Effect of rhizobial isolates and nitrogen fertilizers on nursery performance, nodulation behavior and nitrogenase activity of Dalbergia sissoo Roxb. seedlings

•Dalbergia sissoo Roxb. is a multipurpose tree legume species that form nodules in symbiosis with rhizobia.•A prominent environment was maintained in a Dalbergia sissoo nursery for microbial inoculation of rhizospheric bacteria isolated from different geographic D. sissoo rhizosphere.•The outcomes suggest that the PGPR1+PGPR2 is the best treatment that significantly increased the growth parameters, i.e., root, shoot parameters and nodulation status, and nitrogenase activity in Dalbergia sissoo seedlings. Nursery practice in Dalbergia sissoo seedlings was performed in order to establish the efficacy of the rhizobial inoculants for future nurseries. The rhizospheric bacteria were isolated from different geographic locations of Himachal Pradesh and Uttrakhand. The nursery was set up by sowing the seeds collected from these locations. The rhizospheric bacterial inoculants isolated from D. sissoo rhizosphere were treated in the nursery for the establishment of a successful nursery. The nursery was observed for root, shoot parameters, and nodulation status showing variation in these characters with different geographic locations. From the same nursery, rhizobia were isolated from root nodules in YEMA media. Based on PGPR traits, two rhizobia, i.e., PGPR1 (DBD1) and PGPR2 (DRT5) were treated in the second nursery along with different levels of nitrogenous fertilizers. The consortium of PGPR1+PGPR2 was observed to be the best treatment that significantly increased the growth parameters, i.e., root, shoot parameters and nodulation status, and nitrogenase activity in D. sissoo seedlings.