Screening and Resistance Loci Identification of Mutant fcrZ22 Resistant to Crown Rot Caused by Fusarium pseudograminearum

Crown rot caused by Fusarium pseudograminearum is a devastating wheat disease worldwide. In addition to yield losses, the fungi causing FCR also deteriorate quality and safety of food because of production of mycotoxins. Planting resistant cultivars is an effective way to control FCR. However, most wheat cultivars are susceptible to FCR. Development of new sources and detection of loci for FCR resistance are necessary. In the present study, a resistant mutant fcrZ22 was identified from an EMS-mutagenized population of cultivar Zhoumai 22, and then fcrZ22 was crossed with the wild type to produce a F2 population. Genetic analysis of the F2 population was carried out by mixed inheritance model of major genes plus polygenes, and 20 resistant and 20 susceptible plants were selected to assemble mixed pools. Combining 660K SNP arrays, the resistance loci were detected by bulked segregant analysis (BSA). The resistance to FCR caused by F. pseudograminearum in the F2 population was in accordance with the “mixed model with two major genes of additive-epistasis effect + additive-dominant poly genes”, and heritability of the major gene was 0.92. Twenty-one loci were detected, which were located on 10 chromosomes of 1B (1), 1D (1), 2A (3), 1B (1), 3A (3), 3B (3), 4A (2), 5A (2), 7A (3) and 7B (2). Among the 21 loci, 8 were new loci for FCR resistance. This is the first report to detect loci for FCR resistance from a mutant. Results of the present study provided excellent germplasm resources for breeding wheat cultivars with FCR resistance and laid a foundation for fine mapping of FCR resistance loci.