Nodulation efficiency of five isolates of Rhizobium ciceri

Nitrogen fixation is the third fundamental process in addition to respiration and photosynthesis. Although strictly speaking no plant is known to fix nitrogen. This abirrty is confined to prokaryotes only. Cicer arietinum, a well known pulse crop is very specific for nodulation process. The bacterium Rhizobium isolated from the root nodules of chick pea and cultured in VEMA medium in petriplates. The colonies are selected in response to their specificity. Colony morphology is observed and a relation established between colony morphology and their nodulation efficiency in terms of nodule number and nodular dry weight. Two types of colonies are observed i.e. ·dry· and ·wet·. Wet colonies produce a slime. The size is also vary, the dry colonies is somewhat smaller (0.5 to 1.0 mm) in size while wet colonies attain a size of more than 1.0 mm after the fourth day of stricking. In nod ulation efficiency it is observed that the isolate with wet colonies are much effective. They produce a large no. of nodules and the more nodular dry weight. So it is clear that the isolates of R. ciceri with wet colonies are much effective in nodulation in comparison to dry isolates. In present investigation isolate RCa III 1005 show the highest nodulation efficiency.