Effects of Phosphate Solubilizing Rhizobia on the Growth of Teff (Eragrostis teff) under Greenhouse Conditions in Ethiopia

Abstract

Phosphorus is the second most important nutrient for plant growth, but its availability is very low in the soil. This study was designed to identify phosphate-solubilizing Rhizobia from rhizosphere soil in Gorogutu and Deder districts of Ethiopia. The study evaluates the effects of phosphate-solubilizing Rhizobia on Teff (Eragrostis teff) growth under greenhouse conditions. The greenhouse experiment was assembled in a completely randomized design with 5 treatments including the control with three replications. A total of 30 Rhizobia isolates were obtained from rhizosphere soils in two districts (Gorogutu, and Deder) and screened for phosphate solubilization using Pikovskaya’s Agar. Based on their phosphate solubilization indices, 4 potential isolates (PS-6, PS-22, PS-27, and PS-30) were selected for further study in the greenhouse. Phosphate solubilizing isolates in pot experiment under greenhouse were applied at a rate of 0.5 g per pot and Teff disinfected seeds were suspended in 30 ml thick cell suspension of phosphate solubilizing Rhizobia (1012 cells/ml) in the presence of 0.5% peptone (antidiuretic hormone for 30 minutes), but not the control. The result showed that almost all inoculants, after 30- and 90-days inoculation, have significantly improved the growth parameters of Teff (Eragrostis teff) under greenhouse conditions. Moreover, all the isolates showed a positive impact on all the growth parameters. The results from this experiment are useful in Ethiopia for biofertilizer development and for teff growth under organic farming systems. Therefore, isolates PS-6 and PS-22 are highly recommended to be prospective commercial biofertilizers at field conditions in different teff agroecologies.