Assessing Tolerance of Rhizobial - Lentil Symbiosis Isolates to Salinity and Drought in Dry Land Farming Condition

Document Type : Research Paper

Authors

1 Associate Porfessor in Soil Science Engineering Department., Faculty of Agriculture, University of Tehran, Karaj

2 Research Officer in Soil Science Engineering Department., Faculty of Agriculture, University of Tehran, Karaj

Abstract

In this research 220 rhizobial bacteria were isolated from two lentil dry land farming flat plains of Moghan and Koohin, and then they were tested in vivo and in vitro to assurance of 184 purified strains of rhizobium leguminosarum biovar vicial (lentil). BTB +YMA culture media with different levels of salinity by NaCl (10, 20 …50dS/m) was used in saline tolerance test of rhizobial lentil symbiosis strains. Among 184 rhizobial strains, 101 strains were completely sensitive (EC=10 dS/m) and 25 strains were very tolerant and 10 strains were super strains which were completely tolerant to salinity. The number of Koohin flat plain grown rhizobial strains in salinity levels of 10 to 50 was respectively 55, 51, 50, 27, 29 while for Moghan flat plain , these numbers were as 46,42, 21, 8 and 6. Altogether Koohin flat plain rhizobacteria were more high saline tolerant than Moghan flat plain rhizobacteria. Drought tolerance test of rhizobial strains was performed in PEG 6000 +YMA culture media. The drought level was evaluated based on optical density of bacterial suspension in this test. Drought tolerance of rhizobacteria were grouped in 4 levels of completely tolerant, tolerant, sensitive and completely sensitive by optical density of OD0.5, respectively. Among 10 super strains(very completely tolerant) which are thoroughly tolerant, 6  super strains of Moghan flat plain and 8 super strains of Koohin flat plain were selected. At last we hope that the super strains (salinity and drought) in this step of research can be used in later green house studies.

Keywords

Volume 2, Issue 1 - Serial Number 1
October 2010
Pages 59-68

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