Authors:
Nachaat Sakr
Volume 29, Issue 4;
Pages: 260-268; 2023
ISSN: 2069-0053 (print), Agroprint;
ISSN (online): 2068-9551
Pathogenicity assessment of Fusarium head blight (FHB) species is crucial for disease management in wheat because of the ineffective control measures of pathogens is due to variability among their populations. Ideally, two or more experiments should be conducted and the data should be compared to examine whether the ranking in pathognicity is constant. The objective of this study was to evaluate pathogenicity involved in artificial inoculations and in previous analyzed in vitro and field tests in 16 isolates of four FHB species. Two pathogenicity criteria: disease incidence (DI) of head inoculation and disease severity (DS) of floret inoculation were analyzed in a growth chamber on two Syrian durum and bread wheat cultivars with known in vitro and field reactions to FHB. There were significant differences in pathogenicity intra- and inter-species and in susceptibility between wheat cultivars, suggesting that assessment for disease resistance requires the use of aggressive isolates or a mixture of isolates representative of the FHB diversity. The four FHB species did not vary in their DI and DS because of the relative similarity in pathogenic level among the 16 fungal isolates. The values of DI and DS were significantly correlated with standardized area under disease progress curve values previously obtained in vitro and the values of DI under field conditions, indicating that growth chamber indices can predict pathogenicity at the earliest and latest wheat development stages during FHB infection. Artificial inoculation data confirmed in vitro and field results in which the bread cultivar was more resistant to FHB infection than durum, highlighting that the assessment of resistance level is repeatable and stable under several experimental conditions. The two tested wheat cultivars were shown to exhibit acceptable resistance levels to both initial fungal infection (Type I resistance) and disease spread (type II resistance). The present research shows that Syrian wheat plants could be new resistant donors with favorable agronomical characteristics in FHB-wheat breeding programs.
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