Characterization And Symbiotic Effectiveness Of Indigenous Rhizobial Isolates On Growth Responses Of Trigonella Foenum Graecum. L In East Gojjam Zone, ISOLATES ON GROWTH RESPONSES OF TRIGONELLA FOENUM GRAECUM. L IN EAST GOJJAM ZONE, ETHIOPIA

Abstract

Legumes form symbiotic relationship with some soil bacteria such as Rhizobia. The study was designed to isolate, characterize and evaluate symbiotic effectiveness of Rhizobium from root nodules of T.foenum graecum L. Three to five nodules per plant were collected from six main T. foenumgraecum L.growing areas in Shebel Berenta in East Gojjam Zone. Thirty root nodule samples were collected in glass vial containing silica gel and transported to Holleta agricultural research center. The samples were preserved at room temperature. The collected data were analyzed using SPSS version25 and Microsoft excel. 15. Rhizobium isolates were obtained by the aseptic Rhizobia presumptive and confirmatory screening (YEMA-CR), (YEMA-BTB) tests and selected as candidates for authentication. Those fast growers, gram-negative, rod shaped, culturally round shaped, white milky and sticky mucoid regardless of colony size in the range of 2.8 to 4.3 mm.Cultures were maintained on (0.3%) YEMA slant and (40%) glycerol for further study and field check. A total of 12 (80%) infective isolates out of 15 showed positive reactions for catalase test, motility, starch hydrolysis test and gave a negative test result for urease. But, vary in citrate utilization, gelatin liquefaction and Indole acetic acid production. Isolates were showed a wide range of growth responses to temperature with maximum value at 28±2oC (32.74%), salt (%w/v); 0.01(32.6%), pH; 6.5 (23.14%) and 6.8 (25.47%) in 48 hours of incubation. Isolates were highly sensitive to antibiotics; levofloxacin, gentamycin and chloramphenicol. The isolates utilized different carbon and nitrogen sources. In vivo characterization of 15 isolates under green house conditions, showed significant variations in symbiotic effectiveness JUWgR13 (50.58%), JUGyR53 (55.47%), JUYwR23 (61.63%), JUWgR12 (63.39%) and JUWgR11 (105.65%). The numerical analysis of the isolates on forty one phenotypic features and stastical analysis of symbiotic infective characteristics showed the diversity across areas of collection and between isolates.