Determination of genetic structure of some local and foreign bread wheat genotypes with molecular markers

Wheat is a strategic crop due to having a high ratio in the total agricultural area both in Turkey and the world, and also being raw material for the most basic nutrients. Therefore, it constitutes a considerable important place in both past and present. Due to the limited number of arable land in the world, it will be possible to meet the nutritional needs of the population which is predicted to increase in time only with the increase in the yield per unit area. The best way to increase yield is the breeding of new plant varieties. In recent years, breeders have turned to genetic characterization studies in order to overcome the problems encountered in classical plant breeding. In this thesis, the genetic characterization of 96 wheat genotypes was performed by 8 SSR loci (Xgwm136, Xgwm160, Xgwm161, Xgwm295, Xgwm312, Barc53, Barc84, and Barc319) and 4 ISSR loci (UBC811, UBC823, UBC835, and UBC844). Five SSR loci (Barc53, Barc84, Barc319, Xgwm136, and Xgwm295) were monomorphic and three (Xgwm160, Xgwm161, and Xgwm312) were polymorphic (37.5%). A total of 18 alleles were identified for 8 SSR loci. In the study, 40 bands were determined in ISSR analysis and 33 bands were found to be polymorphic (82.5%). The mean Shannon Index was calculated as ISSR=0.112 and IISSR=0.346. The mean heterozygosity value for SSR and ISSR was calculated as 0.153 and 0.246, respectively. When all markers were evaluated together, the mean polymorphic information content was calculated as PIC=0.269. Dendrogram was formed by UPGMA clustering method with genetic similarity values and it was observed that wheat varieties were divided into two main clusters. The information obtained as a result of this thesis will contribute to other studies on genetic diversity, genetic structure, breeding and cultivation development in wheat in order to facilitate the selection of some wheat varieties for breeding studies and to form the basis of breeding studies. Genetically distant genotypes determined from this study can be used to increase the amount of variation and the success of the wheat breeding study.