Resistance to Fusarium head blight and deoxynivalenol accumulation in wheat

Abstract

Fusarium head blight (FHB), caused by Fusarium graminearum Schwabe (telomorph =Gibberella zeae (Schw.)), is an important wheat disease world‐wide. Production of deoxynivalenol (DON) by F. graminearum in infected wheat grain is detrimental to livestock and is also a safety concern in human foods. An international collection of 116 wheat lines was evaluated for FHB resistance and concentration of DON in grain. Plants were inoculated with mixed isolates of F. graminearum in the greenhouse by injecting conidia into a single spikelet of each spike and in the field by scattering F. graminearum‐infected wheat kernels on the soil surface. FHB symptoms were evaluated by visual inspection in both the greenhouse and field, and DON was analysed by HPLC. Significant differences in FHB ratings and DON levels were observed among cultivars. In the greenhouse test, visual symptoms varied from no spread of FHB from the inoculated spikelet to spread throughout the spike, and DON levels ranged from trace levels to 283 mg/kg. In the field test, DON ranged from 2.8 to 52 mg/kg. The greenhouse test identified 16 wheat lines from various origins that accumulated less than 2 mg/kg DON. These lines may be useful as sources for breeding wheat cultivars with lower DON levels. Correlation coefficients were significant between FHB symptom ratings, seed quality traits, and DON levels. Thus, the percentage of scabbed spikelets and kernels can be generally used to predict DON levels in harvested wheat grain. In breeding programmes, selection for plants having few scabbed spikelets and scabbed kernels is most likely to result in low DON levels.

Resistance of winter wheat varieties registered in the Czech Republic to mycotoxin accumulation in grain following inoculation with Fusarium culmorum

“…On the contrary, the variety Apache expressed the highest resistance to the accumulation of DON and ZEA, but FHB symptoms were clearly developed. Bai et al (2001) reported that severe visual symptoms may not always be associated with high DON levels, especially in varieties possessing moderate Type II resistance. Table 3 presents the results of correlation analyses.…”

“…Resistance to the pathogen spread can be more stable, but it is not so tightly linked with the natural course of infection. Low FHB severity due to Type I and Type II resistance usually coincides with low DON because of fewer infected kernels (Bai et al 2001). Other types of resistance described by Mesterházy (1995) are resistance to kernel infection, to toxin (DON) accumulation and tolerance.…”

Resistance gene analogs associated with Fusarium head blight resistance in wheat

“…Disease severity was calculated as the proportion of symptomatic spikelets (PSS) per inoculated spike at 21st day after inoculation and used for QTL analysis. To validate the STS marker, additional 14 cultivars were evaluated for disease severities by the same method (Bai et al, 2001). …”

Resistance of winter wheat varieties registered in the Czech Republic to Fusarium head blight in relation to the presence of specific Rht Alleles

“…On the other hand, Sultan and apparently also Federer (at a higher resistance level) can be classified according to these experiments as varieties producing less DON at a higher symptom expression and greater grain weight reduction. Bai et al (2001) reported that severe visual symptoms may not always be associated with high DON levels, especially in the varieties possessing a moderate Type II resistance.…”

“…To minimize year/location effects on results, it appears often necessary to support disease development by irrigation of plots. Low FHB severity due to Type I and Type II resistance usually coincides with low DON because of fewer infected kernels (Bai et al 2001). Other types of resistance described by Mesterházy (1995) are resistance to kernel infection, to toxin (DON) accumulation and tolerance.…”