Didovich S. Formation and function of Mesorhіzobіum cіcerі - Cіcer arіetіnum symbiosis in the agrocеnosis of southern Steppe of Ukraine

The thesis is devoted to the investigation of regularities of formation and function of chickpea nodule bacteria soil population in the agrocеnosis of the Steppe of Ukraine and isolation highly effective strains of M. cіcerі adapted to the local soil -climatic conditions and optimization of symbiotic nitrogen fixation in modern agrotechnology of chickpea cultivation. It is established, that chickpea cultivation in field crop rotations forms stable soil population of M. cіcerі, but with the absence of chickpea 10-20 years M. ciceri can disappear from soil microbocenosis. The 68 strains of M. ciceri have been isolated and selectеd 13 highly effective strains in symbiosis with 7 chickpea cultivars. Application of mineral nitrogenous fertilizer in doses of N30, N60 influenced upon formation and function of chickpeas leguminouse-rhizobial system negatively, it was inadvisable in the conditions of the effective symbiosis of C. arіetіnum - M. ciceri. Accumulation of symbiotrophycal nitrogen by cultivars Rosana and Alexandrite in conditions of south Steppe of Ukraine is determined.