Comparative molecular mapping in Ceratotropis species using an interspecific cross between azuki bean (Vigna angularis) and rice bean (V-umbellata)

A genetic linkage map was developed with 86 F-2 plants derived from an inte rspecific cross between azuki bean (Vigna angularis, 2n=2x=22) and rice bea n (V. umbellata, 2n=2x=22). In total, 14 linkage groups, each containing mo re than 4 markers, were constructed with one phenotypic, 114 RFLP and 74 RA PD markers. The total map size was 1702 cM, and the average distance betwee n markers was 9.7 cM. The loci showing significant deviation from the expec ted ratio clustered in several linkage groups. Most of the skewed loci were due to the predominance of rice bean alleles. The azuki-rice bean linkage map was compared with other available maps of Vigna species in subgenus Cer atotropis. Based on the lineage of the common mapped markers, 7 and 16 cons erved linkage blocks were found in the interspecific map of azuki bean x V. nakashimae and mungbean map, respectively. Although the present map is not fully saturated, it may facilitate gene tagging, QTL mapping and further u seful gene transfer for azuki bean breeding.