Biological Confinement Strategies for Seed- and Pollen-Mediated Gene Flow of GM Canola (Brassica napus L.)

Canola (Brassica napus) varieties containing inherent restrictions on gene flow may address problems of seed- and pollen-mediated gene flow. The aim of this study was to explore the effectiveness of 1) low-dormancy varieties in avoiding GM soil seedbanks and volunteers, and 2) cleistogamous (clg) genotypes to avoid outcrossing. GM and non-GM varieties with altered seed ingredients had a wide dormancy range that turned out to be genetically determined. Quantitative trait locus (QTL) mapping identified four QTLs, which together explained 35% of the phenotypic variance. The fiber content of the seeds appeared to additionally affect seed dormancy. A qualitative polymerase chain reaction (PCR) assay was developed for clg canola by cloning and sequencing of clg1-specific DNA fragments. Detection of characteristic bands in 0.1% clg spiked samples illustrated the sensitivity of this method. The inherent traits of low dormancy and cleistogamy may be feasible tools to minimize gene flow and may be considered for coexistence of GM and non-GM canola