Characterization of cultivated sainfoin (Onobrychis mill., fabaceae) taxa and some of their wild relatives by using molecular cytogenetic methods

In this presented thesis study, cultivated species (O. viciifolia, O. arenaria, O. transcaucasica) and some of wild species of Onobrychis genus were analysed in details to obtain information about their genom structure and organisation using molecular cytogenetic methods. Accessions of Onobrychis species used in this study were obtained from USDA-NPGS collection. Chromosome numbers of 35 different Onobrychis species were determined. Two different basic chromosome numbers, x = 7 ve x = 8, were determined. Diploid species have 2n = 2x = 14 and 2n = 2x = 16, while poliplod species (except O. subacaulis 2n = 4x = 32) have 2n = 4x = 28 chromosome number. Chromosome numbers were found for O. pallasi (2n = 14), O. sternohiza (2n = 14) and O. vaginalis (2n = 16) species presented here for the first time. The genom structure of Onobrychis genus is presented here using fluorescense in situ hybridisation and genomic in situ hybridisation methods for the first time. The number and localization of rDNA loci were determined using fluorescense in situ hybridisation with 35S and 5S rDNA probes along somatic chromosomes of 33 Onobrychis species. In diplod species, 35S rDNA loci ranged from 1 to 4 per, 5S rDNA loci was determined 1 or 2 per along somatic chromosomes of Onobrychis species. In analysed diploid species, 35S rDNA loci was more variable than 5S rDNA loci. Except O. subacaulis, 4 per 5S and 2 per 35S rDNA loci were determined in all polyploid species. Elimination of both rDNA loci was observed in O. subacaulis. The genome size of genotypes which were analysed with FISH was estimated using flow cytometry and 2C nuclear DNA content in diploid species studied ranged from 0,65 pg to 1,47 pg shown almost 2,5 fold difference. Genome sizes of poliploid specis changed from 2,43 pg to 2,83 pg. Phylogenetic relationship inferred using nrITS sequences of 30 onobrychis species. In the phylogenetic tree resulting from data set, polyploid species mostly (except O. subacaulis) were placed in same clad whereas diploid species were place in different clades. The nuclear genome size, number of rDNA loci and basic chromosome number were mapped onto the phylogenetic tree seperately. Ancestral basic chromosome number was identified as x = 8. The interpretation of the rDNA locus patterns in a phylogenetic context revealed that the ancestral state was 1 per locus for 5S rDNA. To obtain information about the origin of the most well known cultivated species which is O. viciifolia was tested using GISH. Due the high genome similarity, O. kachetica was suggested one of the putative progenitors or progenitor diploid species. However, more experiments are required to be precise about the progenitor of O. viciifolia.