Біологічні студії (Mar 2023)

The effect of bacterization and pre-sowing seed treatment with benorad on the growth of soybean plants and the realization of the symbiotic potential of pesticide resistant rhizobia

  • P. P. Pukhtaievych,
  • K. P. Kukol,
  • N. A. Vorobey,
  • S. Ya. Kots

DOI
https://doi.org/10.30970/sbi.1701.705
Journal volume & issue
Vol. 17, no. 1
pp. 69 – 79

Abstract

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Background. Bacterial fertilizers based on active strains of nitrogen-fixing microorganisms and fungicides for pre-sowing seed dressing are increasingly used in soybean cultivation technologies. Given the usefulness of combining the specified processes, the selection of chemical and biological preparations for the combined processing of seed material is relevant. Materials and Methods. In vegetation experiments, the effect of treatment of soybean seeds with benorad and inoculation with nodule bacteria resistant to fungicides in pure culture, obtained by the methods of analytical selection and transposon mutagenesis, on plant growth, the number and weight of root nodules and their nitrogenase activity was studied. Physiological, microbiological, statistical methods and gas chromatography were used. Results. Under the complex application of inoculants and benorad, we recorded a decrease in the weight of the aerial part of soybeans by 8.7–20.9 % and the weight of roots by 4.8–16.8 % during the growing season compared to control plants (regardless of the strain of rhizobia used for bacterization). In the case of seeds dressing, the dyna­mics of the formation of the number of root nodules by the B. japonicum B78 differed from other inoculant strains that were used in the research. This indicator decreased by 20.6 and 16.3% at the stage of three true leaves and budding–beginning of flowering and increased (by 28.0 %) at the stage of pods formation compared to control plants. The negative effect of seed dressing on the nitrogenase activity of symbiotic systems was observed after the application of benorad, at the stage of three true leaves and budding–beginning of flowering was noted. The degree of inhibitory effect of the chemical preparation on intensity of N2 assimilation depended on the properties of microsymbionts. In the stage of pods formation, the level of N2 fixation by soybean root nodules formed by the B. japonicum PC07 and B144 during seed dressing exceeded the corresponding level in the control plants by 32.2 and 45.7 %, respectively. Conclusions. The use of microbial preparations for inoculation of soybean seeds, made on the basis of nodule bacteria strains with high resistance to chemical plant protection agents, allows for a gradual reduction of the toxic effect of artificially synthesized compounds on the formation and functioning of symbiotic systems.

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