A.Gashe Berhanu (PhD)Andenow Yeshi2018-07-172023-11-092018-07-172023-11-091984-05http://etd.aau.edu.et/handle/123456789/9005From infected sorghum leaves ~ough~ from three different place, 17 yellol'l coloured bacterial coldmies were isolated. After having conducted hypersensitivi.y, morphological, physiological and biochemical tests, including pathogenicity test using sorghum line W8 1297 as a susceptible host, only one isolate was found to be Xanthomonas ~lc~cola. the causal organism of bacterial streak disease of sorghum. Six different inoculation techniques were compared to achieve an effective method of screening together with pathogenicity test. The isolated organism induced typical symptomatic response when the rub and spray method of inoculation was used. Using the rub and spray method, 31 sorghum lines, 7 from highland (about 2000 metres), 8 from intermediate (1600-1900 metres), 15 from lowland (800_1600 metres) and sorghum WS 1297 as s control were examined for resistance to bacterial streak disease caused by .!.holcicola. High resistance to the disease was sho"m by sorghum lines 80 K 6056, Gambella 1107, 80 ~ 6088, 81 ESIP 21, 81 ESIP 25, Melkamash 79, ETS 0601, ETS 4946. Of these 75% are from lowland and 25% are from highland groups. Sorghum lines IS 9294, IS 9302, IS 9379, .81 ESIP 29, Dobbs, IS 8686, Muyra white,IS 9923 nnd'thll control \~S 1297 showed susceptible reactions. Of the susceptible sorghum lines 62,5% are from intermediate, 25% from lowland and 12.5% from highland groups. The reaction of the other lines range from moderately resistant to moderately susceptible.enBiologyThesis