AUSTRALIA - If genetically modified crops are used wisely in Australia, they will be a fantastic tool in managing existing herbicide resistance problems.

But if they are not used wisely and glyphosate-resistant GM crops are simply grown year after year, more glyphosate-resistant annual ryegrass populations will develop rapidly.

This was the warning from US-based herbicide resistance researcher and former Australian resident Ian Heap, who owns his own Oregon-based company WeedSmart.

Dr Heap was one of the keynote speakers at the recent Herbicide-Resistant Crops and Weeds symposium in Perth.

He said that, although he believed there would be significant public opposition to GM crops in Australia, they would be adopted eventually. Dr Heap predicted Australia could have GM glyphosate resistant wheat in three or four years if it was successful in the US.

GM crops had been a great agronomic boon to US farmers, but warned it would be an absolute disaster if there was not strict management of GM crops released in Australia. "Like all other technologies there are drawbacks, but the drawbacks can be managed," Dr Heap said. The management of volunteers in subsequent crops, not just herbicide resistant weeds, was an issue in herbicide resistant crops. A major lesson Australia could learn from the experience in the US was the importance of strong dialogue with the public about the pros and cons of GM crops.

Dr Heap said the first populations of glyphosate resistant weeds were beginning to emerge in Roundup Ready soybean crops in the US. Other problems in herbicide-resistant GM crops were "species shifts" whereby weeds which were previously insignificant were becoming major weeds.

This was not necessarily because they had evolved resistance to glyphosate, but because they had avoided or were naturally more tolerant to glyphosate.

** NOTICE: In accordance with Title 17 U.S.C. Section 107, this material is distributed for research and educational purposes only. **