Variation for Resistance to Fusarium Head Blight in Triticum Dicoccoides

Head blight of wheat (FHB, scab) caused by Fusarium spp. is a severe fungal disease problem worldwide. Apart from yield and grain quality losses, the contamination of the harvest with toxic fungal metabolites, known as mycotoxins, is of serious impact. In spite of the fact that several sources for resistance against FHB have been found and utilized in hexaploid wheat, virtually no resistant tetraploid wheat cultivar has been identified so far. Wild emmer wheat, Triticum dicoccoides, previously identified as a rich source for disease resistance genes to several pathogens, was tested for resistance to FHB. Single point inoculations were applied to evaluate a set of 151 T. dicoccoides genotypes, originating from 16 habitats in Israel and one habitat in Turkey, for resistance to fungal spread (Type II resistance) in replicated greenhouse experiments. A considerable level of diversity was found among the tested genotypes, the broad sense heritability for Type II FHB resistance was 0.71. Among the eight T. dicoccoides lines with the lowest relative infection rates, five originated from the Mt. Gerizim population, and three from the Mt. Hermon population. These two habitats are characterized by a relatively cool and semi-wet climate. Hence, it may be possible that Fusarium occurrence in these habitats was responsible for natural selection in favor of resistance.