Genetic characterisation of centuries-old oak and linden trees using SSR markers

The main goal of this study was to identify the unique gene pool of old and historically valuable Quercus robur L. and Tilia cordata L. to be able to characterise their genetic diversity in order to determine the polymorphism by expressed sequence tag-single sequence repeat (EST-SSR) markers and identify the most valuable specimens. Morphological description, molecular genetic analysis, and statistical analysis were used in studies. The genetic distances between old-value trees of different Quercus L. and Tilia L. were determined based on EST-SSR markers and morphological characteristics. Using polymerase chain reaction (PCR), alleles of the expected size were obtained. It was determined that four to eight alleles were obtained by seven SSR markers in the studied Q. robur L. samples. According to the calculated value of the locus polymorphism index (polymorphism information content [PIC]), the most polymorphic was the marker SSRQrZAG 65; the PIC was 0.84. The lowest value of PIC was observed in the marker SSRQrZAG 11; the PIC was 0.69. Intragenetic polymorphism was detected for all studied markers. Among the studied samples of linden, two to five alleles were identified. It was found that the highest value of PIC was obtained for the marker Ts920 – 0.72. The least polymorphic was the marker Ts927 (PIC was 0.28), which is not only due to the small number of alleles, but also their uneven distribution in the sample. Intragenetic polymorphism was detected in four of the six markers analysed for T. cordata L. In this study, polymorphism was detected in all studied samples of Q. robur L. and T. cordata L., which allows to assess their genetic diversity based on the distribution of alleles.