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Posted 6:15 AM by Luigi

The importance of cassava seeds

The unappreciated ecology of landrace populations: Conservation consequences of soil seed banks in cassava

by Benoît Pujola, François Renouxc, Marianne Eliasd, Laura Rivale and Doyle Mckey

Biological Conservation

Abstract. Failure to take into account the ecological complexity of landrace populations of crop plants limits our ability to conserve their genetic resources in situ. Soil seed banks are a central feature of the ecology of landrace populations of cassava; their existence has consequences for conservation. Seedlings recruited from seed banks are incorporated by farmers into their stocks of clones of this vegetatively propagated crop, transforming pure clonality into a mixed clonal/sexual reproductive system. Soil seed banks, and farmers’ responses to them, play an important role in maintaining diversity in populations of cassava landraces. In a study combining genetic and ethnobiological approaches, we showed the following: (i) Recruitment from soil seed banks increased diversity of populations at the local scale. At the level of a field, the presence of plants issued from seeds resulted in significantly greater diversity of genotypes and phenotypes than if only individuals planted by farmers had been present. (ii) Farmers’ use of seed banks has enabled indirect ‘exchange’ of locally adapted cassava germplasm between cultural groups, without requiring that groups actually encountered one another and engaged in social exchange of cultivars. (iii) Farmers have responded to catastrophic crop failure by using seed banks to regenerate stocks of clones. This use of seed banks should enable cassava populations to respond to disasters by an increase of genetic diversity, rather than by a narrowing of the genetic base, often feared in such situations.



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This weblog documents the activities of Pacific Agricultural Genetic Resources Network (PAPGREN), along with other information on plant genetic resources (PGR) in the Pacific. The myriad varieties found within cultivated plants are fundamental to the present and future productivity of agriculture. PAPGREN, which is coordinated by the Land Resources Division of the Secretariat of the Pacific Community (SPC), helps Pacific countries and territories to conserve their crop genetic diversity sustainably, with technical assistance from the Bioversity International (BI) and support from NZAID and ACIAR. SPC also hosts the Centre of Pacific Crops and Trees (CEPaCT). The CEPaCT maintains regional in vitro collections of crops important to the Pacific and carries out research on tissue culture technology. The CEPaCT Adviser is Dr Mary Taylor (MaryT@spc.int), the CEPaCT Curator is Ms Valerie Tuia (ValerieT@spc.int). PAPGREN coordination and support IPGRI ACIAR NZAID CTA SPC PAPGREN CEPaCT Click on the thumbnail to see a map of the locations of Pacific genebanks. Click here to download a regional directory of genebanks in the Pacific, including information on their location, contact details and holdings. PAPGREN partners Mr William Wigmore Director of Research Ministry of Agriculture Department of Resources & Development P.O. Box 96 Rarotonga Cook Islands Tel: (682) 28711-29720 Fax: (682) 21881 Email: cimoa@oyster.net.ck Mr Adelino S. Lorens Chief Agriculture Pohnpei Office of Economic Affairs P.O. Box 1028 Kolonia Pohnpei 96941 Federated States of Micronesia Tel: (691) 3202400 Fax: (691) 3202127 Email: pniagriculture@mail.fm Dr Lois Englberger Island Food Community of Pohnpei Research Advisor P.O. Box 2299 Kolonia Pohnpei 96941 Federated States of Micronesia Email: nutrition@mail.fm Mr Apisai Ucuboi Director of Research Ministry of Agriculture, Fisheries & Forest Koronivia Research Station P.O. 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DIVA-GIS	Friday, February 23, 2007 Posted 6:15 AM by Luigi The importance of cassava seeds The unappreciated ecology of landrace populations: Conservation consequences of soil seed banks in cassava by Benoît Pujola, François Renouxc, Marianne Eliasd, Laura Rivale and Doyle Mckey Biological Conservation Abstract. Failure to take into account the ecological complexity of landrace populations of crop plants limits our ability to conserve their genetic resources in situ. Soil seed banks are a central feature of the ecology of landrace populations of cassava; their existence has consequences for conservation. Seedlings recruited from seed banks are incorporated by farmers into their stocks of clones of this vegetatively propagated crop, transforming pure clonality into a mixed clonal/sexual reproductive system. Soil seed banks, and farmers’ responses to them, play an important role in maintaining diversity in populations of cassava landraces. In a study combining genetic and ethnobiological approaches, we showed the following: (i) Recruitment from soil seed banks increased diversity of populations at the local scale. At the level of a field, the presence of plants issued from seeds resulted in significantly greater diversity of genotypes and phenotypes than if only individuals planted by farmers had been present. (ii) Farmers’ use of seed banks has enabled indirect ‘exchange’ of locally adapted cassava germplasm between cultural groups, without requiring that groups actually encountered one another and engaged in social exchange of cultivars. (iii) Farmers have responded to catastrophic crop failure by using seed banks to regenerate stocks of clones. This use of seed banks should enable cassava populations to respond to disasters by an increase of genetic diversity, rather than by a narrowing of the genetic base, often feared in such situations. * Comments: Post a Comment	Archive October 2002 November 2002 December 2002 January 2003 February 2003 March 2003 April 2003 May 2003 June 2003 July 2003 August 2003 September 2003 October 2003 November 2003 December 2003 January 2004 February 2004 March 2004 April 2004 May 2004 June 2004 July 2004 August 2004 September 2004 October 2004 November 2004 December 2004 January 2005 February 2005 March 2005 April 2005 May 2005 June 2005 July 2005 August 2005 September 2005 October 2005 November 2005 December 2005 January 2006 February 2006 March 2006 April 2006 May 2006 June 2006 July 2006 August 2006 September 2006 October 2006 November 2006 December 2006 January 2007 February 2007 March 2007 April 2007 May 2007 June 2007 July 2007 August 2007 September 2007 October 2007 November 2007 December 2007 January 2008 February 2008 March 2008 April 2008 May 2008 June 2008 July 2008 August 2008 September 2008 October 2008 November 2008 December 2008 January 2009 February 2009 March 2009 April 2009 May 2009 June 2009 July 2009 August 2009 September 2009 October 2009 November 2009 January 2010 RSS Feed Alternative feed Contact Tevita Something new: Agrobiodiversity Weblog: For discussions of conservation and sustainable use of the genetic resources of crops, livestock and their wild relatives. 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