Abstract

The work was carried out on the Dagestan OS VIR in the conditions of South-flat Dagestan. The field resistance of barley samples to fungal diseases (powdery mildew, dwarf rust) was studied. On a natural infectious background, 558 local barley varieties from the world collection of VIR of different ecological and geographical origin, systematic affiliation and type of development were estimated. Local forms, being most adapted to the dynamics of environmental conditions of a certain region, where their formation took place, can be used in the study of ecological and geographical confinement of the sign. The studied local varieties cover all the main centers of cultural diversity in N. I. Vavilov: Abyssinian, Persian, Central Asian, East Asian, Mediterranean, European-Siberian and new World. The front-Asian, Mediterranean and European-Siberian centers were more widely represented. According to resistance to pathogens, the samples were distributed in the corresponding 5 classes: very low (1 point), low (3 point), medium (5 point), high (7 point), very high (9 point). The hydrothermal regime of South-planar Dagestan favors the development of fungal diseases. Powdery mildew and dwarf rust are widespread in the region. The observed annual incidence of infectious background allows us to assess the resistance of accessions to these pathogens. Powdery mildew appears in early spring when barley plants are in the tillering phase. The second peak is observed in the earing phase. The disease affects the leaf, the vagina of the leaf, the stem, and in some years can cover the ear. Most studied barley is susceptible to powdery mildew. The causative agent is characterized by broad environmental plasticity. Practically during the whole ontogenesis of plants the possibility of their damage is determined by the presence or absence of genetically determined resistance. Dwarf rust appears much later powdery mildew in the phase of earing-pouring grain. Sometimes the leaves of plants due to weather conditions, early ripening varieties or severe defeat powdery mildew dry before the disease manifests. Therefore, dwarf rust usually develops on late-maturing samples. Care of the plant from the disease is not genetically determined resistance. As sustainable (9 point) is marked 75 varieties, susceptible - 85 (1 point) Among the barleys, Persian, Mediterranean, European-Siberian origin discovered both susceptible and resistant forms, and medium - and East Asian barleys differ in the sensitivity to the pathogen. The samples resistant to powdery mildew and dwarf rust were isolated and can be used as sources.

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