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We Need To Remove Emotion From The Genetically Modified Vines Debate

Posted on May 16, 2017. Featuring topics like Featured, WBM - Expert Opinion, WBM - Viticulture, WBM, WBM - Technology

WORDS Dan Traucki

It’s time to remove the emotion from the debate and look at the facts when it comes to genetically modified vines, Dan Traucki says.

Mention the phrase “genetically modified” (GM) or “genetically engineered” (GE) to most people and they throw their hands up in horror and start screaming “Burn the witches!” This massive overreaction is brought about through ignorance and the all too vivid images on television of the three-eyed fish in The Simpsons.

The reality is, we have been genetically engineering plants and animals for centuries. Every time a farmer came across a plant in his fields that was performing better than the rest of the crop and gathered the seeds or took cuttings for propagation, he was slowly (very slowly) engineering the future genetics of his crops by propagating better performing plants or breeding better performing animals.

For example, at the beginning of the 20th century, wheat used to grow to about twice the height that it does today – it was top-heavy and would often fall down, ruining a considerable part of the crop. In the early 1960s, American biologist Ernest Borlaug PhD (in plant pathology and genetics) developed semi-dwarf, high-yield, disease-resistant wheat in Mexico. In the space of a few years, this genetic research and development turned Mexico from being a wheat importer into a wheat exporting nation. Within a decade, the follow-up dwarf wheat allowed most wheat growing countries to almost double their production, thereby preventing global famine.

Dr Borlaug and his team have been credited with saving more than 1 billion people worldwide from starvation, thanks to the genetic engineering they conducted.

There are countless positive cases of genetic engineering that, while not quite as dramatic as that of Dr Borlaug, have made a huge difference to the world as it is today. However, it has been pointed out that “wine grapes are probably one of the few major crops in the world that have not undergone any significant genetic improvement for nearly 100 years”.*

The Australian wine industry’s mildew losses (powdery and downy) are currently about $150 to $200 million a year, depending on the vintage. This has a two-pronged effect in that not only do the growers incur higher costs by having to spray against these mildews, but also it increases the potential impact of these chemicals on the total vineyard ecology and the health of the vineyard workers. Over recent years, there have been a growing number of complaints – and even court cases in France – over the impact of spraying and the levels of toxins in those sprays.

A recent example of this was a documentary broadcast by the France 2 TV station on the presence of pesticides in hair samples from children from schools near vineyards in Bordeaux. While this issue is potentially much more significant in France – due to wetter weather, they have to spray significantly more often for mildew than growers in Australia – it probably won’t be long before tighter restrictions and possibly bans will be introduced here on the use of these vital fungicides.

Since 1999, CSIRO has been working with INRA (the French National Institute of Agricultural Research) to identify genes that confer resistance to downy and powdery mildew that are found in some wild Vitis species not normally used for wine production. Genes have been identified from the wild North American species Vitis rotundifolia, one (designated MrRUN1) which confers resistance to powdery mildew and another (designated MrRPV1) that confers resistance to downy mildew. When these genes were transferred into mildew-susceptible varieties such as shiraz and tempranillo, the resultant vines were the world’s first premium grape vines with a strong genetic resistance to powdery and downy mildew. Interestingly the genetic composition of the transgenic (GE) vines is at least 99.9 percent the same as the original, whereas using classical breeding techniques to introduce these genes through four generations of backcrossing over several years, the resultant vines are still only 96 to 97 percent Vitis vinifera and three to four percent Vitis rotundifolia. Thus the not-approved transgenic vine is closer to the original than that of the vine bred by the approved method.

Very small trial batches of wines have been made from the field trial vines of the classically bred mildew-resistant vines and to date there has been no appreciable variation in the flavour profile compared to wine made from existing susceptible varieties. However, there have been no trials using the GE-modified vines as current regulations prohibited the planting and evaluation of GE vines in South Australia.Given the number of permutations possible just in the process making of any wine – winemaker input, ripeness etc – the fact that there is no discernible difference in flavour under the classically bred system should augur well for the future of mildew-resistant GE vines, as they are ‘purer’ or closer to the original vines, which means they have the potential of saving the industry millions of dollars every year and reducing the environmental impact of the industry.

However, due to the Winemakers’ Federation of Australia having a policy of “no genetically modified organisms to be used in the production of Australian wine” the work on GE mildew-resistant vines has had to be put on hold. The outcome is that we have the answer to a major problem but cannot use it.

 

Finding the balance1.jpg

 

CSIRO is now focusing on developing disease-resistant vines using more conventional breeding techniques that don’t involve gene splicing; however, they take advantage of information obtained from the sequencing of the grapevine genome to increase the efficiency of breeding through the use of ‘marker assisted selection’. This method may take decades (20 to 30 years) as opposed to around five years using the gene splicing technique described above. The CSIRO has made significant progress with the first generation of new disease-resistant varieties currently under evaluation in ‘no-spray’ vineyards in South Australia and New South Wales. Hopefully these new mildew-resistant varieties will be available to commercial growers within the next 10 years.

The timeframe and significant cost of conventional breeding is due to slow generation times (once per year) and the significant costs incurred in propagating and screening sufficiently large numbers of progeny to not only identify resistant cultivars, but also ensure that they produce acceptable quality wine.

In wine there have been a number of examples of hybrid varieties created by the ‘natural’ cross-breeding of varieties – a crossing between Vitis vinifera and other Vitis species such as Vitis labrusca. 

These hybrids were created to (mainly) withstand cold in the upper northern hemisphere, so that the boundaries of where wine grapes can be grown have expanded dramatically over the last century. This includes varieties such as concord, niagara, vidal blanc, marechall foch and seyval blanc.

Our own CSIRO has developed six hybrid varieties to suit our ‘warmer than usual’ growing conditions:

  • Tarrango – 1975 (touriga national x sultana) slower ripening, lower tannin, good acid, light, bright summer red wine.
  • Taminga – 1982 ([planta pedralba x sultana] X Traminer) higher acidity white that makes sensational botrytis-affected sweet wines.
  • Tyrian – 2000 (sumoll x cabernet sauvignon) deep coloured, full-bodied spicy fruit flavours.
  • Rubienne – 2000 (sumoll x cabernet sauvignon) developed for hotter areas, makes a full-bodied, deeply coloured, plummy wine.
  • Cienna – 2000 (sumoll x cabernet sauvignon) developed for semi-arid areas, makes light-bodied, berry-flavoured, deep-coloured wine.
  • Enigma – around 2010 still officially ‘hush hush’, this red variety was developed in conjunction with Brown Bros and makes a delicious full-bodied tasty red wine.

So while these man-created varieties are totally acceptable, when the CSIRO gene splices mildew resistance into a particular grape variety to reduce the environmental impact of disease mitigation, that is unacceptable to the powers that be.

The world we live in is not simply black and white, it is principally different shades of grey. Yes some forms of genetic engineering are plainly ‘black’, like creating three-eyed fish or glow-in-the-dark grapes, but that is no reason to tar all genetic engineering with the same brush. Surely commonsense dictates that we examine each project on its merits, like one does all the time in life, with a risk assessment or cost-benefit analysis, rather than succumbing to mass hysteria and banning it out of hand.

Imagine if the elders of the time had banned Dr Borlaug’s wheat way back then? Which of us would not have been born due to the ‘natural’ starvation that would have occurred?

Come on people, we have to find the balance when it comes to genetic engineering. Let us remove the sheer emotion and inject the facts into this debate and look at each case/issue on individual merit rather than trying to ‘burn the witches’ every time. GE grapevines created by as respected an organisation as CSIRO must surely be one of the ‘whitest shades of grey’. Let us find the commonsense balance and move forward.

*Fast-tracking grape breeding for disease resistance by Ian Dry and Mark Thomas, CSIRO Agriculture, Waites Campus, Urrbrae South Australia.


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