The results of vine breeding programmes led by Dr Andy Walker at the University of California, Davis, could help the wine industry battle key disease issues such as fan leaf virus and Pierce Disease, according to Global Plant Genetics (GPG).
Claire Donkin and Rupert Hargreaves of GPG, which represents UC Davis for both the rootstocks and the PD-resistant wine grape varieties, recently visited with some vineyards and grapevine nurseries along with Guillaume Mercier from Mercier’s Nursery in France.
According to the company, the visit to the Ojai Vineyard owned by Adam Tolmach in Southern California proved extremely beneficial, it showcased the vine production and different growing techniques and experiences for different varieties. There was also the chance to trying the wines, including three out of the five new varieties, namely Paseante Noir, Caminante Blanc and Ambulo Blanc.
‘The Paseante Noir was extremely impressive,’ said the company. ‘It is deep red in colour with great floral qualities in the aroma. The alcohol content was 13%, impressive to be on the lighter side of the alcohol range for a dark/deep red wine. The vines were extremely high yielding too which is encouraging.
‘Caminante Blanc produced an aromatic white wine being comparable to Sauvignon Blanc with a hint of Gewurtraminer. Once again, it has large yields and produced a wine with 12% alcohol content. Ambulo Blanc has a Chardonnay/Sauvignon Blanc flavour profile. At this particular vineyard, they had a smaller area of this grape variety and were using it successfully in blends.’
Visits were also made to leading grape vine nurseries Wonderful and Sunridge, which proved hugely beneficial to understand and debate the best techniques to improve callusing and grafting of the GRN rootstocks. The first trials of the GRNs have now been planted in the Champagne region of France and GPG expects to soon have indications of their ability to control the nematodes which spread fan leaf virus, and also their adaptability to the limestone soils.
The company added that over the next two years, Claire and the team will also trial and test these varieties and rootstocks with Mercier and Provedo in Spain.
