Western Ghats Kokum Foundation - Organic Farming Association of ...

Malik et al. (2005) reported the efficient method for rapid regeneration of plantlets
via adventitious bud differentiation using mature seeds of Kokum. The maximum
percentage of direct shoot proliferation was noticed in seed segments cultured on
Murashige and Skoog’s medium supplemented with cytokinins such as BAP, KN and
thidiazuron (TDZ) alone and in combination with auxin (NAA). Seed segments cultured on
MS basal medium showed development of shoot along with roots from S-end (emergence
of shoot) and only roots from R-end (emergence of root), while the middle segments
showed no response. Only the creamish-white seed segments produced multiple shoots on
hormones supplemented media, they were subsequently used for all experiments on
adventitious bud differentiation. Significant variations were recorded among the explants
from different accessions. Accession numbers IC-136685-1 and IC-136682-2 showed
maximum response of 100% followed by IC-136687-2 (91.67%) and IC-136687-3
(44.45%).
The concentration of BAP required for induction of maximum number of shoot buds
also varied among the explants from four accessions. Seeds from accession number IC-
136685-1 produced maximum number of buds per segment when cultured on 50 µM BAP
in the medium. Increase in BAP concentration beyond the optimal concentration (More
than 50 µM) did not improve the regeneration response in any of the accessions. The shoot
buds developed at BAP concentrations was found higher than the optimal levels which
were stunted, failed to elongate and their leaves did not expand even after transfer to
hormone-free MS medium. There were differences amongst the genotypes in terms of
in vitro response for adventitious shoot bud development. Seeds of accessions IC-136685-1
and IC-136687-2 developed shoot buds directly on the explants surface without forming
callus or swelling. Seeds of IC-136682-2, showed swelling of explants along with the
development of large number of shoot bud primordia on the whole explants surface, but
only a few of these primordial differentiated into shoots. Seeds from accession IC-136687-3
on the other hand showed development of white, friable callus on the seed segment surface
along with the shoot buds at all the BAP concentrations. Shoot bud formation was observed
within 4–5 weeks of culture. Maximum response was observed at different concentrations
of BAP (12.5–50 µm) in different genotypes investigated.
Effect of NAA (1.0 and 2.5 µM) with BAP (5–50 µM), kinetin (12.5 µM) and TDZ (0.1,
0.2, 0.5 and 12.5 µM) added singly for the induction of adventitious buds was studied in
accession IC-136685-1 seed segments. Media supplemented of NAA along with BAP was
deleterious, as it did not bring any improvement in the regeneration response, these bud
numbers were much less compared to that induced on medium supplemented with only
BAP (25.36–57.67). When the media supplemented with kinetin (12.5 µM) alone induced
less shoot buds as comparison with BAP.
Effect of TDZ on shoot buds induction was 69.45–77.78% explants. However, bud to
shoot conversion rate was only 5–10% when the cultures were subsequently transferred to
basal medium while others turned necrotic. The higher concentration of TDZ (12.5 µM) led
to development of callus in 97.22% explants, but only 36.11% explants producing shoot
buds. Shoots elongation was achieved on MS basal medium containing 0.2% activated
charcoal. Proliferation of shoot was done by repeatedly sub-culturing the shoot nodes on
MS medium supplemented with 5 µm BAP. The maximum percentage (91.66%) of rooting
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Resource Book on Kokum (Garcinia indica Choisy)
Western Ghats Kokum Foundation, Panaji - Goa