Linkage Mapping Study Reveals Conservative QTL and Candidate Genes for Fusarium Ear Rot Resistance in Maize

Fusarium ear rot (FER), caused by Fusarium verticillioides (F. verticillioides), is a major disease of maize that reduces grain yield and quality globally. However, few major loci for FER have been verified and cloned. Resistance to FER is a quantitative trait influenced by environmental conditions, and maize genotypes completely resistant to the pathogen remain unknown. To gain a comprehensive understanding of the genetic basis of natural variation in FER resistance, a recombinant inbred line (RIL) population consisting of 257 progenies was developed by crossing the resistant line BT with the susceptible line Xi502. This population was genotyped using a set of 6807 high-density single nucleotide polymorphism (SNP) markers developed in this study. As a result, a total of five QTLs were identified by linkage mapping across three years, located on five chromosomes, and explaining 4.38-13.13% of the phenotypic variation. Among these was a major QTL, qFER5-2. Located on chromosome 5 within the interval 185568562-185574073, qFER5-2 explained 13.13% of the total phenotypic variance. The two candidate genes within qFER5-2 exhibited distinct expression profiles between the BT and Xi502 inbred lines, suggesting their potential association with FER resistance. Collectively, these findings provide candidate genetic resources for further investigation and offer potentially useful materials for maize disease resistance breeding.