Abstract

Oilseed rape is one of the most important sources of vegetable oil worldwide. Approximately 24% of the world’s total cultivation area in 2015 was planted with genetically modified (GM) varieties. Until now the cultivation of GM oilseed rape in the EU is not approved since coexistence of GM and non-GM oilseed rape is a matter of significant public concern. One reason is the differing information about pollen-mediated gene flow in this crop species. Therefore, in a 3-year field trial we investigated gene flow using a GM-free marker system consisting of a high erucic acid oilseed rape (HEAR) variety as pollen donor and a low erucic acid oilseed rape (LEAR) variety as pollen recipient. Donor and receptor fields were equally-sized (75 by 100 m or 0.75 ha) and separated by an isolation distance of 20 m clover-grass. Two different HEAR varieties, a hybrid variety and a line variety, were compared as pollen donor. Generally, outcrossing rates at 1 m field depth were significantly highest. A significant decrease in outcrossing was observed in the first donor-facing 20 m of recipient fields, with no further significant decrease in field depths > 20 m. Outcrossing rates of the total field harvest never exceeded 0.25%. Due to irregular patterns of outcrossing, a separated harvest of the receptor field edge facing the donor plot only marginally reduced the GM content in the total harvest.

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