Influence of psychrotolerant plant growth-promoting rhizobacteria (PGPR) as coinoculants with Rhizobium on growth parameters and yield of lentil (Lens culinaris Medikus)

Abstract

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 temps. and such PGPRs are metabolically functional at cold conditions. Thirty-five (35) rhizobacterial isolates were isolated from lentil rhizospheric soil, six isolates showing max. exponential growth at both 10 and 15°C after 24 h were selected and characterized belonging to genera Bacillus and Pseudomonas. Prodn. of indole acetic acid (IAA) ranged from 12.7-17.5 $μ$gml-1 at 10°C to 18.4-20.4 $μ$g/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-solubilization at 15°C, ranged from 62.5 - 77.2 $μ$gml-1. However, at 10°C none of the isolates solubilized P. At 15°C, catechol type siderophore prodn. ranged from 523.4 - 606.1 $μ$gml-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 no., nodule dry wt., plant and root dry wt., chlorophyll and legHb 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%). [on SciFinder(R)]