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Agricultural and Biological Diversity in Latin America: Implications for Development, Testing, and Commercialization of Herbicide-Resistant Crops

Published online by Cambridge University Press:  20 January 2017

Charles R. Riches  and
Bernal E. Valverde
Charles R. Riches*
Affiliation:
Weed Science, Natural Resources Institute, University of Greenwich, Chatham Maritime, Chatham, Kent ME4 4TB, U.K.
Bernal E. Valverde
Affiliation:
The Royal Veterinary and Agricultural University, Department of Agricultural Sciences, Weed Science, Agrovej 10, DK-2630 Taastrup, Denmark
*
Corresponding author's E-mail: charlie.riches@bbsrc.ac.uk.
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Abstract

Genetically modified, herbicide-resistant crop (HRC) cultivars, which allow for simplified weed control decisions compared with conventional cultivars, have considerable potential in Latin America. The number of herbicide applications can be reduced in HRCs, and otherwise difficult-to-control species, including red rice in rice or herbicide-resistant weeds, can potentially be managed. The American tropics include the centers of origin of several crops, such as corn and potato, and natural or agrestal floras containing wild near relatives of introduced crops, including rice and cotton, for which HRCs could be used. Potential direct impacts of HRC adoption on biodiversity in Latin America include changes in the genetic diversity of crops, increased volunteer crop problems, and invasion by resistant cultivars of natural areas beyond the farm boundary. Additionally, there is a risk associated with the escape of transgenes from HRCs, involving introgression to weedy relatives on a field scale leading to amplification effects of existing weeds or modification of gene pools of crop progenitors in the centers of origin or diversity. Possible indirect effects of HRCs include the potential expansion of agriculture into uncleared wild areas made economically attractive by the more efficient cropping system, and adverse effects on nontarget organisms and ecosystem processes. The occurrence of spontaneous hybrids of crop–weed or near-relative complexes is known in the United States for rice and sunflower, and the development of HRC–weed hybrids would provide a particularly difficult set of weed management problems. For crops in which HRCs are currently in use or under development, the greatest risks in Latin America appear to be with corn, cotton, and potato. However, some of the genetic and geographical barriers reduce the risk of hybridization between these crops and their wild relatives. Furthermore, unlike the case of feral rapeseed on road verges in Europe, there is no known example of a conventionally bred crop or interfertile hybrid with a near relative becoming established outside of cultivation in Latin America. Soybean, the most widely adopted HRC in Latin America to date, is an exotic beyond the range of its wild relatives. With the exception of O. glumaepatula, there appears to be little threat to endemic wild species from HRC rice as strong infertility barriers should prevent transgene flow, but possible transgene movement to the conspecific red rice may become an issue. Beyond the field boundary, a key question concerns the possible persistence of HRC x wild relative hybrids and the manner in which resistance traits affect their overall fitness. Designing practical risk assessment protocols on which to base HRC release approval is a considerable challenge, and it is vital that Latin American states continue to build and maintain functional biosafety regulatory structures.

Keywords

Sunflower, Helianthus annuus L.rapeseed, Brassica napus L.corn (maize), Zea mays L.cotton, Gossypium hirsutum L.potato, Solanum tuberosum L.rice or wild rice, Oryza sativa L.soybean, Glycine max (L.) MerrBromoxynilglufosinateglyphosateimazapyrimazethapyrpropaniltransgene flowwild relativesGM, genetically modifiedGMO, genetically modified organismHR, herbicide resistantHRC, herbicide-resistant cropIWM, integrated weed management
Type
Symposium
Information
Weed Technology , Volume 16 , Issue 1 , March 2002 , pp. 200 - 214
Copyright
Copyright © Weed Science Society of America 

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References

Literature Cited

AGROW. 1999. Smuggled GM soybeans in Brazil. AGROW 337:17.Google Scholar
Akimoto, M., Shimamoto, Y., and Morishima, H. 1999. The extinction of genetic resources of Asian wild rice, Oryza rufipogon Griff.: a case study in Thailand. Genet. Resource Crop Evol. 46: 419–425.Google Scholar
Al-Khatib, K., Baumgartner, J. R., Peterson, D. E., and Currie, R. S. 1998. Imazethapyr resistance in common sunflower (Helianthus annuus). Weed Sci. 46: 403–407.Google Scholar
Allard, R. W. 1960. Principles of Plant Breeding. London: J. Wiley. 485 p.Google Scholar
Altieri, M. A. 1994. Biodiversity and Pest Management in Agroecosystems. New York: Food Products Press. 170 p.Google Scholar
Altieri, M. A., Schoonhoven, A., and Doll, J. 1977. The ecological role of weeds in insect pest management systems: a review illustrated by bean (Phaseolus vulgaris) cropping systems. Pest Artic. News Sum. 23: 195–205.Google Scholar
Angle, J. S. 1994. Release of transgenic plants: biodiversity and populationlevel considerations. Mol. Ecol. 3: 45–50.Google Scholar
Anonymous. 1994. Assessment Criteria for Determining Environmental Safety of Plants with Novel Traits. Regulatory Directive Dir94-08, Government of Canada.Google Scholar
Anonymous. 1999a. Brazil Farmers Smuggle, Plant GM Soy. AgBiotech Rep., October. p. 22.Google Scholar
Anonymous. 1999b. Monsanto expanding in Brazil. Int. Agric. Dev. 19:18.Google Scholar
Arias, D. M. and Riesberg, L. H. 1994. Gene flow between cultivated and wild sunflowers. Theor. Appl. Genet. 89: 655–660.Google Scholar
Arriola, P. E. 2000. Risks of escape and spread of engineered genes from transgenic crops to wild relatives. Biosafety Reviews, Biosafety Information Network and Advisory Service: Web page: http://www.binas.unido.org/binas/library.Google Scholar
Arriola, P. E. and Ellstrand, N. C. 1996. Crop-to-weed gene flow in the genus Sorghum (Poaceae): spontaneous interspecific hybridisation between johnsongrass, Sorghum halepense, and crop sorghum, S. bicolor . Am. J. Bot. 83: 1,153–1,160.Google Scholar
Baldwin, F. L. 1999. The value and exploitation of herbicide-tolerant crops in the US. Proc. Br. Crop Prot. Conf. Weeds 653–660.Google Scholar
Bergelson, J., Purrington, C. B., Palm, C. J., and Lopez Gutierrez, J. C. 1996. Costs of resistance: a test using transgenic Arabidopsis thaliana . Proc. R. Soc. (Lond.), Ser. B., 263: 1,659–1,663.Google ScholarPubMed
Brar, D. S. and Khush, G. S. 1997. Alien introgression in rice. Plant Mol. Biol. 35: 35–47.Google Scholar
Burnquist, W. L. and Ulian, E. C. 2000. Herbicide Tolerance in Transgenic Sugarcane, an Asexually Propagated Crop. Abstracts. Third International Weed Science Congress. Foz do Iguassu, Brazil: International Weed Science Society. pp. 157–158.Google Scholar
Castro, V. L. S. S. and Capalbo, D. M. F. 1999. GM Crops Worldwide: Today Brazil, China, Asia. Global Working Group on Transgenic Organisms in Integrated Pest Management and Biological Control, Newsletter No. 1. International Organisation of Biological Control.Google Scholar
Christoffoleti, P. J., Victoria-Filho, R., Dechandt, L. G. L., and Monqueiro, P. A. 1997. Biotipos de Amaranthus quitensis Resistente aos Herbicidas Inibidores da Enzima ALS. Resumos. XXI Congresso Brasileiro da Ciencia das Plantas Daninhas. Caxambu, MG, Brazil: Sociedade Brasileira da Ciência das Plantas Daninhas. p. 63.Google Scholar
Colwell, R. K. 1994. Potential ecological and evolutionary problems of introducing transgenic crops into the environment. In Krattiger, A. F. and Rosemarin, A., eds. Biosafety in Sustainable Agriculture: Sharing Biotechnology Regulatory Experiences of the Western Hemisphere. Ithaca, NY: International Service for the Acquisition of Agri-Biotech Applications. pp. 33–46.Google Scholar
Conner, A. J. and Dale, P. J. 1996. Reconsideration of pollen dispersal data from field trials of transgenic potatoes. Theor. Appl. Genet. 92: 505–508.Google Scholar
Crawley, M. J., Hails, R. S., Rees, M., Kohn, D., and Buxton, J. 1993. Ecology of transgenic oilseed rape in natural habitats. Nature 363: 620–623.Google Scholar
[CTNBio] Comissão Técnica Nacional de Bioassegurança. 2200. Libbração planejada de organismos geneticamente modificados. Web page: http://www/ctnbio.gov.br.Google Scholar
Dale, P. J. 1994. The impact of hybrids between genetically modified crop plants and their related species: general considerations. Mol. Ecol. 3: 31–36.Google Scholar
Daniell, H. and Varma, S. 1998. Chloroplast-transgenic plants: Panacea-no! Gene containment-Yes! Nat. Biotechnol. 16:602.Google Scholar
Daniell, H., Datta, R., Varma, S., Gray, S., and Lee, S. B. 1998. Containment of herbicide resistance through genetic engineering of the chloroplast genome. Nat. Biotechnol. 16: 345–348.Google Scholar
Daniels, R. E. and Sheail, J. 1999. Genetic pollution: concerns and transgenic crops. In Lutman, P.J.W., ed. Gene Flow and Agriculture: Relevance for Transgenic Crops. Farnham, U.K.: British Crop Protection Council. pp. 65–72.Google Scholar
Darmency, H., Assémat, L., and Wang, T. 1999. Millet as a model crop to assess the impact of gene flow toward weed populations. In Lutman, P.J.W., ed. Gene Flow and Agriculture: Relevance for Transgenic Crops. Farnham, U.K.: British Crop Protection Council. pp. 261–267.Google Scholar
de Kathen, A. 1996. The impact of transgenic crop releases on biodiversity in developing countries. Biotechnol. Dev. Monit. 28: 10–14.Google Scholar
de Kathen, A. 1997. Biotechnology, biosafety and impact assessment: field trials of transgenic crops in developing countries. Biosafety Journal 3: Paper 4. Web page: http://www.bioline.bdt.org.br/bioline/by.Google Scholar
de Wet, J. M. J., Timothy, D. H., Hilu, K. W., and Fletcher, G. B. 1981. Systematics of South American Tripsacum (Gramineae). Am. J. Bot. 68: 269–276.Google Scholar
Doebley, J. 1990. Molecular evidence for gene flow among Zea species. Bioscience 40:443.Google Scholar
Douches, D. S. and Pett, W. 1995. Potential environmental concerns vis-à-vis the introduction of a specific trait: experiences with potatoes engineered to express insect or virus resistance. In Frederik, R. J., Virgin, I., and Lindarte, E., eds. Environmental Concerns with Transgenic Plants in Centers of Diversity: Potato as a Model. Stockholm, Sweden: Biotechnology Advisory Commission and San Jose, Costa Rica: Inter-American Institute for Cooperation on Agriculture. pp. 44–52.Google Scholar
Duffy, M. and Ernst, M. 1999. Does planting GMO seed boost farmers’ profits? Leopold Lett. 11: 1–5.Google Scholar
Eberlein, C. V., Guttieri, M. J., and Steffen-Campbell, J. 1998. Bromoxynil resistance in transgenic potato clones expressing the bnx gene. Weed Sci. 46: 150–157.Google Scholar
Ellstrand, N. C. and Hoffman, C. A. 1990. Hybridization as an avenue of escape for engineered genes. Bioscience 40: 438–442.Google Scholar
Eubanks, M. W. 1997. Molecular analysis of crosses between Tripsacum dactyloides and Zea diploperennis (Poaceae). Theor. Appl. Gen. 94: 707–712.Google Scholar
Eyre-Walker, A., Gaut, R. L., Hilton, H., Fieldman, D. L., and Gaut, B. S. 1998. Investigation of the bottleneck leading to the domestication of maize. Proc. Natl. Acad. Sci. USA 95: 4,441–4,446.Google Scholar
[FAO] Food and Agriculture Organization. 1996. Report on the State of the World's Plant Genetic Resources. International Technical Conference on Plant Genetic Resources, Leipzig, Germany, June 17-23, 1996. Rome: Plant Production and Protection Division, FAO. 65 p.Google Scholar
Foloni, L. L. and Christoffoleti, P. J. 1999. Chemical weed control in soybeans in Brazil using new herbicides and mixtures. Proc. Br. Crop Prot. Conf. Weeds 315–318.Google Scholar
Forcella, F. 1999. Weed seed bank dynamics under herbicide tolerant crops. Proc. Br. Crop Prot. Conf. Weeds 409–416.Google Scholar
Gaut, B. S. 1996. Evolution in the genus Zea: lessons from studies of nucleotide polymorphism. Plant Sci. Biol. 11: 1–11.Google Scholar
Ghislain, M. 2000. Traits and genes: benefits and risks. In Proceedings of the International Workshop on Transgenic Potatoes for the Benefit of Resource Poor Farmers in Developing Countries. Leeds, U.K.: Leeds Institute for Plant Biotechnology and Agriculture: Web page: http://www.biology.leeds.ac.uk.Google Scholar
Gray, A. J. and Raybould, A. F. 1998. Reducing transgene escape routes. Nature 392: 653–654.Google Scholar
Gressel, J. 1999. Tandem constructs for mitigating risks of weediness from transgenic crops. Trends Biotechnol. 17: 361–366.Google Scholar
Groombridge, B., ed. 1994. Biodiversity Data Sourcebook. Cambridge, U.K.: World Conservation Monitoring Centre, World Conservation Press. 155 p.Google Scholar
Hails, R. S. 2000. Genetically modified plants—the debate continues. Trends Ecol. Evol. 15: 14–18.Google Scholar
Halford, N. G. 1999. GM crops—is there a future? Pestic. Outlook December: 246–251.Google Scholar
Haney, R. L., Senseman, S. A., Hons, F. M., and Zuberer, D. A. 2000. Effect of glyphosate on soil microbial activity and biomass. Weed Sci. 48: 89–93.Google Scholar
Hanneman, R. E. Jr. 1994. The testing and release of transgenic potatoes in the North American center of diversity. In Krattiger, A. F. and Rosemarin, A., eds. Biosafety for Sustainable Agriculture: Sharing Biotechnology Regulatory Experiences of the Western Hemisphere. Ithaca, NY: International Service for the Acquisition of Agri-Biotech Applications. pp. 47–67.Google Scholar
Hanneman, R. E. Jr. 1995. Ecology and reproductive biology of potato: the potential for and the environmental implications of gene spread. In Frederik, R. J., Virgin, I., and Lindarte, E., eds. Environmental Concerns with Transgenic Plants in Centers of Diversity: Potato as a Model. Stockholm, Sweden: Biotechnology Advisory Commission and San Jose, Costa Rica: Inter-American Institute for Cooperation on Agriculture. pp. 19–38.Google Scholar
Harlan, J. R. 1982. Relationships Between Crops and Weeds. Madison, WI: American Society of Agronomy. 295 p.Google Scholar
Harlan, J. R. 1992. Crops and Man. Madison, WI: American Society of Agronomy. 295 p.Google Scholar
Hawkes, J. G. 1978. Biosystematics of the potato. In Harris, P. M., ed. The Potato Crop: The Scientific Basis for Improvement. London: Chapman and Hall. pp. 15–69.Google Scholar
Hawkes, J. G. and Hjerting, J. P. 1969. The Potatoes of Argentina, Brazil, Paraguay, and Uruguay: A biosystematic Study. Oxford: Clarendon Press. 525 p.Google Scholar
IFOAM. 2000. IFOAM policy on genetic engineering. International Federation of Organic Agricultural Movements: Web page: http://ifoam.org/gmo/ge2.html.Google Scholar
Iltis, H. H. and Benz, B. F. 2000. Zea nicaraguensis (Poaceae), a new teosinte from Pacific coastal Nicaragua. Novon 10: 382–390.Google Scholar
James, C. 1999a. Global Review of Commercialised Transgenic Crops: 1999. ISAAA Briefs, 12. Ithaca, NY: International Service for the Acquisition of Agri-Biotech Applications. 8 p.Google Scholar
James, C. 1999b. Global Review of Commercialised Transgenic Crops: 1998. ISAAA Briefs, 8. Ithaca, NY: International Service for the Acquisition of Agri-Biotech Applications. 12 p.Google Scholar
Janssen, G. J. W., Van Norel, A., Verkerk-Bakker, B., Janssen, R., and Hoogendoorn, J. 1997. Introgression of resistance to root-knot nematodes from wild Central American Solanum species into S. tuberosum ssp. tuberosum. Theor. Appl. Genet. 95: 490–496.Google Scholar
Kareiva, P., Parker, I. M., and Pascual, M. 1996. Can we use experiments and models in predicting the invasiveness of generically engineered organisms? Ecology 77:1, 651–1, 675.Google Scholar
Juliano, A. B., Naredo, M. E. B., and Jackson, M. T. 1998. Taxonomic status of Oryza glumaepatula Steud. I. Comparative morphological studies of New World diploids and Asian AA genome species. Genet. Res. Crop Evol. 45: 197–203.Google Scholar
Keeler, K. H., Turner, C. E., and Bolick, M. R. 1996. Movement of crop transgenes into wild plants. In Duke, S. O., ed. Herbicide-Resistant Crops: Agricultural, Environmental, Economic, Regulatory and Technical Aspects. Boca Raton, FL: CRC Lewis. pp. 303–330.Google Scholar
Khush, G. S. 1997. Origin, dispersal, cultivation and variation in rice. Plant Mol. Biol. 35: 25–34.Google Scholar
Langevin, S. A., Clay, K., and Grace, J. B. 1990. The incidence and effects of hybridization between cultivated rice and its related weed red rice (Oryza sativa L.) Evolution 44:1, 000–1,008.Google Scholar
Linder, C. R., Taha, I., Seiler, G. J., Snow, A. A., and Rieseberg, L. H. 1998. Long-term introgression of crop genes into wild sunflower populations. Theor. Appl. Genet. 96: 339–347.Google Scholar
Lockwood, J. A. 1999. Agriculture and biodiverity: finding our place in this world. Agric. Hum. Values 16: 365–379.Google Scholar
Lu, B.-R., Naredo, M. E. B., Juliano, A. B., and Jackson, M. T. 1998. Taxonomic status of Oryza glumaepatula Steud. III. Assessment of genomic affinity among AA genome species from the New World, Asia, and Australia. Genet. Res. Crop Evol. 45: 215–223.Google Scholar
Lubberstedt, T., Dussle, C., and Melchinger, A. E. 1998. Application of microsatellites from maize to teosinte and other relatives of maize. Plant Breed. 117: 447–450.Google Scholar
Macilwain, C. 1999. Access issues may determine whether agri-biotech will help the world's poor. Nature 402: 341–345.Google Scholar
Majumder, N. D., Ram, T., and Sharma, A. C. 1997. Cytological and morphological variation in hybrid swarms and introgressed population of interspecific hybrids (Oryza rufipogon Griff. -Oryza sativa L.) and its impact on evolution of intermediate types. Euphytica 94: 295–302.Google Scholar
Mallory-Smith, C. 1998. Bromoxynil resistant common groundsel (Senecio vulgaris). Weed Technol. 12: 322–324.Google Scholar
Mangelsdorf, P. C. 1974. Corn: Its Origin, Evolution and Improvement. Cambridge, MA: Harvard University Press. 262 p.Google Scholar
Maredia, M. K. 1998. The economics of biosafety: implications for biotechnology in developing countries. Biosafety Journal 3: Paper 1. Web page: http://bioline.bdt.org.br/bioline/by.Google Scholar
Marshall, G. M. 1998. Herbicide-tolerant crops—real farmer opportunity or potential environmental problem? Pestic. Sci. 52: 394–402.Google Scholar
Martinez-Soriano, J. P. R. and Leal-Klevezas, D. S. 2000. Transgenic maize in Mexico: no need for concern. Science 287:139.Google Scholar
Massieu, Y., Gonzélez, R. L., Chauvet, M., Castañeda, Y., and Barajas, R. E. 2000. Transgenic potatoes for small-scale farmers: a case study in Mexico. Biotechnol. Dev. Monit. 41: 6–10.Google Scholar
May Montero, A. 1997. Transgenic plants in Costa Rica: legislation, regulation and enforcement applicable to transgenic plants. In Hrusaka, A. J. and Lara Pavon, M., eds. Transgenic Plants in Mesoamerican Agriculture. Zamorano, Honduras: Zamorano Academic Press. pp. 58–61.Google Scholar
Merotto, A. Jr., Vidal, R. A., and Fleck, N. G. 1999. Soybean tolerance to synthetic auxin and potential of mixtures with protox-inhibiting herbicides. Proc. Br. Crop Prot. Conf. Weeds 319–324.Google Scholar
Missouri Botanical Garden. 2001. Missouri Botanical Garden's VAST nomenclatural database. Web page: http://mobot.mobot.org/W3T/Search/vast.html. Accessed August 20, 2001.Google Scholar
Munro, J. M. 1987. Cotton. London: Longman. 436 p.Google Scholar
Nap, J. P. 1999. A transgene-centred approach to the biosafety of transgenic herbicide tolerant crops. Biotechnol. Dev. Monit. 38: 6–11.Google Scholar
Naredo, M. E. B., Juliano, A. B., Lu, B.-R., and Jackson, M. T. 1998. Taxonomic status of Oryza glumaepatula Steud. II. Hybridization between New World diploids and AA genome species from Asia and Australia. Genet. Res. Crop Evol. 45: 205–214.Google Scholar
OECD. 2000. Online database of GMO field releases. Organisation for Economic Co-operation and Development: Web page: http://www.oecd.org/ehs/service.htm.Google Scholar
Oka, H. I. 1991. Genetic diversity of wild and cultivated rice. In Khush, G. S. and Toenniessen, G. H., eds. Rice Biotechnology. Oxford: CAB International. pp. 55–81.Google Scholar
Olofsdotter, M., Valverde, B. E., and Madsen, K. H. 2000. Herbicide resistant rice (Oryza sativa L.): global implications for weedy rice and weed management. Ann. Appl. Biol. 137: 279–295.CrossRefGoogle Scholar
Palmer, R. G., Hymowitz, T., and Nelson, R. I. 1996. Germplasm diversity within soybean. In Verma, D.P.S. and Shoemaker, R. C., eds. Soybean: Genetics, Molecular Biology and Biotechnology. Wallingford, U.K.: CABI Publishing. pp. 1–35.Google Scholar
Parker, I. M. and Kareiva, P. 1996. Assessing the risks of invasion for genetically engineered plants: acceptable evidence and reasonable doubt. Biol. Conserv. 78: 193–203.Google Scholar
Perfecto, I., Van der Meer, J., Hanson, P., and Catín, V. 1997. Arthropod biodiversity loss and the transformation of a tropical agro-ecosystem. Biodivers. Conserv. 6: 935–945.Google Scholar
Persley, G. J., Giddings, L. V., and Juma, C. 1992. The safe Application of Biotechnology in Agriculture and the Environment. The Hague, The Netherlands: International Service for National Agricultural Research. 39 p.Google Scholar
Pessel, F. D., Leconte, J., Emeriau, V., Krouti, M., Messean, A., and Gouyon, P. H. 2001. Persistence of oilseed rape (Brassica napus L.) outside cultivated fields. Theor. Appl. Genet. 102: 841–846.Google Scholar
Polaszek, A., Riches, C. R., and Lenne, J. M. 1999. The effects of pest management strategies on biodiversity in agroecosystems. In Wood, D. and Lenne, J. M., eds. Agrobiodiversity: Characterisation, Utilization and Management. Wallingford, U.K.: CABI Publishing. pp. 273–303.Google Scholar
Ponchio, J. A., Victoria-Filho, R., and Christoffoleti, P. J. 1997. Resistencia de Biotipos de Bidens pilosa aos Herbicidas Inibidores da ALS/AHAS. Resumos. XXI Congresso Brasileiro da Ciencia das Plantas Daninhas. Caxambu, MG, Brazil: Sociedade Brasileira da Ciência das Plantas Daninhas. p. 126.Google Scholar
Prance, G. T. 1977. Floristic inventory of the tropics: where do we stand? Ann. Mo. Bot. Gard. 64: 659–684.Google Scholar
Pratley, J., Unwin, N., Stanton, R., Baines, P., Broster, J., Cullis, K., Schafer, D., Joseph, B., and Krueger, R. 1999. Resistance to glyphosate in Lolium rigidum . 1. Bioevaluation. Weed Sci. 47: 405–411.Google Scholar
Purseglove, J. W. 1968a. Tropical Crops: Monocotyledons. London: Longman. 607 p.Google Scholar
Purseglove, J. W. 1968b. Tropical Crops: Dicotyledons. London: Longman. 719 p.Google Scholar
Raven, P. H. 1988. Tropical floristics tomorrow. Taxon 37: 549–560.Google Scholar
Sage, G. C. M. 1999. The role of DNA technologies in crop breeding. In Lutman, J.P.W., ed. Gene Flow and Agriculture: Relevance for Transgenic Crops. Farnham, U.K.: British Crop Protection Council. pp. 23–31.Google Scholar
Scott, S. E. and Wilkinson, M. J. 1999. Low probability of chloroplast movement from oilseed rape (Brassica napus) into wild Brassica rapa . Nat. Biotechnol. 17: 390–393.Google Scholar
Siciliano, S. D. and Germida, J. J. 1999. Taxonomic diversity of bacteria associated with the roots of field-grown transgenic Brassica napus cv. Quest, compared to the non-transgenic B. napus cv. Excel and B. rapa cv. Parkland. FEMS Microbiol. Ecol. 29: 263–272.Google Scholar
Sittenfeld, A., Espinoza, A. M., Muñoz, M., and Zamora, A. 2000. Costa Rica: challenges and opportunities in biotechnology-biodiversity. In Persley, G. J. and Lantin, M. M., eds. Proceedings of the International Conference, October 21-22, 1999. Washington: Consultative Group of International Agricultural Research. pp. 79–89.Google Scholar
Smartt, J. and Simmonds, N. W. 1995. Evolution of Crop Plants. 2nd ed. Harlow, U.K.: Longman. 531 p.Google Scholar
Snow, A. A. and Jorgensen, R. B. 1999. Fitness costs associated with transgenic glufosinate tolerance introgressed from Brassica napus ssp. olifera (oilseed rape) into weedy Brassica rapa . In Lutman, P.J.W., ed. Gene Flow and Agriculture: Relevance for Transgenic Crops. Farnham, U.K.: British Crop Protection Council. pp. 23–31.Google Scholar
Spahillari, M., Hammer, K., Gladis, T., and Diederichsen, A. 1999. Weeds as part of agrobiodiversity. Outlook Agric. 28: 227–232.Google Scholar
Squire, G. R., Crawford, J. W., Ramsay, G., Thompson, C., and Brown, J. 1999. Gene flow at the landscape level. In Lutman, P.J.W., ed. Gene Flow and Agriculture: Relevance for Transgenic Crops. Farnham, U.K.: British Crop Protection Council. pp. 57–72.Google Scholar
Strandberg, B., Kjellsson, G., and Lokke, H. 1998. Hierarchical risk assessment of transgenic plants: proposal for an integrated system. Biosafety Journal 4: Paper 2. Web page: http://bioline.bdt.org.br/by.Google Scholar
Sweet, J. B., Norris, C. E., Simpson, E., and Thomas, J. E. 1999. Assessing the impact and consequences of the release and commercialisation of genetically modified crops. In Lutman, P.J.W., ed. Gene Flow and Agriculture: Relevance for Transgenic Crops. Farnham, U.K.: British Crop Protection Council. pp. 241–246.Google Scholar
Theisen, G., Vidal, R. A., and Fleck, N. G. 1997. Ocorrencia de Resistencia Cruzada aos Herbicidas Inibidores de ALS em Picao-Preto. Resumos. XXI Congresso Brasileiro da Ciencia das Plantas Daninhas. Caxambu, MG, Brazil: Sociedade Brasileira da Ciência das Plantas Daninhas. p. 463.Google Scholar
Tiedje, J. M., Colwell, R. K., Grossman, Y. L., Hodson, R. E., Lenski, R. E., Mack, R. N., and Regal, P. J. 1989. The planned introduction of genetically engineered organisms: ecological considerations and recommendations. Ecology 70: 298–315.Google Scholar
Valdez, M., Cabrera-Ponce, J. L., Sudhakar, D., Herrera-Estrella, I., and Christou, P. 1998. Transgenic Central American, West African and Asian elite rice varieties resulting from particle bombardment of foreign DNA into mature seed-derived explants utilizing three different bombardment devices. Ann. Bot. 82: 795–801.Google Scholar
Valverde, B. E., Merayo, A., Reeder, R., and Riches, C. R. 1999. Integrated management of itchgrass (Rottboellia cochinchinensis) in maize in seasonally-dry Central America: facts and perspectives. Proc. Br. Crop Prot. Conf. Weeds 131–140.Google Scholar
Valverde, B. E., Riches, C. R., and Caseley, J. C. 2000. Prevention and Management of Herbicide Resistant Weeds in Rice: Experiences from Central America with Echinochloa colona . San José, Costa Rica: Cémara de Insumos Agropecuarios de Costa Rica. 123 p.Google Scholar
Vidal, R. A., Fleck, N. G., Theisen, G., Neves, R., and Petry, L. A. 1997. Picao-Preto e Leiteira Resistentes aos Inibidores de ALS nao Apresentam Resistencia aos Herbicidas com Diferentes Mecanismos de Acao. Resumos. XXI Congresso Brasileiro da Ciencia das Plantas Daninhas. Caxambu, MG, Brazil: Sociedade Brasileira da Ciência das Plantas Daninhas. p. 465.Google Scholar
Virgin, I. 1997. Field testing and commercialization of genetically modified plants in developing countries—biosafety aspects. Biosafety Journal 3: Paper 3. Web page: http://bioline.bdt.org.br/bioline/by.Google Scholar
Wang, R. L., Stec, A., Hey, J., Lukens, L., and Doebley, J. 1999. The limits of selection during maize domestication. Nature 398: 236–238.Google Scholar
Watanabe, Y. 1997. Phylogeny and geographical constitution of genus Oryza . In Matsuo, T., Futsuhara, Y., Kikuchi, F., and Yamaguchi, H., eds. Science of the Rice Plant. Tokyo: Food and Agriculture Policy Research Centre. pp. 29–39.Google Scholar
[WCMC] World Conservation Monitoring Centre. 1994. Priorities for Conserving Global Species Richness and Endemism. Caldecott, J. O., Jenkins, M. D., Johnson, T., and Groombridge, B., eds. Cambridge, U.K.: World Conservation Press. 36 p.Google Scholar
White, S. and Doebley, J. 1998. Of genes and genomes and the origin of maize. Trends Genet. 14: 327–332.Google Scholar
Wilkes, H. G. 1977. Hybridization of maize and teosinte, in Mexico and Guatemala and the improvement of maize. Econ. Bot. 31: 254–293.Google Scholar
0 Wilkes, G. 1993. Conservation of maize crop relatives in Guatemala. In Potter, C. S., Cohen, J. I., and Janczewski, D., eds. Perspectives on Biodiversity: Case Studies of Genetic Resource Conservation and Development. Washington: American Association for the Advancement of Science. pp. 75–88.Google Scholar
Willcox, M. and Bergvinson, D. 1997. Considerations for Bt corn in Mexico. In Hruska, A. J. and Lara Pavon, M., eds. Transgenic Plants in Mesoamerican Agriculture. Zamorano, Honduras: Zamorano Academic Press. pp. 98–104.Google Scholar
Witcombe, J. R. 1999. Does plant breeding lead to a loss of genetic diversity. In Wood, D. and Lenne, J. M., eds. Agrobiodiversity: Characterisation, Utilization and Management. Wallingford, U.K.: CABI Publishing. pp. 245–272.Google Scholar