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Title: Pattern of Nodulation and Nitrogen Fixing Performance of Introduced Forage Legumes in Some Parts of North Gondar, Ethiopia
Authors: Fekadu, Shimekite
Keywords: Introduced forage legumes
Nitrogen fixation
Rhizobium leguminosarum var viceae
Sinorhizobium meliloti
Bradyrhizobium spp
Date Added: 31-Aug-2007
Abstract: Six exotic herbaceous forage legumes namely, Desmodium uncinatum (desmodium), Lablab purpureus (lablab), Medicago sativa (alfalfa), Trifolium repens (white clover), Vigna unguiculata (cowpea) and Vicia dasycarpa (common vetch) were induced for nodulation on Dembia and Wegera soils for which all except, desmodium and white clover legumes nodulated their host. From the nodulated legumes, nineteen isolates were isolated and characterized based on their morphological, cultural, and physiological properties. In the preliminary screening eleven isolates of alfalfa, three isolates of vetch were assigned as fast growing Sinorhizobium meliloti and R. leguminosarum var viceae respectively. The isolates of lablab (three) and cowpea (two) were assigned as slow growing Bradyrhizobium species. The vetch isolates AUVR11, AUVR13 from Wegera and AUVR14 (R. leguminosarum var viceae) from Dembia and alfalfa isolates AUMR3 and AUMR10 from Wegera; and AUMR9 from Dembia (S. meliloti) were found to renodulate their respective hosts. The nodulating isolates were studied with respect to their relative effectiveness in nitrogen fixation. Inoculation of vetch by R. leguminosarum var viceae showed significant differences in percent effectiveness (30%-83%) on vetch, and (50-100%) on alfalfa. AUVR13 (vetch) and AUMR9 (alfalfa) were found to be the most efficient strains with percentage effectiveness of 83% and 100% respectively. Although the performance of the vetch isolates on two different soils showed that there was no any inter strain difference on each soil, Dembia soil responded better in SDW and TN than Holetta soil indicating that some soil-related factors such as pH affect symbiotic effectiveness. Generally, the fact that the number of infective and effective isolates of the introduced legumes in Dembia and Wegera weredas was very small may necessitate more exhaustive screening in different regions and the need for inoculation with effective exotic endosymbionts to fully realize the potential of Biological Nitrogen Fixation in forage production in animal husbandry.
Description: A Thesis Submitted to the School of Graduate Studies of Addis Ababa University in Partial Fulfillment of the Requirements for the Degree of Masters of Science in Applied Microbiology
URI: http://hdl.handle.net/123456789/35
Appears in:Thesis - Biology

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