Effect of the combination of bio-organic fertiliser with Bacillus amyloliquefaciens NJN-6 on the control of banana Fusarium wilt disease, crop production and banana rhizosphere culturable microflora

Soil amended with organic amendments has been suggested to be a strategy for managing the Fusarium wilt disease which severely hindered the banana production. The effects of four fertilisation regimes, including chemical fertiliser, manure composts and bio-organic fertiliser (BIO) containing Bacillus amyloliquefaciens NJN-6 for 2-year continuous application on the banana Fusarium wilt disease incidence, crop yield and rhizosphere culturable microbial community were investigated. To explore the soil microflora, plate counting method, in vitro screening method for antagonism, eco-physiological index and culture-dependent denaturing gradient gel electrophoresis method (CD DGGE) were used. The highest banana yield, culturable bacteria, actinobacteria and Bacillus populations, culturable bacteria to fungi (B/F) value, antagonistic Bacillus ratio and lowest Fusarium wilt disease incidence were observed in the BIO treatment. Based on CD DGGE results, the BIO application significantly altered the soil bacteria structure and showed highest richness and diversity. The phylogenetic analysis of the selected bands showed that the most abundant phyla were Proteobacteria and Bacteroidetes and BIO application enriched the genera Comamonas, Chitinophaga, the species Bacillus flexus and uncultured Bacillus. All the results showed that 2-year continuous application of BIO containing B. amyloliquefaciens NJN-6 more effectively controlled Fusarium wilt disease and improved fruit yields under field conditions and modulated banana rhizosphere microflora.