QTL Analysis for Resistance to Ralstonia solanacearum in Capsicum Accession ‘LS2341’

Abstract

A Malaysian pepper accession, ‘LS2341’ (Capsicum annuum L.) is highly resistant to bacterial wilt (BW) caused by Ralstonia solanacearum E. F. Smith (species complex). Quantitative trait locus (QTL) analysis was performed using a double haploid (DH) population derived from a cross between the susceptible cultivar ‘California Wonder’ and ‘LS2341’. A linkage map was constructed using simple sequence repeats (SSRs) and amplified fragment length polymorphism (AFLP). The map spans 974 cM, and consists of 15 linkage groups (LGs). Growth chamber evaluations of BW resistance detected a QTL on LG 11. This LG corresponds to pepper chromosome 1 (P1). The QTL explained 33% of the resistance derived from ‘LS2341’, and was named Bw1. An SSR marker, CAMS451 was mapped in the centre of the QTL. Although BW-resistance is thought to be polygenically controlled, use of this linkage marker may improve the efficiency of breeding BW-resistant cultivars.