ACRE Advice

Consideration of a Report Concerning the Implications of 'Gene Stacking' of Herbicide Tolerance Genes in Oil Seed Rape

Advice of the Advisory Committee on Releases to the Environment under Section 124 of the Environmental Protection Act 1990

On 21 February ACRE reviewed a report by J. Orsen (2002) commissioned by English Nature ¹ concerning the implications of 'gene stacking' of herbicide tolerance genes in oil seed rape.

The study investigated the occurrence of multiple herbicide tolerant oil seed rape (canola) in Canada and sought to provide information concerning the potential rate of formation and spread of 'stacked gene' volunteers of oil seed rape in the UK. The report concluded that similar gene stacking could occur in the UK if varieties containing different herbicide tolerance genes were planted commercially. It also noted that 'there would be little impact on other agricultural practices if only genetically modified (GM) varieties tolerant to glyphosate (Roundup Ready) or glufosinate (Liberty Link) were introduced into the UK'.

ACRE considered the study and its implications for the release and marketing in the UK of oil seed rape crops genetically modified (GM) to express herbicide tolerance.

ACRE's advice:

ACRE welcomed the study and felt that it would provide important information for the consideration of any release of herbicide tolerant varieties on a commercial scale in the future. An examination of the potential for 'gene stacking' and its consequences already forms a key part of ACRE's assessment of the impact of releases of GMOs into the environment. The Committee felt that 'gene stacking' of herbicide tolerance genes was unlikely to create so-called 'superweeds' but was a problem of control of volunteers in agriculture. The Committee emphasised that this study did not provide information that changed current risk assessments of herbicide tolerant oil seed rape.

1 Orsen, J. (2001) Gene stacking in herbicide tolerant oil seed rape: lessons from the North American experience. English Nature Reports No. 443
(www.english-nature.org.uk/pubs/publication/PDF/Enrr443.pdf)