Integration of a molecular linkage group containing the broomrape resistance gene Or5 into an RFLP map in sunflower

Abstract

A linkage group containing the Or5 gene conferring resistance to Orobanche cumana race E, as well as 5 SCAR markers and 1 RAPD marker has been recently identified in sunflower. A SCAR marker RTS05, mapped 5.6 cM proximal to the Or5 locus, was analysed in an F2 population for which the segregation data of 80 RFLP markers (GIE cartisol - Phase II, France) were available. An association was found between the SCAR marker RTS05 and an RFLP marker S009 (32.1 cM, LOD = 4.7) that had been mapped to the linkage group 17 of the GIE Cartisol RFLP map. Another RFLP marker S010, tightly linked to S009 (0.0 cM) in the same linkage group, was screened in the F2 population that had been previously used for the Or5 linkage map identification. S010 was found to be significantly linked to all 5 SCAR markers as well as to the single RAPD marker with a LOD > 3.0 in each case. This RFLP marker was mapped between two SCAR markers and was situated at 35.1 cM from the resistance gene with a LOD = 2.7. These results showed that the Or5 linkage group could be integrated with the linkage group 17 of the GIE Cartisol RFLP map.Key words: Helianthus, Orobanche, RFLP, SCAR, linkage map.