Feral populations of GE Canola (Brassica napus) in North Dakota

De-domestication or feralization of genetically engineered (GE) crops increases the risk that transgenes will escape cultivation and become integrated into natural and naturalizing populations of conspecifics and close relatives. A key assumption of the management of GE crops is that populations of escaped plants are short-lived and that the risks they pose, therefore, are limited. However, few populations of escaped crop plants have been tracked over the long term so our understanding of their persistence in ruderal or natural landscapes is limited. In 2021, we repeated a large-scale road survey of feral GE canola populations in North Dakota, USA, initially conducted in 2010. Our objectives were to determine the current distribution of feral canola populations, and to establish the relative frequency of GE and non-GE phenotypes in populations of canola throughout North Dakota, USA. In 2010 and 2021,we conducted systematic roadside surveys to quantify the presence and abundance of feral GE and non-GE canola populations in North Dakota, USA, beginning in June and continuing through July. Field crews established east-west transects on major roads throughout the state. A 2×50 m quadrat was established every 8.05 km (5 miles) of roadway on one or both sides of the road, where traffic permitted, in which all identifiable B. napus plants were counted. Sampling was conducted early in the summer prior to the onset of flowering of cultivated canola. When canola was present at a sampling site, one randomly selected plant was collected, photographed and archived as a voucher specimen. Leaf fragments from voucher specimens were tested for the presence of CP4 EPSPS protein (confers tolerance to glyphosate herbicide) and PAT protein (confers tolerance to glufosinate herbicide) with TraitChek™ immunological lateral flow test strips (Romer Labs, Inc., Newark, DE).