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Management of herbicide-tolerant oilseed rape in Europe:a case study on minimizing vertical gene flow

Published online by Cambridge University Press:  15 April 2005

Yann Devos
Affiliation:
Service of Biosafety and Biotechnology, Scientific Institute of Public Health, Juliette Wytsmanstraat 14, 1050 Brussels, Belgium
Dirk Reheul
Affiliation:
Department of Plant Production, Faculty of Bioscience Engineering, University of Ghent, Coupure Links 653, 9000 Ghent, Belgium
Adinda DE Schrijver
Affiliation:
Service of Biosafety and Biotechnology, Scientific Institute of Public Health, Juliette Wytsmanstraat 14, 1050 Brussels, Belgium
François Cors
Affiliation:
Department of Pesticide Research, Walloon Agricultural Research Centre, Rue du Bordia 11, 5030 Gembloux, Belgium
William Moens
Affiliation:
Service of Biosafety and Biotechnology, Scientific Institute of Public Health, Juliette Wytsmanstraat 14, 1050 Brussels, Belgium

Abstract

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The potential commercialization of genetically modified herbicide-tolerant (GMHT) oilseed rape in Europe raises various concerns about their potential environmental and agronomic impacts, especially those associated with the escape of transgenes. Pollen of oilseed rape can be dispersed in space, resulting in the fertilization of sympatric compatible wild relatives (e.g. Brassica rapa) and oilseed rape cultivars grown nearby (GM and/or non-GM Brassica napus). The spatial and temporal dispersal of seeds of oilseed rape may lead to feral oilseed rape populations outside the cropped areas and oilseed rape volunteers in subsequent crops in the rotation. The incorporation of a HT trait(s) may increase the fitness of the recipient plants, making them more abundant and persistent, and may result in weeds that are difficult to control by the herbicide(s) to which they are tolerant. Vertical gene flow from transgenic oilseed rape to non-GM counterparts may also have an impact on farming and supply chain management, depending on labelling thresholds for the adventitious presence of GM material in non-GM products. Given the extent of pollen and seed dispersal in oilseed rape, it is obvious that the safe and sound integration of GMHT oilseed rape in Europe may require significant on-farm and off-farm management efforts. Crucial practical measures that can reduce vertical gene flow include (1) isolating seed production of Brassica napus, (2) the use of certified seed, (3) isolating fields of GM oilseed rape, (4) harvesting at the correct crop development stage with properly adjusted combine settings, (5) ensuring maximum germination of shed seeds after harvest, (6) controlling volunteers in subsequent crops, and (7) keeping on-farm records. The implementation of the recommended practices may, however, be difficult, entailing various challenges.

Type
Research Article
Copyright
© ISBR, EDP Sciences, 2004

References

Baker, J, Preston, C (2003) Predicting the spread of herbicide resistance in Australian canola fields. Transgen. Res. 12: 731737 CrossRef
Becker, H, Karle, R, Han, S (1992) Environmental variation for outcrossing rates in rapeseed (Brassica napus). Theor. Appl. Genet. 84: 303306
Beckie H, Hall L, Warwick S (2001) Impact of herbicide resistant crops as weeds in Canada. Proc. Brighton Crop Protect. Conf. – Weeds, pp 135–142
Beckie, H, Warwick, S, Nair, H, Séguin-Swartz G (2003) Gene flow in commercial fields of herbicide-resistant canola (Brassica napus). Ecol. Appl. 13: 12761294 CrossRef
Beckie, H, Séguin-Swartz, G, Nair, H, Warwick, S, Johnson, E (2004) Multiple herbicide-resistant canola (Brassica napus) can be controlled by alternative herbicides. Weed Sci. 52: 152157 CrossRef
Beismann, H, Roller, A, Zeitler, R (2003) Assessing the number of transgenic oilseed rape seed in the soil seed bank of former release sites. Asp. App. Biol. 69: 209215
Bilsborrow, P, Evans, E, Bowman, J, Bland, B (1998) Contamination of edible double-low oilseed rape crops via pollen transfer from high erucic cultivars. J. Sci. Food Agric. 76: 1722 3.0.CO;2-9>CrossRef
Bing D, Downey R, Rakow G (1995) An evaluation of the potential of intergeneric gene transfer between Brassica napus and Sinapis arvensis. Plant Breed. 114: 481–484
Bing, D, Downey, R, Rakow, G (1996) Hybridisation among Brassica napus, B. rapa and B. juncea and their 2 weedy relatives B. nigra and Sinapis arvensis under open pollination conditions in the field. Plant Breed. 115: 470473 CrossRef
Blackshaw, R, Brandt, R, Janzen, H, Entz, T, Grant, C, Derksen, D (2003) Differential response of weed species to added nitrogen. Weed Sci. 51: 532539 CrossRef
Blackshaw, R, Brandt, R, Janzen, H, Entz, T (2004) Weed species response to phosphorus fertilization. Weed Sci. 52: 406412 CrossRef
Chadoeuf, R, Darmency, H, Maillet, J, Renard, M (1998) Survival of buried seeds of interspecific hybrids between oilseed rape, hoary mustard and wild radish. Field Crops Res. 58: 197204 CrossRef
Champolivier J, Gasquez J, Messéan A, Richard-Molard M (1999) Management of transgenic crops within the cropping system. In Lutman P, ed, Gene Flow and Agriculture: Relevance for Transgenic Crops, British Crop Protection Council, pp 233–240
Chèvre, AM, Eber, F, Baranger, A, Kerlan, P, Festoc, G, Vallee, P, Renard, M (1996) Interspecific gene flow as a component of risk assessment for transgenic Brassicas. Acta Hortic. 407: 169179 CrossRef
Chèvre, AM, Eber, F, Baranger, A, Renard, M (1997) Gene flow from transgenic crops. Nature 389: 924 CrossRef
Chèvre, AM, Eber, F, Baranger, A, Hureau, G, Barret, P, Picault, H, Renard, M (1998) Characterisation of backcross generations obtained under field conditions from oilseed rape-wild radish F1 interspecific hybrids: an assessment of transgene dispersal. Theor. Appl. Genet. 97: 9098
Chèvre, AM, Eber, F, Darmency, W, Fleury, A, Picault, I, Letanneur, J, Renard, M (2000) Assessment of interspecific hybridisation between transgenic oilseed rape and wild radish under normal agronomic conditions. Theor. Appl. Genet. 100: 12331239
Chèvre AM, Ammitzbøll H, Breckling B, Dietz-Pfeilstetter A, Eber F, Fargue A, Gomez-Campo C, Jenczewski E, Jørgensen R, Lavigne C, Meier M, den Nijs H, Pascher K, Seguin-Swartz G, Sweet J, Stewart N, Warwick S (2004) A review on interspecific gene flow from oilseed rape to wild relatives. In den Nijs H, Bartsch D, Sweet J, eds, Introgression from Genetically Modified Plants into Wild Relatives, CABI publishing, pp 235–251
Colbach, N, Clermont-Dauphin, C, Meynard, J (2001a) GENESYS: a model of the influence of cropping systems on gene escape from herbicide tolerant rapeseed crops to rape volunteers. I) Temporal evolution of a population of rapeseed volunteers in a field. Agric. Ecosyst. Environ. 83: 235253 CrossRef
Colbach, N, Clermont-Dauphin, C, Meynard, J (2001b) GENESYS: a model of the influence of cropping systems on gene escape from herbicide tolerant rapeseed crops to rape volunteers. II) Genetic exchanges among volunteer and crop populations in a small region. Agric. Ecosyst. Environ. 83: 255270 CrossRef
Crawley, M, Brown, S (1995) Seed limitation and the dynamics of feral oilseed rape on the M25 motorway. Proc. R. Soc. Lond. 259: 4954 CrossRef
Crawley, M, Hails, R, Rees, M, Kohn, D, Buxton, J (1993) Ecology of transgenic oilseed rape in natural habitats. Nature 363: 620623 CrossRef
Crawley, M, Brown, S, Hails, R, Kohn, D, Rees, M (2001) Transgenic crops in natural habitats. Nature 409: 682683 CrossRef
Cresswell, J, Bassam, A, Bell, S, Collins, S, Kelly, T (1995) Predicted pollen dispersal by honey-bees and three species of bumble-bees foraging on oilseed rape – a comparison of three models. Funct. Ecol. 6: 829841 CrossRef
Cresswell, J, Osborne, J, Bell, S (2002) A model of pollinator-mediated gene flow between plant populations with numerical solutions for bumblebees pollinating oilseed rape. Oikos 98: 375384 CrossRef
Daniell, H (2002) Molecular strategies for gene containment in transgenic crops. Nature Biotechnol. 20: 581586 CrossRef
Darmency, H, Fleury, A (2000) Mating system in Hirschfeldia incana and hybridisation to oilseed rape. Weed Res. 40: 231238 CrossRef
Dale, P (1992) Spread of engineered genes to wild relatives. Plant Physiol. 100: 1315 CrossRef
Dale, P (1994) The impact of hybrids between genetically modified crop plants and their related species: general considerations. Mol. Ecol. 3: 3136 CrossRef
Deville A, Garnier A, Lecomte J, Adamczyk K, Huet S, Merrien A, Messéan A (2003) Origin and dynamics of feral oilseed rape populations. In Boelt B, ed, 1st European Conference on the Co-existence of Genetically Modified Crops with Conventional and Organic Crops, Research Centre Flakkebjerg, pp 100–101
Dietz-Pfeilstetter A, Zwerger P (2003) Pollen and seed dispersal during the large scale cultivation of transgenic oilseed rape. In Boelt B, ed, 1st European Conference on the Co-existence of Genetically Modified Crops with Conventional and Organic Crops, Research Centre Flakkebjerg, pp 97–99
Downey R (1999) Gene flow and rape – the Canadian experience. In Lutman P, ed, Gene Flow and Agriculture: Relevance for Transgenic Crops, British Crop Protection Council, pp 109–116
Eastham K, Sweet J (2002) Genetically modified organisms (GMOs): the significance of gene flow through pollen transfer. Environmental Issue Report No 28, European Environment Agency
Ellstrand, N (1992) Gene flow by pollen: implications for plant conservation genetics. Oikos 63: 7786 CrossRef
Ellstrand N (2003) Dangerous liaisons? When cultivated plants mate with their wild relatives. In Scheiner S, ed, Synthesis in Ecology and Evolution, the Johns Hopkins University Press
Ellstrand, N, Hoffman, C (1990) Hybridization as an avenue of escape for engineered genes. BioScience 40: 438442 CrossRef
Ellstrand, N, Prentice, H, Hancock, J (1999) Gene flow and introgression from domesticated plants into their wild relatives. Annu. Rev. Ecol. Syst. 30: 539563 CrossRef
Fredshavn, J, Poulsen, G, Huybrechts, I, Rüdelsheim, P (1995) Competitiveness of transgenic oilseed rape. Trans. Res. 4: 142148 CrossRef
Frello, S, Hansen, K, Jensen, J, Jørgensen, R (1995) Inheritance of rapeseed (Brassica napus)-specific RAPD markers and a transgene in the cross B. juncea × (B. juncea × B. napus). Theor. Appl. Genet. 91: 236241 CrossRef
Friesen, L, Nelson, A, Van Acker R (2003) Evidence of contamination of pedigreed canola (Brassica napus) seedlots in western Canada with genetically modified herbicide resistance traits. Agron. J. 95: 13421347 CrossRef
Gray, A, Raybould, A (1998) Reducing transgene escape routes. Nature 392: 653654 CrossRef
Gruber, S, Pekrun, C, Claupein, W (2004) Population dynamics of volunteer oilseed rape (Brassica napus L.) affected by tillage. Eur. J. Agron. 20: 351361 CrossRef
Guéritaine, G, Sester, M, Eber, F, Chèvre, AM, Darmency, H (2002) Fitness of backcross six of hybrids between transgenic oilseed rape (Brassica napus) and wild radish (Raphanus raphanistrum). Mol. Ecol. 11: 14191426 CrossRef
Gulden R (2003) Secondary seed dormancy and the seed bank ecology of Brassica napus L. in western Canada. Ph.D. thesis, University of Saskatchewan, Saskatoon, Canada
Gulden, R, Shirtliffe, S, Thomas, A (2003a) Harvest losses of canola (Brassica napus) cause large seed bank inputs. Weed Sci. 51: 8386 CrossRef
Gulden, R, Shirtliffe, S, Thomas, A (2003b) Secondary seed dormancy prolongs persistence of volunteer canola in western Canada. Weed Sci. 51: 904913 CrossRef
Hails, R, Rees, M, Kohn, D, Crawley, M (1997) Burial and seed survival in Brassica napus subsp. Oleifera and Sinapsis arvensis including a comparison of transgenic and non-transgenic lines of the crop. Proc. R. Soc. Lond. 264: 17 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
Hall L, Good A, Beckie H, Warwick S (2003) Gene flow in herbicide-resistant canola (Brassica napus): the Canadian experience. In Lelley T, Balász E, Tepfer M, eds, Ecological Impact of GMO Dissemination in Agro-Ecosystems, Proceedings of an International OECD Workshop, pp 57– 66
Hansen, L, Siegismund, H, Jørgensen, R (2001) Introgression between oilseed rape (Brassica napus L.) and its weedy relative B. rapa L. in a natural population. Genet. Resour. Crop Evol. 48: 621627 CrossRef
Hauser, T, Jørgensen, R, Østergård H (1998a) Fitness of backcross and F2 hybrids between weedy Brassica rapa and oilseed rape (B. napus). Heredity 81: 436443 CrossRef
Hauser, T, Shaw, R, Østergård H (1998b) Fitness of F1 hybrids between weedy Brassica rapa and oilseed rape (B. napus). Heredity 81: 429435 CrossRef
Hauser, T, Damgaard, C, Jørgensen, R (2003) Frequency dependent fitness of hybrids between oilseed rape (Brassica napus) and weedy B. rapa (Brassicaceae). Am. J. Bot. 90: 571578 CrossRef
Hobson, R, Bruce, D (2002) Seed loss when cutting a standing crop of oilseed rape with tow types of combine harvester header. Biosyst. Eng. 81: 281286 CrossRef
Hoffman, C (1990) Ecological risks of genetic engineering of crop plants. BioScience 40: 434437 CrossRef
Ingram J (2000) Report on the separation distances required to ensure cross-pollination is below specified limits in non-seed crops of sugar beet, maize and oilseed rape. MAFF Project No RG0123
Jenczewski, E, Ronfort, J, Chèvre, AM (2003) Crop-to-wild gene flow, introgression and possible fitness effects of transgenes. Environ. Biosafety Res. 2: 924 CrossRef
Jørgensen, R, Andersen, B, Hauser, T, Landbo, L, Mikkelsen, T, Østergård H (1998) Introgression of crop genes from oilseed rape (Brassica napus) to related wild species – an avenue for the escape of engineered genes. Acta Hortic. 459: 211217 CrossRef
Jørgensen, R, Andersen, B, Snow, A, Hauser, T (1999) Ecological risks of growing genetically modified crops. Plant Biotechnol. 16: 6971 CrossRef
Jørgensen R, Hauser T, Hansen L, Siegismund H, Andersen B (2003) Gene flow from oilseed rape (Brassica napus) and beet (Beta vulgaris) to wild relatives: effects of herbicide tolerant cultivars. In Lelley T, Balász E, Tepfer M, eds, Ecological Impact of GMO Dissemination in Agro-Ecosystems, Proceedings of an International OECD Workshop, pp 67–75
Jørgensen R, Ammitzbøll H, Hansen L, Johannessen M, Andersen B, Hauser T (2004) Gene introgression and consequences in Brassica. In den Nijs H, Bartsch D, Sweet J, eds, Introgression from Genetically Modified Plants into Wild Relatives, CABI publishing, pp 253–277
Kareiva, P, Morris, W, Jacobi, C (1994) Studying and managing the risk of cross-fertilisation between transgenic crops and wild relatives. Mol. Ecol. 3: 1521 CrossRef
Klinger T, Ellstrand N (1999) Transgene movement via gene flow: recommendations for improved biosafety assessment. In Amman K, Jacot Y, Simonsen V, Kjellsson G, eds, Methods for risk assessment of transgenic plants. III Ecological risks and prospects of transgenic plants, Birkhäuser Verlag Basel, pp 129–140
Lavigne, C, Klein, E, Vallée, P, Pierre, J, Godelle, B, Renard, M (1998) A pollen-dispersal experiment with transgenic oilseed rape. Estimation of the average pollen dispersal of an individual plant within a field. Theor. Appl. Genet. 96: 886896 CrossRef
Lefol, E, Danielou, V, Darmency, H (1996a) Predicting hybridisation between transgenic oilseed rape and wild mustard. Field Crops Res. 45: 153161 CrossRef
Lefol, E, Fleury, A, Darmency, H (1996b) Gene dispersal from transgenic crops. II. Hybridisation between oilseed rape and the hoary mustard. Sex. Plant Reprod. 9: 189196 CrossRef
López-Granados, F, Lutman, P (1998) Effect of environmental conditions on the dormancy and germination of volunteer oilseed rape seed (Brassica napus). Weed Sci. 46: 419426
Lutman P (2003) Co-existence of conventional, organic and GM crops – role of temporal and spatial behaviour of seeds. In Boelt B, ed, 1st European Conference on the Co-existence of Genetically Modified Crops with Conventional and Organic Crops, Research Centre Flakkebjerg, pp 33–42
Lutman, P, Cussans, G, Wright, K, Wilson, B, Wright, G, Lawson, H (2002) The persistence of seeds of 16 weed species over six years in two arable fields. Weed Res. 42: 231241 CrossRef
Lutman, P, Freeman, S, Pekrun, C (2004) The long-term persistence of seeds of oilseed rape (Brassica napus) in arable fields. J. Agricult. Sci. 141: 231240 CrossRef
Messéan A (1997) Management of herbicide tolerant crops in Europe. Proc. Brighton Crop Protect. Conf. – Weeds, pp 947–954
Mesquida, J, Renard, M (1982) Study of the pollen dispersal by wind and of the importance of wind pollination in rapeseed (Brassica napus var. oleifera Metzger). Apidologie 4: 353366 CrossRef
Momoh, E, Zhou, W, Kristiansson, B (2002) Variation in the development of secondary dormancy in oilseed rape genotypes under conditions of stress. Weed Res. 42: 446455 CrossRef
Morgan C, Bruce D, Child R, Ladbrooke Z, Arthur A (1998) Genetic variation for pod shatter resistance among lines of oilseed rape developed from synthetic B. napus. Field Crops Res. 58: 153–165
Moyes C, Lilley J, Casais C, Cole S, Haeger P, Dale P (2002) Barriers to gene flow from oilseed rape (Brassica napus) into populations of Sinapis arvensis. Mol. Ecol. 11: 103–112
Norris C, Sweet J (2002) Monitoring large scale releases of genetically modified crops (EPG 1/5/84) incorporating report on project EPG 1/5/30: Monitoring releases of genetically modified crop plants
Norris C, Simpson E, Sweet J, Thomas J (1999) Monitoring weediness and persistence of genetically modified oilseed rape (Brassica napus) in the UK. In Lutman P, ed, Gene Flow and Agriculture: Relevance for Transgenic Crops, British Crop Protection Council, pp 255–260
Norris C, Sweet J, Parker J, Law J (2004) Implications for hybridization and introgression between oilseed rape (Brassica napus) and wild turnip (B. rapa) from an agricultural perspective. In den Nijs H, Bartsch D, Sweet J, eds, Introgression from Genetically Modified Plants into Wild Relatives, CABI publishing, pp 107–123
Orson J (2002) Gene stacking in herbicide tolerant oilseed rape: lessons from the North America experience. English Nature Research Reports No 443, English Nature
Orson J, Oldfield J (1999) Gene flow and the practical management of genetically modified crops in the UK. In Lutman P, ed, Gene Flow and Agriculture: Relevance for Transgenic Crops, British Crop Protection Council, pp 247–252
Osborne, J, Clark, S, Morris, R, Williams, I, Riley, J, Smith, A, Reynolds, D, Edwards, A (1999) A landscape-scale study of bumblebee foraging range and constancy, using harmonic radar. J. Appl. Ecol. 36: 519533 CrossRef
Paul, E, Thompson, C, Dunwell, J (1995) Gene dispersal from genetically modified oilseed rape in the field. Euphytica 81: 283289 CrossRef
Pekrun, C, Lutman, P (1998) The influence of post-harvest cultivation on the persistence of volunteer oilseed rape. Asp. App. Biol. 51: 113118
Pekrun, C, Lutman, P, Baeumer, K (1997a) Induction of secondary dormancy in rape seeds (Brassica napus L.) by prolonged inhibition under conditions of water stress or oxygen deficiency in darkness. Eur. J. Agron. 6: 245255 CrossRef
Pekrun C, Potter T, Lutman P (1997b) Genotypic variation in the development of secondary dormancy in oilseed rape and its impact on the persistence of volunteer rape. Proc. Brighton Crop Protect. Conf. – Weeds, pp 243–247
Pekrun, C, Hewitt, J, Lutman, P (1998) Cultural control of volunteer oilseed rape (Brassica napus). J. Agricult. Sci. 130: 155163 CrossRef
Pekrun C, Gruber S, Lutman P, Claupein W (2003) The potential impact of volunteer rape as a link between previous and current rape crops – its relevance for managing HT-rape. In Boelt B, ed, 1st European Conference on the Co-existence of Genetically Modified Crops with Conventional and Organic Crops, Research Centre Flakkebjerg, pp 187–189
Pertl, M, Hauser, T, Damgaard, C, Jørgensen, R (2002) Male fitness of oilseed rape (Brassica napus), weedy B. rapa and their F1 hybrids when pollinating B. rapa seeds. Heredity 89: 212218 CrossRef
Pessel, D, Lecomte, J, Emeriau, V, Krouti, M, Messéan, A, Gouyon, H (2001) Persistance of oilseed rape (Brassica napus L.) outside of cultivated fields. Theor. Appl. Genet. 102: 841846 CrossRef
Price, J, Hobson, R, Neale, M, Bruce, D (1996) Seed losses in commercial harvesting of oilseed rape. J. agric. Engng. Res. 65: 183191 CrossRef
Rajani, S, Sundaresan, V (2001) The Arabidopsis myc/bHLH gene Alcatraz enables cell separation in fruit dehiscence. Curr. Biol. 11: 19141922 CrossRef
Ramsay G, Thompson C, Neilson S, Mackay G (1999) Honeybees as vectors of GM oilseed rape pollen. In Lutman P, ed, Gene Flow and Agriculture: Relevance for Transgenic Crops, British Crop Protection Council, pp 209–214
Ramsay G, Thompson C, Squire G (2003) Quantifying landscape-scale gene flow in oilseed rape. DEFRA Project RG0216
Raybould, A, Gray, A (1993) Genetically modified crops and hybridisation with wild relatives: a UK perspective. J. Appl. Ecol. 30: 199219 CrossRef
Rieger, M, Preston, C, Powles, S (1999) Risks of gene flow from transgenic herbicide-resistant canola (Brassica napus) to weedy relatives in southern Australian cropping systems. Aust. J. Agric. Res. 50: 115128 CrossRef
Rieger, M, Potter, T, Preston, C, Powles, S (2001) Hybridization between Brassica napus L. and Raphanus raphanistrum L. under agronomic field conditions. Theor. Appl. Genet. 103: 555560 CrossRef
Rieger, M, Lamond, M, Preston, C, Powles, S, Roush, R (2002) Pollen-mediated movement of herbicide resistance between commercial canola fields. Science 296: 8688 CrossRef
Roller, A, Beismann, H, Albrecht, H (2003) The influence of soil cultivation on the seed bank of GM-herbicide tolerant and conventional oilseed rape. Asp. App. Biol. 69: 131135
Salisbury P (2002) Genetically modified canola in Australia: agronomic and environmental considerations. In Downey R, ed, Australian Oilseeds Federation
Scheffler, J, Dale, P (1994) Opportunities for gene transfer from transgenic oilseed rape (Brassica napus). Trans. Res. 3: 263278 CrossRef
Scheffler, J, Parkinson, R, Dale, P (1993) Frequency and distance of pollen dispersal from transgenic oilseed rape (Brassica napus). Trans. Res. 2: 356364 CrossRef
Scheffler, J, Parkinson, R, Dale, P (1995) Evaluating the effectiveness of isolation distance for field plots of oilseed rape (Brassica napus) using a herbicide resistance transgene as a selectable marker. Plant Breed. 114: 317321 CrossRef
Schiemann, J (2003) Co-existence of genetically modified crops with conventional and organic farming. Environ. Biosafety Res. 2: 213217 CrossRef
Schlink S (1998) 10 years survival of rape seed (Brassica napus L.) in soil. Z. Pflanzenk. Pflanzen. XVI, 169–172
Scott, S, Wilkinson, M (1998) Transgene risk is low. Nature 393: 320 CrossRef
Scott S, Wilkinson M (1999) Low probability of chloroplast movement from oilseed rape (Brassica napus) into wild Brassica rapa. Nature Biotechnol. 17: 390–392
Senoir, I, Dale, P (2002) Herbicide-tolerant crops in agriculture: oilseed rape as a case study. Plant Breed. 121: 97107 CrossRef
Senior, I, Moyes, C, Dale, P (2002) Herbicide sensitivity of transgenic multiple herbicide-tolerant oilseed rape. Pest Manage. Sci. 58: 405412 CrossRef
Shirtliffe S, Entz M (2004) Chaff collection reduces seed dispersal of wild oat by a combine harvester. Weed Sci. (in press)
Simard, M, Légère, A, Pageau, D, Lajeunnesse, J, Warwick, S (2002) The frequency and persistence of canola (Brassica napus) volunteers in Québec cropping systems. Weed Technol. 16: 433439 CrossRef
Simpson E, Sweet J (2001) Consequence analysis of the impact on agriculture and the environment of the release of herbicide tolerant oilseed rape. MAFF report RG0217
Simpson E, Sweet J (2004) Out-crossing between field scale areas of genetically modified herbicide tolerant and other winter oilseed rape cultivars. Pl. Gen. Resources J. (in press)
Simpson E, Norris C, Law J, Thomas J, Sweet J (1999) Gene flow in genetically modified herbicide tolerant oilseed rape (Brassica napus) in the UK. In Lutman P, ed, Gene Flow and Agriculture: Relevance for Transgenic Crops, British Crop Protection Council, pp 75–81
Snow, A (2002) Transgenic crops – why gene flow matters? Nature Biotechnol. 20: 542 CrossRef
Snow, A, Palma, P (1997) Commercialization of transgenic plants. BioScience 47: 8696 CrossRef
Snow A, Andersen B, Jørgensen R (1999) Costs of transgenic herbicide resistance introgressed from Brassica napus into weedy B. rapa. Mol. Ecol. 8: 605–615
Squire G, Crawford J, Ramsay G, Thompson C, Bown J (1999) Gene flow at landscape level. In Lutman P, ed, Gene Flow and Agriculture: Relevance for Transgenic Crops, British Crop Protection Council, pp 57–64
Squire G, Begg G, Askew M (2003) The potential for oilseed rape feral (volunteer) weeds to cause impurities in later oilseed rape crops. DEFRA project RG0114
Sweet J (2003) Pollen dispersal and cross-pollination. In Boelt B, ed, 1st European Conference on the Co-existence of Genetically Modified Crops with Conventional and Organic Crops, Research Centre Flakkebjerg, pp 21–32
Sweet J, Shepperson R, Thomas J, Simpson E (1997) The impact of releases of genetically modified herbicide tolerant oilseed rape in the UK. Proc. Brighton Crop Protect. Conf. – Weeds, pp 1291–1302
Thomas, D, Breve, M, Raymer, P (1991) Influence of timing and method of harvest on rapeseed yield. J. Prod. Agric. 4: 266272 CrossRef
Thompson C, Squire G, Mackay G, Bradshaw J, Crawford J, Ramsay G (1999) Regional patterns of gene flow and its consequences for GM oilseed rape. In Lutman P, ed, Gene Flow and Agriculture: Relevance for Transgenic Crops, British Crop Protection Council, pp 95–100
Tiedje, J, Colwell, R, Grossman, Y, Hodson, R, Lenski, R, Mack, R, Regal, P (1989) The planned introduction of genetically modified organisms: ecological considerations and recommendations. Ecology 70: 298315 CrossRef
Timmons A, O’Brien E, Charters Y, Dubbels S, Wilkinson M (1995) Assessing the risks of wind pollination from fields of genetically modified Brassica napus ssp. oleifera. Euphytica 85: 417–423
Timmons, A, Charters, Y, Crawford, J, Burn, D, Scott, S, Dubbels, S, Wilson, N, Robertson, A, O’Brian, E, Squire, G, Wilkinson, M (1996) Risks from transgenic crops. Nature 380: 487 CrossRef
van Tienderen P (2004) Hybridization in nature: lessons for the introgression of transgene into wild relatives. In: den Nijs H, Bartsch D, Sweet J, eds, Introgression from Genetically Modified Plants into Wild Relatives, CABI publishing, pp 7–25
Walklate, P, Hunt, J, Higson, H, Sweet, J (2004) A model of pollen-mediated gene flow for oilseed rape. Proc. R. Soc. Lond. 271: 441449 CrossRef
Warwick, S, Beckie, H, Small, E (1999) Transgenic crops: new weed problems for Canada? Phytoprotection 80: 7184 CrossRef
Warwick, S, Simard, M-J, Légère, A, Beckie, H, Braun, L, Zhu, B, Mason, P, Séguin-Swartz, G, Stewart, N (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
Warwick S, Beckie H, Simard M-J, Légère A, Nair H, Séguin-Swartz G (2004) Environmental and agronomic consequences of herbicide-resistant (HR) canola in Canada. In den Nijs H, Bartsch D, Sweet J, eds, Introgression from Genetically Modified Plants into Wild Relatives, CABI publishing, pp 323–337
Wilkinson M, Charters Y, Timmons A, Dubbels S, Robertson A, Wilson N, Scott S, O'Brian E, Lawson H (1995) Problems of risk assessment with genetically modified oilseed rape. Proc. Brighton Crop Protect. Conf. – Weeds, pp 1035–1044
Wilkinson, M, Davenport, I, Charters, Y, Jones, A, Allainguillaume, J, Butler, H, Mason, D, Raybould, A (2000) A direct regional scale estimate of transgene movement from genetically modified oilseed rape to its wild progenitors. Mol. Ecol. 9: 983991 CrossRef