Patterns and dynamics of genetic diversity in Sorghum
Background. Sorghum, the fourth cereal worldwide, was domesticated in Sub-Saharan Africa and is now cultivated on most continents. There are large ex situ collections and many breeding programs. Understanding the patterns of genetic diversity is essential for its conservation and use. Methods. Various projects conducted at CIRAD with INERA and ICRISAT analysed molecular variation at various geographical scales (field, village, region, country, continent), sometimes including temporal variation, using various marker systems. Results. Global assessment of ex situ germplasm collections enabled development of representative samples for association studies. Diversity was highest in the area of origin, with a level of linkage disequilibrium confined to genome segments within the Mb range. Yet certain genes involved in cereal grain quality revealed cases of novel alleles that appeared during geographical radiation, likely selected by the action of the farmers. Studies in Cameroon and Niger villages highlighted the tremendous diversity maintained in traditional agroecosystems, reflecting specific practices of seed exchange in relation to social structure. Conclusion. Crop genetic diversity illustrates intimate association with human populations, their history, practices and needs, to be taken into account for breeding strategies.
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| Format: | conference_item biblioteca |
| Language: | eng |
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s.n.
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| Subjects: | F30 - Génétique et amélioration des plantes, F70 - Taxonomie végétale et phytogéographie, |
| Online Access: | http://agritrop.cirad.fr/569892/ http://agritrop.cirad.fr/569892/1/document_569892.pdf |
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