Rhizobacterial growth and yield promotion of cucumber plants inoculated with Pythium aphanidermatum

Abstract

The potential of rhizobacterial strains to reduce the adverse effects of Pythium aphanidermatum on plant growth and yield was examined under in vitro and greenhouse cropping conditions. Rhizobacterial cultures of 10 strains of Pseudomonas putida, 24 strains of Bacillus subtilis, 4 strains of Enterobacter aerogenes, 1 strain of Bacillus cereus, and 1 unknown bacterial strain were evaluated for antagonism against P. aphanidermatum in laboratory and greenhouse conditions. In a dual culture test on potato dextrose agar, only AG-1 of B. subtilis and strains 2xyta75 and B8 of E. aerogenes were antagonistic to P. aphanidermatum. Under sterile in vitro conditions in pouches, 40 bacterial strains were tested for growth promotion of cucumber (Cucumis sativus) seedlings in the absence of P. aphanidermatum. All bacteria except strain PPG-7-1 of P. putida, strains AGS-3 and AGS-1 of B. subtilis, and strain AG-0 of an unidentified bacterium increased root length of cucumber compared with the P. aphanidermatum inoculate...