Evaluation of symbiotic effects of different strains of Mesorhizobium cicer on drought stress tolerance of chickpea cultivars (Cicer arietinum L.)

A factorial experiment based on completely randomized design with three replications was carried out in order to study the effect of different strains of Mesorhizobium ciceri on chickpea tolerance under drought stress. In the first step of experiment، five native cultivars of chickpea (bivanij، arman، greet، jam and hashem) were inoculated with eight native (C-15، C-22، SWRI7، SWRI9 and SWRI4) and non-native (CP-31، CP-36 and IC-59) strains of M. ciceri. Growth traits (nodule number، dry weight of nodules، shoot and root) were measured four weeks after inoculation. The results showed that symbiosis of bivanij cultivar with considered Rhizobium strains is the most effective symbiosis according to the evaluated growth indicators. In the next stage of experiment، different strains of M. ciceri were inoculated with bivanij cultivar and drought stress was imposed by using PEG6000 (Ѱπ=-0. 3) on four- week-old plants for 15 days. Results showed that growth traits such as nodule and shoot dry weight of chickpea plants inoculated with C-15 strain had lower reduction than those inoculated with other strains at stress conditions. Thus it can be concluded that the selection of effective strains could lead to the enhancement of chickpea production. Moreover، the tolerance of chickpea plants to drought stress could be enhanced by selection of effective strains.