MOLECULAR-GENETIC ANALYSIS OF PROPAGATED IN VITRO CLONES OF POPULUS ALBA L. AND POPULUS TREMULA L. USING MICROSATELLITE MARKERS

Use of planting material of forest trees with improved hereditary characteristics is one of the ways to increase the productivity and biological stability of forest stands. It requires taking measures to develop and improve selection base using modern approaches and methods of genetics and biotechnology. A molecular genetics assessment of clone plants of aspen (Populus tremula L.) and white poplar (Populus alba L.) from a long-term in vitro collection (up to 24 years), planted in a greenhouse and field conditions (nursery), was carried out. SSR loci of the PTR series (PTR5, PTR7, PTR8, PTR12, PTR14) were used as DNA markers. Evaluation of clones' ploidy was carried out on the basis of the diagnosis of "loss of heterozygosity" (LOH) effect. Analysis of 5 microsatellite loci of the specimens showed their high intraclonal genotypic stability and homogeneity in vitro and ex vitro. For the first time, data on the results of a comparative determination of ploidy using karyological and microsatellite analysis were presented. Based on the results of the SSR analysis, it can be concluded that the structure of molecular markers is stable among the samples of one clone that are in long-term cultivation. The ratio of the representation (dose) of electrophoretic variants of PCR products serves as an indirect sign of determining ploidy, but for its reliable assessment it is necessary to study the number of loci that are three times larger than the main set of chromosomes. The specimen also requires information on the amplification coefficient of the markers under study. Thus, it is necessary to use both chromosomal and microsatellite analyzes for reliable assessment of intraclonal homogeneity of various specimens, the development of understanding of clone genotypes formation and determination of their ploidy