Tamarind monograph.pdf - Crops for the Future

the seeds’ volume and weight, and serve as the sole food storage organs.
Seeds average 1800 to 2600 per kg (Jøker, 2000).
Germination of tamarind seed is epigeal. The radicle swells and emerges
from one end of the seed and descends rapidly. The hypocotyl elongates,
arches slightly and raises the cotyledons and shoot apex above the ground
towards the light. The testa falls to the ground when the cotyledons expand
(Troup, 1921).
The seed storage behaviour of tamarind is orthodox (Riley, 1981 quoted by
Hong et al., 1996) which means that they can be kept in good condition if
attention is paid to the moisture content. Fresh seeds retain viability for at
least six months when kept dry at ambient temperature. Seeds store well in
dry sand, remaining viable for at least two years if kept in closed vessels for
protection from insect pests (Teel, 1984; Morton 1987; Parrotta, 1990).
When handling seeds therefore their viability can be maintained if the seeds
are well-dried, mixed with sand and kept in air-tight containers. Reducing
the temperature is also helpful in maintaining viability of dry seeds. Albrecht
(1993 quoted by Hong et al. 1996) reported that seeds could be stored for
several years in air-tight packs at 10 o C and 7-15% moisture content.
On average, tamarind seeds begin to germinate about 13 days after sowing
(Padolina, 1931; Galang, 1955) but may take a month to complete (Jøker,
2000). It is recommended that up to 45 days from planting be allowed to
ensure that maximum germination has been achieved (El-Siddig et al.,
2001). The germination pattern is similar to that of other leguminous species
in which the hard seed coat interferes with water and oxygen uptake, thereby
limiting germination. The germination capacity of fresh or well stored
tamarind seed is reported to vary from 65-75%. Coronel (1991), stated that,
depending on the conditions, germination might vary from 30 - 70%. In
another study, 90% success was achieved (Teel, 1984). However, much
depends on the degree of maturity of the seeds when harvested and their
moisture content prior to testing the germination.
5.2.1.2 Seed treatments
Germination of tamarind seed can be accelerated by overcoming the hard
seededness through acid or mechanical scarification and soaking in hot
water.
Scarification with concentrated sulphuric acid has proved to be highly
effective with tamarind seed. Muhammad and Amusa (2003) observed the
highest germination percentage in seed lots treated with 50% sulphuric acid
for 60 minutes. El-Siddig et al. (2001) reported that immersion of tamarind
seeds in 97% sulphuric acid for at least 45 minutes at 25º C is an effective
method for promoting fast and synchronous germination. Scarification with
sulphuric acid at 200 ml kg -1 for 15 minutes increased seed germination to
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