Agriculture Reference
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fertilized ovaries obtained from closed flower buds of an adult 54-year-old neem
tree were used as explants. Maximum shoot regeneration (78 %) was observed
when calli, induced from ovaries of 4 mm size flower buds and proliferating on
MS + 2,4-D (0.5 µM), were transferred to MS containing BAP (5 µM). Histological
analysis revealed that 4 mm sized flower buds corresponded to a 2-nucleate stage
of the embryo sac. The best medium for inducing calli from unfertilized ovaries
was MS medium with 9 % sucrose, 2,4-D(1 µM) + BAP(5 µM). The shoots were
multiplied by forced axillary branching on MS medium supplemented with BAP
(1 µM) and Casein hydrolysate (250 mg/l). The shoots were rooted on ¼ strength
MS medium supplemented with IBA (0.5 µM) at a frequency of 79 %. The plants
were subsequently hardened with transplantation rate of 81.8 %. Although all the
regenerated plants were diploid, an efficient protocol for ovary culture of neem
was established which can be used as a platform to produce gynogenic haploids
of neem in future.
4.2 Camellia spp (Family: Theaceae)
Camellia sinensis
(L.) O. Kuntze commonly referred to as tea, belonging to the fam-
ily Theaceae, is an evergreen, perennial, cross-pollinating plant. It grows naturally
as tall as 15 m; however, it is usually trimmed to below 2 m when cultivated for its
leaves (Mondal and Parathi
2003
). The cultivated taxa of tea consists of three main
natural hybrids. They are
Camellia sinensis
(L.) O. Kuntze or China type,
Camellia
assamica
(Masters) or Assam type and
Camellia assamica
sub spp
lasiocalyx
(Plan-
chon ex Watt.) or Cambod or Southern type. Tea is the oldest non-alcoholic caffeine
containing beverage in the world. The medicinal properties of tea are also widely
acclaimed. It is an important socio-economic crop that plays a significant role in the
foreign exchange of developing countries like India. Polyphenols account for about
25-35 % of the total dry weight of freshly plucked tea leaves of which two-thirds is
contributed by catechins alone (Saravanan et al.
2005
). Research progress on tissue
culture of tea has been rather slow for the last 20 years because tea is less amenable
to these techniques, due to the high level of polyphenols, the presence of systemic
bacterial contamination and its recalcitrant nature in tissue culture medium (Dood
1994
).
The initial attempts to produce haploids through anther culture of tea were pio-
neered by Katsuo (
1969
) and Okano and Fuchinone (
1970
). They obtained roots
from anther-derived callus. Later, Hoken Toi (1981) also achieved similar response
on medium supplemented with NAA (9.67 µM) and Kinetin (10.1 µM) (Mondal
et al.
2004
). However, it was Chen and Liao in
1982
, who produced complete
plantlets from tea anthers of cultivar Fuyun No-7 out of nine different tea culti-
vars on which they worked. The plantlets were obtained when the anthers were
cultured on N
6
medium supplemented with Kinetin (9.3 µM), 2,4-D (2.26 µM),
L-Glutamine (800 mg/l), and Serine (100 mg/l), followed by sub culturing on N
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