Mapping main effect QTL and epistatic interactions for leaf rust and yellow rust using high density ITMI linkage map

Abstract

The present study was undertaken to identify QTL for leaf rust (LR) and stripe or yellow rust (YR) using ITMI-mapping population under Indian environmental conditions. A high density framework linkage map consisting of 1,345 markers was used to conduct single and two locus QTL analyses using QTLCartographer and QTLNetwork. A total of 14 main-effect QTL (M-QTL) for LR and 12 M-QTL for YR were detected. Among all these M-QTL, 7 for LR and 4 for YR were novel, and have not been reported in earlier studies using same population. Eight significant Q×Q interactions for each trait were also identified, which involved 16 epistatic-QTL (E-QTL) for LR and 14 E-QTL (including 2 M-QTL) for YR. Four genomic regions had QTL for both LR and YR. The phenotypic variation explained (PVE) ranged from 2.16% - 29.07% for M-QTLLR and from 0.80%-7.05% for E-QTL. Epistasis contributed a significant portion of the PVE (26.01% for LR and 31.51% YR) for the two traits. Minor environment interactions were observed for YR.