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Cold-tolerant plant growth-promoting rhizobacteria (PGPR) are of immense agronomic importance due to the fact that the winter season crop growing cycle is subject to varying spells of low temperatures and such PGPRs are metabolically functional at cold conditions. Thirty-five (35) rhizobacterial isolates were isolated from lentil rhizospheric soil, six isolates showing maximum exponential growth at both 10 and 15°C after 24 h were selected and characterized belonging to genera Bacillus and Pseudomonas. Production of indole acetic acid (IAA) ranged from 12.7-17.5 µgml-1 at 10°C to 18.4-20.4 μg/ml at 15°C. At 15°C, an isolate J-17 was found to be strong HCN producer whereas at 10°C, only two isolates: J-26 and J-30 were moderate producers. P-solubilizion at 15°C, ranged from 62.5 - 77.2 µgml-1. However, at 10°C none of the isolates solubilized P. At 15°C, catechol type siderophore production ranged from 523.4 - 606.1 µgml-1. On the basis of the PGP traits, four isolates J-3, J-17, J-18 and J-30 were selected for evaluation under field conditions of lentil at research farm of PAU, Ludhiana, Punjab, India. Coinoculation exhibited a significant increase in nodule number, nodule dry weight, plant and root dry weight, chlorophyll and leghaemoglobin content over Rhizobium alone. Application of J-3, J-17, J-18 and J-30 along with Rhizobium further enhanced the grain yield (1.8, 4.4, 3 and 1.4%). Key words: HCN production, indole acetic acid, siderophore, P-solubilization.

The antagonistic activity against Fusarium oxysporum f. sp. ciceris was determined for 40 chickpea rhizobacteria. Twenty eight isolates showed antagonistic activity against test fungus ranging from 18.2 to 41.8%. Characterization of the antagonistic attributes showed that all the antagonistic isolates produced diffusible and volatile antifungal metabolites in terms of growth inhibition, maximum being with the isolates 39P (77.8%) and 15B (64.2%), respectively. Nineteen of the isolates showed catechol and hydroxamate type siderophore production. All the isolates produced ammonia and twelve showed HCN production. On the basis of their antagonistic and PGP functionality traits, five isolates (2B, 7B, 28P, 34P and 38P) were selected for glass house studies on two chickpea varieties (JG-62 and GPF-2). Isolates 28P, 34P and 38P were found to be most promising for wilt control and plant growth promotion. Isolate 38P reduced the wilt incidence to 44.6% which was at par with fungicide treatment (55.5%) and had a significant edge over negative control (85%) in the chickpea variety JG-62. Similar trend of wilt incidence was observed in GPF-2 variety. Green house experiments on two varieties of chickpea JG-62 and GPF-2 showed that seed treatment with plant growth promoting rhizobacteria (PGPR) + Mesorhizobia had a synergistic effect in terms of disease control and growth promotion as compared to use of single bioinoculants, thus positively influencing plant microbe interaction. Key words: Antagonism, chickpea, Fusarium, plant growth promoting rhizobacteria (PGPR), Rhizobium.

To mitigate environmental stresses, use of aminocyclopropane-1-carboxylic acid (ACC)-deaminase containing plant growth promoting rhizobacteria (PGPR) as agricultural inputs for improved crop production is required. A total of 47 bacterial isolates from different rhizospheric soils of chickpea from Punjab were biochemically characterized and found to be representatives of genus Bacillus (25) and Pseudomonas (22). Ten (10) of the isolates were able to utilize ACC as a sole source of nitrogen, maximum growth (in terms of optical density λ600) being recorded with Bacillus isolate 23-B (0.463) followed by Pseudomonas 6-P (0.317). Three isolates were P-solubilizers and their relative P-solubilization efficiency ranged from 14.6 to 21.6 mg/100 ml culture broth. All the isolates produced Indole-3-acetic acid (IAA) (4.4-22.8 µg/ml). Two PGPR’s 23-B and 6-P alone and in combination with recommended (for Punjab state) Mesorhizobium ciceris, were evaluated for water stress mitigation and plant growth promotion under axenic conditions on Cicer arietinum varieties (Kabuli L-552 and Desi GPF-2). Both the rhizobacteria significantly improved germination, root and shoot length and fresh weight of chickpea seedlings under osmotic potential of up to 0.4 MPa over uninoculated control. Proline content was considerably higher in PGPR treated varieties of chickpea under water stress. Co-inoculation of 23-B with Mesorhizobium enhanced all growth parameters under water stress. Key words: Aminocyclopropane-1-carboxylic acid (ACC)-deaminase, axenic, chickpea, polyethylene glycol (PEG), proline.