Development of an interspecific <i>Vigna</i> linkage map between <i>Vigna umbellata</i> (Thunb.) Ohwi & Ohashi and <i>V. nakashimae</i> (Ohwi) Ohwi & Ohashi and its use in analysis of bruchid resistance and comparative genomics

<jats:title>Abstract</jats:title><jats:p>To facilitate transfer of bruchid resistance to azuki bean (<jats:italic>Vigna angularis</jats:italic>) from its relatives an interspecific mapping population was made between rice bean, <jats:italic>V. umbellata</jats:italic>, and the related wild species <jats:italic>V. nakashimae</jats:italic>. The <jats:italic>V. umbellata</jats:italic> parent is completely resistant and <jats:italic>V. nakashimae</jats:italic> is completely susceptible to the bruchid beetle pests, azuki bean weevil (<jats:italic>Callosobruchus chinensis</jats:italic>) and cowpea weevil (<jats:italic>C. maculatus</jats:italic>). There is very low cross compatibility between <jats:italic>V. umbellata</jats:italic> and azuki bean. Therefore, <jats:italic>V. nakashimae</jats:italic>, that crosses with both <jats:italic>V. umbellata</jats:italic> and <jats:italic>V. angularis</jats:italic> without the need for embryo rescue, is used as a bridging species. A genetic linkage map was constructed based on an interspecific F<jats:sub>2</jats:sub> mapping population between <jats:italic>V. umbellata</jats:italic> and <jats:italic>V. nakashimae</jats:italic> consisting of 74 plants. A total of 175 DNA marker loci (74 RFLPs and 101 SSRs) were mapped on to 11 linkage groups spanning a total length of 652 cM. Segregation distortion was observed but only three markers were not linked to any linkage group due to severe segregation distortion. This interspecific genome map was compared with the genome map of azuki bean. Of 121 common markers on the two maps, 114 (94.2%) were located on the same linkage groups in both maps. The marker order was highly conserved between the two genome maps. Fifty F<jats:sub>2</jats:sub> plants that produced sufficient seeds were used for quantitative trait locus (QTL) analysis and locating gene(s) for <jats:italic>C. chinensis</jats:italic> and <jats:italic>C. maculatus</jats:italic> resistance in <jats:italic>V. umbellata</jats:italic>. The resistance reaction of these F<jats:sub>2</jats:sub> plants differed between <jats:italic>C. chinensis</jats:italic> and <jats:italic>C. maculatus</jats:italic>. Both resistances were quantitatively inherited with no F<jats:sub>2</jats:sub> plants completely susceptible to <jats:italic>C. chinensis</jats:italic> or <jats:italic>C. maculatus</jats:italic>. One putative QTL for resistance to each of these bruchid species was located on different linkage groups. Other putative QTLs associated with resistance to both <jats:italic>C. chinensis</jats:italic> and <jats:italic>C. maculatus</jats:italic> were localized on the same linkage group 1. Linked markers associated with the bruchid‐resistant QTL will facilitate their transfer to azuki bean breeding lines.</jats:p>