Identification of basmati rice (Oryza sativa L.) rhizobacteria and their effect on plant growth traits for sustainable development in agriculture

Abstract

Plant growth-promoting rhizobacteria (PGPR) play an important role to support the plant growth on sustainable basis. The present study was undertaken to identify the potential PGPR associated with the rhizosphere of basmati rice and in vivo screen for their effect on morphological traits. It also investigates the combined study of PGPR with synthetic fertilizers on basmati rice production. A total of 617 bacterial isolates were selected randomly from the rhizosphere, endorhizosphere and bulk soil of different rice fields. The preliminary characterization of bacteria for different plant growth promoting (PGP) traits led to the selection of PGPR for further studies. The 16S rRNA sequencing of the isolates classified the PGPR into nine different genera i.e. Bacillus, Pseudomonas, Streptomyces, Exiguobacterium, Aeromonas, Chryseobacterium, Enterobacter and Stenotrophonomonas. Overall, 18 most promising native strains of PGPR were applied alone or in combination with 50% recommended dosage of NPK fertilizers (RDF) to study their role in morphological growth parameters of rice. All the PGPR isolates showed an increase in plant growth compared to the control but in combination with 50% RDF, more significant growth was observed. Pseudomonas otitidis sp. SB 5 (T5) along with dose of fertilizers exhibited highest increase in root length (37 cm/plant) compared to the control and individual treatment of PGPR. Enterobacter sp. (T4 + NPK) showed highest shoot length (109.75 cm/plant) with significant increases (p < 0.5) over the uninoculated control. Chryseobacterium sp. (T18 + NPK) gave significant increase in fresh and dry weight of root and shoot, compared to T18 and control plant. This is the first report for identification of PGPR in basmati growing area under Geographical Indicator (GI) and their effect on plant growth `promotion. Thus, their use can improve the yield and profit of rice crop with reduced synthetic fertilization.