Rhizobacterial growth and yield promotion of cucumber plants inoculated withPythium aphanidermatum

摘要

The potential of rhizobacterial strains to reduce the adverse effects ofPythium aphanidermatumon plant growth and yield was examined under in vitro and greenhouse cropping conditions. Rhizobacterial cultures of 10 strains ofPseudomonas putida, 24 strains ofBacillus subtilis, 4 strains ofEnterobacter aerogenes, 1 strain ofBacillus cereus, and 1 unknown bacterial strain were evaluated for antagonism againstP. aphanidermatumin laboratory and greenhouse conditions. In a dual culture test on potato dextrose agar, only AG-1 of B.subtilisand strains 2xyta75 and B8 ofE. aerogeneswere antagonistic toP. aphanidermatum. Under sterile in vitro conditions in pouches, 40 bacterial strains were tested for growth promotion of cucumber (Cucumis sativus) seedlings in the absence ofP. aphanidermatum. All bacteria except strain PPG-7-1 ofP. putida, strains AGS-3 and AGS-1 ofB. subtilis, and strain AG-0 of an unidentified bacterium increased root length of cucumber compared with theP. aphanidermatuminoculated controls. Of the 16 bacterial strains evaluated for antagonistic activity againstP. aphanidermatumunder greenhouse conditions, only one strain (BACT-0) ofB. subtilisincreased shoot growth by 9 and weight of cucumber plants by 29 compared with theP. aphanidermatuminoculated controls. The same strain increased the fruit yield by 14 and fruit number by 50 of cucumber plants compared with theP. aphanidermatuminoculated controls. This study has demonstrated that the strain BACT-0 ofB. subtilishas the potential to increase growth, fruit yield, and fruit number of cucumber plants inoculated withP. aphanidermatumin soilless culture under near commercial greenhouse conditions.