Phd Degree / Doktora
Permanent URI for this collectionhttps://hdl.handle.net/11147/2869
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Doctoral Thesis Molecular Genetic Analysis in Cotton (gossypium Hirsutum L.)(Izmir Institute of Technology, 2021) Akköse Baytar, Asena; Doğanlar, SamiCotton is a valuable fiber crop for different industries especially the textile, food and oil industries. Drought causes serious yield losses in cotton throughout the world. Association mapping reveals genomic loci controlling fiber quality and drought-related traits which will be helpful in cotton breeding because these loci can provide the genetic adaptability needed to produce good fibers and yield under water limitation. In the present study, 177 simple sequence repeat (SSR) markers were used to characterize an Upland cotton germplasm panel consisting of 99 G. hirsutum cultivars for their genetic diversity and to detect the ancestral structure of the population. Moreover, association analysis was conducted to reveal significant quantitative trait loci (QTLs) linked to a total of 22 traits for fiber quality, plant structure, yield and drought-related parameters in the panel using GLM and MLM analysis. The morphological characters were tested under both well-watered and water-limited irrigation in two locations. At both locations, GLM and MLM identified different sets of QTLs at significance level of p ≤ 0.005 and p ≤ 0.001. Of the identified QTLs, some loci were considered as stable and reliable QTLs detected in both locations. The QTLs identified herein could be useful in the development of cotton cultivars with high yield that have adaptability to drought conditions worldwideDoctoral Thesis Molecular Genetic Analyis in Faba Bean (vicia Faba L.)(Izmir Institute of Technology, 2019) Abuzayed, Mazen Ali; Doğanlar, SamiFaba bean (Vicia faba L.) is an important food legume crop with a huge genome. In this study, we used Next Generation Sequencing (NGS) technology for development of genomic simple sequence repeat (SSR) markers. A total of 14,027,500 sequence reads were obtained comprising 4,208 Mb. From these reads, 56,063 contigs were assembled (16,367 Mb) and 2138 SSRs were identified. Mono and dinucleotides were the most abundant, accounting for 57.5% and 20.9% of all SSR repeats, respectively. A total of 430 primer pairs were designed from contigs larger than 350 nucleotides and 50 primers pairs were tested for validation of SSR locus amplification. Nearly all (96%) of the markers were found to produce clear amplicons and to be reproducible. Thirty-nine SSR markers were then applied to 46 faba bean accessions from worldwide origins, resulting in 161 alleles with 87.5% polymorphism, and an average of 4.1 alleles per marker. Gene diversity (GD) of the markers ranged from 0.00 to 0.48 with an average of 0.27. Testing of the markers showed that they were useful in determining genetic relationships and population structure in faba bean accessions. In addition, 26 morphological and seven biochemical (phenolics content, flavonoids, protein, L-DOPA, tannins, vicine and convicine) characters of 61 landraces and 53 faba bean cultivars were analyzed. There was high diversity for the studied characters among the accessions. Association mapping for these morphological and biochemical characters with 59 SSR markers (442 fragments) was conducted using a general linear model based on the Q matrix. As a result, 48 significant loci were detected for 22 morphological characters, and 26 loci were detected for six biochemical traits. The range of LD (r2) was from 0.09 to 0.18, and from 0.06 to 0.13 for morphological and biochemical associations, respectively. This study can help breeding programs in selection and improvement of faba bean production.Doctoral Thesis Molecular Genetik Analysis in Hazelnut (corylus Avellana)(Izmir Institute of Technology, 2017) Öztürk, Süleyman Can; Doğanlar, SamiEuropean hazelnut (Corylus avellana L.), cultivated in several areas of the world including Europe, Anatolia, and the USA, is an economically important nut crop due to its high mineral, oleic acid, amino acid, and phenolic compound content and pleasant flavor. This study examined molecular genetic diversity and population structure of both Slovenian and Turkish hazelnuts. In the first part of the work, genetic diversity of 54 wild accessions and 48 cultivars from the Slovenian national hazelnut collection was determined using amplified fragment length polymorphism (AFLP) and simple sequence repeat (SSR) markers. The accessions were also characterized for ten nut and seven kernel traits and some wild accessions were shown to have breeding potential. An association mapping panel composed of 64 hazelnut cultivars and wild accessions had considerable variation for the nut and kernel quality traits. Morphological and molecular data were associated to identify markers controlling the traits. In all, 49 SSR markers were significantly associated with nut and kernel traits [P < 0.0001 and LD value (r2) = 0.15–0.50]. This work is the first use of association mapping in hazelnut and has identified molecular markers associated with important quality parameters in this important nut crop. In the second part of the work, 402 Turkish hazelnut accessions were screened with 30 SSR markers. The data obtained from this screen allowed selection of a national core collection of hazelnut. This core collection represents a maximum of genetic diversity in a minimum number of individuals. Turkish cultivar ‘Tombul’ was sequenced using next generation sequencing technology and new SSR markers were developed. It was found that seven SSR markers were sufficient to discriminate Turkish hazelnut cultivars from each other. This study provides molecular information for marker-assisted selection in hazelnut and gives new insight to discover the genetic potential of hazelnut germplasm.Doctoral Thesis Molecular Genetic Analysis in Opium Poppy(Izmir Institute of Technology, 2017) Çelik, İbrahim; Doğanlar, SamiAs the sole plant source of many potent alkaloids, opium poppy (Papaver somniferum L.) is an important medicinal crop. Nevertheless, few studies have characterized opium poppy germplasm with crop-specific molecular markers. In this study, recently developed SSR markers were validated for diversity analysis and tested in an opium poppy world collection. The limited diversity of the world collection suggested that other genetic resources such as those from Turkey, a diversity center for the crop, should be explored. Thus, molecular and morphological characterization of Turkish opium poppy germplasm were performed. As a result, Turkish germplasm (11%) was found to have higher diversity than the world collection (5%). Also potentially useful morphological variation was observed for morphine content, plant height, and capsule index. However, the landraces exhibited limited breeding potential for stigma number, and seed and straw yields. Two core sets containing 22 and 21 accessions were selected from the world and Turkish germplasm, respectively, for effective management of collections in seed banks and breeding programs. The primary findings showed that Turkish germplasm is a valuable genetic resource to identify QTLs controlling morphine content and agronomic traits using an association mapping approach. Thus, a total of 164 SSR and 367 AFLP polymorphic loci were applied to an opium poppy association mapping panel composed of 95 opium poppy landraces which were grown for two seasons. One SSR and three AFLP loci were found to be significantly associated with morphine content (P < 0.01 and LD value (r2) = 0.10-0.32) and six SSR and 14 AFLP loci were significantly associated with five agronomic traits (plant height, stigma number, capsule index, seed and straw yield) (P < 0.01 and LD value (r2) = 0.08-0.35). This is the first report of association mapping in this crop. The identified markers provide initial information for marker-assisted selection of important traits in opium poppy.Doctoral Thesis Metabolic and Genetic Profiling for Primary and Secondary Metabolites in Tomato(Izmir Institute of Technology, 2017) Gürbüz, Nergiz; Doğanlar, SamiUnderstanding the metabolic content of plants and its genetic basis is important to determine the most appropriate breeding strategies for traits such as yield, fruit quality, nutritional content, tolerance to disease factors, adaptation to various environmental conditions, and tolerance to abiotic and biotic stresses. Recently, post-genomic studies such as metabolomics, proteomics and transcriptomics are attracting attention and being used in conjunction with genomic studies. These studies help to speed research progress with crops as well as model plants. Tomato (Solanum lycopersicum) is an important crop which is cultivated widely in the world and in our country, and is also important for our daily diet. Although there is growing attention to studies on tomato day by day, there are limited studies that identify the quantitative trait locus (QTL) regions responsible for important agronomic, economic, nutritional and health related traits by correlation of metabolomics and genomics data. In this study, an interspecific IBL (inbred backcross line) population derived from the cross S. lycopersicum cv. Tueza x S. pimpinellifolium (LA1589) was both genotyped via genotyping by sequencing (GBS) and quantified for primary and secondary metabolites affecting yield, quality and nutritional value of the fruit to determine QTL regions for the targeted metabolites. In total, 187 QTLs were identified for 143 important traits. The data obtained from this study will help to shed light on the genetic control of plant metabolism and to develop high yield and nutrient-rich cultivars with improved agronomic traits by breeding strategies.Doctoral Thesis Development of Single Nucleotide Polymorphism Markes for Fingerprint Analysis of Turkish Olive (olea Europaea L.) Cultivars and Detection of Adulteration in Turkish Olive Oil(Izmir Institute of Technology, 2015) Uncu, Ali Tevfik; Doğanlar, SamiOlive (Olea europaea L.) tree and oil are signature figures of the Mediterranean culture. Because of its high economic value, olive oil is extremely vulnerable to fraud. The aim of this study was to develop molecular tests for authenticating cultivar and botanical origin in olive oils. In order to authenticate the botanical origin and detect adulteration, a plastid DNA region was utilized for standardizing a capillary-electrophoresis barcode assay. The performance of the assay was evaluated on series of olive oil : seed oil admixtures. The assay proved successful in identifying seed oils in olive oil down to a limit of 10%. The molecular assay described in this work enables adulteration detection regardless of compositional similarities between the adulterant and adulterated oil species, thus will complement the shortcomings of analytical chemistry approaches. In order to establish a DNA-based identification key to ascertain the cultivar origin of Turkish monovarietal olive oils, short fragments from five olive genes were sequenced for SNP (Single Nucleotide Polymorphism) identification. CAPS (Cleaved Amplified Polymorphic DNA) assays were designed for SNPs that alter restriction enzyme recognition motifs. When applied on the oils of 17 olive cultivars, a maximum of five CAPS assays were necessary to discriminate the varietal origin of the samples. Admixture detection threshold of the assays was identified as 20% when tested on olive oil admixtures. The SNP-based CAPS assays developed in this work can be used for testing and verification of the authenticity of Turkish monovarietal olive oils, for olive tree certification, and in germplasm characterization and preservation studies.