The spring wheat variety Varyag whith high potential nitrogenase activity and the greater contents of chlorophyll in leaves and the active strain of the bacteria Azospirillum sp. 77, selected from the washed roots of the spring wheat variety Varyag, were used for creation of effective association “wheat – diasotrophs of genus Azospirillum”. Inoculation of wheat variety Varyag seeds with the bacterial suspension Azospirillum sp. 77 promoted the reliable increase of nitrogenase activity on roots of plants (by 46 %), content of chlorophyll in leaves (by 18 %) and structural parameters of wheat crop (weight of grain from 1 ear and weight of 1000 grains were increased as a result of inoculation by 16,5 and 16 % accordingly).

Objective. To compare morphological, cultural, physiological, biochemical, and symbiotic properties of strains of nodule chickpea bacteria isolated from different soil and climatic zones of Ukraine. Methods. Microbiological, microscopic, gas-chromatographic, statistical. Results. From the nodules of chickpea plant of varieties Skarb, Admiral, Odissei, Budzhak, Triumf and Pamiat, grown in the steppe zone of Ukraine (Region of Odessa), where an active rhizobia population was formed due to the continuous cultivation of this crop, 58 isolates of bacteria were isolated; 11 iso-lates were isolated from the nodules of plants of Triumf and Pamiat varieties selected in the forest-steppe zone (Region of Lviv), in the fields where chickpea was grown for the first time. It has been established that the strains of Mesorhizobium sp. 1 and Mesorhizobium sp. 2, which were isolated from the nodules of chickpea plants grown in the fields with an active rhizobia population of this culture, form colonies of 2–4 mm in size at day 3–4 on the mannitol yeast agar and, according to cultural and morphological properties correspond to the characteristics of the species Mesorhizo-bium ciceri. Their use for pre-sowing chickpea inoculation increases the mass of nodules (2– 3 times) and nitrogenase activity (1.4–2 times) compared with the results obtained using the pro-duction strain of Mesorhizobium ciceri H-12. Inoculation with Mesorhizobium sp. 11, isolated from the forest-steppe zone, which on a mannitol yeast agar forms a colony of 1–2 mm in size at day 5–6, contributed to a significant increase in the number of nodules on the roots of plants (by 40.5 %), their mass (by 31 %), but the increase in nitrogenase activity was negligible. Conclusion. Strains of Mesorhizobium sp. isolated from chickpea nodules grown in different soil-climatic zones of Ukraine, have similar cell morphology, but differ in growth rate, cultural, physiological, biochemi-cal, and symbiotic properties.

Use of new strain of nitrogen fixing bacteria Azospirillum sp. 77 for inoculation of spring wheat and spring triticale permitted to form an effective associative system diasotroph - plant. The bacterization promoted the reliable increase of potential nitrogenase activity in root zone of plant by 38-220 %, activated the biosynthetic processes, in particular, glutamine synthetase activity increased by 57,0-71,9 %, content of protein in leaves - by 9,7-16,3 %, top of the plants - by 11,9- 18,9 %, weight of the roots - by 7,2-7,3 %.