Guinea, a centre of diversity
Winged bean exhibits considerable
diversity (cick here to see) across its distribution. This observed diversity reaches
its zenith in the island of New Guinea, where in just one location,
Mt Hagen, 48 named varieties have been recorded. This diversity led
to speculation that New Guinea itself might be a natural Centre of Origin
for the winged bean.
In part to test this hypothesis, a variety trial was
planted out in Malaysia in 1978, in which 135 winged bean accessions-
representative of collections from Papua new Guinea, Indonesia, Malaysia,
Thailand, and Sri Lanka - were grown under artificially extended daylength
conditions, as well as in natural equatorial daylengths.
135 winged bean accessions, replicated
twice, growing under lights
(another block of the 135 accessions was grown without lights)
Forty seven characteristics were measured on these
135 accessions. The assembled data was then analysed statistically.
The results confirmed that the highlands of New Guinea
is a unique centre of diversity
for the winged bean (Table
However, there was no direct support in the data for the hypothesis
that New Guinea is the Centre of Origin for the species. This trial
and a supplementary replicated
variety trial (click here to see) showed that Papua New Guinea varieties as a whole
are earlier to mature, have fewer low-growing branches, and have higher
mature seed yields at day 165 after planting (Table
2). These were all signs that the New Guinea varieties of winged
bean were typical of a more advanced domesticate.
Of all the varieties tested, the one group of accessions
that had the characteristics most expected of an imagined prototype
for the species, was the group of accessions from Bogor in the island
of Java. This group of accessions failed to flower in the 165 days allotted
to the experiment, had strong horizontal branching from low down on
the main stem and leaf nodes which quickly formed roots when in contact
with moist soil, and had a sparse flowering habit when they eventually
did flower (Table 2).
Other varieties tested were intermediate between the
New Guinea and the Bogor collections.