Construction of an integrated map and location of a bruchid resistance gene in mung bean

Bruchid beetle (Callosobruchus chinensis) poses a serious threat to the production and storage of mung bean (Vigna radiata). Mapping bruchid resistance (Br) will provide an important basis for cloning the responsible gene(s) and elucidating its functional mechanism, and will also facilitate marker-assisted selection in mung bean breeding. Here, we report the construction of the genetic linkage groups of mung bean and mapping of the Br1 locus using an RIL population derived from a cross between Berken, a bruchid-susceptible line, and ACC41, a bruchid-resistant line. A total of 560 markers were mapped onto 11 linkage groups, with 38.0% of the markers showing distorted segregation. The lengths of the linkage groups ranged from 45.2 to 117.0 cM with a total coverage of 732.9 cM and an average interval of 1.3 cM between loci. Br1 was located on LG9 between BM202 (0.7 cM) and Vr2-627 (1.7 cM). Based on 270 shared SSR markers, most of the linkage groups were assigned to specific chromosomes. These results should further accelerate the genetic study of this crop.