Local scale patterns of gene flow and genetic diversity in a crop–wild–weedy complex of sorghum (Sorghum bicolor (L.) Moench) under traditional agricultural field conditions in Kenya

Mutegi, E and Sagnard, F and Labuschagne, M and Herselman, L and Semagn, K and Deu, M and Villiers, S de and Kanyenji, B M and Mwongera, C N and Traore, P C S and Kiambi, D (2012) Local scale patterns of gene flow and genetic diversity in a crop–wild–weedy complex of sorghum (Sorghum bicolor (L.) Moench) under traditional agricultural field conditions in Kenya. Conservation Genetics, 13 (4). 1059-1071 . ISSN 1566-0621

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Abstract

Little information is available on the extent and patterns of gene flow and genetic diversity between cultivated sorghum and its wild related taxa under local agricultural conditions in Africa. As well as expanding knowledge on the evolutionary and domestication processes for sorghum, such information also has importance in biosafety, conservation and breeding programmes. Here, we examined the magnitude and dynamics of crop–wild gene flow and genetic variability in a crop–wild–weedy complex of sorghum under traditional farming in Meru South district, Kenya. We genotyped 110 cultivated sorghum, and 373 wild sorghum individuals using a panel of ten polymorphic microsatellite loci. We combined traditional measures of genetic diversity and differentiation with admixture analysis, population assignment, and analyses of spatial genetic structure to assess the extent and patterns of gene flow and diversity between cultivated and wild sorghum. Our results indicate that gene flow is asymmetric with higher rates from crop to wild forms than vice versa. Surprisingly, our data suggests that the two congeners have retained substantial genetic distinctness in the face of gene flow. Nevertheless, we found no significant differences in genetic diversity measures between them. Our study also did not find evidence of isolation by distance in cultivated or wild sorghum, which suggests that gene dispersal in the two conspecifics is not limited by geographic distance. Overall our study highlights likely escape and dispersal of transgenes within the sorghum crop–wild–weedy complex if genetically engineered varieties were to be introduced in Africa’s traditional farming systems

Item Type: Article
Divisions: UNSPECIFIED
CRPS: UNSPECIFIED
Uncontrolled Keywords: Gene flow; Natural introgression; Hybridization; Genetic diversity; Sorghum bicolor; Traditional agro-ecosystem
Subjects: Mandate crops > Sorghum
Depositing User: Ms K Syamalamba
Date Deposited: 23 Jan 2013 08:50
Last Modified: 07 Feb 2014 05:13
URI: http://oar.icrisat.org/id/eprint/6455
Official URL: http://dx.doi.org/10.1007/s10592-012-0353-y
Projects: Environmental Risk Assessment of Genetically Engineered Sorghum in Mali and Kenya
Funders: USAID Biotechnology and Biodiversity Interface (BBI) and Plant Biosafety Systems (PBS)
Acknowledgement: UNSPECIFIED
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