Genetic Dissection of Azuki Bean Weevil (Callosobruchus chinensis L.) Resistance in Moth Bean (Vigna aconitifolia [Jaqc.] Maréchal)

Abstract

The azuki bean weevil (<i>Callosobruchus</i> <i>chinensis</i> L.) is an insect pest responsible for serious postharvest seed loss in leguminous crops. In this study, we performed quantitative trait locus (QTL) mapping of seed resistance to <i>C.</i> <i>chinensis</i> in moth bean (<i>Vigna</i> <i>aconitifolia</i> [Jaqc.] Maréchal). An F₂ population of 188 plants developed by crossing resistant accession 'TN67' (wild type from India; male parent) and susceptible accession 'IPCMO056' (cultivated type from India; female parent) was used for mapping. Seeds of the F₂ population from 2014 and F_2:₃ populations from 2016 and 2017 were bioassayed with <i>C.</i> <i>chinensis</i>, and the percentage of damaged seeds and progress of infestation severity were measured. Segregation analysis suggested that <i>C.</i> <i>chinensis</i> resistance in TN176 is controlled by a single dominant gene, designated as <i>Rcc</i>. QTL analysis revealed one principal and one modifying QTL for the resistance, named <i>qVacBrc</i><i>2.1</i> and <i>qVacBrc5.1</i>, respectively. <i>qVacBrc</i><i>2.1</i> was located on linkage group 2 between simple sequence repeat markers CEDG261 and DMB-SSR160 and accounted for 50.41% to 64.23% of resistance-related traits, depending on the trait and population. Comparative genomic analysis suggested that <i>qVacBrc</i><i>2.1</i> is the same as QTL <i>Brc2.1</i> conferring <i>C.</i> <i>chinensis</i> resistance in wild azuki bean (<i>V</i><i>.</i> <i>nepalensis</i> Tateishi and Maxted). Markers CEDG261 and DMB-SSR160 should be useful for marker-assisted selection for <i>C.</i> <i>chinensis</i> resistance in moth bean.