Mapping QTL contributing to SCMV resistance in tropical maize.

Sugarcane mosaic virus (SCMV) has been increasing in importance as a maize disease in Brazil. In this study, we mapped and characterized quantitative trait loci (QTL) associated with resistance to SCMV in a maize population consisting of 150 F2:3 families from the cross between two tropical maize inbred lines, L520 (resistant) and L19 (susceptible). F2 individuals were genotyped with microsatellite (SSR) markers, and the derived F2:3 families were evaluated for their response to artificial inoculation with SCMV under field conditions at Sete Lagoas, MG, Brazil, in 2001 and 2005. Multiple interval mapping was used for QTL detection with a linkage map based on 19 SSR markers. Three QTLs for SCMV resistance were identified with two QTLs (Scm2a and Scm2b) clustered on chromosome 3, bin 3.04, and one QTL (Scm1) on chromosome 6, bin 6.01, explaining 13.34, 41.85 and 7.66% of the phenotypic variation for SCMV resistance, respectively