Grains Research and Development

Date: 01.04.2002

GM plants - how far will pollen travel?

WHILE THE herbicide-tolerant types of canola currently available have been produced by standard breeding procedures, the first of the genetically modified varieties are currently under trial in Australia. Many growers are concerned about the potential for pollen from GM varieties to travel and pollinate non-GM paddocks.

Mary Rieger, in collaboration with a number of other agencies including the Departments of Agriculture in NSW and Victoria and the University of Western Australia, has investigated gene movement in a number of paddocks around Australia.

The study examined the movement of Group B herbicide-resistant genes between resistant and susceptible paddocks. No herbicide resistance was found at more than 3 kilometres from the source paddock. While the amount of pollen carried dropped off over distance, there was no smooth decline as the distance between paddocks increased.

"We tested sites as far out as 5 km," Dr Rieger said, "and found no gene flow beyond 3 km. In some cases there was no transfer of genes between crops just across the fence from each other, while in others the genes moved up to 3 kID from the source." Gene flow between crops was detected in only 30 per cent of her samples, the rest had no detectable gene flow.

Dr Rieger says that in most cases the gene flow was "somewhere between zero and 0.25 per cent". The methods used were very sensitive, with the detection rate 100-fold lower than the proposed int6fnational standard of I per cent. The levels were lower than expected and would comply with the current regulation for GM crops around the world, she said.

"We tested sites as far out as 5 km," Dr Rieger said, "and found no gene flow beyond 3 km. In some cases there was no transfer of genes between crops just across the fence from each other, while in others the genes moved up to 3 kid from the source." Gene flow between crops was detected in only 30 per cent of her samples, the rest had no detectable gene flow.

Dr Rieger says that in most cases the gene flow was "somewhere between zero and 0.25 per cent". The methods used were very sensitive, with the detection rate IOO-fold lower than the proposed int6fnational standard of I per cent. The levels were lower than expected and would comply with the current regulation for GM crops around the world, she said.