Influence of PGPR and PSB on Rhizobium leguminosarum Bv. viciae Strain Competition and Symbiotic Performance in Lentil

In a field experiment conducted during Rabi 2002-03 at Pantnagar, seed inoculation with Rhizobium leguminosarum bv. viceae (LB-4), PSB (Bacillus megaterium) and PGPR LK-786 (Kurthia sp.) alone significantly increased the nodule number at different intervals, nodule dry weight at 45 and 90 DAS, plant dry weight at 70 and 90 DAS and N uptake by grain and straw in lentil over the uninoculated control. PGPR LK-884 (Pseudomonas diminuta) alone recorded only significantly more number and dry weight of nodule and N uptake by grain and straw. Rhizobium sp. alone recorded the highest occupancy of 34.4% in nodules at 70 DAS. Co-inoculation of PSB and both PGPRs further improved the nodule occupancy of inoculated Rhizobium sp. and recorded highest value at 90 DAS. Dual inoculation of Rhizobium sp.+PSB was statistically comparable to Rhizobium sp. and PSB alone in different parameter, but Rhizobium sp.+LK-786 and Rhizobium sp.+LK-884 recorded significantly more plant dry weight than their individual inoculation at 90 DAS. Combined inoculation treatment of Rhizobium sp.+PSB+LK-786 produced the highest and significantly more number and dry weight of nodules and plant dry weight than Rhizobium sp. alone at different intervals. It also gave highest and significantly more nodule occupancy at 45 and 90 DAS of 34.7 to 42.3% than Rhizobium sp. alone inoculation. This treatment recorded significant increases of 20.8 and 23.5% in grain yields and numerical increases of 13.2 and 14.0% in straw yields over Rhizobium sp. and PSB alone inoculation, respectively. N and P uptake by grain and straw with this treatment were also significantly more than individual inoculation of Rhizobium sp., PSB and LK-786. Combined inoculation treatment of Rhizobium sp.+PSB+LK-884 was also significantly superior to Rhizobium sp. alone in plant dry weight at different intervals and P uptake by grain and straw. Both the latter treatments were statistically comparable to application of 20 kg N+40 kg P O ha in 2 5 1 most parameters, except nodule number at different intervals.