Plant Growth Promoting Properties of Rhizobactel'ia Isolated from Chickpea and Lentil Producing Areas of Ethiopia: Implication for Productivity in Low-inputs Agricultural system
No Thumbnail Available
Date
2013-06
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Addis Ababa Universty
Abstract
Chickpea (Cieer arielinulIl L.) and lentil (Lens euinaris Medik.) are among the major sources of
dietary protein for the majority of population in Ethiopia. They also restore and maintain soil
fertility through their symbiotic nitrogen-fixation in association with rhizobia. This study was
intended to investigate plant growth promoting propelties of chickpea and lentil nodulating
rhizobia and phosphate solubilizing bacterial isolates fi'om major producing areas of the country.
Accordingly, a total of 157 bacterial isolates were obtained and characterized using different
standard methods. Phenotypic and plant gro\\1h promoting characteristics of 66 rhizobia I isolates
recovered fi'omroot nodules of chickpea and lentil grown in soils collected fi'Dln producing areas
of the country were investigated. These rhizobial isolates showed wide diversity in their different
C and N-sources utilization pattern and tolerance to salinity, high temperatures, acid and alkaline
pH, heavy metals and antibiotics. Symbiotic and morphological characterization also showed a
wide diversity among these rhizobial isolates. Moreover, some of these rhizobial isolates
exhibited plant groMh promoting characteristics such as phosphate solubilization, IAA
production and antagonistic activity against FusariulIl o.\)'sporulll. In addition, a total of 91
phosphate solubilizing bacterial isolates were obtained fi'om chickpea and lentil rhizosphere soil
samples collected fi'om different producing areas of the country. These isolates were identified
using the API biochemical test kits and partial 16S rDNA sequences analysis. The result showed
the presence of genera such as Aeinelobacler, Aerolllonas, Agl'ObacleriulIl, Bacillus,
Brevibacillus, BUl'khoideria, Chl)iSeOmOnas, Empedobaclel', Enlel'Obaclel', Pseudomonlls,
Raislonia, Sphingomonas and Slenoll'Ophomonas. Phosphate solubilizing efficiency of the
isolates was assessed qualitatively using solubilization index and quantitatively. Quantitative estimation of the phosphate solubilization efficiency of different insoluble phosphorus sources
showed that most isolates have good solubilization ability of tricalcium phosphate, rock
phosphate and bone meal. Furthermore, some of these isolates showed multiple plant growth
promoting characteristics; production of indole acetic acid and fluorescent siderophore, and
inhibition of FusariulII oxysporulII growth under ill vitro conditions. The effects of inoculation of
isolates with multiple plant growth promoting properties on chickpea and lentil growth in pot
culture showed significant improvement in number of nodules, shoot dry matter, shoot nitrogen
and phosphorus contents. Generally, the present study indicated that Ethiopian soils contain
symbiotically effective chickpea and lentil rhizobia which are endowed with different plant
growth promoting attributes. Moreover, chickpea and lentil rhizosphere harbor phosphate
solubilizing bacteria which are diverse in their taxonomy and phosphate solubilizing efficiency.
Some of these isolates are of particular interest for further research under different tield
conditions.
Key words: IAA, MesorhizohiulII species, PGPR, PSB, RhizobiulII species
Description
Keywords
IAA, MesorhizohiulII species, PGPR, PSB