Micropropagation of betula pendula roth including genetically modified material

Abstract

Silver birch or European white birch (Betula pendula Roth) is medium size deciduous tree, which is naturally widespread in Eurasia and as an escape in North America. According to Organisation for Economic Co-operation and Development (OECD) consensus document on the biology of silver birch (2003), there are some 40 Betula species distributed throughout of the northern temperate region. Silver birch is economically the most important deciduous tree species in Nordic countries. In Finland, approximately 15% of growing stock (311 mill. m3) is birch (Finnish Statistical Yearbook of Forestry, 2003), and the birch roundwood is used as a raw material in the chemical pulp industry. Therefore silver birch is the main broad-leaf species of conventional tree breeding in Nordic countries and for instance in Finland and Sweden seed material needed for forest regeneration is derived from seed orchards grown in the polythene greenhouses. These seed orchards have generally been established with grafts but also micropropagated clones are appropriate (Viherä- Aarnio & Ryynänen, 1994). A comprehensive review of the promises and constraints of silver birch breeding, generally and specifically in Finland, is provided by Koski & Rousi (2005).