Fine mapping of a quantitative trait locus conferring resistance to maize rough dwarf disease

Key message A QTL qMrdd8 that confers resistance to MRDD was fine mapped into an interval of 347 kb; one SNP and two InDels identified in the interval were significantly associated with resistance to MRDD. Maize rough dwarf disease (MRDD) is highly prevalent in the summer maize-growing areas in China, and leads to significant yield losses in maize ( Zea mays L.). In this study, the quantitative trait locus (QTL) qMrdd8 , which confers resistance to MRDD, was fine mapped. Initially, qMrdd8 was consistently identified in the interval between the simple sequence repeat markers umc1617 and phi121 in three F 2 sub-populations derived from a cross between the resistant recombinant inbred line NL203 and the susceptible line B73. Subsequently, qMrdd8 was fine mapped into an interval of 347 kb defined by the markers IDRQ2 and IDRQ20 using a recombinant-derived progeny test strategy. Based on single nucleotide polymorphism (SNP) genotypes identified using the MaizeSNP50 BeadChip, a long haplotype including qMrdd8 was identified in four resistant inbred lines. One SNP, the 2549-bp insertion/deletion polymorphism (InDel) InDel25, and the 2761-bp InDel27, which all were significantly associated with resistance to MRDD in a set of 226 maize inbred lines ( P