Gene flow in wheat: Cultivation trial

Outcrossing potential of GM wheat through pollen dispersal

Crop Barley /wheat
Year 2011
Country Switzerland Switzerland
Execution Institute of Evolutionary Biology and Environmental Studies, Zurich


Type of experiment: Planting trial, measurement of GMO presence
Experimental design and realization:

The outcrossing rate rate between adjacent small plots was measured as a function of distance in the years 2008-2010. Various GM wheat lines with increased fungal resistance were used as the GM donor plants. To determine the outcrossing rate, five samples each containing 100 grains were taken from each plot. The grains were ground to flour and examined for the presence of the foreign genes from the GM lines using PCR analysis.


Over a distance of 0 to 0.5 metres, an average outcrossing rate of 0.7 per cent was observed. This fell to 0.03 per cent when the distance increased to 2.5 metres.

A relatively small separation between wheat fields can, according to these results, almost entirely prevent undesirable gene transfer.

The observed cross-fertilisation rates were within similar ranges for the various GM and non-GM wheat plants studied, but differed slightly. The study authors therefore recommend investigating the outcrossing rates of GM wheat lines on a case-by-case basis.