16.marker.37-38

A genetic linkage map was constructed using a subset of 103 individuals from a previous F2 mapping population derived from the cross between the white-root wild carrot Queen Annes Lace (QAL) and the cultivated orange-root carrot inbred line B493. Details concerning the development of the mapping population, plant cultivation, DNA extraction, and detection/scoring of previously mapped AFLP, SCAR, DcMTD (DcMaster Transposon Display), and gene specific markers were described before [5, 8, 9, 52]. Separate maps were constructed for each parent to avoid problems related to the use of repulsion phase dominant markers, as described previously [52]. This map corresponds to the B493 parent. Dominant markers from a single parent linked in coupling were used in conjunction with all codominant markers. Linkage maps were constructed with MapMaker/EXP 3.0 [54], where markers were associated with the ‘group’ command at LOD = 4.0 and a maximum recombination frequency of 0.30. Markers within a group were ordered using ‘three point’ analysis followed by the ‘order’ command. Remaining markers were located using the ‘try’ command, and the map order was re-tested using the ‘ripple’ command. Recombination frequencies were converted to centimorgans (cM) using the Kosambi function.