Georgiivna V. Tree improvement assessment of the genus Larix species and hybrids perspective in the Forest-Steppe of Ukraine.

The object of research is the introduction of larch species and hybrids in the Forest-Steppe of Ukraine. The subject of research is the selection assessment of larch species and hybrids in forest stands and eхperimenta experimental plantations to expand the permanent forest seed base. For the first time for the conditions of the Forest-Steppe of Ukraine the dynamics of correlations relationship between taxonomic indexes in provenance tests of different species and provenances of larch was detected; the types of disorders in the formation of microspores during the generative development of larch hybrid forms on clonal seed orchards and in experimental plantations were determined and analyzed; approaches to the biochemical parameters of phloem use for estimating the growth rate of Japanese larch (L. kaempferi) and hybrid (L. kaempferi × L. decidua) have been determined; the method of complex assessment was applied to determine the prospects of different species of larch for the creation of forest plantations. The obtained results have scientific and practical significance for solving silvicultural and tree improvement problems, in particular with the introduction of larch species and hybrids in forest plantations and expansion of their forest seed base in the Forest-Steppe of Ukraine.