The question of co-existence

Dr Phil Salisbury

By Jason Major

One of the over-arching issues in the debate about genetically modified grain crops is whether or not they can co-exist with non-GM varieties. While few would argue with the benefits to be gained from new market opportunities if segregation can be assured, the issue for many is the "if".

Two recent reports in the UK and US have both stated that GM crops are successfully coexisting with non-GM and organic crops in the US and EU without economic or commercial problems. The US report says the only issue of relevance has occurred where crops have been sold to some users in the human food sector or export markets where there is a distinct demand for non-GM products.

In Australia, a Gene Technology Grains Committee (GTGC) report, "Canola Industry Stewardship Principles", says that for coexistence to succeed there needs to be a commitment to integrity of the final product - prevention of what industry calls "presence of adventitious material" (unwanted GM material), full traceability through the supply chain and adequate and reliable testing to verify product integrity.

Both sides of the GM debate outline similar requirements and hazards. Where they differ is in their assessment of risk and of the industry"s ability to manage that risk.

One hazard, and the focus of considerable research, is how to limit adventitious presence on the farm. In Australia, much of this research has been done on the basis of an allowed one percent adventitious presence. The Organic Federation of Australia and some markets are demanding a zero tolerance.

Dr Jan Viljoen from CSIRO"s Stored Grain Research Laboratory in Canberra is advocating a more pragmatic "one size fits as many as possible" system. "The EU"s GM requirements of 0.9 percent as a common benchmark probably presents the best chance of meeting the GM requirements of most export and domestic markets," he says.

Dr Rob Norton, a principal lecturer in agronomy at University of Melbourne, says if managed properly, the level of outcrossing in a crop like canola is so low that it is almost impossible to test for. "Any unwanted volunteers appearing in adjacent crops or surrounding paddocks can be controlled using cultivation or herbicides. Canola is a poor competitor and is not persistent as it produces almost no hard seed," he says.

Off-farm, the issue of supply chain management involves storage, transport and hygiene. One of the contributors to the Canola Industry Stewardship Principles report, Avcare, believes that existing supply chain structures should be sufficient for successful segregation of GM from non-GM material, if current best practice is used. Avcare is the National Association for Crop Production and Animal Health, representing manufacturers, formulators and distributors of crop protection, animal health and biotechnology products. It says an area that does need more work is traceability.

"We need to improve some business practices to ensure the ability to document a product"s movement from seed supplier to consumer," says Avcare"s executive director, Claude Gauchat. One of the influential players in the GM debate in the grains industry is AWB Ltd, which released a policy paper concluding that the current supply chain system would be incapable of complete segregation of GM and non-GM grains.

For this reason it has been against any commercialisation of GM canola or wheat for fear of jeopardising markets. However, AWB does support co-existence trials to test the system.

The key to identity preservation will be the development of accurate and cost-effective tests to detect the presence of GM grains. Currently available tests detect either the novel DNA or the novel protein.

The most common tests to detect novel proteins are based on a technique called ELISA (Enzyme Linked Immunosorbent Assay) that uses antibodies to recognise specific proteins. Lateral flow strip technology is a variation of ELISA that is currently used to detect the novel proteins in the Australian approved GM canola. It is cheap (about $1 per test) and can detect the presence of GMOs to a level of about one percent. Their limitation is they only detect the presence of GMOs, not the amount.

DNA detection methods are regarded as the only realistic way to determine the quantity of GMO present. However, these tests can range from $100 to $250 a test.

Research by CSIRO Stored Grain Laboratories that assessed the reliability and accuracy of current testing technologies is the subject of a report that will be released later this year.

Given the need for more work into cheaper tests, and the reliance on industry best practice to be maintained in product segregation, the other question being asked by some growers is who pays if there is a system breakdown. The current industry position is that because genetically modified organisms pose no unique risks, then common law is an adequate mechanism for providing relief. For now, the Australian Government agrees, as do the governments of the United Kingdom, New Zealand, Canada and the US.

The most notable exception is Austrian law which dictates that the company releasing a GM product is liable for any harm to health, property or environment. The Australian Greens and the Network for Concerned Farmers want similar legislation in Australia.

So the debate about coexistence still may have some distance to travel, but if predictions by specialists like Dr Viljoen are true, the rewards for resolving this issue may be substantial.

Industry has argued that a five-metre isolation distance between GM and non-GM canola crops will limit outcrossing to acceptable levels. There is considerable research to support this position, especially if an allowable limit of one percent adventitious presence is accepted.

Dr Phil Salisbury (left) a senior lecturer in plant breeding at the University of Melbourne, is author of one report that, in principle, supports the five-metre barrier.

Dr Salisbury"s report, "Genetically Modified Canola in Australia", reviewed an Australian study by Dr Mary Reiger from Adelaide University that used 63 field sites throughout Victoria, South Australia and NSW. It recorded the outcrossing rate (percentage of resistant seedlings found) of imidazolinone tolerant canola with adjacent conventional canola crops. The maximum outcrossing rate found was 0.197 percent with the majority of fields showing less than 0.03 percent.

No outcrossing was recorded at 69 percent of the sites.

But because some outcrossing does occur, complete containment of a GM trait using isolation distance alone is regarded as impractical under commercial production.

As an additional management option, Dr Salisbury recommends growing a band of the non-GM crop, alongside the GM crop to act as a pollen trap. There is evidence that this technique may be more effective in reducing gene flow than small isolation distances.