Protocols for Micropropagation of Woody Trees and Fruits

MICROPROPAGATION OF ELITE NEEM TREE 357
that any reliable micropropagation protocol should use mature tissues to minimize
the chances of variations. It is not certain if the seedling-derived juvenile tissues will
also possess the same genetic make up as that of the mother plant. The protocol
described here involves the nodal explants and apical meristems of an old value-
added neem tree where callus is not formed during caulogenesis.
Surface sterilization is a major challenge in tree tissue culture, particularly if the
donor is the solitary elite tree and that too shows high bacterial infection. A serious
problem faced presently in establishing aseptic cultures of elite neem tree was the
inborn bacterial infection. This has been resolved by culturing the apical meristems.
Earlier, on a single cytokinin (BA, Kn, 2iP or zeatin) containing medium multiple
shoots have been regenerated which is, of course, species specific. A combination of
two cytokinins (BA+Kn, Kn+2iP, Kn+zeatin and BA+zeatin) has yielded appreciable
caulogenesis. Addition of lower concentrations of adjuvants with a combination of
two cytokinins has supported best morphogenesis presently. Adenine sulphate has
enhanced the number of shoot buds if used in combination with cytokinins, BA and Kn.
In vitro raised neem shoots have been presently rooted best on half-strength
Nitsch’s or Knop’s basal salts, which are cost effective, compared to the earlier
reports using auxins. A significant point in favor of this protocol is that the tissue
culture raised offsprings have maintained genetic fidelity with the mother elite
A. indica tree as demonstrated by RAPD analysis. Thus, the clonal propagation
protocol of the value-added neem tree has a great potential for commercial production,
specially when scientists are keen to produce biodegradable pesticides in large
quantities.
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