Dagne, Kifle (PhD)Fetene, Masresha (Professor)Bekele, Dagnachew2018-06-262023-11-082018-06-262023-11-082008-07http://etd.aau.edu.et/handle/123456789/3403In Ethiopia, the extent of genetic diversity among sorghum germplasm collections from drought prone areas has not been well studied. To determine the extent of genetic diversity among different sorghum genotypes grown in major moisture stressed areas of Ethiopia, a total of 495 sorghum accessions were evaluated at two representative moisture stress areas. Thirteen quantitative and six qualitative traits were used in this study. For the quantitative traits, univariate, bivariate and multivariate statistical methods were applied to analyse the genetic diversity. Moreover, the phenotypic diversity between the accessions and regions of origin were estimated based on the qualitative traits using Shannon-Weaver diversity index (H  ). Analysis of variance revealed significant difference among the accessions for all quantitative traits. Based on their field performance in moisture stress areas, 95 potential drought tolerant sorghum accessions were identified for further evaluation. Moreover, cluster analysis grouped the test accessions into eight clusters with different genetic distance between each cluster. Maximum genetic distances were obtained between clusters C7 & C8, C4 & C8, and C6 & C7 with D2 190.78, 160.95 and 147.98, respectively. In principal component analysis, the first four principal components explained 62.09% of the total variation, indicating existence of high genetic diversity among the accessions. Furthermore, all the qualitative characters showed high diversity in their distribution as well as in the amount of variation. The overall average phenotypic diversity (H) among accessions was 0.82, varying from 0.66 for inflorescence exertion to 0.93 for grain color. The partitioning of the phenotypic diversity into within and between regions of origins indicated that 87 % of the total variation was within regions of origin, while only 13% was found between regions of origin. Therefore, this study confirms the existence of very high genetic diversity in sorghum germplasm accessions grown in the drought prone areas of Ethiopia, providing a great opportunity to isolate a number of promising parents with good traits related to drought tolerance, for crossing to develop drought tolerant/resistant sorghum varieties. Key words: Sorghum, Genetic diversity, Drought, Ethiopia, Quantitative traits, Qualitative traitsenSorghumGenetic diversityDroughtEthiopia,Quantitative traitsQualitative traitsThesis