Growth Promotion of ICCV 2 Variety of Chickpea ( Cicer arietinum L.) by Diazotrophic Bacteria Isolated From Root and Stem Nodules of Leguminous Plants

Six rhizobia-like-bacterial strains in total, secluded from the root and stem nodules of various leguminous plants were characterized for growth promoting ability and nitrogen fixation potential on ICCV 2 variety of chickpea. All the six bacteria, were found to produce PGP traits including IAA, NH 3 , protease, lipase, cellulase, β-1, 3-glucanase, siderophore, ACC deaminase (except IHSR), chitinase (except IHSR, IHAA and IHCP-1), amylase (except IHSR, IHRG and IHAA), hydrocyanic acid  (except IHGN-3), solubilize phosphate, zinc (except IHSR), rock phosphate (except IHSR and IHCP-2) and  potassium (except IHSR, IHRG, IHGN-3 and IHCP-2). The sequences of 16S rRNA gene of IHSR, IHRG, IHAA, IHGN-3, IHCP-1 and IHCP-2 showed maximum identity with Rhizobium sp., Rhizobium tropici , Rhizobium multihospitium , Mesorhizobium sp., Burkholderia cepacia and Rhizobium pusense . All the isolated bacteria showed nodule formation with chickpea, amplified nifH gene and fixed nitrogen. SEM study of chickpea roots showed a significant degree of colonization by all the six bacterial strains in solo and by consortium. Seeds of chickpea, when treated with the isolated bacteria, increased the plant height, number of branches, total chlorophyll, nodule number, nodule weight, shoot weight, root weight, root volume and root surface area respectively at 30 and 45 DAS, over the control plants. At the crop maturity, the diazotrophic bacteria treated pots exhibited enhanced pod number, shoot weight, seed number, total NPK respectively, over the control plants. This study suggests that bacteria associated with root and stem nodules can be a promising resource for enhancing nodulation, nitrogen fixation, PGP and crop yields in chickpea.