Morpho-agronomical and molecular marker based genetic diversity analyses and quality evaluation of sorghum [Sorghum bicolor (L.) Moench] genotypes

English: Sorghum is the most important cereal crop providing food to millions of people in the world. It is well known for its adaptation to harsh environments, specifically to drought and heat stresses, which accounts for its success throughout the semi-arid regions of the world. Africa, specifically the northeast quadrant of Africa is believed to be the primary centre of origin and domestication of the crop. In these parts of Africa, genetic variability is available both in cultivated races and the wild progenitors. In regard to sorghum utilization in general, developing countries use it primarily as food, whereas developed countries use it as feed. A wide variety of traditional foods are used from sorghum in the semi-arid tropics. Despite its importance, the genetic characterization of sorghum is very limited. The accurate estimation of genetic diversity of the species is important for conservation of valuable resources and possible future use in its improvement. Farmers' varieties or landraces (locally adapted populations bred through traditional methods of direct selection) are usually the major sources of genetic variation. Cultivated sorghums in Ethiopia show diverse morpho-agronomic diversity, and have not been studied using the recently developed molecular markers. The aim of this study was to estimate genetic diversity by using DNA markers, morpho-agronomical traits and food quality attributes in sorghum accessions. Forty-five accessions, including landrace collections, breeding materials and improved cultivars from the eastern highlands of Ethiopia were used. A total of 552 and 43 polymorphic AFLP and microsatellite alleles, respectively were scored and used to calculate pair-wise genetic distances and clustering. In addition, 10 qualitative and 16 quantitative traits with 96 variants were scored and used to analyse the genetic distances and clustering. The physical and chemical composition and food (injera)-making qualities of selected sorghum samples were also investigated. A high phenotypic, chemical and genetic variability among the accessions was observed. The resulting knowledge of genetic distance and discrimination of sorghum accessions, chemical composition variability and injera-making quality in this study will contribute towards sorghum improvement programmes in Ethiopia, and conservation of novel genotypes. It permits an organization of germ plasm resources and identification of parents for crossing blocks. This will enable the breeder/ improvement scientist to make more scientific based choices. These findings have shown that both AFLP and microsatellite techniques can be successfully used and that they are informative in estimation of genetic diversity and identification of sorghum accessions. The result from morphoagronomical traits analysis generally agreed with the molecular marker results in estimating diversity, hence it can be used in the management of sorghum genetic resources. A further extensive investigation of Ethiopian sorghum genetic diversity including wider areas and more samples is recommended.