Phenotypic diversity and plant growth promoting characteristics of Mesorhizobium species isolated from chickpea (Cicer arietinum L.) growing areas of Ethiopia

Abstract

Chickpea (Cicer arietinum L.) is one of the major sources of dietary protein for majority of Ethiopian population. It also maintains soil fertility through its symbiotic nitrogen-fixation in association with Mesorhizobium species. Therefore, this study was aimed at isolation, characterization and selection of symbiotically effective native chickpea nodulating rhizobia endowed with different plant growth promoting (PGP) characteristics. Hence, phenotypic and plant growth promoting characteristics of thirty-six rhizobia isolates recovered from root nodules of chickpea grown in soils collected from different chickpea producing areas found in Central and Northern part of Ethiopia were investigated. The result of our study indicated that chickpea rhizobial isolates have shown 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 tested isolates. Moreover, screening for PGP characteristics indicated that 44.4% of the isolates were phosphate solubilizer while 27.8% of them were found to be indole-3-acetic acid (IAA) producer. Furthermore, 19.4% tested isolates showed antagonistic activity against Fusarium oxysporum in dual culture assay. Generally, the present study indicates that Ethiopian soils contain symbiotically effective chickpea nodulating rhizobia which are endowed with different PGP characteristics.

Keywords: Chickpea, Mesorhizobium, plant growth promoting, Ethiopia, symbiotic nitrogen fixation

African Journal of Biotechnology Vol. 11(29), pp. 7483-7493, 10 April, 2012