Grapevine breeding breakthroughs just around the corner

The ability to breed a grapevine tolerant to Botrytis cinerea is next on the breakthrough agenda for CSIRO principal research scientists Ian Dry and Mark Thomas.

This and ongoing research into the already established powdery and downy mildew resistance vines is part of a new research project titled ‘Identification and marker-assisted selection of genes for reducing the susceptibility of new winegrape cultivars to fungal pathogens’.

The project will be partly funded by the recent multi-million dollar research investment by GWRDC to identify and evaluate rootstocks and varieties that possess desirable viticultural and winemaking properties for the Australian grape and wine sector.

Over the next four years, GWRDC will invest more than $7.6 million into several research projects that address key industry priorities such as adaptation to climate change, tolerance to drought and salinity, and nematode and Phylloxera resistance.

The research is being undertaken by CSIRO, which is contributing an additional $5.9 million to the projects over the four-year period. The University of Adelaide and the SARDI will also contribute additional funds to some of the projects.

Dr Dry says the Botrytis work is made more difficult as it’s a fungus that is necrotrophic, which means it grows on dead or dying tissue and there’s no known resistant gene.

‘Instead, research suggests the secret might lie in being able to open up the bunch to reduce humidity and disease potential’, he said.

‘So we will begin looking to identify the genes responsible for bunch architecture, which will then allow for us to start selecting for open bunches’.

The next 10 to 20 years will be one of the most significant periods of discovery for the global winegrape industry, according to Dr Dry.

Drs Dry and Thomas are part of the team of CSIRO researchers who are leading the Australian advances in grapevine breeding and genetics.

‘The big discoveries are happening now and there’s much more to come’, Dr Dry said.

Drs Dry and Thomas were part of the first team of researchers – in collaboration with the National Institute for Agronomic Research, in France – to successfully transfer two resistance genes, one for powdery mildew (MrRUN1) and another conferring resistance to downy mildew (MrRPV1) from the wild American grape species Muscadinia rotundifolia into several premium grape cultivars.

Since then they have been able to trace the inheritance of disease resistance genes in several wild cultivars and are now working on a method to ‘pyramid’ additional resistance genes from other wild cultivars to help create a grapevine with a more durable resistance to downy and powdery mildew.

Marker Assisted Selection (MAS) allows researchers to test seedlings for the presence of specific DNA sequences associated with resistance genes or other specific traits such as aroma, flavour or even physical characteristics such as bunch architecture and yield.

Just as importantly, it’s dramatically reduced the cost, time and space previous associated with breeding trials.

‘We’re now undertaking work on the first generation of our MAS powdery and downy resistant vines – with 1000 vines (about 50% divided between red and white) now planted’, Dr Dry said.

‘We’ve also done the first small-scale winemaking with our white varieties – and early results are promising’.

Dr Thomas will carry out winemaking trials on the red varieties in the 2014 vintage. He also plans to move several of the new MAS varieties to other trial vineyards with more challenging climate and environments – to test their continued resistance to downy and powdery mildew.

Dr Dry’s focus will be to further investigate the powdery and downy resistance genes expressed in the Chinese Vitis species V. romanetii and V. amurensis.

For more information contact Dr Liz Waters, GWRDC R&D Program Manager, liz@gwrdc.com.au

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