Determining the levels of genetic variation using SSR markers in three Turkish barley materials known as Tokak

Authors: NEJDET KANDEMİR, AHMET YILDIRIM, RAHİME GÜNDÜZ

Abstract: Genetic variations are the raw materials of plant breeding and have been increasingly narrowed due to various reasons. Landraces are good sources of genetic variation, but need to be characterized first. This study was conducted to determine the levels of genetic variation in 3 barley materials originated in Turkey, all known as Tokak. Of the 3 materials used, PI 470281 is a landrace and CIHO 10093 is a pure line. The third is Tokak 157/37, a major cultivar of Turkey considered to be a landrace. In order to detect the levels of polymorphism within and among these materials 30 SSR (microsatellite) markers were used. Some morphological markers were also studied. Ten CIHO 10093 plants did not show any polymorphism with 30 SSR markers. Only 5 SSR markers yielded polymorphism within the 60 lines of cv. Tokak 157/37 studied. There were only 2 different genotypes. The common genotype was observed in 58 lines and the rare one in 2 lines. This finding shows that Tokak 157/37 has lost its variation and is no longer a landrace. Twenty-three of the 30 SSR markers were polymorphic in PI 470281. The 30 SSR markers produced 70 alleles in 52 of the PI 470281 plants. Among the 52 plants studied, 46 different genotypes were detected, indicating a very high level of polymorphism. No polymorphism was observed for the morphological markers. Moreover, variation in plant characteristics was not very high. These facts indicate that farmers who have been using this landrace for a long time might have performed mass selections based on phenotype within the cultivar. A dendrogram was made using 52 PI 470281 lines (a common type of Tokak 157/37), 2 rare lines of Tokak 157/37, and CIHO 10093. Genetic variation observed at the DNA level, but not at the morphological level, might indicate that, despite the uniform appearance, PI 470281 might have novel alleles of the loci that affect the major agronomic traits.

Keywords: Barley, genetic variation, landrace, microsatellite markers

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