Cultivation of medicinal plants by Seed / Sexual Propagation

1. Cultivation Of Medicinal Plants by
Seed Propagation / Sexual Propagation
PREPARED BY,
Ms. M.S. Divya Sree, M.Pharm,
Assistant Professor,
Department of Pharmacognosy,
Sree Vidyanikethan College of Pharmacy,
Tirupati, Andhra Pradesh.

2. Propagation
2 types
1) Seed Propagation (Sexual)
2) Vegetative Propagation (Asexual)

3. Seed /sexual Propagation
• Plants raised from seeds – seedlings
• Drawbacks
a)Loss through transplantation.
b)Failure to germinate (very slow or no
germination).

4. Germination failure is mainly due to
i) Natural chemical inhibitors.
ii) Physical inhibitors.
Natural chemical inhibitors
 Treat – soaking with chemical reagents like H2So4/water
to specific period – depending on the type of the seed.
 Hard coat seeds – soak in 0.2% gibberlic acid for 48 hrs.
 Ex: Henbane, castor seeds – with H2So4.

5. Physical inhibitors
 By abbration techniques - treat with coarse sand or
stones.
 By removing testa of seeds(partial or complete removal)
- It should be done carefully without disturbing the
embryo of the seed.
Ex: Indian senna.
When the seeds are prepared, they should be
evenly distributed / spread over the seed bed.

6.  There should be proper contact between seeds
and soil.
(For this a small layer of soil should be placed
between the seeds)
 If any plantation is done in the polythene bags
then care should be taken to maintain proper
moisture in the soil.
 Seed sown – depth 2-3 / 2-4 cm.

7. Seeds – shouldn’t sow very deep –
germination doesn’t take place
3-5 seeds in single hole(small) & cover with
single layer of soil.
 When seedlings come up with 2-4 leaves,
stronger one can be selected.
 Other seedlings can be removed.

8. Methods of seed propagation
A. Broad casting
B. Dibbling
C. Drilling
D. Nursery bed

9. Broad casting

10. Broad casting
 Method of seeding - involves scattering seed, by hand or mechanically
over a relatively large area.
 Seed is placed at a precise spacing and depth.
 For extremely small seeds.
 This process involves direct sprinkling of seeds into the soil.
 Seeds sown in this manner are distributed unevenly (which may result in
overcrowding).
 Also this method may not ensure that all seeds are sown at the correct
depth .
Ex: Isapgol, sesame, linseed

11. Dibbling
• Seeds – average size and weight.
• Making small holes in the ground for seeds or
plants.
• 3-5 seeds (in single dibble).
Ex: Groundnut, Castor, Cotton, nutmeg.

12. Dibbling

13. Drilling
• The sowing is done through seed drills/seed cum
fertilizer drill.
• The seeds are covered by wooden plank or
harrow to have contact between seed & soil.
• Seeds are dropped at uniform depth and results
in uniform germination and regular stand
Ex: Jowar, wheat, maize

15. Nursery beds
• Plant your seeds in rows. The lines must face
where the sun raises from.
• Make the lines at a spacing of 15 cm apart.
• Use a string to make straight lines.
• The line must be 2 cm deep.
• The seeds will start germinating after 5 – 7 days.

17. Advantages
• It is the simple and cheap method and can be employed by
the growers at their own fields.
• Plants produced are hardy and have strong root system.
• When the plant cannot be propagated through vegetative
means, then it is the only method of propagation.
• Many commercial cultivars originated as chance seedlings.
• Hybridization work depends upon seed germination.

18. Disadvantages
• Plants raised through seeds have long juvenile period.
• It takes long time to fruiting.
• The seedling trees have very deep root system hence
the trees attain big size at maturity.
• Some viruses are seed borne.
• Some seedless fruits cannot be propagated through
seed.