Rubber tree, Hevea brasiliensis Muel-
Arg. is indigenous to Brazil. It yields latex
which is commercially the most important
source of natural rubber (NR). It was
first introduced in Bangladesh in the year
1970 in tea gardens. The commercial
introduction of this species was done by
Bangladesh Forest Industries Development
Corporation (BFIDC) in 1962. Since then
an area of 5512 ha in eight different estates
of Chittagong and Sylhet has been covered
with rubber plantation, mostly on unproductive
waste land and scrub forest land.
It has been decided to raise 24280 ha of
plantation to achieve self-sufficiency in
rubber in the country. Of this 19187 ha
would be raised in the public sector and
the rest private participation
(Amin 1977, Hussein 1982).

Sal seeds generally mature between the
months of April and May. It may vary
according to location. The seeds fall as
soon as they mature. The germination of
seed starts soon after maturity and it may
germinate even on the tree (Troup 1921).
When germination starts, the tip (apex)
of the fruits splits longitudinally (at right
angle to the pedicel of the seed) and the
radicle emerges from the apex of the seed.
Germination percentage is influenced
by various factors. Cockburn and Wong
(1969) stated that germination percentage
of Sal depended on the size of seed trees
and collection of seeds from the tree rather
than from ground. Troup (1921) reported
that sound fresh seed had a high germinative
capacity. Sal seed, however, rapidly
loses its viability. Depth of sowing is
also an important factor in germination.
Cayford and Waldron (1969) found
that germination depended on sowing
methods and depth of sowing. Defective
sowing of Sal seed in nursery in India
had led to low germination percentage
(Singh et al. 1975). The present investigation
was, thus, undertaken to determine the
effect of sowing orientation of seed on
germination.