The new rootstocks – tested with the codes C114, C113 and C20 – maintain productivity in replant situations in the warm climate of Sunraysia, perform well when irrigated with moderately saline water in the cooler region of Padthaway; produce fruit with acceptable fruit composition; and are resistant to selected root knot nematode and phylloxera isolates.
The findings are exciting because currently, the Australian wine sector relies on rootstocks bred and selected overseas for conditions that are sometimes quite different to those in Australia.
‘Breeding and selecting new locally adapted rootstocks offers the potential to have a positive impact on vine performance and wine quality while addressing the issues of sustainability and risk management’, said principal investigator Mr Peter Clingeleffer from CSIRO Agriculture and Food at Waite.
Mr Clingeleffer said a number of rootstocks that are still under evaluation also showed ‘great potential’.
However, Mr Clingeleffer said the project’s findings suggested there would be no ‘one size fits all’ solution to rootstocks for the Australian wine sector.
‘Significant rootstock by scion interactions and rootstock by region interactions were found from field trials with Chardonnay, Cabernet Sauvignon and Shiraz in Sunraysia and Shiraz in Padthaway. This indicates that a suite of rootstocks will be required to meet the sector’s needs – and no single rootstock will be suited to all varieties and regions.’
For example, in Sunraysia, fruitfulness and yield were higher for Cabernet Sauvignon grafted on rootstocks with moderate vigour.
Mr Clingeleffer said the next stage of the project would be to develop rootstocks with more durable resistance to root knot nematodes and phylloxera genotypes.
The team will use rapid screening techniques, including the use of molecular markers, to develop the new rootstocks.
‘Traditional breeding approaches to develop rootstocks with resistance to plant parasitic nematodes and other soil borne pests is costly, time consuming and labour intensive. Marker assisted breeding with molecular markers that predict nematode resistance is much more time efficient and cost-effective’.
Trials are underway with regional groups and interested growers to further the work, including the establishment of mother vine plantings of new selections to ensure that adoption is not limited by the supply of propagation material.
Mr Clingeleffer said the sector’s involvement had been key to the project’s success.
The results of our project show significant potential to identify new rootstocks not only with better fruit and wine composition, but that are water efficient; and resistant to drought and other abiotic stresses.
‘Over the course of the project, trials have been established in Mornington Peninsula, Yarra Valley and Adelaide Hills in addition to the research trials in Padthaway.
‘We have also had significant interaction with growers, wine companies and sector groups in the form of presentations, updates and tastings of the wines produced from the new rootstock selections and commercial rootstock varieties.’
‘This engagement with the sector is valuable, as it gives us greater insight into which rootstocks are best suited to individual regions.’