Protocols for Micropropagation of Woody Trees and Fruits

CHAPTER 15
MICROPROPAGATION OF BETULA PENDULA ROTH
INCLUDING GENETICALLY MODIFIED MATERIAL
H. HÄGGMAN 1 , S. SUTELA 1 AND M. WELANDER 2
1
Department of Biology, University of Oulu, Finland
Department of Plant Breeding and Biotechnology, Swedish University
of Agricultural Sciences, Sweden
2
1. INTRODUCTION
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. m 3 ) 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).
Molecular breeding of the species is also potential due to the existing genetic
transformation techniques (Keinonen-Mettälä et al., 1998; Valjakka et al., 2000) and
due to the availability of the extensive expression sequence tag (EST) libraries of the
species (Palva, 2000). Vegetative propagation of silver birch can be achieved by
several means. Grafts have traditionally been used in establishment of seed orchards.
The use of cutting techniques has suffered from a poor rooting success, which has
lead to a development of a wide range of in vitro techniques. Clonal propagation
in vitro has succeeded by somatic embryogenesis (Kúrten et al., 1990) but it has not
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S.M. Jain and H. Häggman (eds.), Protocols for Micropropagation of Woody Trees and Fruits, 153–162.
© 2007 Springer.