Niger-wide assessment of in situ sorghum genetic diversity with microsatellite markers

Deu, M and Sagnard, F and Chantereau, J and Calatayud, C and Hérault, D and Mariac, C and Pham, J L and Vigouroux, Y and Kapran, I and Traore, P C S and Mamadou, A and Gerard, B and Ndjeunga, J and Bezançon, G (2008) Niger-wide assessment of in situ sorghum genetic diversity with microsatellite markers. Theoretical and Applied Genetics, 116 (7). pp. 903-913. ISSN 0040-5752

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Abstract

Understanding the geographical, environmental and social patterns of genetic diversity on different spatial scales is key to the sustainable in situ management of genetic resources. However, few surveys have been conducted on crop genetic diversity using exhaustive in situ germplasm collections on a country scale and such data are missing for sorghum in sub-Saharan Africa, its centre of origin. We report here a genetic analysis of 484 sorghum varieties collected in 79 villages evenly distributed across Niger, using 28 microsatellite markers. We found a high level of SSR diversity in Niger. Diversity varied between eastern and western Niger, and allelic richness was lower in the eastern part of the country. Genetic differentiation between botanical races was the first structuring factor (Fst=0.19), but the geographical distribution and the ethnic group to which farmers belonged were also significantly associated with genetic diversity partitioning. Gene pools are poorly differentiated among climatic zones. The geographical situation of Niger, where typical western African (guinea), central African (caudatum) and eastern Sahelian African (durra) sorghum races converge, explained the high observed genetic diversity and was responsible for the interactions among the ethnic, geographical and botanical structure revealed in our study. After correcting for the structure of botanical races, spatial correlation of genetic diversity was still detected within 100 km, which may hint at limited seed exchanges between farmers. Sorghum domestication history, in relation to the spatial organization of human societies, is therefore key information for sorghum in situ conservation programs in sub-Saharan Africa

Item Type:	Article
Divisions:	UNSPECIFIED
CRP:	UNSPECIFIED
Subjects:	Mandate crops > Sorghum
Depositing User:	Ms K Syamalamba
Date Deposited:	04 Nov 2011 09:17
Last Modified:	07 Sep 2017 05:08
URI:	http://oar.icrisat.org/id/eprint/3643
Official URL:	http://dx.doi.org/10.1007/s00122-008-0721-7
Projects:	UNSPECIFIED
Funders:	Institut Francais de la Biodiversite
Acknowledgement:	We thank the different people who took part in the 2003 sampling operation, and particularly Djibo Moussa, Moussa Tidjani and H. Yahaya Bissala. We are also grateful to Claire Billot and the Montpellier Languedoc-Roussillon Genopole platform for technical assistance. This work was supported by Institut Franc¸ais de la Biodiversite´ (IFB). We thank Seydou B. Traore´ (AGRHYMET) for providing access to 1971–2000 yearly rainfall normals
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