Marker-Assisted Backcross Breeding for Improving Bruchid (Callosobruchus spp.) Resistance in Mung Bean (Vigna radiata L.)

Abstract

Mung bean is vulnerable to bruchids (Callosobruchus spp.), resulting in low quality and losses worldwide. Developing resistant cultivars is the most effective, economical, and eco-friendly way to protect mung bean seeds from the damage of bruchids. Previously, we identified two gene loci that are tightly linked with bruchid resistance, which makes new cultivar development possible using molecular assisted selection (MAS). In the present study, marker-assisted backcross (MABC) breeding was employed to introgress the bruchid resistance gene VrPGIP2 locus from the donor parent V2802 into a popular cultivar, Kamphaeng Saen 1. Markers VrBR-SSR013 and DMB-SSR158 were used for foreground selection, and phenotypic selection was used for background selection. Three advanced inbred lines (R67-11, R67-22, and R92-15) carrying the resistance gene VrPGIP2 were developed from the BC3F6 population. Further analysis showed that the line R67-22 performed best; it was highly resistant to bruchids and showed excellent agronomic traits in the field. Therefore, R67-22 could be further evaluated in large-scale trials for release as a variety.