Effects of rhizobia and plant growth promoting bacteria inoculation on germination and seedling vigor of lowland rice

Abstract

Plant growth promoting rhizobacteria (PGPR) stimulate plant growth by producing phytohormone which enhances the growth and physiological activities of the host plant. Recently, legume bacteria (Rhizobium spp.) have been considered as a PGPR for legume as well as non-legumes and have the potential for growth stimulation. A laboratory experiment was conducted to observe the effect of PGPR and Rhizobial inoculation on seed germination, seedling emergence, growth and development of lowland rice variety MR219. The experiment was conducted under laboratory condition using filter paper in Petri dish. The design of the experiment was completely randomized (CRD) with six replicates. The PGPR strains UPMB10 (Bacillus sphaericus), Rhizobium strains SB16, UPMR1006 and UPMR1102 were used in the experiment. Seeds inoculated with those PGPR and Rhizobium strains and the Petri dish were kept in an incubator at 30 ± 2°C for 120 h. The seeds germination and other related attributes were measured. The results suggested that inoculation significantly increased the seedling emergence, seedling vigor, root growth namely root length, root surface area and volume. Among the strains, UPMB10 performed better in seedling growth and strain UPMR1006 produced profuse hair in the radical. The results concluded that PGPR and Rhizobia strain can promote seed emergence and seedling attributes which benefits the early seedling establishment and consequently the crop growth and development.

Key words: Rhizobium, PGPR, seedling vigor, germination, rice.