Mapping of QTL for resistance to fusarium stalk rot (FSR) in tropical maize (Zea mays L.)

Fusarium stalk rot disease (FSR) caused by Fusarium verticilloides is emerging as the major production constraint in maize across theworld.As a prelude to developing maize hybrids resistant to FSR, an attempt was made to identify QTL as the genetics of resistancewas found to be quantitative in nature.Two doubled haploid (DH) mapping populations induced from F2 of crosses VL1043 × CM212and VL121096 × CM202 were challenged with FSR during two seasons. The FSR response was influenced by significant DHs × seasoninteraction. The DH populations were genotyped employing 199 and 193 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 the rainy season of 2019 and winter 2019-20, respectively. The QTL identified in the linkage group 10 (qFSR_10_1) was common across two seasons in DHs derived from the cross VL1043 × CM212. Similarly, two QTL were identified for FSR resistance in DHs derived from the cross VL121096 × CM202 and one QTL (qFSR_6_2) was common. The QTL qFSR_10_1 was common in both the crosses. The position and effect of the QTL varied with the seasons. Seven di-QTL interactions were detected for FSR resistance in both DH populations.