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Hybridization and backcrossing between transgenic oilseed rape and two related weed species under field conditions

Published online by Cambridge University Press:  15 September 2004

Matthew D. Halfhill
Crop Science Department, North Carolina State University, Raleigh, NC, USA Department of Plant Sciences, University of Tennessee, Knoxville, TN, USA
Bin Zhu
National Water Research Institute, Environment Canada, Saskatoon, SK, Canada
Suzanne I. Warwick
Agriculture and Agri-food Canada, Ottawa, Ontario, Canada
Paul L. Raymer
Georgia Experiment Station, University of Georgia, Griffin, GA, USA
Reginald J. Millwood
Department of Plant Sciences, University of Tennessee, Knoxville, TN, USA
Arthur K. Weissinger
Crop Science Department, North Carolina State University, Raleigh, NC, USA
C. Neal Stewart Jr.
Department of Plant Sciences, University of Tennessee, Knoxville, TN, USA


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Determining the frequency of crop-wild transgene flow under field conditions is a necessity for the development of regulatory strategies to manage transgenic hybrids. Gene flow of green fluorescent protein (GFP) and Bacillus thuringiensis (Bt) transgenes was quantified in three field experiments using eleven independent transformed Brassica napus L. lines and the wild relatives, B. rapa L. and Raphanus raphanistrum L. Under a high crop to wild relative ratio (600:1), hybridization frequency with B. rapa differed among the individual transformed B. napus lines (ranging from ca. 4% to 22%), however, this difference could be caused by the insertion events or other factors, e.g., differences in the hybridization frequencies among the B. rapa plants. The average hybridization frequency over all transformed lines was close to 10%. No hybridization with R. raphanistrum was detected. Under a lower crop to wild relative ratio (180:1), hybridization frequency with B. rapa was consistent among the transformed B. napus lines at ca. 2%. Interspecific hybridization was higher when B. rapa occurred within the B. napus plot (ca. 37.2%) compared with plot margins (ca. 5.2%). No significant differences were detected among marginal plants grown at 1, 2, and 3 m from the field plot. Transgene backcrossing frequency between B. rapa and transgenic hybrids was determined in two field experiments in which the wild relative to transgenic hybrid ratio was 5–15 plants of B. rapa to 1 transgenic hybrid. As expected, ca. 50% of the seeds produced were transgenic backcrosses when the transgenic hybrid plants served as the maternal parent. When B. rapa plants served as the maternal parent, transgene backcrossing frequencies were 0.088% and 0.060%. Results show that transgene flow from many independent transformed lines of B. napus to B. rapa can occur under a range of field conditions, and that transgenic hybrids have a high potential to produce transgenic seeds in backcrosses.

Research Article
© ISBR, EDP Sciences, 2004


Baranger A, Chèvre AM, Eber F, Renard M (1995) Effect of oilseed rape genotype on the spontaneous hybridization rate with a weedy species: and assessment of transgene dispersal. Theor. Appl. Genet. 91: 956–963
Beckie, HJ, Warwick, SI, Nair, H, Sequin-Swartz G (2003) Gene flow in commercial fields of herbicide-resistant oilseed rape (Brassica napus). Ecol. Appl. 13: 12761294 CrossRef
Chèvre, AM, Eber, F, Darmency, H, Fleury, A, Picault, H, Letanneur, JC, Renard, M (2000) Assessment of interspecific hybridization between transgenic oilseed rape and wild radish under agronomic conditions. Theor. Appl. Genet. 100: 12331239
Darmency, H, Lefol, E, Fleury, A (1998) Spontaneous hybridizations between oilseed rape and wild radish. Mol. Ecol. 7: 14671473 CrossRef
Eber, F, Chèvre, AM, Baranger, A, Vallee, P, Tanguy, X, Renard, M (1994) Spontaneous hybridization between a male-sterile oilseed rape and two weeds. Theor. Appl. Genet. 88: 362368
Halfhill, MD, Richards, HA, Mabon, SA, Stewart, CN Jr (2001) Expression of GFP and Bt transgenes in Brassica napus and hybridization and introgression with Brassica rapa. Theor. Appl. Genet. 103: 362368 CrossRef
Halfhill, MD, Millwood, RJ, Raymer, PL, Stewart, CN Jr (2002) Bt-transgenic oilseed rape hybridization with its weedy relative, Brassica rapa. Environ. Biosafety Res. 1: 1928 CrossRef
Halfhill MD, Millwood RJ, Weissinger AK, Warwick SI, Stewart CN Jr. (2003) Additive transgene expression and genetic introgression in multiple GFP transgenic crop × weed hybrid generations. Theor. Appl. Genet. 107: 1533–1540 CrossRef
Hall, L, Topinka, K, Huffman, J, Davis, L, Good, A (2000) Pollen flow between herbicide-resistant Brassica napus is the cause of multiple-resistant B. napus volunteers. Weed Sci. 48: 688694 CrossRef
Hansen, LB, Siegismund, HR, Jorgensen, RB (2001) Introgression between oilseed rape (Brassica napus L.) and its weedy relative B. rapa L. in a natural population. Genet. Res. Crop Evol. 48: 621627 CrossRef
Haseloff J, Siemering KR, Prasher D, Hodge S (1997) Removal of a cryptic intron and subcellular localization of green fluorescent protein are required to mark transgenic Arabidopsis plants brightly. Proc. Natl. Acad. Sci. USA 94: 2122–2127 CrossRef
Hauser TP, Jorgensen RB, Osttergard H (1997) Preferential exclusion of hybrids in mixed pollinations between oilseed rape (Brassica napus) and weedy B. campestris (Brassicaceae). Am. J. Bot. 84: 756–762 CrossRef
James C (2001) Global Review of Commercialized Transgenic Crops: 2001. ISAAA Briefs No. 24-2001 ISAAA (International Service for the Acquisition of Agri-Biotech Applications), Ithaca, NY
Jorgensen, RB, Andersen, B (1994) Spontaneous hybridization between oilseed rape (Brassica napus) and weedy B. campestris (Brassicaceae): a risk of growing genetically modified oilseed rape. Am. J. Bot. 81: 16201626 CrossRef
Landbo, L, Andersen, B, Jorgensen, RB (1996) Natural hybridization between oilseed rape and a wild relative: hybrids among seeds from weedy B. campestris. Hereditas 125: 8991 CrossRef
Landbo, L, Jorgensen, RB (1997) Brassica campestris and its hybrids with B. napus: implications for risk assessments of transgenic oilseed rape. Euphytica 97: 209216 CrossRef
Légère A, Simard M‑J, Thomas AG, Pageau D, Lajeunesse J, Warwick SI, Derksen DA (2001) Presence and persistence of volunteer oilseed rape in Canadian cropping systems. Proc. Brighton Crop Prot. Conf. – Weeds. British Crop Protection Council, Farnham, Surrey, UK, pp 143–148
Mikkelsen, TR, Andersen, B, Jorgensen, RB (1996) The risk of crop transgene spread. Nature 380: 31 CrossRef
Pertl, M, Hauser, TP, Damgaard, C, Jorgensen, RB (2002) Male fitness of oilseed rape (Brassica napus), weedy B. rapa and their F1 hybrids when pollinating B. rapa seeds. Heredity 89: 212218 CrossRef
Richards, HA, Halfhill, MD, Millwood, RJ, Stewart, CN Jr (2003) Quantitative GFP fluorescence as an indicator of recombinant protein synthesis in transgenic plants. Plant Cell Rep. 22: 117121 CrossRef
Rieger, MA, Potter, TD, Preston, C, Powles, SB (2001) Hybridization between Brassica napus L. and Raphanus raphanistrum L. under agronomic field conditions. Theor. Appl. Genet. 103: 555560 CrossRef
Simard, MJ, Légère, A, Pageau, D, Lajeunnesse, J, Warwick, S (2002) The frequency and persistence of oilseed rape (Brassica napus) volunteers in Québec cropping systems. Weed Technol. 16: 433439 CrossRef
Stewart CN Jr., Halfhill MD, Warwick SI (2003) Transgene introgression from genetically modified crops to their wild relatives. Nat. Rev., Genet. 4: 806–817
Warwick, SI, Simard, MJ, Légère, A, Beckie, HJ, Braun, L, Zhu, B, Mason, P, Seguin-Swartz, G, Stewart, CN Jr (2003) Hybridization between transgenic Brassica napus L. and its wild relatives: B. rapa L., Raphanus raphanistrum L., Sinapis arvensis L., and Erucastrum gallicum (Willd.) O.E. Schulz. Theor. Appl. Genet. 107: 528539 CrossRef