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Title: Symbiotic Effectiveness and phenotypic Characterization of Rhizobia Nodulating Chickpea (Cicer arietinum) from some growing areas of South and North Wollo zones
Authors: Ahmed, Seid
Advisors: Fassil Assefa (PhD)
Keywords: Biological nitrogen fixation,
Phenotypic diversity
Copyright: Jun-2010
Date Added: 6-May-2012
Abstract: ABSTRACT Chickpea is one of the cool seasons legume cultivated in many part of the world. Ethiopia is the largest chickpea growing country in Africa. The major producing areas are concentrated in Amhara and Oromia Regional States. In areas where there is depletion of soil with nitrogen fertilizer, must be inoculated with the most symbiotically effective isolates to restore the fertility status of the soil. Therefore to develop inoculants, isolates must first be screened and characterized to know their status. The failure of some rhizobial isolates to re-inoculate their host in the previous work by Daniel Muleta (2009) needed further search for screening of isolates. So this study was aimed to characterize chickpea isolates from some major growing areas. Thirty eight chickpea root nodules were collected from farmers plots in South and North Wollo zones. Ten of the isolates were rejected in the process of isolation and presumptive tests. The rest were reinoculated in to their host for authentication. From the reinoculated isolates, twenty seven formed nodules in their host but one isolate failed to form nodule upon reinoculation. The authenticated rhizobia were characterized based on their, morphological and eco-physiological features. From the preliminary screening 96% of the isolates were fast growing rhizobia. Symbiotic effectiveness of isolates showed significant difference in percent effectiveness (34-92%) on the host plant. AAUCR 27 and AAUCR 9 were found to be the most effective isolates with percent effectiveness of 81% and 92% respectively. The majority of isolates were categorized under effective rate which posses percent of effectiveness 50-80%. Isolates were also tested for their tolerance to different eco-physiological features such as pH, temperature, salt concentration, intrinsic antibiotic resistance and utilization of different nitrogen sources. These tests showed the presence of wide physiological diversity between isolates. Plants inoculated with different isolates displayed differences in respect to nodule number, nodule dry weight and shoot dry weight. The numerical analysis of isolates based on forty six phenotypic features showed the presence of diversity among isolates and also statistical analysis indicates their diversity towards symbiotic effectiveness. Some isolates such as AAUCR 9 and AAUCR 27 that are highly effective and tolerant to a wide range of phenotypic features are promising in the development of inoculants.
URI: http://hdl.handle.net/123456789/2624
Appears in:Thesis - Biology

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