African Journal of
Agricultural Research

  • Abbreviation: Afr. J. Agric. Res.
  • Language: English
  • ISSN: 1991-637X
  • DOI: 10.5897/AJAR
  • Start Year: 2006
  • Published Articles: 6574

Full Length Research Paper

In vitro interaction between fungicides and beneficial plant growth promoting Rhizobacteria

Gaurav Mishra1*, Narendra Kumar2, Krishna Giri1 and Shailesh Pandey1
1Rain Forest Reasearch Institute, P. O. Box-136, Sotai, Jorhat, Assam, (785 001) India. 2Department of Soil Science, GB Pant University of Agriculture and Technology, Pantnagar, 263145 India.
Email: [email protected]

  •  Accepted: 12 November 2013
  •  Published: 21 November 2013

Abstract

Laboratory experiments were conducted to study the effects of five fungicides on the growth of Bradirhizobium japonicum and Phosphate solublizing bacteria (PSB) at different concentrations that is, (0, 0.1, 0.2, 0.3, 0.4 and 0.5%). Fungicide effects on bacteria were determined on the basis of their growth in respective medium. The population of B. japonicum declined significantly while PSB population showed non-significant growth reduction. Minimum (13.5 × 104 CFU ml-1) of B. japonicum were recorded at 0.5% concentration. However, reduction in PSB at 0.5% thiram was non-significant. The mean population of microorganisms declined significantly by carbendazim. Maximum reduction in B. japonicum and PSB population was recorded at 0.5 and 0.4% carbendazim concentration respectively. Vitavax exhibited maximum population reduction at 0.5% concentration where (6.5 × 104 CFU ml-1) of microorganisms were recorded. The mean population of microorganisms declined significantly with increasing carboxin concentration and 5.6 × 104 CFU ml-1 of B. japonicum was recorded at 0.5% concentration of carboxin. The effective mean population irrespective of the organisms showed significant decrease with increasing concentration of thiomethaxam. Among all the fungicides, minimum bacterial growth was observed at 0.5% thiomethaxam concentration. Experimental results revealed that, higher concentration of all the fungicides exerted toxic effect on beneficial soil microflora.

Key words:  Bradirhizobium japonicum, Phosphate solublizing soil bacteria (PSB), fungicides, growth.