%0 Articles %T Clonal variation in Scots pine (Pinus sylvestris) and in transgenic silver birch (Betula pendula) %A Niskanen, Anna-Maija %D 2013 %J Dissertationes Forestales %V 2013 %N 157 %R doi:10.14214/df.157 %U http://dissertationesforestales.fi/article/1940 %X The aim of this study is to assess the clonal variation in Scots pine (Pinus sylvestris L.) clones and in transgenic lines of silver birch (Betula pendula Roth) and its causes, with special attention to the effects of cloning and transgenesis in tree breeding programmes. The parental effect on cloning success variation was studied in an experiment where Scots pine embryogenic lines were initiated from immature seeds of a full diallele cross. The evaluation was made after culture initiation, on maintenance medium and by mature embryo production. Growth and stem straightness of Scots pine clones were assessed in a 10-year field trial established with rooted cuttings. The effect of a single gene transfer, the sugar beet chitinase IV gene (chiIV), was assessed on plant growth, susceptibility to fungal diseases and development of root associated fungal communities and phenology, in a 3-year field trial established with micropropagated transgenic silver birch lines and wild-type clones. The results of the somatic embryogenesis experiment with Scots pine showed that the initiation success, as well as maturation, was more affected by the genotype of the mother than the one of the father, while during the proliferation period the mother s effect decreased and the father s increased. The field trial with Scots pine showed that the tree s genotype,