Mixed results from GM canola trials in Australia

Trials of genetically modified canola have found the controversial technology isn't always meeting promises of higher yields.

The Birchip Cropping Group in western Victoria carried out trials of 27 varieties of the oilseed, including conventional, triazine-tolerant and GM canola.

It found little differences in yield between the conventional and round-up ready GM varieties.

For the highest-yielding types, GM canola had the lowest gross margin, while triazine-tolerant had the highest.

Roundup Ready had a lower margin because of higher freight and seed costs.

Research agronomist Simon Craig says the most cost effective was the triazine-tolerant canola.

"We've always assumed that TT varieties will always yield less than the other three groups - conventional, clearfield and round-up ready," he said.

"However, the newer varieties within the TT have started to improve in yield and we're starting to say select a canola variety based on the herbicide group, because you can pick an equally performing variety in terms of yield in each of those groups."