Study on plant growth promoting and antagonistic activities of rhizobacteria isolated from urad bean (Vigna mungo)

The availability of a reliable biofertilizer is essential for achieving high yields at a low cost. In the present study, rhizospheric soil and root nodules of Urad bean were collected from ACRA, Dhiansar. Isolation was done by serial dilution method. Ten isolates were isolated from rhizospheric soil and root nodules. The isolates were screened for PGP activities under in vitro condition viz, phosphate solubilizing, nitrogen producing activity, ammonia producing activity, HCN production and indole production test and for antagonistic activities against Fusarium sp. and Colletotrichum sp. using agar well diffusion method. Result showed that out of 10 isolates, 5 isolates showed significant results for PGP and antagonistic activities. I-1, I-3, I-4, I-8, I-10. All the isolates were identified as Gram-negative bacteria. These isolates were tested biochemically and it was observed that isolates I-3, I-4 and I-10 had resemblance to the genus Pseudomonas and I-1 and I-10 had resemblance to the genus Xenorhabdus. Further, these isolates were evaluated under in vivo study to see their efficacy on growth parameters of urad bean. Seven treatments were carried out in two sets. In first set of treatment T0 is taken as control T1 is taken as inoculated control i.e., Fusarium sp. was inoculated to pot soil with no seed treatment. T2, T3, T4, T5 and T6 were inoculated with Fusarium sp. and seed was treated with potential isolates I-1, I-3, I-4, I8 and I-10 respectively. In second set of treatment same treatment was taken but the soil was inoculated with Colletotrichum sp. Out of seven treatments, two treatments i.e., T4 and T6 in which seeds were treated with I-4 and I-10 showed the best results in terms of fresh root weight root length, shoot length, no. of pods. This study concludes that these isolates were used as bio-fertilizers for improving plant growth and used as antifungal against Fusarium sp. and Colletotrichum sp.