2007 B493×QAL Ver3 B493

A genetic linkage map was constructed using a set of 159 F2 progeny from the cross between the wild (QAL) and the cultivated (line B493) carrot. Details concerning the production of the mapping population, plant cultivation, DNA extraction, and identification of AFLP, SCAR, SSR and gene specific markers were reported previously (Santos and Simon, 2002, 2004; Just, 2004).

Polymorphic DcMTD products were used to saturate the existing genetic linkage map of the F2 population QAL × B493 (Santos and Simon, 2002; Just, 2004). Separate maps were constructed for each parent to avoid problems related to the use of repulsion phase dominant markers, as described previously (Santos and Simon, 2004). This map corresponds to the B493 parent. The maps were constructed with MAPMAKER 3.0 (Lander et al., 1987). Dominant markers from a single parent linked in coupling were used in conjunction with all codominant markers. The ‘two point’ command was used to establish linkage groups at LOD=4.0. Three point analysis was then performed for each linkage group followed by the ‘order’ command. Remaining markers were added using the ‘try’ command. To test whether the mapped DcMTD markers were evenly distributed among the nine linkage groups, we used a χ² test for goodness of fit, where the expected number of markers per linkage group was estimated from the proportion of the linkage group length related to the total length of the corresponding map.