Isolation and characterization of bacteria were done from the root nodules of African dhaincha (Sesbania rostrata) to study their effects on growth parameters, nodulation and N uptake. Five isolates were obtained from African dhaincha and were identified them as Azorhizobium on the basis of their colony, morphological and biochemical characteristics. A pot experiments were conducted by using 6 treatments, comprising 5 isolates of Azorhizobium and an uninoculated control to evaluate the performance of the isolates. The experiment was laid out in a Completely Randomized Design (CRD) with 3 replications. Azorhizobium inoculation gave statistically higher values for all the parameters viz. plant height, leaf number plant-1, dry weight of nodule, dry matter yield, N content of shoot (%), total N in shoot over uninoculated control (T1). The highest values of all the parameters except stem nodule number plant-1, root nodule weight and N content of shoot were obtained with the treatment T5 (SR-R-4). The total dry matter yield of African dhaincha ranged from 1217 mg plant-1 noted in the uninoculated control (T1) to 5483 mg plant-1 recorded for the treatment T5 (SR-R-4). The total dry matter yields were increased by 138, 219, 273, 351 and 290 % over control (T1) due to T2 (SR-R-1), T3 (SR-R-2), T4 (SR-R-3), T5 (SR-R-4) and T6 (SR-R-5), respectively. Total N uptake by shoot of African dhaincha had been influenced significantly due to different treatments and the corresponding percent increases in total N uptake by shoot were 359, 496, 429, 629, and 490, respectively, due to T2 (SR-R-1), T3 (SR-R-2), T4 (SR-R-3), T5 (SR-R-4) and T6 (SR-R-5).Considering all the growth parameters, nodulation, dry matter yield, N content of shoot and total N uptake by shoot, it may be inferred that the isolate SR-R-4 showed the best performance. The isolates SR-R-5 and SR-R-3 were also found promising.
Key words: Azorizobial strains, Sesbania rostrata, Nodulation, N uptake
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