries. Research in old ampelography manuals has uncovered precise descriptions of Diolle, which can now be added to the list of indigenous grape varieties in Valais.
Source for the full article and for the researchers' work: