Application of Plant Growth Promoting Rhizobacteria in Growth Enhancement of a Multipurpose crop Crotalaria Juncea (Sunhemp) in Saline Soil

Abstract

Salinity is a major abiotic stress which limits the crop productivity. In this study salt tolerant bacteria were isolated from root nodules of Crotalaria juncea plant collected from different salt affected sites. Salt tolerance activity of all the isolates was checked and it was observed that 47% of the isolates showed up to 8% salt tolerance. On the basis of morphological, biochemical and physiological characterization isolates were found to be Gram negative, rod shaped and motile bacteria that belong to rhizobia. All the isolates also showed nodulation in host plant. Most of the isolates were positive for various plant growth promoting attributes. On the basis of salt tolerance and plant growth promoting characterization isolate CR6 was selected for further studies. CR6 showed positive results for phosphate and zinc solubilisation, and was able to produce indole acetic acid (IAA), siderophore and exopolysaccharides (EPS). CR6 also showed nitrogen fixation and ACC deaminase activity. CR6 was applied on Crotalaria plant to enhance growth in saline soil. After application of CR6 seed germination rate and various growth parameters such as root length, shoot length, nodule number, fresh weight, dry weight, leaves count, chlorophyll and proline content of plants were enhanced in comparison to control, hence CR6 can be used as an efficient bioinoculant to enhance crop growth in saline soil.