Studies of genetic variation at the DNA level in the genus Daucus have been very limited. Molecular markers based on restriction fragment length polymorphism (RPLP) have been shown to be highly useful and efficient gene markers in other plant species.
We have used a total of 20 carrot types (inbreds, varieties, species) for this study. Genomic DNA probes cloned in pGEM (Promega) plasmid of Escherichia coli were hybridized to DNA of these types digested with EcoRI and HindIII restriction enzymes. Based on 50 probe-enzyme combinations we have found RFLP variation to be extensive in Daucus, even among related cultivated genetic stocks. The implications of these results in the germplasm diversity in Daucus will be discussed.
Also, a genetic linkage map of carrot will be constructed. The map will be used to determine the genomic regions conditioning traits like root and core diameter, root length, and nematode resistance.