by
J.S. de Muckadell 1
The above interim report, published within the framework of FAO/UNDP Project MAL/78/009, summarizes the early results of attempts to root juvenile material of Albizia falcataria, Araucaria cunninghamii and A. hunsteinii at the Forest Research Centre, Sepilok, Sabah, from April to November 1983 and suggests avenues for continuing the work. For A. falcataria the number of rootable cuttings harvested per ortet must be increased, variability of rooting success reduced and - of highest priority - reliable potting methods developed. For the Araucaria species further work is required to increase coppice growth rates and the speed of rooting.
A. falcataria: A vegetative propagation method for A. falcataria is needed because of the difficulty of obtaining seed of well formed trees. For this species two different rooting techniques were used: an intermittent misting unit with electronic leaf control; and high humidity polythene propagator. The latter gave poor results. The efficiency of the misting unit was affected by unreliable electricity supply and the difficulty of obtaining spare parts.
The rooting medium that gave best results was sand from which the coarse and the fine factions were removed. Transplants about 4–12 months old were used as ortets, some of them repeatedly. Single node cuttings with part of one leaf were tested. In early experiments “first top node” cuttings were much poorer than cuttings which included second or third nodes from the apex, it was too early to conclude how cuttings from lower down on the ortet would perform. There was some indication that better rooting occurred in cuttings from younger than older ortets.
No clear trend resulted from tests of shading cuttings, though it seemed to promote rooting in younger “first top node” cuttings. Hormone treatment with NAA and IBA suspended in talc seemed to have a negative effect, while IAA trended to promote rooting of “2nd top node” cuttings. In trials to date water stress seems to lower rooting percentages. Excessive reduction of the leaf left on the cutting appeares to have the same effect.
Survival after potting of rooted cuttings ranged from 10 to 50% in spite of the several weaning periods and transplanting methods tried. The reason for this, the most important problem encountered, is not known. This transplanting phase is the highest priority for future work.
Araucaria cunninghamii and A. hunsteinii: Seed of both species is in short supply and that of A. hunsteinii of a recalcitrant nature. The use of rooted cuttings is an obvious possible alternative. It is practised successfully in Australia and mainland Malaysia using main stem material; material of the branches is persistently plagiotropic.
Propagation systems and rooting media tried are the same as those described above for A. falcataria. Ortet material used for A. hunsteinii was seedlings eight months old from the time of sowing. For A. cunninghamii, three-year old material was available. Most cuttings were apical with one reduced whorl of branches; a few comprised the apical shoot only.
Six weeks after insertion, 10% of the A. hunsteinii cuttings had rooted and 74% were still alive. In A. cunninghamii many cuttings had neither rooted nor died after eight months. Cuttings from coppice seemed to root faster than those from original main shoots. Propagation under mist was the most successful technique. The cuttings with reduced branch whorls seemed to root best. Although growth after potting was disappointing even at the age of eight months, mortality was low.
Many problems thus still remain to be explained and solved in vegetation propagation by cuttings of Araucaria spp.
