Abstract
Fusarium head blight (FHB) is a devastating disease in wheat. The use of resistant germplasm from diverse sources can significantly improve resistance to the disease. “Surpresa” is a Brazilian spring wheat cultivar with moderate FHB resistance, different from currently used sources. In this study, we aimed to identify and map the genetic loci for FHB resistance in Surpresa. A mapping population consisting of 187 recombinant inbred lines (RILs) was developed from a cross between Surpresa and a susceptible spring wheat cultivar, “Wheaton.” The population was evaluated for FHB by the point-inoculation method in three greenhouse experiments and four field trials between 2016 and 2018. Mean disease severity for Surpresa and Wheaton was 41.2 and 84.9% across the 3 years of experiments, ranging from 30.3 to 59.1% and 74.3 to 91.4%, respectively. The mean FHB severity of the NILs was 57%, with an overall range from 7 to 100%, suggesting transgressive segregation in the population. The population was genotyped using a two-enzyme genotyping-by-sequencing approach, and a genetic map was constructed with 5,431 single nucleotide polymorphism (SNP) markers. Four QTL for type II resistance were detected on chromosomes 3A, 5A, 6A, and 7A, explaining 10.4–14.4% of the total phenotypic variation. The largest effect QTL was mapped on chromosome 7A and explained 14.4% of the phenotypic variation; however, it co-localized with a QTL governing the days to anthesis trait. A QTL for mycotoxin accumulation was also detected on chromosome 1B, explaining 18.8% of the total phenotypic variation. The QTL for FHB resistance identified in the study may diversify the FHB resistance gene pool and increase overall resistance to the disease in wheat.
Highlights
Fusarium head blight (FHB) is a destructive disease of wheat worldwide
The FHB severity of the two parents differed significantly (P < 0.05), with Surpresa exhibiting moderate resistance while Wheaton was very susceptible in all experiments
Distribution of disease severity and DON accumulation was continuous in all experiments (Figures 1–3), indicating quantitative inheritance of FHB resistance
Summary
Fusarium head blight (FHB) is a destructive disease of wheat worldwide. It is primarily caused by the fungus Fusarium graminearum in North America and can significantly reduce grain yield and quality (McMullen et al, 2012; Del Ponte et al, 2017). Grains can be contaminated with deoxynivalenol (DON) produced by the disease, further restricting their end-use. These implications lead to a higher risk for growers, who may adopt more costly management practices or switch to less risky crops (Dahl and Wilson, 2018). An integrated approach that incorporates genetic resistance, fungicide application, and agronomic practices is required to minimize losses to the disease
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