“When the world goes all ‘Mad Max‘…” is a clause I’ve noticed myself tacking to sentences with regular frequency lately. With the increased understanding/acceptance of climate change science and scientific studies – not to mention observations recorded on numerous citizen science blogs (here and here, for example) and on popular podcasts, etc. – I think about what the future may hold, not just for humans, but for agriculture. Really, though, we – and by “we” I refer to fellow plant pathologists, plant breeders, plant biologists – are already trying to answer agricultural problems before they occur, while others work valiantly to solve long-standing problems in countries with poor access to vital nutrients.
So, as someone in the viticulture and enology industry, at first, it was refreshing to see Mitch Frank‘s recent article in the Wine Spectator. How can we adapt to sustainable agricultural systems with fewer pesticides? What will make the most sense when it comes down to saving an industry? To be sure, humans have shaped the genetics of agricultural plants for centuries through breeding trials (and some errors – consider Sr31 – the gene that confers resistance to stem wheat rust. While it worked beautifully for decades, the wheatrust fungus was able to overcome this resistance gene in wheat, leading to a lethal disease that could potentially threaten wheat crops once again).
In conversations with fellow scientists in the viticulture and enology industry, we wonder whether growers would replant vineyards with a GM grapevine, even if that meant fewer trips through the vineyard with sprayers. Growers don’t actually *enjoy* spraying pesticides. They really don’t. But they DO want to sell their crop, so they spray out of necessity – especially here in the Eastern part of the US, where rain is (in most years) abundant and spurs most fungal grape diseases. If you ask a grower whether he or she would prefer to grow a grape that 1) requires fewer sprays, 2) makes an excellent wine, and 3) sells at a profitable price, you can bet that he or she would be on that bandwagon. But we always get stuck on public acceptance of GMO crops. Carefully designed studies have determined that GMO crops pose no greater risk to animal (including human) health than conventionally bred* crops.
And here’s where this post takes a turn….
But, wait a minute, don’t we already have grapes that fulfill those three preferences – without the need for GMO labeling? Indeed we do; they are called hybrid varieties, and the general public is only vaguely aware of them. Arguably, the price point for some hybrid varieties is not nearly high enough to justify their production in some regions, but in other regions in the US and Canada, growers can make a decent sum on good quality hybrid grapes. After all, a winemaker can make an excellent wine from excellent fruit, but s/he cannot make excellent wine from marginal fruit. So does it make sense to grow fruit on your site that will reach marginal ripeness, at best, or to challenge the market to learn more about varieties outside of the Merlot/Pinot Noir/Chardonnay/Syrah box by growing what actually ripens? If your site can accommodate Riesling production, go for it! If Chambourcin is best-suited to your site, go all in! Ohio produces some of the nicest Chambourcin wines I have ever had the pleasure to try, and this is certainly nothing to be ashamed of! My grandmother could not, and I cannot, sing the praises of Vidal loudly enough. Really, could you get a more versatile grape?
Anyway, I started this post as an opportunity to talk about GM crops – grapevines in particular – because the debate has been on the interwebs for a while, and GM crops are certainly nothing to fear. But as I got going on this post, I found myself thinking more of hybrid grapes and wondering why Mr. Frank only mentioned the word “hybrid” to describe a chimeric gene inserted into grapevine to confer resistance to Pierce’s Disease. Scientific feat aside, the challenge with using one gene to overcome a plant pathogen is that said pathogen eventually overcomes that types of resistance – it just takes a little time. So, growing vast monocultures of PD-resistant grapevines might buy a particular variety a little more time on the wine market, but the industry certainly would not be able to rely solely on this type of grapevine. As with any perennial crop, grape production is complex, multifaceted. Frankly, we have most of the tools – including hybrid grape varieties and general viticultural knowledge – now to produce grapes successfully around the world. Barring the emergence of any major, unforeseen super-duper nasty grapevine-eating microbe, of course.
*Conventionally bred crops are those that are painstakingly crossed by hand in greenhouses and the field to yield several hundred progeny that need to be evaluated for ideal phenotypes – physical traits – that best suit the needs of the industry (disease resistance, drought tolerance, etc.. This usually take several decades. GM science can get us there in less time; not much less, but generally less time – like maybe a couple of decades. Why? Extensive evaluation and testing of plants with the selected markers, among other reasons.