Trials raise doubts on yield benefits of GM rapeseed

Trials of genetically modified and herbicide resistant rapeseed in Australia have found that there is no real benefit for yields from Roundup Ready varieties.

The 2009 study was funded by the Grains Research and Development Corporation, which said that it is important to look at a range of data. The corporation said Roundup Ready rapeseed varieties performed significantly higher than other herbicide tolerant crops in only two of eleven published trials.

It equalled the varieties commonly known as Clearfield in six of the trials. Clearfield performed the best in three of the trials.

But James Nielsen, from Monsanto, which owns the GM technology, said Roundup Ready is the best performer.

When you look at the data provided by the National Variety Trials, what you will see is that Roundup Ready is consistently higher yielding that the Triazine tolerant variety, he said.

"Really, what we're showing is growers can have higher yield, without compromising on their weed control," he added.

Scientist Dr Judy Carman said the main problem with the trials is that they have not compared GM rapeseed with conventional rapeseed. Dr Carman said studies need to be done to directly compare the yields.

Dr Chris Preston, from the University of Adelaide, said it is not that easy to just compare GM rapeseed to conventional varieties.

"Varieties without herbicide resistance were not included because these trials were placed within paddocks of farmers who had signed up to grow Roundup Ready rapeseed and not on field stations," he said.