III. 10 Somatic Embryogenesis in Western Larch (Larix occidentalis)

摘要: Western larch (Larix occidentalis Nutt.) is the tallest species in the genus Larix (Harrison and Dallimore 1966). It produces a valuable lumber which is rated for its mechanical stress capabilities (Balatinecz 1983). The species is fast-growing. Its range extends from south-central British Columbia to Oregon and from western Washington to Montana (Owens and Molder 1979). Throughout its range it is a successional species, dependent on periodic fires for establishment. It is restricted to altitudes between 600 and 1500 m in the northern parts of its range and up to 2200 m in the southern portions of its distribution. Generally found on north-facing slopes, it is also common in valley bottoms and in quite a variety of forest types (Fowells 1965).Although generally considered a good seed producer, western larch varies greatly in consistency from year to year in particular locations, so much so that there are almost constant seed shortages. In these areas a good seed crop may only occur once a decade, which is a bottleneck to local reforestation efforts. Somatic embryogenesis may provide a method of propagation which could alleviate shortfalls in seed supply. Orchards for seed production and breeding have only recently been implemented (Jaquish 1987).