- V — Gestion Dynamique des Ressources Génétiques Dynamic Management of Genetic Resources
- Open access
- Published:
Gestions locales et dynamiques régionales de la diversité variétale du manioc en Amazonie
Local management and regional dynamics of varietal diversity of cassava in Amazonia
Genetics Selection Evolution volume 33, Article number: S465 (2001)
Résumé
- Le manioc constitue la base de l’alimentation de la très grande majorité des populations amazoniennes et leur principale culture. Selon les régions et les populations (amérindiennes, métissées ou d’immigration récente) cette culture s’accompagne d’une plus ou moins ample diversité variétale, de deux à trois variétés cultivées par parcelle à une trentaine. Les stratégies de conservation des ressources phytogénétiques doivent s’appuyer tant sur une meilleure compréhension des bases génétiques de cette diversité que sur les conditions de production ou de maintien de celle-ci. La recherche comparative menée associe des approches génétique, écologique, ethnobiologique et socio-anthropologique et s’attache à expliciter les liens entre diversité variétale, pratiques agricoles et représentations associées, et environnement socio-économique. Les analyses génétiques soulignent un important polymorphisme inter et intravariétal. Les résultats montrent aussi la spécificité de chaque groupe culturel quant à la valeur accordée aux variétés, aux modalités de circulation des boutures et à la place donnée aux maniocs issus de graines. Des dynamiques plus globales jouent aussi sur la diversité variétale (commercialisation croissante de farine, changements d’habitudes alimentaires, politiques agricoles). Elles tendent à réduire le nombre de variétés cultivées et à modifier la structure de cette diversité. Les résultats plaident en faveur de la constitution de pôles régionaux de conservation, qui pourraient prendre le relais des structures centralisées actuelles ou les compléter.
Abstract
Cassava is the staple food crop of the great majority of Amazonian populations. Depending on the region and on the type of population (Amerindians, mixed, or recent immigrants), a more or less high diversity of manioc varieties are grown, ranging from two to three varieties per farm to 30 or more. Strategies for conserving genetic resources of manioc must be based on firm understanding of the genetic base of this diversity and on how this diversity is produced and maintained. The comparative research we have conducted incorporates genetic, ecological, ethnobiological and social-anthropological approaches, and aims to elucidate the causal links between varietal diversity, agricultural practices and associated representations, and socio-economic environment. Genetic analyses have demonstrated a high degree of polymorphism, both within and among varieties. Results of ethnobiological studies have also shown that cultural groups vary in the value attached to varietal diversity, as revealed both in the patterns of circulation of propagation material (stem cuttings) and the place given to manioc originating from spontaneous seedlings. In addition to these factors affecting local dynamics, more global dynamics - increasing commercialisation of flour, changing food habits, and changing agricultural policies - also affect varietal diversity. These factors tend to reduce the number of varieties cultivated and to modify the structure of diversity. Our results suggest the utility of developing regional poles of conservation, which can extend or complement the centralised structures now in place.
References
Balée W., Qui a planté les décors de l’Amazonie ? La Recherche 333 (2000) 18–23.
Bellon M.R., Brush S.B., Keepers of maize in Chiapas, Mexico, Econom. Bot., 48 (1994) 196–209.
Brush S.B., Ethnoecology, biodiversity and modernization in Andean potato agriculture, J. Ethnobiol. 12 (1992) 161–185.
Brush S.B., In situ conservation of landraces in centers of crop diversity, Crop Sci. 35 (1995) 346–354.
Bureau des Ressources Génétiques, Complexes d’espèces, flux de gènes, et ressources génétiques des plantes, Publications du Bureau des ressources génétiques, Paris, 1992.
Chakraborty R., Jin L., A unified approach to study hypervariable polymorphisms: statistical considerations of determining relatedness and population distances, in: Pena S.D.J, Chakraborty R.,. Epplen J.T., Jeffreys A.J., (eds.), DNA Fingerprinting: State of the Science, Springer-Verlag, Basel, 1993. pp. 153–175.
Chiwona-Karltun L., Mkumbira J., Saka J., Bovin M., Mahungu N.M., Rosling H., The importance of being bitter - a qualitative study on cassava cultivar preference in Malawi, Ecol. Food Nutr. 10 (1998) 1–27.
Colombo C, Étude de la diversité génétique de maniocs américains (Manihot esculenta Crantz) par les marqueurs moléculaires (RAPD et AFLP), Thèse de Doctorat, Ensam, Montpellier, 1997.
Dagnélie P., Analyses statistiques à plusieurs variables, Les presses Agronomiques de Gembloux, Belgique, 1975.
Elias M., McKey D., The unmanaged reproductive ecology of domesticated plants in traditional agroecosystems: an example involving cassava and a call for data, Acta cecol. 21 (2000), 223–230.
Elias M., McKey D., Panaud O., Anstett, M.C., Robert, T., Traditional management of cassava morphological and genetic diversity by the Makushi Amerindians (Guyana, South America): perspectives for on-farm conservation of crop genetic resources, Euphytica (2000), sous presse.
Elias M., Panaud O., Robert T., Assessment of genetic variability in a traditional cassava (Manihot esculenta Crantz) farming system using AFLP markers, Heredity 85 (2000), 219–230.
Emperaire L., Elementos de discussão sobre la conservaçao da agrobiodiver-sidade: o exemplo da mandioca (Manihot esculenta Crantz) na Amazonia brasileira, in: Instituto Socioambiental (org.) Atas do seminario Avaliação e iden-tificaçâodas açoes prioritarias para a conservaçao, o uso sustentável e repartiçâo dos beneficios da biodiversidade da Amazonia brasileira, Macapá, Amapá, Brasil, 20–25.de setembro 1999.
Emperaire L., Pinton F., Second G., Gestion dynamique de la diversité variétale du manioc (Manihot esculenta) en Amazonie du Nord-Ouest, Nat. Sci. Soc. 6 (1998) 27–42.
Fresco L., Cassava in Shifting Cultivation: A Systems Approach to Agricultural Technology Development in Africa, Royal Tropical Institute, Amsterdam, Netherlands, 1986.
Hahn S.K., Keyser J., Cassava: a basic food of Africa, Outlook on Agriculture, 14 (1985) 95–99.
Hamilton M.B., Ex situ conservation of wild plant species: time to reassess the genetic assumptions and implications of seed banks, Conservation Biol. 8 (1994) 39–49.
Herren H.R., Neuenschwander P., Biological control of cassava pests in Africa, Annu. Rev. Entomol. 36 (1991) 257–283.
Jennings D.L., Cassava in Africa, Field Crop Abstr. 23 (1970) 271–278.
Lefèvre, F, Charrier A., Isozyme diversity within African Manihot germplasm, Euphytica 66 (1993) 73–80.
Louette D., Charrier A., Berthaud J., In situ conservation of maize in Mexico: genetic diversity and maize seed management in a traditional community, Econom. Bot. 51 (1997) 20–38.
Lozano J.C., Nolt B.L., Pests and pathogens of cassava, in: Kahn R.P. (ed.), Plant Protection and Quarantine, Vol. II. Selected Pests and Pathogens of Quarantine Significance, CRC Press, Boca Raton, Florida, USA, 1989. pp. 169–182.
McKey D.B., Beckerman S., Chemical ecology, plant evolution and traditional cassava cultivation systems, in: Hladik C.M., Hladik A., Pagezy H., Linares O.F., Koppert G.J.A., Froment A. (eds.) Tropical Forests, People and Food, UNESCO, Paris, 1993. pp. 83–112.
Miller K., Allegretti M.H., Johnson N., Johnson B., Measures for conservation of biodiversity and sustainable use of its components, in: Heywood V.H. (ed.), Global Biodiversity Assessment, United Nations Environment Programme, Cambridge University Press, Cambridge, 1995.
Nassar N.M.A, Vieira M.A., Vieira C, Grattapaglia D., A molecular and embryonic study of apomixis in cassava (Manihot esculenta Crantz), Euphytica 102 (1998) 9–13.
Nei M., Li W., Mathematical model for studying genetic variations in terms of restriction endonucleases, Proc. Natl. Acad. Sci., USA 76 (1979) 5269–5273.
Nordenskiöld E., The Ethnography of South America Seen from Mojos in Bolivia, Comparative Ethnological Studies 3, Gothenburg, 1924.
Pickersgill, B., Crop introductions and the development of secondary areas of diversity, in: Prendergast H.D.V., Etkin N.L., Harris D.R., Houghton P.J. (eds.), Plants for Food and Medicine, Royal Botanic Gardens, Kew, UK, 1998. pp. 93–105.
Pinton F., Emperaire L., Le manioc en Amazonie brésilienne: diversité variétale et marché, ce volume.
Renvoize S.A., The area of origin of Manihot esculenta as a crop plant - a review of the evidence, Econom. Bot. 26 (1972) 352–360.
Second G., Costa Allem A., Emperaire L., Ingram C, Colombo C, Mendes R.A., Carvalho L.J.C.B., AFLP based Manihot and cassava numerical taxonomy and genetic structure analysis in progress. Implications for dynamic conservation and genetic mapping. Afr. J. Root Tuber Crops 2 (1997) 10–17.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.
About this article
Cite this article
McKey, D., Emperalre, L., Élias, M. et al. Gestions locales et dynamiques régionales de la diversité variétale du manioc en Amazonie. Genet Sel Evol 33 (Suppl 1), S465 (2001). https://doi.org/10.1186/BF03500895
Published:
DOI: https://doi.org/10.1186/BF03500895