918-923Eleven strains of Rhizobium and five strains of Bradyrhizobium
were examined for their viability as well nodulation and nitrogen fixation
ability after storage under different conditions for two years. The storage
conditions comprised lateritic soil, lateritic soil plus 1% mannitol, lateritic
soil plus 0.1% yeast extract, lateritic soil plus 1% mannitol and 0.1% yeast
extract, organic soil, organic soil plus 1% mannitol, organic soil plus 0.1%
yeast extract, organic soil plus 1% mannitol and 0.1% yeast extract, and
sterile distilled water. All the slow growing strains showed better viability
than the fast growing strains in any of these conditions. The survived strains
maintained their nodulation ability about 50-60% after one year and 40-50%
after two years of preservation as compared to control, but the nodulation
ability in sterile distilled water was very poor. Acetylene reduction activity
in the nodules was found to be 70-90% and 50-70% after 12 and 24 months of
preservation, respectively. The strains retained their phenotypic characters
like antibiotic resistance and salt tolerance up to their highest survivability
in respective nutritional condition