Efficiency of rhizobium strains as plant growth promoting rhizobacteria on morpho-physiological properties of Brassica napus L. under salinity stress

Abstract

Soil Salinity stress has been considered as one of the most severe environmental factors limiting the agricultural production worldwide. This study was aimed to evaluate the influence of plant growth promoting Rhizobium bacteria treatments (T1=without bacteria inoculation, T2=strain Sm29, T3=strain Sm103, T4=strain Rlp307, T5=strain Rlp281, T6=strain Rlp258, T7=strain Rlp266) on morpho-physiological parameters of canola (Bras-sica napus L.) under salinity stress (0, 3, 6 and 9 ds/m). Experimental treatments were performed as factorial in a Randomized Complete Block Design (RCBD) with three replications (n=3). Inoculation with halotolerant bacteria containing ACC-deaminase activity, IAA producing and mineral phosphate-solubilizing properties (i.e., T5) showed significant (p < 0.05) effect on growth indices, especially plant height and dry weight of the shoot with an increase of 35 and 26% in comparison with the control, respectively. However, T4 treatment with ACC deaminase-producing halotolerant and IAA producing bacteria was more efficient in increasing dry weight of the root (up to 56.5%). Moreover, Inoculation with bacteria that have more growth promoting attributes (e.g., ACC-deaminase activity, IAA producing and mineral-phosphate solubilizing attributes) was found to be highly promising under saline environment and can be taken up for the further field level testing.