Seeds generally germinate readily o

Seeds generally germinate readily on
imbibition of water if they are harvested at
the right time, dried properly and aptly
stored, either immediately or after a period of dormancy depending on the species.
Even though, generally legumes do not
show seed dormancy, there are reports,
that dormancy exists in some varieties of
P. tetragonolobus (L.) DC.
A perusal of literature revealed that the
germination percentage of seeds of P.
tetragonolobus varied in different varieties
(40- 80 %) [7,8]. However, in the present
study, a germination percentage of 96%
was achieved immediately after
harvesting. This difference existing in
different varieties of P.
tetragonolobus substantiates that the
genotype of the plant has a role in
determining the germinability of the seeds.
There was a decline in the percentage of
germination of the seeds of P.
tetragonolobus on storage and was found
to cease completely after six months.
However, Hew and Lee [9], observed that
in a local cultivar of Sri Lanka, the seed
germination was reduced by 50% when
fresh seeds were stored for two weeks and
no germination was observed after two
months of storage. But the report of
Senanayake and Thiruketheeswaran [10]
was in paradox to this observation.
According to them, seeds stored in dry
pods at room temperature for 12 months
had comparable viability and better vigour
than fresh seeds.
For increasing the percentage of seed
germination, the seeds (four months after
harvest) were treated with various
chemicals at different temperatures in the
present study. There are reports on the use
of various physical and chemical
treatments for increasing the germination
of seeds Ninety to hundred percentage germination
could be achieved when seeds were treated
with 80% H2SO4 at 600C and 0.5 % KNO3
at 500C for 5 minutes. An increase in
temperature upto 500C for all treatments
was found to be effective for increasing
the germinability of the seeds. 700C was
found to be supraoptimal for seed
germination except in 0.1 % KNO3, which
gave the maximum response of 60 % at
700C. Solanki and Joshi [4], has reported
the detrimental effect of temperature
above 650C on germination when H2SO4,
GA3 and KNO3 were used.