MICROCULTURE OF WESTERN WHITE-PINE (PINUS-MONTICOLA) BY INDUCTION OF SHOOTS ON BUD EXPLANTS FROM 1- TO 7-YEAR-OLD TREES

We developed a protocol for the production of shoots from bud explants from 1- to 7-year-old trees of western white pine (Pinus monticola Do ugl.). The best explant was a 2-mm-thick cross-sectional slice of the early winter bud. Genotype of the donor tree was a significant factor affecting shoot production, but more than 80% of the genotypes tested produced shoots. Of the media tested, bud slices from 1- to 3-year-old trees grew best in Litvay's medium containing N-6-benzyladenine in th e range of 1 to 30 mu M, whereas bud slices from older trees grew best in Gupta and Durzan's DCR medium with zeatin riboside. Up to 400 shoo ts more than 3 mm in height were obtained from 100 bud-slice explants taken from 7-year-old western white pine trees.