Different cultivars of in vitro plants of potato Solanum tuberosum L. were cultivated with a bacterium Clavibacter michiganensis ssp. sepedonicus (Spieck. et Kott.) Skaptason et Burkh., causing wilt of the overground part and ring rot of tubers. Development of disease symptoms (chlorosis, growth suppression) closely correlated with strong acidification of the medium, caused by the bacterium producing extracellular polysaccharides. However, root cells of the host plant (potato) and other non‐host plants (seedlings of tomato, wheat and radish) were able to restore extracellular pH. The efficiency of such restoration correlated with the resistance of the potato cultivar to bacteriosis. Plasma membrane and vacuolar H+‐ATPases were not involved in the stabilization of extracellular pH‐homeostasis, but a significant role was played by the buffer capacity of the cells. The maintenance of pH‐homeostasis in the plants is inferred to be one of the main factors of nonspecific resistance.

A comparative assessment of a remontant and common raspberries biochemical composition is given. The biochemical composition of a remontant raspberries cultivated in Cisbaikalia corresponds to the minimum physiological human need for biologically active substances. The content of sugars, vitamins (C, A, B1, B2, E and PP) and microelements has been studied. It was found that the frozen berry contains a sufficient amount of vitamin C, sugars and trace elements for daily consumption. The dietary value of raspberries is noted, due to the predominant accumulation of fructose and glucose. The minimum sugar content of berries in the Eurasia variety. A variety with a high content of vitamin C and sugars has been identified, it is Rubinovor ozherelie. The Zharptitsa and Rubinovoe ozherelie varieties are sources of iron, manganese, zinc and copper, and Penguin, Hercules, Orange miracle, Bellflower, form 16-136-6 are calcium. The Rubinovoe ozherelie variety contains a lot of sugars, vitamins and micronutrients, and also has a high organoleptic rating.

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The article presents the research results of seed germination of woody and shrubby introduced species. Depending on the depth of dormancy, the studied plant species were divided into 3 groups. The first group includes plants with the absence of dormancy or with a short dormancy; the seeds of these species do not need stratification. The second group includes plants whose seeds are in a state of a rather long intermediate physiological dormancy; they need cold stratification. The organic dormancy period of plant seeds of the second group is different – from 25 to 160 days. As a rule, these are plants with a well-formed seed bud. The physiological dormancy of the seed bud and the inhibitory effect of its covers can be an obstacle to its formation. The third group includes plants whose seeds may not germinate for several years. As a rule, the seeds of these plants are in a state of a deep physiological or morphophysiological dormancy; multi-stage stratification is recommended for their germination. The introduced species of the third group are the most difficult to study since their seeds can belong to different variants of deep dormancy, which combines the physiological immaturity of different structures of the seed bud with the incomplete morphological maturity and exogenous dormancy.

The purpose of this work was to study biological and economic peculiarities of repair raspberry varieties cultivated in the south-eastern part of Irkutsk region. The research was conducted on the territory of the collection site of SIFIBR SB RAS. The objects of research were 10 varieties and 3 selected forms of repair raspberries of selection of FSBNU "All-Russian Breeding and Technological Institute of Horticulture and Nursery Management". Raspberries were cultivated in annual culture.Biological and economic peculiarities of the object of research on the territory of the forest-steppe zone of the Predbaikal region were studied by the route method. Actual productivity was taken into account by mass of ripe berries on one bush before severe frosts. The research was carried out according to the program and methods of variety study of fruit, berry and nut crops. According to the results of observations a comparative biological and economic assessment of the studied objects by productivity and terms of fruit ripening, peculiarities of bush formation in some varieties was given.