New Breadfruit Trees from Stem Cuttings
Scientific name: Artocarpus altilis
Family: Moraceae
A
preliminary report of results in growing breadfruit from stem cuttings
by Len Muller at Mt. Mirinjo Farm, Woopen Creek, north of Innisfail.
Breadfruit Propagation
Past Endeavours
The
traditional method of propagating breadfruit trees is from natural
suckers which emerge from damaged roots, or from root cuttings. From
Bligh of the "Bounty" to modern times, it was believed that breadfruit
will not grow from stem cuttings.
In "The Propagation of Tropical
Fruit Trees" (Commonwealth Bureau of Horticulture and Plantation Crops,
Kent 1976), Patricia Rowe-Dutton reviewed experiments on the
propagation of Artocarpus altilis, Breadfruit. The section on
propagation by stem cuttings is discouraging. She notes, however, that
it was achieved by J. Leon in Costa Rica in 1968. Other attempts failed
or were laborious and complex. I have not read Leon's paper, so do not
know his method.
I have found that striking stem cuttings under
the climatic conditions we had this year from December to the beginning
of March is actually very easy indeed. The period was one of wet
weather, with temperatures 30°C max. temp. and 24°C min. temp.
My System, Materials, and Methods
Stem
cuttings 20-25 cm long and 3 cm diameter were taken from a seedless
breadfruit, var. 'Noli'. A pruning saw was used - not secateurs, which
crush the tissues. The leafy ends of the branches were discarded. No
growth hormones were applied.
Standard black plastic pots 20 cm in
diameter and 20 cm deep were chosen, with six or eight large drainage
holes around the perimeter of the base. The holes run up the side of
the pot about 2 cm and permit some aeration of the potting mix as well
as perfect drainage
Peatmoss and coarse sand were used for the
potting medium. We use German "Moorgold" peatmoss because it seems to
be free of mould. The sand was from the Johnstone River and had been
sieved by the supplier (Vince Reale, Innisfail), to remove stones and
fine particles. The sand was mostly composed of quartz and basalt. No
fertilizers were added to the mix.
The procedure was as follows: the
cuttings were set on 13.12.90. The pots were filled with pure peatmoss
(unsifted) to a depth of 4 cm. The cuttings were supported with their
bases resting on the peatmoss, and the pots were filled with 50:50
mixture of coarse sand and peatmoss. They were then watered thoroughly
and placed in the shadehouse and kept moist.
During the first
month, light-coloured pores appeared on the surface of the bark at the
exposed ends of the cuttings. Lateral shoots at the nodes began to
enlarge and turn green. At two months, large creamy-white roots began
to emerge from the bases of the pots. Two weeks later (1.3.91) the
cuttings were repotted in 50:50 coarse sand and peatmoss. They had
already grown several quite large leaves, and were well in advance of
root cuttings set on the same day. They had numerous and vigorous roots.
After
allowing the repotted plants to settle down for a week, they were moved
into morning sun and given a weak mixture of "Thrive", a general
purpose liquid fertilizer. A week later, full strength "Thrive" was
applied as the plants were fully established in their pots.
Breadfruit Trees and Cold Winters
I
first saw the breadfruit tree almost 25 years ago in East Timor,
Indonesia. The beautiful leaves seemed to express the wonder of the
Tropics, and I decided that my life would seem empty unless I had a
tree growing near me. I was able to buy a tree grown from a root
cutting at Limberlost Nursery, Cairns, and took it back to Darwin,
where I lived at that time. I began propagating them and selling them
there, and once, even a lady from Tahiti came to buy one! People knew
that breadfruit could only be grown from root cuttings and were willing
to pay a good price. In Darwin the breadfruit tree flourishes, but it
is not grown commercially. It is a tree which required hot wet
conditions.
The wet areas around Innisfail and Tully, North
Queensland, are ideal for breadfruit except that winter temperatures in
some years make it difficult for young trees to survive after planting.
At Woopen Creek, we may expect a few days as cold as 12°C. The
record low is 8°C.
At 10°C., the life of a young tree is threatened, but they will survive 10°C. in a nursery.
Sketch of breadfruit leaves and fruit
by Len Muller
Despite
several cold winters at Mt. Mirinjo Farm, Laurie Smith and I have
succeeded in growing several large trees which are bearing good crops
for the second year in a row. Last year (1990) could be classed as a
colder than average winter. We had 12°C and 11°C min. for a
total of 8 cold days: 3 in June, 3 in July and 2 in August. During the
cold spell, all of the young trees in our breadfruit block were
severely affected, the symptom being numerous brown spots on the leaves
and the young stems. If cold continues for some days, most of the parts
of the plants above ground will die. The cultivar 'Noli' appeared to be
hardier than the others. (This cultivar was obtained from Kamerunga
Horticultural Research Station, Cairns in 1982, courtesy of Brian
Watson).
Adult trees were unaffected, or only mildly affected.
They are bearing good crops of fruit in March 1991. Mature trees also
exist on other properties in the Innisfail- Tully area, so there are
good grounds for expecting that the breadfruit can be grown
commercially here. I therefore put forward the stem-cutting method of
propagating breadfruit as a means of obtaining numerous plants at
little or no financial risk.
Conclusion and Ongoing Projects
Growing
breadfruit trees from stem cuttings is the 'fast-track' way of
obtaining a lot of trees, and has been easy to accomplish. This makes
them more of an expendable item, unlike the precious trees grown from
root cuttings. Thus it seems worth while to propagate them madly and
plant them anywhere where they have a chance of surviving.
Regarding
previous negative findings on breadfruit stems as reviewed by
Rowe-Dutton, I cannot comment at length, not having read the original
papers. I suspect that cloggy, water-logged potting mixes have been
used.
Out of interest, I am continuing the experiment on
striking cuttings throughout the winter without artificial heat to see
how important ambient temperature is in the rooting process. I am also
working on Marang, Chempedak, and Jakfruit, using wood of similar size
to the seedless breadfruit cuttings. Present indications are that the
method as described is not suitable for these species. This is a
preliminary report and the method is still being refined (March 1991).
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