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 trialled 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.