Diversity of Plant Growth Promoting Rhizobacteria Communities Associated with Thiamethoxam in Cassava Production Systems

Abstract

The use of chemical pesticide always leaves chemical residues on soil and may affect the population, function and diversity of soil microorganisms. Therefore, the aim of the study was to determine the effect of thiamethoxam, pesticide in the group of neonicotinoid to control insect pest, on diversity of plant growth promoting rhizobacteria (PGPR) communities in cassava production systems. Bacteria were isolated from rhizosphere of cassava grown in the field of 5 treatments, including cassava production system without thiamethoxam and fertilizer application, cassava production system with thiamethoxam application, cassava production system with thiamethoxam and organic fertilizer application, cassava production system with thiamethoxam and chemical fertilizer application, and cassava production system with thiamethoxam, organic and chemical fertilizer application, and then screened for plant growth promoting traits. The genotypic diversity of isolates was determined on a basis of amplified rDNA restriction analysis (ARDRA). The findings of this study indicated that the majority of bacteria were found to belong to the genera of Bacillus, Ochrobactrum, and Brevibacillus. Interestingly, the application of thiamethoxam in cassava production system has no effect on PGPR diversity.