An experiment was set up in Kapir sub-county, Ngora district to evaluate the effect of Bradyrhizobium Mak-biofixer inoculum on seedling vigor, seed germination and nodulation ability of NAROGRAM 2 variety. A completely randomized block design was set up to evaluate different nodulation attributes including; nodule color, nodule number and nodule position from the second week of seedling emergence till the sixth week of seedling emergence. Two treatments were used for this study (10g of inoculum/1000g of seeds and 12g of inoculum/1000g of seeds) and the control involved the seeds which were not inoculated with the rhizobium. The field experiment had twelve replicates in total. Another experiment in a screen house was set up following a completely randomized design. Two treatments (10g of inoculum/1000g of seeds and 12g of inoculum/1000g of seeds) and the control involved the seeds which were not inoculated with the rhizobium were used. The screen house experiment had twelve replicates/petri-dishes in total. Data on seed germination was collected on 100 seeds for 30 days. Data on seedling vigor (root and shoot length) were collected on ten plants per petri-dish for 3 days, 6 days and 9 days after germination. The treatment of 12g of inoculum/1000g of seeds had a higher seed germinability than a treatment of 10g of inoculum/1000g of seeds. On the 9th day of germination, the treatment of 12g of inoculum/1000g of seeds had the non-significantly (P˃0.05) longer root and shoot length compared to a treatment of 10g of inoculum/1000g of seeds. Application of different treatments of rhizobium inoculation had varying effects on nodulation of NAROGRAM 2. In the 4th week of data collection, the treatment of 12g of inoculum/1000g of seeds had a non-significantly (P˃0.05) higher value of nodule color score, nodule number and nodule position scores relative to the treatment of 10g of inoculum/1000g of seeds. The rhizobium application of 12g of inoculum/1000g of seeds had higher seed germination and seedling vigor therefore, enhances rapid field seedling emergence and establishment which in turn result in higher yields. Application of 12g of inoculum/1000g of seeds had higher nodule color compared to 10g of inoculum/1000g of seeds implying more effective nitrogen fixation. Furthermore, the application of 12g of inoculum/1000g of seeds had higher nodule number and nodule position score implying presence of both lateral and crown nodules which enhances efficient nitrogen fixation.

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