Pinus sylvestris L. mature seeds megagamethophytes cultured in vitro. Influence of the genotype and the growth regulators content in nutrient medium on the initiation of callus formation

Despite the significant progress in forest biotechnology Scots pine still remains difficult for mass propagation via somatic embryogenesis (SE) due to the influence of many factors, such as genotype and location of the donor plant, the composition of the nutrient medium, including the concentration of growth regulators, etc. Mature seeds were collected from Pinus sylvestris trees growing in the northern (Loukhsky district, Engozerskoye district forestry, natural phytocoenosis) and middle (Prionezhsky district, Petrozavodsk seed orchard) boreal subzone in Karelia (Russia). The influence of various growth regulators content in the composition of the DCR medium on the initiation of callus formation from mature seeds megagametophytes of both habitats was analyzed. Cytogenetic analysis of explants (root meristem of seedlings) showed that the frequency of mitosis pathologies is 4 times, and the proportion of cells with micronuclei is 6 times higher in P. sylvestris plants from a natural phytocoenosis than from Petrozavodsk seed orchard. Nevertheless explants collected from trees growing in the northern boreal subzone more often formed a cell culture (initiation frequency 13.4%) than megagametophytes from seed orchard (8.83%). The most active callus formation was registered on medium containing (1) 9 µM benzyladenine and 13.6 µM 2,4-dichlorophenoxyacetic acid; (2) 9 µM benzyladenine and 2.7 µM 1-naphthylacetic acid.