Abstract

• Phosphorus is an important macronutrient in plant metabolism, ultimately reflected on crop yields. Phosphate solubilizing bacteria (PSB) play essential role in inorganic and organic soil P solubilization and mineralization for plant growth. This experiment was conducted to study the effect of phosphate solubilizing bacteria (PSB) on the growth of Black gram. Among 10 isolated phosphate solubilizing bacteria from the rhizosphere of Vigna catjang Walp (Cow pea) and Phaseolus mungo Lin (Black gram), six strains, PSBCPR-1, PSBCPR-2, PSBBGR-2, PSBBGR-6, PSBBGS-1 and PSBBGS-2 were selected and used as inoculums. Laboratory experiment with six treatments and one control (only diluted peptone water) with five replicates was carried out in Microbiology Laboratory, Zoology Department, Pathein University during June to December 2019. In this study, root length, shoot length and total seed germination rate of treated plants significantly increased (p<0.05) over control. The maximum root length on treatment 2 (PSBCPR.2) and maximum shoot length on treatment 3 (PSBBGR-2) and treatment 6 (PSBGBS-2) were observed. Fresh weight and dry weight of treated seedling were also significantly increased over control. The isolates obtained in this study showed a significant in vitro plant growth promoting activity onto black gram. The use of these bacteria as bioinoculants could be a sustainable practice to facilitate the nutrient supply to black gram plants and preventing negative side-effects.