Screening and characterization of plant growth promoting rhizobacteria and their effect on growth and yield of barley (Hordeum vulgare L.)

Abstract

A multitude of roles are played by microbes in food and agriculture that include nutrient cycling and management, organic matter decomposition and fermentation. Plant growth promoting rhizobacteria (PGPR), representing microbial groups and with the ability of colonizing plant roots, influence plant growth through various indirect and direct modes in order to promote its growth and/or protect it from diseases or damage due to insect attack. This research was conducted during August 2022 to April 2023 at Chandigarh University, Punjab, wherein 15 bacterial isolates were isolated from rhizospheric soils of different crop plants. Isolates were identified based on biochemical characteristics and their plant growth promotional efficiencies were tested in-vitro. A total of ten isolates were found positive for four or more than 4 plant growth promoting traits. These isolates were further identified at molecular level using amplification and sequencing of 16S rDNA sequences. Sequences were submitted to the NCBI GenBank portal and accessions numbers were obtained. Potential microbial strains were inoculated with Barley seeds and a significant increase in plant height, dry weight and wet weight as well as number of seeds was recorded in inoculated plants as compared to control plants. However, maximum plant growth and yield was recorded in the plants inoculated with isolates 21B (Klebsiella quasivariicola) and 28B (Arthrobacter sp.). These isolates may become very crucial alternatives of chemical fertilizers for sustainable agriculture.