Fruits, Seed and Germination
Among the six ovules, one develops into a seed. Two or three layers of nucellar cells persist
in the seed as perisperm. Both the integuments contribute to the formation of the seed coat.
In a mature seed the outer integument consist of a thin-walled epidermis and two layers of
loosely arranged cells. The inner integument is two or three layered. The fruit is an ovoid
drupe. Neem fruits are green when young and turn yellow to brown when ripe. The epicarp is
thin and endocarp is hard and bony. The mesocarp is pulpy and is eaten by humans and
animals. A large variety of birds notably parrots visit the tree when it is in fruit.
The seed is ovoid of spherical, pointed above and has a thin testa. It is exarillate with a small
adaxial sacrotesta. Under natural conditions the seed generally falls to the ground during the
rainy season and germinates in 8-15 days. The percentage of germination is very high,
although survival under the tree is poor. Waterlogging appears detrimental to seeding
growth. Neem can be raised easily in a nursery and transplanted. However, direct sowing is
more successful than transplanting. Neem is also propagated by shoot and root cuttings.
Rooting is promoted when growth regulators such as indole-3-butyric acid (IBA) and α-
naphthaleneacetic acid (NAA) are used.
Germinability of the seeds can be improved
by soaking in warm water (65-700C) for 30
min or by passing through the gut of
baboons or birds. Germination is
phanerocotylar, the cophylls are opposite
and trifoliate. Leaflets are deeply incised and
pinnatified or partite.
Neem seeds lose their viability within 2-3
weeks. Seeds are classified as recalcitrant.
Cold storage can extend the viability to 6-8
weeks but they lose viability completely when
store at Zero degree. It is reported that
germination differs depending on whether
the seed is elongated or spherical. However
no evidence are available on effectiveness of
neem oil in extreme tempratures.