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Electronic Journal of Biotechnology
Universidad Católica de Valparaíso
ISSN: 0717-3458
Vol. 1, No. 3, 1998, pp. 103-117
Bioline Code: ej98015
Full paper language: English
Document type: Review Article
Document available free of charge

Electronic Journal of Biotechnology, Vol. 1, No. 3, 1998, pp. 103-117

 en Medium-term and long-term in vitro conservation and safe international exchange of yam ( Dioscorea check for this species in other resources spp.) germplasm
Malaurie, Bernard; Trouslot, Marie-France; Berthaud, Julien; Bousalem, Mustapha; Pine, Agnès & Dubern, Jean

Abstract

Yam edible tubers feed million of peoples in the intertropical area, where they represent 12% of human feeding. However, as a vegetatively propagated crop, yam is seriously affected by an accumulation of pathogens. Establishing in vitro germplasm collection is a process that cleans the plants from all diseases but viruses. It gives a good control on the preservation of the yam genetic resources and facilitates international exchanges of healthy plant material.

Two kinds of in vitro germplasm preservation were considered : slow growth condition culture for mid-term preservation, and cryopreservation using the encapsulation/dehydration technique for long-term preservation. Virus eradication was approached by meristem culture and chemo and thermotherapy. Production of virus-free plants was controlled by ELISA.

We succeeded in the introduction and maintenance of 20 yam species, under slow growth conditions. Cryopreservation was applied successfully on two edible yam species, Dioscorea. alata L and D. bulbifera L. Virus-free plants were obtained by meristem culture in D. cayenensis-D. rotundata complex and D. praehensilis. Indexation allowed the detection of different virus (poty-, potex-, badna- and cucumovirus), where the most important potyvirus was YMV.

Mid-term conservation of yam germplasm is used routinely, and from these conditions a direct acclimatization is possible. On the cryopreservation aspect, experiments are under way to apply the optimized protocol to genotypes which are more representative of the diversity, to insure a routinely use. More work can be conducted now on virus eradication, based on knowledge accumulated on potyvirus diversity, on several tests available for yam indexing (ELISA, rt/PCR, monoclonal antibodies) and on new sanitation techniques.

Keywords
Active and base in vitro genebanks', Chemotherapy, Cryopreservation, Disease-free techniques, Indexation techniques, Slow growth condition culture, Virus eradication, Yam viruses.

 
© 1998 by Universidad Católica de Valparaíso -- Chile
Alternative site location: http://www.ejbiotechnology.info

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