2014 yel×cola

The F2 mapping population DM19 was developed from an initial cross of the homozygous recessive yellow leaf (yel yel) mutant as the maternal parent and the compressed lamina (cola cola) mutant as the pollen parent. The population consisted of 161 individuals.

The linkage map was constructed with JoinMap version 4.0. AFLP-, RAPD-, and dpRAPD-markers were scored in a dominant and SSR-markers in a co-dominant manner. The p-value was calculated after chi-square-test for all markers. Linked loci were grouped using a LOD thresholds from 2.0 to 10.0 in steps of 0.2 and recombination frequency lower than 0.4. The jump threshold was set to 5.0 and the third mapping round was carried out. The recombination frequencies were converted to mapping distances (in cM) using the Kosambi function.

In total, 319 markers were polymorphic between the parents of DM19 and were used for map construction. Nine major groups encompassing 285 markers were generated. The resulting carrot linkage map had a total length of 781 cM. The number of markers per LG ranged from 18 to 45. LG-1 was the largest LG with 145 cM, while LG-7 was the shortest with 66 cM. The average distance between two neighboring markers was 2.7 cM.