Tamarind monograph.pdf - Crops for the Future

The correct spacing of mother plants is important to produce shoots for
commercial production of grafted plants. Feungchan et al. (1996 a) reported
that a spacing of 2 x 2 m is the most suitable for multiplication purposes.
The age of the rootstocks for soft wood grafting is also important for
success. Scions pre-conditioned for 30 days prior to grafting on to 6- and 9-
month-old rootstocks growing in the green house resulted in 69-72% success
at 60 days. Grafting success has been attributed to the fact that rootstocks of
this age contain a higher proportion of reducing sugars to total sugars than at
other ages (Kulwall, 1997, quoted in Rao et al., 1999; Satisha et al., 1997).
Tamarind provenances differ in their graft success (Sathishkumar and
Mokashi, 2003). Provenance may also influence traits such as hardiness,
growth rate and adaptability to climatic conditions, and this should be kept
in mind when purchasing or collecting scion materials from different
locations.
Root stock selection for vegetative propagation of tamarind is important as it
controls the vigour and the equilibrium between yield and quality. Dwarfing
rootstocks are considered best because they result in short trees, which are
easy to manipulate for management practices, have increased fruit
production, and require less land and labour inputs. In Thailand, a dwarf
rootstock has been identified based on morphological characteristics, such as
internode length and leaf area. These characters were correlated with the
number of stomata on the leaves. Attempts to reduce canopy size by
intergeneric grafting tamarind scions on to root stocks of other leguminous
species have not been successful. The application of growth inhibiting
chemicals has also had no dwarfing effect (Feungchan et al., 1996 b).
5.2.2.3 Layering
Layering is a simple and easy method of rooting a branch of a shrub or tree
while it is still attached to the parent plant. It is a widely practised
propagation method for tamarind. In ground layering, a flexible branch is
bent down and pegged to the ground, and the point of contact covered with
soil. A small cut is made in the lower side of the stem where it touches the
ground to impede sap circulation and encourage rooting. After 3-6 weeks
roots form at the point of contact with the soil and a new plant can be
obtained by severing the branch above the place of rooting.
For air layering or marcotting, a branch is selected and a 2.5 cm lenght of the
bark is removed. This area is covered with a moist soil mixture or a moist
porous material, such as coir fibre dust, and kept in position by wrapping
with polyethylene film. It is kept moist for 2-3 months. When large
quantities of roots are observed through the polyethylene film, the branch
with its roots is severed from the parent tree and potted up for later planting
(see Plates 8,9).
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