Abstract
This research is devoted to analysing the impact of modern breeding measures in forestry on the level of genetic diversity of forest tree species. It has been found that the main source of improved seed material for the genetic restoration of forests is base forest seed orchards. Aspects of the influence of determining factors – background pollination and the number of clones – on the indicators of genetic variability of progeny have been analysed in detail. The potential of background pollination in forest seed orchards in the context of a significant decrease in the effectiveness of breeding measures and a parallel increase in the level of genetic variability of progeny has been studied. An analysis of data on the minimum number of clones in seed orchards has been carried out based on the practical experience of other developed countries. The dynamics of clone variability in terms of fertility have been investigated. The potential impact of clonal selection on the genetic diversity of tree species, particularly in reducing it, has been identified. It has been confirmed that integrating the concept of family forestry, which involves the use of vegetative propagation techniques, into the breeding strategy significantly increases the level of genetic variability in progeny. The study has demonstrated that the multiple-population breeding system provides the optimal preconditions for synergising the process of long-term intensive breeding and preserving the gene pool of tree species. It has been determined that there is no negative impact on genetic diversity from implementing a complex of optimally planned breeding programs. At the same time, the potential for intensifying the quality of gene pool conservation in the process of forest ecosystem restoration through the use of improved seed material and clones in artificial orchards has been established. Special attention is given to the maintenance of ex situ – valuable genetic material in forest seed production facilities, including forest seed orchards, trial cultures, and clone archives of plus trees. Research has shown that the implementation of modern innovative solutions and scientific recommendations can minimise the loss of genetic diversity in forest tree species. The results can be applied in contemporary forestry breeding programs