Evaluation of symbiotic effectiveness and size of resident Rhizobium leguminosarum var. viciae nodulating lentil (Lens culinaris medic) in some Ethiopian soils

Abstract This study was initiated to isolate, characterize and select symbiotically effective rhizobia nodulating lentil (Lens culinaris medic) and to enumerate of indigenous rhizobia nodulating lentil in some Ethiopian soils. More than 84 nodule and soil samples were collected. In sand culture, only 62 isolates were authenticated as rhizobia nodulating lentil. Analyses of variance indicated that most of the parameters measured were significantly (p< 0.05) improved by inoculation except root length. Inoculation increased the shoot length, shoot dry weight, and plant total nitrogen as 82.3%, 196.7% and 452%, respectively, over negative control. Tested isolates was found to be very effective (20.9%), effective (77.4%), and only one ineffective isolate. Indigenous rhizobia in investigated soils ranged from 30 to 5.8x103 cell g-1 of dry soil. A pot experiment with selected rhizobia and nitrogen fertilizer on Chefedonsa and Debrezeit soils did not show any significant difference in shoot dry weight at P <0.05. From the study it was observed that most Ethiopian soils were inhabited with moderate to high number of indigenous rhizobia and also rhizobia inoculation did not improve lentil productivity in investigated soils.