SURVIVAL AND SYMBIOTIC PROPERTIES OF BRADYRHIZOBIUM-JAPONICUM IN THE PRESENCE OF THIRAM - ISOLATION OF FUNGICIDE RESISTANT STRAINS

The fungicide thiram, widely used as a chemical seed protectant, induc es a strong inhibition of primary nodulation in the crown zone of soyb ean roots. The present work reports on the isolation of Bradyrhizobium japonicum strains resistant to thiram, some of which (T3B, A86 and A2 ) maintained their capacity for nodulation and were still efficient sy mbionts, but some (A1, C1 and C6) lost the ability to stimulate nodula tion. Characterization tests such as growth at different pH, denitrify ing ability, salt tolerance, production of siderophores and phosphate solubilization were performed on the resistant strains. Inoculants pro duced from these strains could be appropriate for use with thiram-trea ted seeds, without causing a loss of bacteria viability.