Abstract: This invention is a method for asexual reproduction of coniferous trees. It combines in vivo hormone treatments with in vitro tissue culture for multiplication of a clone of the original genotype. The first step is repetitive cytokinin treatment of the living tree, preferably on weekly intervals. This will induce buds or shoots, usually in axillary locations or at the apex of fasciles. These shoots have a morphology typical of juvenile plants or even newly sprouted seedlings. In culture, the buds will give rise to juvenile-like shoots. The shoots or buds are placed in various media to induce growth and further budding. These second order buds are again placed in a growth medium to give rise to shoots that can then be rooted. The method appears unique in its ability to rapidly and inexpensively multiply a large clone of genotypically superior trees of physiologically and morphologically mature age.

Abstract: Young Douglas-fir cotyledon tissue is cultured to grow a soft callus on an agar medium containing mineral salts, organic nutrients and an auxin. No cytokinins are present except those that might be endogenous in the tissue itself. After one to two months the explants and callus are placed in a liquid suspension culture medium similar to the first in composition. Again, auxins are present and cytokinins are omitted. After about one month, bipolar embryoids have been generated in the suspension. These have chloroplasts and a vascular system with organized meristemic centers for ultimate development into stems and roots. The embryoids can be removed from the culture and placed on a growth medium for production of plantlets.