Study of Barberry Shrubs Role in Transferring Wheat Stem Rust Disease Agent to the Next Season

Puccinia graminis f. sp. tritici is the causal agent of wheat stem rust disease. This fungus is heteroecious with complete life cycle that its intermediate host plant is barberry (Berberis spp.) In some areas that urediniospores cannot survive in winter conditions, basidiospores produced from teliospores in feat barberry which result in the survival of the fungus and its transmission to the next season. In this research, samples of barberry leaves showing symptoms of rust disease were collected from North Khorasan, Mazandaran, Golestan, Semnan, Fars, Lorestan and South Khorasan provinces. Host plant species and infecting fungal species were determined based on their morphological characteristics. In addition, the relationship of these fungal species to stem rust of wheat was investigated by inoculating them on two susceptible wheat cultivars Moroco and Local Red. A total of five hybrids and species of barbery as Berberis vulgaris, B. integerrima × vulgaris, B. integerrima × cartingia, B. orthobotrys and B. integerrima were identified as the host. According to morphological characteristics, three fungal species were identified as: Puccinia magelhaenica, P. brachypodii s.lat. And Aecidium berberidis, where none of these species are known as wheat stem rust disease agent. Inoculation of aecidiospores obtained from Barberry species on the susceptible wheat cultivars showed that only two samples produced stem rust symptoms indicating most barberry shrubs in Iran are the host for rust species that are not pathogenic on wheat and may not have significant impact on epidemic of stem rust in the region.