Genetic characterization of pear cultivars (Pyrus communis) in Çoruh river basin

Date

2019

Author

Çoban, Abdulbaki

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The genus Pyrus contains more than 20 different pear species which are used as food source, horticultural, and ornamental purposes. Overall, pear is the second most consumed pome fruit after apple. P. communis is the most cultivated pear species in Europe and Asia Minor. However, more than 10 species of genus Pyrus can be found naturally in Europe and Asia Minor. In this study, 8 P. communis populations (one wild and 7 cultivated) and 1 P. eleagnifolia population was used to reveal genetic structure of those populations by using 11 SSR markers previously used in genus Pyrus and Malus. 84 genotypes of P. communis were sampled from Artvin Province, Turkey and 20 genotypes of P. eleagnifolia were sampled from METU campus in Ankara, Turkey for the current study. Overall, there were no null alleles in the studied populations. There is no duplicated genotypes and no linkage between loci were found. Expected heterozygosity, allelic richness, and polymorphic information content were calculated to check the usefulness of the studied loci. All loci were found to be highly polymorphic for the further studies. Structure analysis of the studied populations of P. communis revealed that there are significant gene flow between populations. Therefore, no clear population vi differentiation was found. AMOVA results supported this finding as most of the differentiation was among genotypes within population. However, the wild population of P. communis were found to be distinct from other populations. Thus, it is summed as during domestication of P. communis, there were hybridization between genotypes within and between populations. As for the genetic structure analysis of P. communis and P. eleagnifolia populations, it was revealed that P. communis and P. eleagnifolia populations were significantly different from each other as expected. Since those are totally different species and due to geographical isolation, there were no gene flow between those populations. The study was one of the first studies conducted on P. communis populations in Turkey. Thus, outcomes of the study are important for possible further studies which will be conducted on genus Pyrus. Besides, findings are important for further conservation studies of P. communis genotypes and breeding studies.

Subject Keywords

Common pear., Pyrus communis, Pyrus eleagnifolia, SSR, population structure, Genetic diversity.

URI

http://etd.lib.metu.edu.tr/upload/12623189/index.pdf
https://hdl.handle.net/11511/43359

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Graduate School of Natural and Applied Sciences, Thesis