Tamarind monograph.pdf - Crops for the Future

immediately dipped for ten seconds in 1000 ppm of indole butyric acid
(IBA), and in 50% isopropyl alcohol, before being planted in polypropylene
tubes containing vermiculite/perlite (1:1) and placed in a mist propagator
with 70-80% humidity. The use of the growth regulator IBA increased the
rooting of cuttings to over 94% compared to the control, which recorded
only 25%. Furthermore, the time taken to initiate rooting was only 10-15
days with IBA, while the control took 40-50 days. Terminal cuttings have an
advantage over mid stem cuttings because there is only one cut end thus
reducing the possibility of infection by disease causing organisms during or
after the rooting phase.
Soft or semi-soft stem cuttings, 15-20 cm long, taken from 1-2 year old
branches can also be rooted (Swaminath et al., 1990). In this method, the
cuttings are wrapped in moist cloth after removal from the trees to prevent
moisture loss. They are then dipped in a rooting hormone, preferably IBA at
1000 ppm, and placed in a sand bed in a mist chamber. Bud initiation and
root formation occurs after about 20 days and new leaves are formed after
about 45 days. Hard wood cuttings will not root and hence their use should
not be attempted.
5.2.2.2 Budding and Grafting
Vegetative propagation by shield and patch budding, cleft grafting, whip
grafting and approach grafting are reliable methods, although they are
expensive and time consuming (Purushotham and Narasimharao, 1990).
Successful budding requires that the scion material has fully-formed, mature,
dormant buds, and that the rootstock be in a condition of active growth such
that the ‘bark is slipping’. In tropical areas, the bark slips anytime the plant
is in active growth - which is practically year-round. For patch budding,
seedling rootstocks should be grown in raised beds and budded when they
are 6-9 months old. This is a suitable method for large-scale multiplication
of tamarind. Pathak et al. (1992) reported 96% and 94% success respectively
of patch budding and modified ring budding of 9-month-old seedling
rootstocks. Shield and patch budding and cleft grafting have been used for
producing plants for large plantations in the Philippines and Thailand (see
Plates 3-5).
Approach grafting is successful for difficult-to-graft species, even when
others techniques fail, because both the scion (upper portion of the grafted
pair) as well as the seedling root stock remain attached to their own root
systems during the period of graft union formation. Approach grafting has
been used in tamarind with up to 95% success (Swaminath and Ravindran,
1989; Daniel, 1998, personal communication).
The veneer grafting method possesses promise for mass scale commercial
propagation. For conducting this grafting operation, rootstocks about six
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