Floods and spread of GM seed
By Jason Major
TechNhyou
What are the risks for uncontrolled spread of GM caused by the recent floods?
This was a question from a member of the public, one that I didn’t have a ready answer to.
After a bit of research and time on the phone, the short answer for this flood event, at least, is not much. But in 5, 10 or 20 years time if we have a greater area of land growing a greater variety of GM crops the answer may be different – but that depends on your perception of risk, of course. Everyone has a different idea of risk when it comes to GM crops. From the email, the person making this enquiry sees a huge risk with GM crops of any sort and doesn’t want them anywhere, which means my answer to her below is probably not going to allay any fears she will have. For others that see low risk, this or future flood event will arouse no more than a shrug of the shoulders.
One thing I can say is that the scientific literature didn’t help me out much on this. Nobody seems to have examined the risk of unintended presence of GM caused by flood events.
My answer
re: your question about what effect the floods might have on spread of GM crops. I have done a pretty extensive search of the scientific literature and found loads of research on gene flow, cross-contamination, and all sorts of other environmental studies re: GM crops, but none that specifically looked at how flooding would influence the spread of GM seed.
The expert opinion
I talked to Associate Professor Chris Preston from the University of Adelaide who has done a lot of research into the gene flow of canola and other environmental implications of GM crops. Essentially, as you suggest there will be some drift of seed outside the paddock caused by the flooding, but the risks associated with this are dependant on many factors including the following:
- The timing of the flood and the stage the crop is at when the flood goes through.
- The species of GM seed we are talking about – how does it cope with extended inundation?
- The likelihood of the seed actually germinating once deposited and where it germinates (if at all) also needs to be considered – eg roadside, pasture land, crop land, etc
Canola
In the case of the canola this year, any canola seed that was dispersed by the flood and wasn’t buried or destroyed by too long in the water has already germinated – at least this is what Chris has observed in southern Vic. Chris’s research and that of others has shown that canola only persists for one or two generations before dying out. And the timing of the germination (ie last month) means it will not be part of nor affect any subsequent canola crop. Where it has sprung up in a farmers cropping paddock it will be controlled by normal means when the farmer prepares their paddock for next season’s crop – chemical (where farmers usually use a mix of herbicide to control various weed types) or cultivation. The only problem that Chris suggested is that if the farmer only used glyphosate and found that his few canola volunteers didn’t die, which means he would have to use other means of control – a different chemical or cultivation.
In a nutshell, Chris said that this time around the floods will disperse some of the canola seed, but the germination will be minimal and management simple. re: canola, the risk of exceeding the adventitious level of 0.9% is low.
Other crops
If we ever get GM wheat or other cereals, any flood water will destroy the seed. How the seed of other species survives will depend on the species, how it is deposited – ie is it buried, sitting on top of the soil, etc. And again, it will depend on the timing of the germination. For any gene flow to occur with crops it must germinate and flower at exactly the right time as any subsequent crop that it springs up in.
Canola Crop, Dowerin Western Australia
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