The Australian Wine Research Institute

Assessing diversity and clonal variation of Australia’s grapevine germplasm (Shiraz)

Project summary

The Australian wine industry relies on a small number of international grapevine varieties for 95% of its production, and, within those, a small number of clones. However, there are many clones of the major wine-grape varieties available and Australia holds a unique repository of mature vine material, with selections taken from very old vineyards planted on their own roots. This is particularly the case for Shiraz but also pertains to other cultivars such as Riesling. Little clonal trial work has been undertaken in the last 10 years; however, there are, for example, mature plantings of replicated clonal trials of the major varieties established in 2005 by the Riverland Vine Improvement Committee (RVIC), that have not yet been evaluated. These are an as yet untapped extremely valuable resource to the industry. This project provides the opportunity to evaluate the diversity within our clonal population to identify potential quality parameters.

Chardonnay and Shiraz represent the two major wine-grape varieties in Australia. Both varieties are grown in a wide range of climatic sites for different price points. An increasing number of clones of each variety are widely planted. In the light of potential climate change impacts, information on the clonal performance of these varieties under different climatic conditions may provide management strategies to mitigate potential adverse effects on fruit quality. For this SARDI-led Wine Australia-funded project, clones of Chardonnay and Shiraz will be evaluated and differences in fruit quality and potential disease tolerance, berry sensory qualities, harvest data (°Brix, TA, pH), bunch architecture, yield components and other relevant parameters will be determined (SARDI). Full sensory analysis will be undertaken on small lot wines (AWRI). Finally, whole genome sequence data will be used to map genetic diversity in clones of Shiraz (AWRI), similar to what has already been done for Chardonnay in Project 121.

Understanding genetic variation in Shiraz

Comparative genomic evaluation of Shiraz has commenced. DNA from designated clones used in the SARDI winemaking trials has been extracted and sequencing has been initiated. Understanding of the genetic differences among clones will be combined with knowledge about their different behaviour in the vineyard and winery. This will include both chemical and sensory data from winemaking trials of multiple different Shiraz clones, evaluated across multiple sites in multiple vintages.