I started rooting research 1982. My thesis "Rooting of Pinus sylvestris and Pinus contorta hypocotyl cuttings in vitro" came out 1987. Thereafter were a number of other publications produced until 1998 when I changed profession. The rooting research on conifers is continued at the Swedish University of Agricultural Sciences (SLU) Department of Forest Genetics by Anders Lindroth and others.
Rooted cuttings (clones) are more useful than seedlings in forest tree improvement programmes.
Traits can be studies with indentical genetic background in several environments.
The precision in repetitive experiments is increased with no genetic variability.
Other ways to obtain clones such as somatic embryogensis of conifers are also available. and further developed at Department of Forest Genetics (SLU) and SkogForsk.
Conifers has been rooted from cuttings for more than 1000 years in China and 500 years in Japan. In Sweden were commersially propagated conifer cuttings marketed during 1980:ies.
This is a good question that have some answers and still a lot of research to be done before we know all about it.
Where are roots initiated ? On root are lateral rootsformed. Om the stem may roots form from different tissues. The stem has two very different parts hypocotyl (2-3 cm next to the root) and epicotyl (the rest of the tree). In case we only cut and culture the seedlings they will induce a wound tissue or callus this way.
We start to culture the plants in vitro to obtain plants that are free from other organisms. After about three weeks can the seedling be severed on the hypocotyl. An treatment with IBA (indolebutyricacid) usually stimulates rooting. To find the optimal treatment I have tested a series of IBA concentrations (0-2560 µM) and treatment times of up to a week. For Norway spruce it can look like this 1 month after treatment for 24 h with different concentations.
Updated Thursday, 17-Apr-2014 09:23 by Roland Grönroos