Development of doubled haploid population and QTL mapping for Fusarium stalk rot (FSR) resistance in tropical maize

Abstract Fusarium stalk rot disease (FSR) caused by Fusarium verticilloides is emerging as the major production constraint in maize across the world. As a prelude to develop maize hybrids resistant to FSR, an attempt was made to identify QTL as the genetics of resistance was found to be quantitative in nature. Two doubled haploid (DH) mapping populations induced from F2 of crosses VL1043 × CM212 and VL121096 × CM202 were challenged with FSR during two seasons. The FSR response was influenced by significant DHs × season interaction. The DH populations were genotyped employing 164 and 132 polymorphic SNP markers in the DHs induced from the crosses VL1043 × CM212 and VL121096 × CM202, respectively. Inclusive composite interval mapping was performed to detect significant QTL, QTL × QTL, QTL × season interaction effects. Two and one QTL were identified in rabi 2019 and summer 2020, respectively. The QTL identified on the linkage group 10 (qFSR_10_1) was common across two seasons in DHs derived from the cross VL1043 × CM212. Similarly, two QTL each in rabi 2019, summer 2020 and one common QTL (qFSR_6_2) were identified for FSR resistance in DHs derived from F2 of the cross VL121096 × CM202. The QTL qFSR_10_1 was common in both the crosses. The position and effect of the QTL were varied with the seasons. Seven di-QTL interactions were detected for FSR resistance in both DH populations.