Jan
Meerman
Introduction
M. balbisiana
Colla - this seedy-fruited, species from southern Asia has
been used as a parent in several cultivars, due to its disease
resistance, drought tolerance, and general hardiness to
environmental factors. It is a diploid, symbolized BB. Its
natural range does not overlap that of M. acuminata,
but human migration in this region allowed these two species
to hybridize in nature many years ago. This gave rise to
3 additional genotypes, AB, AAB, and ABB, being 1/2, 1/3,
and 2/3 balbisiana, respectively. Hybrids (AB, AAB,
ABB) are sometimes given the name Musa x paradisiaca
L. (syn.s Musa x sapientum L., M. acuminata
x M. balbisiana Colla).
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In the field
(at least Belize), M. balbisiana is easily
recognized by the leaves that grow in a more upright
position compared to cultivated bananas.
The fruit
bunch is pendent, very compact, the crowded fruits
having little room (except in the basal hand) and
reflex geotropically. Consequently the fruits, for
the most part are standing out from the rachis.
The individual
fruit is about 10 cm. long and 4 cm in diameter. The
pale yellow fruit is also distinctly angulate at maturity.
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The pulp is
whitish, the seeds are black, irregularly globose, scarcely
depressed, minutely warty, 5 - 6 mm. across and 4 -
5 mm. high. |
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In contrast to
the polymorphic Musa acuminata with numerous
subspecies identified, Musa balbisiana is
a remarkably uniform species with only one variety reported.
Locally, the fruits
of Musa balbisiana are used to produce a beverage.
Ripe fruits are strained to remove the seeds. Musa
balbisiana is the true Japanese Fiber Banana grown
in the Ryukyu Islands of Japan from which the cloth basho
is woven.
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Situation in Belize
Musa Balbisiana was not originally reported in Balick
et al (2000) and was finally identified during a Rapid
Ecological Assessment of the Mayflower Bocawina
National Park.
In the more disturbed lowland parts of this Park,
M. balbisiana was very common. Just outside
the park in abandoned farmland, this banana had reached
pest proportions and locally outcompeted anything
else.
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Further surveys indicated that M. balbisiana also occurred
along the Hummingbird Highway. Subsequently these locations
were mapped using GPS coordinates and entered in a GIS system.
In total two centers of distribution were located in the
Stann Creek district and one in the Cayo district. It is
quite possible that not all locations have been identified
and that the distribution of the species is more wide than
the map suggests. Reports that this species also occurs
in the Toledo district have, so far, not been confirmed.
Species displacement
Where the species
occurs it is found in lowland areas that are headily disturbed
as a result of agricultural activities. Typically the highest
densities are found along streams. At such locations the
density can be very high and very few other plant species
can be found. In areas regenerating back to forest such
as in the Mayflower Bocawina National Park, the species
persists for a long time, but seems to disappear as soon
as the canopy cover of the new forest closes.
Natural propagation
The presence of
M. balbisiana in Belize is without question the result
of introduction by man. Possibly plants were introduced
as experimental material for the improvement of existing
banana stocks. The current distribution pattern of the species,
suggest a more natural distribution, probably birds and/or
bats.
The fruits are
filled with seeds (see picture above), and germination experiments
I carried out using fresh seed, revealed a seed-viability
of approximately 95%. This high viability, and the fact
that banana's are readily eaten by a large number of frugivorous
bats and birds, would seem to guarantee a rapid spread of
the species.
The fact that the
species is still restricted to a limited area is probably
the result of the ecological requirements of the species.
The species, like all bananas needs fairly fertile soils
and abundant moisture. Also, it is incapable of surviving
and reproducing under a closed forest canopy. The current
locations with the species are essentially locked up between
areas with an intact forest cover and areas with poor (savanna)
soils. However, as deforestation progresses, the species
is likely to expand further throughout Belize.
References:
Balick, M.J., M.H.Nee &
D.E.Atha. 2000. Checklist of the Vascular Plants of Belize.
New York Botanical Garden Press. 246 pp.
Constantine, D. 2003. The genus Musa - an annotated list
of species (website)
INIBAP, 2001. Banana Taxonomy (*.pfd)
Sauer, J.D. 1993. Historical geography of crop plants -
a select roster. CRC Press, Boca Raton, Florida.
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