Tamarind monograph.pdf - Crops for the Future

67.2% and reduced the incidence of abnormal seedlings to 9.9% and left no
hard seeds (Parameswari et al. 2001 a). In another study, Parameswari et al.
(2001 b) reported that seed size and duration of acid scarification are
positively related, where bigger sized seeds require 20 minutes of acid
scarification while only 15 and 10 minutes respectively was needed for
medium and small sized ones. In Burkina Faso, the seeds were scarified
using 7% sulphuric acid washed and dried and then stored in sealed
containers for 52 weeks at 4 o C. The germination percentages after 20, 28
and 52 weeks was satisfactory, but showed little improvement over untreated
seed (Some et al., 1990).
MacDonald et al. (2002) showed that the highest germination percentage
and subsequent growth development of tamarind seed occurred following
pretreatment with methanol for 10 minutes. Seeds immersed in methanol,
ethanol and sulphuric acid for 10 minutes produced seedlings with high
vigour (Idu and Omonhinmin, 2001).
On the other hand, studies undertaken at the Malawi Forest Research
Institute clearly indicate that seed pre-treatment is not required for the
enhanced germination of tamarind seed (Muabamba and Sitaubi, 1995).
Although no seed pre-treatments are essential, various pre-treatments can
accelerate the speed of germination. Soaking in cold or tepid water for 24 -
48 hours has been reported to hasten germination (Troup, 1921; Von
Carlowitz, 1986). In Malawi, seeds of tamarind thoroughly cleaned and
soaked in water overnight to encourage germination resulted in more than
80% germination (Prins and Magehembe, 1994).
The hard seed coat of tamarind can also be softened by hot water treatment.
Muhammad and Amusa (2003) found that soaking seeds in hot water may
overcome seed coat dormancy and stimulate germination. The germination
response of tamarind seed to hot water treatment increases with increasing
temperature (up to 100º C) and soaking period (up to 60 min).
Gashaw et al. (2002) reported that short exposure of seeds for one minute to
high temperatures (200ºC) generally stimulated germination whereas
prolonged exposure to these temperatures reduced seed germination,
suggesting that frequent and light burning in wooded savanna grasslands
seems to stimulate and enhance germination of tamarind seed.
Vanangamudi and Vanangamudi (2003) compared seven growth stimulants
on seed germination and seedling growth of tamarind and found that three of
them (IAA, succinic acid and KH2PO4) proved to be effective in enhancing
the germination and seedling vigour. According to Sankaranarayan et al.
(1994), seed germination can also be accelerated by soaking in 10% cow
urine or cow dung solution (500 g in 10 l) for 24 hours, when germination
more than doubled.
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