IMPROVEMENT OF GROWTH AND SALINITY TOLERANCE OF RICE (Oryza sativa L.) CV. NAVEEN AND LUNA SANKHI BIOPRIMED WITH OSMOTOLERANT PHYTONIC PLANT GROWTH PROMOTING BACTERIA

Abstract

Five osmotolerant plant growth promoting bacteria (PGPB) viz. Bacillus (SV4, W1), Pseudomonas (NR4), Enterobacter (RP8) and Salinicola (S36) spp. were evaluated for enhancement of growth and osmotolerance of rice cv. Naveen (NV) and Luna Sankhi (LS) to select most prospective PGPB to enhance rice production. Biopriming of NV seeds with Salinicola and Pseudomonas spp. increased radical/plumule length, root no., seedling fr./dr. wt. (114.29 - 229.32%) more than three (SV4, W1, RP8) other bacteria (84.62 - 140.48%) and control (100%). Vegetative and reproductive growth of LS seedlings for NR4 (103.33-181.94%) or S36 (108.19- 209.39%) and N:1/2P:K fertilizer co-treatments were either comparable or more than those of sole N:1/2P:K (103.58-195.75%) treatment. LS seedling (7d) growth declined for ≥ 0.21% NaCl (11.61 - 94.74%) and secondary root emergence for ≥ 0.43% NaCl (0%) in petriplate test but S36 (superior) and NR4 priming reduced stress effects, enhanced osmotolerance of seedlings from inherent 6-8 dS/m for 15-21d to 8 dS/m (0.43% NaCl) for 30d in submerged pot test, 12 dS/m (0.7% NaCl) for 30d by S36 treatment in salinity tank and growth components by 124.96-400% over control (12dS/m). Investigations identified S36 and NR4 as prospective osmotolerant PGPB for rice improvement under saline and normal conditions.