Master Degree / Yüksek Lisans Tezleri
Permanent URI for this collectionhttps://hdl.handle.net/11147/3008
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Master Thesis Quatitative Trait Loci Analysis(qtl) of Fruit Characteristics in Tomato(Izmir Institute of Technology, 2008) Ökmen, Bilal; Doğanlar, SamiTomato has a crucial part in the human diet. Therefore, many plant breeders have tried to improve horticulturally important traits such as yield, fruit size, shape and color. With increased attention on human health, plant breeders also consider the improvement of health-related traits of fruits and vegetables such as antioxidant characters. However, because most plant traits are controlled by more than one gene, improvement of crops that possess the desired traits is very difficult.Development of molecular marker techniques makes these processes feasible for plant breeders. In this study both health-related and horticulturally important traits were characterized for identificaton of their locations in the tomato genome using 152 Lycopersicon hirsutum BC2F2 mapping individuals. For this aim, all plants were phenotypically and genotypically characterized. It was expected that some alleles from the wild species L.hirsutum had the capacity for improvement of both antioxidant and agronomically important traits of elite lines.A total of 75 QTLs were identified for all traits. Of the 75 QTLs, 28 were identified for five antioxidant traits including total water soluble antioxidant capacity, vitamin C, phenolic, flavonoids and lycopene content and 47 QTLs were identified for 8 agronomic traits including external and internal fruit color, fruit weight, firmness, fruit shape, stem scar size, locule number and wall thickness. Seventeen of these QTLs were also identified by previous studies. Markers linked with these QTLs can be used in Marker Assisted Selection (MAS) for improvement of elite tomato lines.Master Thesis Genetic Characterization of Cucumber Mosaic Virus (cmv) Resistance in Tomato and Pepper(Izmir Institute of Technology, 2005) Balcı, Evrim; Doğanlar, SamiIn this study, tomato and pepper populations were phenotypically and genotypically characterized to identify cucumber mosaic virus (CMV) resistant lines and determine the genetic control of resistance. Populations of both crops and their resistant and susceptible parents were mechanically inoculated with CMV. Plants were evaluated visually and by enzyme-linked immunosorbent assay (ELISA). Since virus was detected only in inoculated leaves but was not usually present in uninoculated leaves of symptomless plants, CMV resistance appeared to be true resistance not immunity. According to phenotypic analysis of F2 tomato population, it was hypothesized that two dominant genes were controlling resistance as the plants fit a 9:7 (resistant:susceptible) segregation ratio as determined by Chi square goodness-of-fit analysis. In order to perform quantitiative trait locus (QTL) analysis, molecular markers were surveyed for polymorphism using the two parents of the tomato population, L. esculentum and L. hirsutum LA1223. According to QTL analysis (using 107 polymorphic markers), 11 genomic regions were linked to CMV resistance. For seven loci, resistance alleles were coming from the L. hirsutum parent as expected. However, for four loci, resistance was associated with alleles from the CMV susceptible parent, L. esculentum. These results show that the genetic potential for resistance cannot be determined by only looking at the phenotype of the two parents. As a result of this work, developing elite lines or transferring resistance genes into cultivated species by marker assisted selection will be easier.Master Thesis Characterization and Genetic Mapping of Health Related Traits in Tomato(İzmir Institute of Technology, 2005) Rusçuklu, Dane; Doğanlar, SamiTomato is consumed in the daily diet and has a diverse nutritional content including antioxidants, lycopene, vitamin C and phenolics. However, the content of these compounds in tomato cultivars could be higher. There are two ways of increasing the nutritional quality of tomato. One of them is a transgenic way which is still questioned and is not approved in many countries. The other way is molecular breeding which is based on introgression of wild genes into cultivated tomatoes via the combination of classical breeding with molecular marker analysis. This method lets us obtain nontransgenic tomatoes with increased nutritional quality. In this project a population that was obtained from a cross between wild type L.pimpinellifolium and cultivated tomato L.esculentum was used. This population includes 145 inbred backcross lines (IBLs). It was expected that some individuals of this population had increased nutritional quality derived from the wild parent. In order to test this hypothesis, antioxidant activity of each line was measured. The method used to measure antioxidant activity was based on spectrophotometric measurement which gave mol Trolox equivalent antioxidant activity. It was observed that the IBLs were phenotypically close to L.esculentum and that some individuals did have higher antioxidant activity than the cultivated parent. The population was also mapped with molecular markers and 31 possible QTLs which control antioxidants in tomato were found. The source of alleles associated with increased antioxidant characters was usually L.pimpinellifolium. This result confirmed that wild type tomatoes can be a resource for increasing nutritional quality of tomatoes.