Abstract:
In sexual reproduction of plants, a male and a female gamete fuse to
from a single cell, the zygote, which develops into a new plant through an
embryo. Formation of an embryo is known as "Embryogenesis" and
formation of an embryo from a zygote is "Zygotic embryogenesis" (Esau,
1977). The resulting plant is a new individual arising from a single cell and
has characters of both male and female plants. Another type of embryogenesis
is possible by the induction of somatic (vegetative) cells. This is known as
"Somatic embryogenesis" (or non-zygotic embryogenesis) and the embryos
are known as "Somatic embryos" (or non-zygotic embryos). This may occur
in nature (as seen in citrus family) or may be induced by in vitro. The latter
is known as "In vitro somatic embryogenesis". This is reported in a wide
variety of angiosperm species, both form reproductive tissues such as
nucellus and synergid cells, and from true vegetative (somatic) tissues such
as leaf margins (Veyret, 1974; Raghavan, 1976: Tisserat et al, 1979, L i t z &
Gray, 1992).
Somatic embryogenesis in general can be defined as "The development
of embryos from somatic haploid or diploid cells, without fusion of
gametes". Somatic embryogenesis has been reported in dicotyledons more
than in monocotyledons despite the fact that the latter consist most of the
world major food crops. This is also true for invitro somatic embryogenesis.
It is reported that many difficulties of in vitro culture in monocotyledons
have hindered such studies (Williams and Maheswaran, 1986). However, in
vitro somatic embryogenesis and plant regeneration have been reported in
