Antagonistic Potential of Rhizobium japonicum Against Fusarium solani And Macrophomina phaseolina The Causal Agent Of Soybean Wilt and Root Rot Disease On Soybean

Abstract

This study was carried out to evaluate the efficiency of Rhizobium japonicum to reduce the severity of Fusarium solani and Macrophomina phaseolina the causal agent of wilt and root rot on Soybean plants. Results showed a significant inhibition activity of culture filtrate of Rhizobium japonicum against the two pathogens as determined on yeast manitol agar, by agar well diffusion or food poisoning techniques. A positive correlation between the inhibition activity and the concentration of culture filtrate was observed. It has been found, in the first technique , that the concentrations 25 , 50 , 75 and 100 % of the filtrate induced an inhibition percentage of 33.84 , 46.46 , 56.02 and 65.58 % for Fusarium solani , 39.61 , 47.12 , 60.90 and 64.04 % for Macrophomina phaseolina respectively as determined by agar well diffusion. The same concentrations of filtrate induced inhibition percentage of 54.11 , 63.33 , 67.11 and 72.66 % for F. solani . 46.33 , 52.66 , 59.66 and 71.33 for M. phaseolina as determined by food poison technique. Results of greenhouse experiments showed that the bacteria caused an increase in the percentage of seed germination and decrease of disease severity on foliage and root system of plants treated by the two pathogens.