Symbiotic Effectiveness of Rhizobium Leguminosarum Bv. Viciae With Pea Plants as Influenced by Azotobacter Chroococcum

The aim of this work was to examine the effects of A. chroococcum on the prolifera-tion of R. leguminosarum bv. viciae (Rlv) in a solid-carrier inoculant and on symbiotic effectiveness of Rlv with pea plants grown under laboratory and field conditions. In a laboratory experiment it was found that proliferation of both bacterial species, Rlv and A. chroococcum, in the dual-culture inoculants was efficient, and that A. chroococ-cum had no adverse effects on the development of the rhizobia (Rlv) in the solid-carrier inoculant. In a pot experiment the highest number of nodules was detected on roots of pea plants inoculated with the dual-culture inoculant containing Rlv and A. chroococcum, slightly lower numbers on pea roots inoculated with the mono-culture inoculum of Rlv and almost no nodules were found on the roots of pea un-inoculated (control treatment) with the bacteria. In the micro-plot experiment conducted in the years 2011–2012 pre-sowing inoculation of pea seeds with the mono-culture inocu-lant of Rlv or with the mixed inoculant of Rlv and A. chroococcum slightly increased nodule numbers/plant, pod numbers/plant and seed numbers/pod, as compared to the un-inoculated control, but these differences were not reflected in pea seed yields/m2, which were similar in all treatments.