Biodiversity and domestication of yams in West Africa: traditional practices leading to Dioscorea rotundata Poir.

Manley David, Dumont Roland, Dansi Alexandre, Vernier Philippe, Zoundjihekpon Jeanne. 2006. Biodiversity and domestication of yams in West Africa: traditional practices leading to Dioscorea rotundata Poir.. Montpellier : CIRAD-IPGRI, 95 p. (Update sciences et technologies) ISBN 2-87614-632-0 ; 92-9043-704-9

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Résumé : The domestication of wild yams is still common practice in West Africa. It also offers one of the few remaining opportunities to understand how farmers use their empirical knowledge to tap the genetic resources of wild plants and create products suitable for agriculture. Yam agronomist and breeders have, until recently, focused little attention on this process of organizing and generating agrobiodiversity. This book aims to fill the gap by pooling existing knowledge on the subject. This original field offers a wealth of prospects for scientific progress at a time when scientists are becoming increasingly aware of the fact that local farmer's knowledge and practices relating to genetic resource management substantially enhances the potentials for technical progress and adaptation to environmental change. The focus is deliberately only on domestication leading to Dioscorea rotundata yams, the type most widely cultivated in West Africa. Several chapteres are devoted the biodiversity of Dioscorea rotundata yams and the wild forms from which they derive.The authors conclude by putting forward hypthoseses to explain the phenotype transformations induced by domestication practices and their maintenance by vegetative propagation. Futher research, especially by geneticists, is needed to confirm these hypotheses. Some are already being assessed, using the most advanced molecular marker analysist techniques, by joint teams of scientists from developed and developing countries. Contents: Acknowledgements. Foreword. Introduction. The Dioscorea rotundata Poir. yam: Botanical aspects; Geographical distribution; Botanical origins of Dioscorea rotundata; Organization of diversity in Dioscorea rotundata (Yam diversity on African farms; State of the scientific knowledge; Morphological and physiological diversity; Genetic diversity; Chemical diversity; Cooking quality; Sexual features; Cultivation requirements; Intrinsic productivity of the plant material; Market adaptation). Wild yams Dioscorea praehensilis Benth and Dioscorea abyssinica Hochst ex Kunth: General; Dioscorea praehensilis; Dioscorea abyssinica; Addendum: Dioscorea togoensis Knuth. Phenomena that could explain the variability of wildand domesticated yams: Climatic disturbance; Anthropogenic pressure; Reciprocal gene flow between wild and cultivated yams; Effects of periodic fallows; Variations in genome expression; Mutation; Ploidization. Domestication leading to Dioscorea rotundata: Definitions and general aspects; Rationales and limits of domestication (Significance and importance of domestication for farmers; Framework of domestication). Cultivation techniques used to transform wild yams into double-harvest Dioscorea rotundata yams: General; Domestication process and effects; Thoughts on domestication leading to double-harvest Dioscorea rotundata yams. Conclusion. Glossary of technical terms. References

Mots-clés Agrovoc : variation génétique, pratique culturale, Dioscorea rotundata, Dioscorea, biodiversité, domestication, igname, botanique, distribution géographique, espèce

Mots-clés géographiques Agrovoc : Afrique occidentale

Classification Agris : F30 - Génétique et amélioration des plantes
F01 - Culture des plantes

Champ stratégique Cirad : Axe 1 (2005-2013) - Intensification écologique

Editeurs scientifiques et affiliations