“…For example, between the two adjacent markers InDel1 and InDel2, the ratio was 31.6 kb/cM, but the ratio was only 0.68 kb/cM between InDel2 and InDel3. This phenomenon was also observed in other plants, such as barley, where long genetic distances translated into short physical distances, and vice versa , and that was thought to be related to different frequencies of recombination events at different chromosome regions ( Bustamante et al, 2017 ). However, based on our results, it is hard to clarify whether there exists unequal distribution of recombination frequency along the linkage group, because the limitation of mapping population size and marker number used for map construction may influence the uniformity of marker distribution, thus affecting the ratio of physical to genetic distance.…”