Effects of rhizobium strains isolated from wild chickpeas on the growth and symbiotic performance of chickpeas (Cicer arietinum L.) under salt stress

Abstract

This study was conducted in order to evaluate the symbiotic effectiveness of Rhizobium leguminosarum bv. ciceri strains isolated from perennial wild chickpeas (Cicer anatolicum) in comparison to standard bacterial culture, N application, and uninoculated control under NaCl salinity stress conditions. For this purpose, 4 strains (DN1, DN7, TN3, and TN4) were obtained from wild chickpeas. Chickpea (Cicer arietinum L.) seeds were inoculated with these strains and grown in pots containing sterile sand under different levels of NaCl (0, 50, and 100 mM) in a controlled plant growth cabinet. Dry weights of root and shoot, root-to-shoot ratio (RSR), number and dry weights of nodules, chlorophyll and N content of the plant, and amounts of total and fixed N decreased progressively with increasing salinity levels. In both non-saline and saline (50 and 100 mM NaCl) conditions, inoculations with Rhizobium leguminosarum by. ciceri strains isolated from wild chickpeas significantly increased all the above parameters compared-with the uninoculated control treatment, equal to or higher than standard culture and N application. However, chickpea rhizobia exhibited diversity in their salt tolerance. The plants inoculated with DN7, TN4, and standard culture produced more shoot mass, nodule dry weight, total N, and fixed N under saline conditions, especially at 50 mM NaCl, than the plants inoculated with DN1 and TN3. These results indicated that the ability of chickpea to grow and survive in saline conditions improved when it was inoculated with Rhizobium leguminosarum by. ciceri strains isolated from wild chickpeas, especially DN7 and TN4.