Genetic structures of Salix alba and Salix excelsa populations from two major river systems in Turkey


Tezin Türü: Doktora

Tezin Yürütüldüğü Kurum: Orta Doğu Teknik Üniversitesi, Fen Edebiyat Fakültesi, Biyolojik Bilimler Bölümü, Türkiye

Tezin Onay Tarihi: 2017

Öğrenci: FUNDA ÖZDEMİR DEĞİRMENCİ

Danışman: ZEKİ KAYA

Özet:

Salix alba (white willow) is an indicator species and an important component of an healthy riparian ecosystem with great renewable energy potential in Turkey. It is used as one of the most effective phytoremediation tool in the world for river cleaning and ecosystem rehabilitation efforts. Genetic structure of Salix alba populations in two river systems (Göksu and Kızılırmak Rivers) in Turkey were studied with the use of 20 microsatellites markers to provide information for effective conservation and breeding programs. Since Salix excelsa was used an a synonym of Salix alba and was not well differentiated from S. alba, 112 genotypes of S. alba belonging to the Göksu River from four populations and 147 genotypes belonging to the Kızılırmak River from five populations were sampled. Only some loci showed evidences of null alleles that are specific to a certain population. No significant linkage disequilibrium and clonal duplication were detected in populations. Effectiveness of markers were evaluated by Allelic richness, Polymorphic Information Content, Probability of identity, Shannon Index and expected vi heterozygosity measures which revealed that all loci were found to be highly polymorphic. Genetic structure analysis clearly revealed that S. alba populations in two different river systems represent two different founder populations with very high membership values. All populations maintain moderate level of genetic diversity. The highest pairwise Fst values with the lowest number of migrants were obtained from the Kızılırmak downstream populations. Therefore, these populations were genetically most distant to the remaining populations. Cluster, Bayesian, PCoA analysis, and AMOVA clustered 259 genotypes from nine different locations of two rivers to two major groups because of high level of gene flow within river systems, but less gene flow between river systems. The genetic structure data of the studied river systems will be useful for future breeding programmes, efficient conservation, management and utilization of genetic resources of S. alba. Under increasing habitat deterioration and fragmentation, efficient in situ and ex situ conservation studies should utilize and conserve the species‟ genetic resources.