Demissew, Sebsebe (Professor)Jorge, Alexandra (PhD)Tsegaye, Martha2018-07-032023-11-182018-07-032023-11-182007-03http://etd.aau.edu.et/handle/12345678/6007Lathyrus sativus (grasspea) has been widely cultivated in South Asia and Ethiopia for over 2500 years and is used as a food and feed. It is rich in protein content, around 30 g/100 g edible seeds. Agronomically, the species is able to withstand both severe drought as well as water logging. Although seeds of grasspea are tasty and protein rich, excessive consumption of the seeds causes a motor neuron disease called neurolathyrism which is characterized by the paralysis of the lower limbs. The neurotoxic causal agent of this disease is believed to be a non protein aminoacid called Oxalyl Di aminopropionic Acid (ODAP). Morphological marker analysis and molecular analysis have been used widely to estimate genetic variability of populations. These methods have useful in addressing questions on population genetic structure and genetic conservation. Knowledge of genetic diversity of species is particularly important, since modern breeding practices have narrowed the genetic diversity of cultivated crops. In the case of grasspea, the problem of Lathyrism is leading to the banning of its production which in turn aggravates genetic erosion and loss of diversity of the crop. Fifty one grasspea accessions which were selected from the genebank collection of International Livestock Research Institute (ILRI) were evaluated and characterized for different qualitative and quantitative morphological characters. Cluster analysis was performed to estimate differences between accessions. Randomly Amplified Polymorphic DNA (RAPD) was also used to study the nature of variation. In addition to L. sativus, three other species of the genus (L.cicera, L. clymenum and L. ochrus) and seventeen unidentified populations of Lathyrus were also evaluated for morphological and biochemical characters and characterized accordingly. Cluster analysis of both the morphological and the RAPD data showed that all of the unidentified Lathyrus populations were found to be L. sativus. The result also showed that two of the accessions (5295 and 5296) represented by L. ochrus and one accession (5282) represented by L. cicera were found to be L. sativus. The results would suggest that germplasm evaluation is important for proper characterization of populations. Key words: Lathyrus sativus, grasspea, genetic diversity, morphological characters, RAPD, cluster analysisenBiologyThesis