OBSERVATION OF THE PHENOLOGICAL PHASES OF SCOTS PINE (PINUS SYLVESTRIS L.) CLONES IN THE SEED ORCHARD OF SCOTS

Abstract

Scots pine (Pinus sylvestris L.) is a commercially and culturally important species in many European countries. In order to ensure the protection of forests, biodiversity, the multifunctionality and sustainability of forest ecosystems in the context of climate change, it is necessary to take care of genetic resources and to increase the production of appropriate forest reproductive material. The study evaluated the synchrony of sporification and the possibility of crossbreeding between populations of clones from geographically distant regions of Lithuania (Labanoras and Juodkrante) in the second–generation seed orchard of Scots pine located in the Kapėnai Forest District of the Mažeikiai Regional Division of the State Forest Enterprise of Lithuania. The study was carried out 2021 – 2022, in the first 30 rows of a seed orchard with 391 ramet and 59 clones. The phenological phases of the vegetative buds, female and male strobils of each tree were evaluated according to the TREES4FUTURE (2006) phenology assessment methodology. The study on the synchrony of the receptive stage of male and female strobils in clones showed that about 50% of the receptive stages of male and female strobils in clonal ramets overlapped, indicating the possibility of crossbreeding. It was found that clones from populations of Labanoras (northern part of Lithuania) and Juodkrantė (coastal region of Lithuania) from different geographical regions of Lithuania do not differ significantly in the sporulation stages of either male or female strobili, indicating the possibility of their crossbreeding.