Feyissa TileyeTadesse TayeOlani Gamachu2018-06-182023-11-182018-06-182023-11-182017-06http://etd.aau.edu.et/handle/12345678/1095Sorghum [Sorghum bicolor (L.) Moench], a cereal crop of family Poaceae, is believed to be originated in Ethiopia and Sudan. It is an important food security crop mainly in semi arid and tropical parts of the African countries. Although many morphological and molecular diversity studies reveal the existence of genetic bvariations with sorghum populations, their distribution within basic races were not considered. Hence, the present study aimed to analyze the extent and distribution of genetic variation within basic Ethiopian sorghum landraces using SSR markers. A total of 107 landraces obtained from Ethiopian Biodiversity Institute (EBI) representing 12 ecological zones grouped according to their race types based on inflorescence and spiklet on field at their maturity time. Twelve SSR markers revealed a total of 110 alleleswith average polymorphic content of 0.76 and the allele frequencies shows 42 of alleleswere rare (less than 0.05), 22 ranged from 0.05 to 0.1, while 46 of them were higher than0.1. Expected and observed heterozygosity were 0.78 and 0.2 respectively. The geneticdifferentiation between populations were also moderate (FST=0.07 for races and 0.13 forE/zones) indicating continuous exchange of genes among them. Partitioning the totalgenetic variation also indicated 61.38% and 55.17% of the variations were amongindividuals within racial and zonal populations respectively. Neighbor-Joining clusteranalysis also indicated four major grouping of the landraces according to their racialgroups where majority of race caudatum and durra form separate groups whileintermediate durra-bicolor form two separate sub-clusters. Overall locus the intra-racialpopulation diversity showed the greatest genetic diversity (He=0.77 and 0.75) amongrace bicolor and caudatum respectively. Information with sorghum races along theirimportant agronomic traits could be used for conservation and future breeding programsof sorghum. Key words: Sorghum bicolor; races; Genetic diversity;SSRenSorghum bicolor; races; Genetic diversity;SSRThesis