Tesfaye, Kassahun (PhD)Dagne, Kifle (PhD)Jifar, Habte2019-11-152023-11-082019-11-152023-11-082018-12-05http://etd.aau.edu.et/handle/123456789/20130Tef [Eragrostis tef (Zucc.) Trotter] is an indigenous major cereal crop widely grown and utilized in Ethiopia. It is an excellent source of healthy and nutritious human food and livestock feed. However, its productivity is significantly lower than that of major cereals grown in Ethiopia. Although diverse constraints contribute for its inferior grain yield, the huge diversity present in tef germplasm has not been exploited. This study was, therefore, conducted to assess the phenotypic and molecular diversity, genotype by environment interactions and variation of food-feed traits in tef genotypes from various sources. The field experiments were conducted at Holetta, Debre Zeit, Alem Tena, Adet, Axum and Shambu using randomized complete block design with three replications whereas, the laboratory analyses were conducted at the University of Bern in Switzerland, Sci-Co in South Africa, International Livestock Research Institute (ILRI) in Ethiopia and International Crops Research Institute for Semi-Arid Tropics (ICRISAT) in India. Phenotypic diversity was assessed based on 12 quantitative and five qualitative traits of 188 tef genotypes while, the genotyping study was conducted using 189 genotypes with 16 SSR markers. Results from phenotypic study revealed the existence of huge variability in plant height (60.7 to 107.1 cm), panicle length (19.5 to 39.5 cm), number of fertile tillers per plant (2.1 to 5.5), number of spikelets per panicle (156.7 to 441.7), thousand kernel weight (20.7 to 33.0 mg), grain yield (3.7 to 7.3 t/ha) and lodging index (44.7 to 79.3%). Molecular diversity study generated a total of 260 alleles for the total studied loci. Cluster and STRUCTURE analyses showed four gene pools, but with high level of admixtures due to geographic proximity and/or trans human seed exchange. Analysis of molecular variance showed significant variation of 56.6% within individuals, 40.8% among individuals within population and 2.6% among populations. Based on SSR study, furthermore, a core collection composed of 64 genotypes (33.9%) is suffice to capture the entire alleles of studied genotypes. Significant variations were also detected for all traits due to genotypes, environments and their interaction. Based on AMMI, GGE and Eberhart Russell’s model, G6 (Melko) was identified as the highest yielding and moderately stable variety while, E5 (Debre Zeit-1) was the highest yielding and ideal environment. GGE biplot grouped the test environments into four mega environments and the studied genotypes into seven groups. Analysis of food-feed traits revealed significant (P<0.01) effect of genotypes, year, locations and their interactions. Based on this, the highest mean crude protein (CP), in vitro organic matter digestibility (IVOMD), metabolic energy (ME), total biomass (TBM) and straw yield (STY), and the lowest mean for neutral detergent fiber (NDF), acid detergent fiber (ADF) and acid detergent lignin (ADL) were obtained from genotypes evaluated at Debre Zeit. Cluster analysis and PCA-biplot grouped the genotypes into four. These are, (i) those with improved feed quality traits such as Kena, Genet and Ambo Toke;(ii)) those with high food-feed traits such as Dukem, Gimbichu and Dega Tef; (iii) those with dual purpose such as Melko, Koye and Key Tena; and (iv) those with low food-feed traits such as Simada, Etsub and Mechare. The overall results of the present study enabled to identify tef genotypes with sufficient morpho-agronomic and molecular variations, better yield and stability, and food-feed traits having implications for collection, conservation and proper utilization of germplasm which are the basis of tef improvement.enAllelic RichnessEragrostis TefGenetic DiversityGenotypesPhenotypic DiversityPopulation StructureSimple Sequence RepeatsTefThesis