Costs of transgenic herbicide resistance introgressed from Brassica napus into weedy B. rapa

Journal or Publishing Institution: Molecular Ecology

Study: http://onlinelibrary.wiley.com/doi/10.1046/j.1365-294x.1999.00596.x/abstract

Author(s): Snow, A.A., Andersen, B. and Jørgensen, R.B.

Article Type: Peer Reviewed Study

Record ID: 2144

Abstract: Wild relatives of genetically engineered crops can acquire transgenic traits such as herbicide resistance via spontaneous crop–wild hybridization. In agricultural weeds, resistance to herbicides is often a beneficial trait, but little is known about possible costs that could affect the persistence of this trait when herbicides are not used. We tested for costs associated with transgenic resistance to glufosinate when introgressed into weedy Brassica rapa. Crosses were made between transgenic B. napus and wild B. rapa from Denmark. F₁progeny were backcrossed to B. rapa and BC₁ plants were selected for chromosome numbers similar to B. rapa. Further backcrossing resulted in a BC₂ generation that was hemizygous for herbicide resistance. We quantified the reproductive success of 457 BC₃ progeny representing six full‐sib families raised in growth rooms (plants were pollinated by captive bumblebees). Pollen fertility and seed production of BC₃ plants were as great as those of B. raparaised in the same growth rooms. Segregation for herbicide resistance in BC₃plants was 1:1 overall, but the frequency of resistant progeny was lower than expected in one family and higher than expected in another. There were no significant differences between transgenic and nontransgenic plants in survival or the number of seeds per plant, indicating that costs associated with the transgene are probably negligible. Results from this growth‐chamber study suggest that transgenic resistance to glufosinate is capable of introgressing into populations of B. rapa and persisting, even in the absence of selection due to herbicide application.

Keywords: Bombus, Brassica napus, Brassica rapa, backcrossing, chromosome number, crops, glufosinate, herbicide resistance, hybridization, pesticide application, pollen, progeny, seeds, transgenes, weeds, wild relatives, Denmark

Citation: Snow, A.A., Andersen, B. and Jørgensen, R.B., 1999. Costs of transgenic herbicide resistance introgressed from Brassica napus into weedy B. rapa. Molecular Ecology, 8(4), pp.605-615.