MSc

Studies were conducted to optimise the in vitro
propagation techniques via somatic embryogenesis in
polyembryonic mango varieties (Vellari, Kalluvarikka,
Thalimanga, Kilichundan, Pulichi and Varikka) of Kerala,
during 1993-1994 at the Department of Horticulture, College
of Agriculture, Vellayani.
Culture media and conditions could be standardised
for the first two stages of somatic embryogenesis, namely



induction and initiation.


However, attempts for inducing



normal maturation and germination of the embryoids were not
so successfu I .
Five out of the six varieties of mango (except
Ki I ichundan) responded to the induct ion treatments for



somatic embryogenesis.


Kalluvarikka recorded the highest per



cent cultures (87.50) initiating somatic embryoids from



the nucellar tissue.


Puliehi was observed to initiate the



highest per cent eultures (91.66) initiating somatic
embryoids from embryo mass cultured.

Somatic embryoids were induced and initiated from
nucellus as well as embryo mass. From the nucellus, the
embryoids were produced directly, without any intervening



callus.


The embryo mass gave rise to emb r y og e n i c ca I I us,



multiple embryos or zygotic embryos.
The somatic embryoids from nucellar tissue were



best induced when cultured in darkness


on half strength



Murashige and Skooge basal medium supplemented with 2,4-D 5.0
mg/l, GA3 5.0 mg/l, glutamine 400.0 mgll, sucrose 60.0 g/l,
coconut water 200.0 mIll, agar 6.0 g/l and activated charcoal
2.5 g/l.
Somatic embryoids from nucellar tissue were found
to be initiated in 55.50 per cent cultures on half strength
Murashige and Skoog basal medium supplemented with 2,4-D 5.0
mg/l, BA 0.05 mg/l, glutamine 400.0 mg/l, casein hydrolysate
500.0 mg/l, sucrose 60.0 g/l, coconut water 200.0 mill, agar



6.0 g/l and activated charcoal 2.5 g/l.


Darkness was



essential for the initiation.


Ambient temperature and in the



culture room temperature (26°C) were equally effective for
the initiation.



Abscisic acid was tried, among other treatments,
for inducing proper maturation of the somatic embryoids
initiated from nucellar tissue.
The maximum size of the
embryoids was observed on half strength Murashige and Skoog
basal medium supplemented with ABA 16.0 uM, casein
hydrolysate 100.0 mgll, sucrose 40.0 gll, coconut water 200.0

mIll, agar 6.0 g/l and activated charcoal 2.5 g/l.
the embryoids was not influenced by light.
Size of
Attempts for inducing normal germination of the
somatic embryoids from the maturation medium were made using
treatments involving plant growth substances (BA,
2iP,
GA
3
and NAA),
factors known to
impart osmotic stress
(Polyethelene glycol and high concentrations of sucrose and
a g a r) ,
sodium butyrate, known to influence histone
deacetylation, and activated charcoal, capable of absorbing
inhibitors.
However, the treatments were not very useful in
inducing normal germination of the embryoids.