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Cirad

Linkage disequilibrium among modern sugarcane cultivars

Jannoo N., Grivet L., Dookun A., D'Hont A., Glaszmann J.C.. 1999. In : Shearago International. The international conference on the status of plant and animal genome research : Workshop abstracts. New York : Scherago International, p. 70-70. numero_rapport: W173. Plant and Animal Genomes Conference. 7, 1999-01-17/1999-01-21, San Diego (Etats-Unis).

Modern sugarcane cultivars are derived from a few interspecific hybrids created early in this century. Linkage disequilibrium was investigated in a population of 59 cultivars representing the most important commercial clones bred in Mauritius as well as a few old cultivars involved in their genealogy. Thirty seven probes scattered over the sugarcane genome map were used to reveal RFLPs. Fourty two cases of bilocus associations were observed involving a total of 32 probes. Most of them involved loci separated by less than 10cM. All the corresponding allele couples were found in at least one of the first created cultivars suggesting that they depict ancient associations. This global disequilibrium is interpreted as the result of the foundation bottleneck related to the first interspecific crosses; the preferential allele associations thus created have been maintained through the subsequent crosses when the loci were closely linked. This phenomenon is likely to apply also to genes of agricultural interest. A practical consequence is that markers can be used to track known QTLs in modern breeding materials without the necessity to repeatedly study segregating progenies. Another perspective is the detection of additionnal QTLs by comparing molecular markers with agricultural traits among cultivars. (Texte intégral)

Mots-clés : saccharum; variété; carte génétique; rflp; maurice; qtl

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