2. SEED
Ripened ovule consisting of embryo, an
endosperm (in many seeds) all enclosed
in an envelope.
Embryo: miniature plant
Radicle
Epicotyl
One or more cotyledons
Hypocotyl
3. KINDS OF SEED:
1. Monocotyledonous:
2. Dicotyledonous:
3. Endospermic:
4. Non-endospermic:
5. Perispermtic:
Seed size:
Varies from species to species.
Largest being coconut, smallest:
Anthocephalus chinensis, Eucalyptus
spp.
4. SEED GERMINATION: FACTORS
Water:
Temperature:
Light:
O2 supply :
Biocides:
Change during seed germination:
Germination- resumption of embryo rapture of seed coat
emergence of young plant.
Cell division and cell elongation both occurs.
Essential steps:
Absorption of water.
Initiation of cell enlargement and division.
Increased enzymatic activity.
Translocation of food
Increase in respiration and assimilation.
Increase in cell division and enlargement.
Differentiation of cells into tissue and organs of seedlings.
5. PATTERN OF SEED GERMINATION
Epigeous:
Cotyledons are pushed out of the
ground by hypocotyl. i.e. bean
Hypogeous
Cotyledon remains underground
while epicotyl grows upward and
develop foliage. i.e. mango
Viviparous:
Seed germinates while still attached
to parent plant. i.e.: Heritiera fomes
6. SEED DORMANCY
Seed do not germinate even supplied with the
suitable factors for germination.
Viable seed: which can germinate under suitable
condition.
Seed dormancy is caused because of the following
conditions
Seed coat is impermeable.
Immature embryo.
Presence of inhibition in the seed.
Advantages:
Improves chance of survival against temporary
adverse condition.
Allows the dispersal of seed.
Disadvantages:
Delayed and irregular germination in nursery.
Cost increases due to the elongated storage
period and treatment requirements.
7. METHODS TO BREAK DORMANCY:
Physical method:
Cut drill of file a small hole in the seed coat.
Soaking in water
In tap water for number of hours or in hot water for short period.
Acid treatment:
Immersed in sulfuric acid for required period and immediately
washed by running water.
Biological method:
Happens in nature, swallowed by animal.
Dry heat and fire:
Covered with 3cm thick grasses, and then get on fire. As the grass
burned, seeds are kept in water.
Pit method:
Seeds are buried in pit saturated in water for 10 days (Tectona
grandis)
Irradiation of seed:
8. SOURCES OF SEED
Common sources of seeds are:
1. Seed zone or provenance:
Zone of tree with relatively uniform genetical composition.
Largest unit for seed collection.
Uniform and definite geographic bound, climatic and growing
condition.
Only for natural forest
How to delineate seed zone?
9. HOW TO DELINEATE SEED ZONE?
Pre-provenance trial: growth chamber, greenhouse,
nurseries.
Similarity in ecological condition= similar genetical
constitution.
Guidelines:
Much narrower area than forest region.
Use of maps.
Decision about choice of species
Map of the distribution of those species.
Utilize available informations: racial pattern, interaction with
planting site, environment etc.
Expectation of adaptation and variation.
One system for all species
Superimposing distribution map on forest map.
Establish a map with code no, zone ID, condition etc.
10. Seed production area
Young plantation opened by removing undesired
trees
Cultured for early and abundant seed production.
It can be both natural or artificial.
Main objectives
Improved quality seed
Concentrate on few specially treated parts of forest.
11. 3. Seed orchard.
Plantation primarily established for seed
production.
Seed-source garden.
Genetically superiors trees, isolated from
pollination by inferior plants,
Intensively managed to produced
adequate seeds.
From clones (graft or cutting) or seedlings
from desired progeny.
Objective of seed orchard
Kinds of seed orchard:
Conservation, region, provenance, HYBRID,
advanced .
4. Individual plus tree.
Quick and inexpensive manner of seed
collection.
12. SEED COLLECTION
seed collection time and procedure
Where to collect?
Points need to be observed in collecting seed:
The parent plant should be of desirable form.
The position of the tree.
Flowering habitats and seed production.
Good sampling.
Mature seed with good development.
Information from local forest office, conducting a
survey.
Testing the soundness of seeds by cutting open
portion of fruit.
13. TIME OF SEED MATURITY
Helps to decide when to collect seed.
Species that retains unopened fruit, permits harvesting
anytime.
Species with heavy and big fruits which falls to the ground
usually have first fruit defective.
Time of seed collection for species:
Determining seed quantities to be collected
Areas to be planted
Initial spacing
Losses and culls in the nursery.
Replacements needed after planting.
Germinated seed to be expected from the source.
14. SEED MATURITY
How to recognize a mature seed?
Experienced collectors:
General appearance
Color
Degree of milkiness.
Hardness of the seed coat.
Attractiveness to animals
Some may not show maturity in external appearance
Outer seed coat changes color.
Kernel looses its soft milky characteristics.
Fleshy and pulpy fruit lose their hardness and
becomes soft.
For dipterocarp seeds, collection should be done
as soon as the wing begins to turn brown
15. EQUIPMENT FOR SEED COLLECTION
Hand held Hooper Mechanical means
Cone picker
16. METHOD FOR SEED COLLECTION
Three methods
1. Collecting from the ground
2. Collecting from standing tree.
Mahagoni , chhatim etc
Breaking the twigs or branches.
Applied to following classes of
fruits
Fruit to small to be picked
commercially from ground.
Wind disseminated.
Small seeds falling from fruits still
attached with trees.
3. From felled trees.
17. SEED EXTRACTION
Separation from the fruit.
Cleaning fruit parts or debris.
Helps to
Prevent spoilage.
Conserve space and weight while
shipment.
Facilitates handing and sowing.
Methods of extraction.
Drying
Threshing
Depulping
Fanning or sieving.
18. METHOD OF CLEANING SEED
Four general methods.
1. Dewinging : rubbing seeds
between moistened hand.
2. Screening :
3. Fanning :
To remove wings or light chaffs,
empty seeds.
4. Flotation.
Pulpy and fleshy fruits.
19. SEED STORAGE
Objective:
Main objective is to bridge the gaps between seeding year.
Prevent excessive loss of water from seed.
Prevent bio-chemical activities.
Break the dormancy.
Extending the storage life from 1-2 weeks to 1-2 years.
Factors affecting seed storage:
A. Moisture content of seed:
Seed with low moisture content (orthodox seed- bellow 20%)
Many leguminous seeds belong to this group.
Can be stored without any specific treatment.
Parkia javanica remains viable for 3 years in 4°C temp.
20. Seed with high moisture content (recalcitrant seed- above 20%)
Such as dipterocarp seeds.
If moisture content is bellow or equals 20%, these can’t survive.
So moisture content should be above threshold level.
Can be done:
Placing in a close container with relative humidity over 95%.
Using desiccating chemicals like: CaO, silica gel.
For long term storage, reducing moisture content bellow 10% without
loosing viability.
For long term storage, increasing low temperature tolerance of seed.
B. Storage temperature
Storage at low temperature prolongs seed life.
Reduces metabolism.
Reduces insect damage.
Dry seeds can survive bellow freezing point.
21. STORAGE TYPES
Dry storage:
Storage without temperature control
Seeds which can withstand moderate desiccation.
Seeds should be sufficiently dry to prevent heating and
molding.
Three types :
Storage under fluctuating temperature and humidity.
Dry cold storage.
Storage in sealed cans, boxes and bags.
Examples:
Moist storage:
Seeds of which viability is weakened by dry storage.
On or in the ground.
In cold storage plants.
Must be immediately sown after removal from cold
storage.
Examples:
Ordinary air temperature:
Simplest and oldest method.
Closed tin, cool cellars or insulated buildings.
22. SEED CERTIFICATION
Object is to maintain the sources of seed, plant and other plant
propagating materials.
To ensure the genetic identity and high quality of seed and plant.
Necessary elements:
1. Planning
2. Implementation:
Organization and management
Certifying agency
Advising committee.
Working group
Inspectors
Which information should be provided for approved category of seeds
or for seed certification?
• Classification and approval
of sources
• Recommendation for
choice of provinance
• Production and control of
procedure
• Data recording and
documentation.
• Marketing of reproductive
material
Later
23. SEED TESTING
Objectives:
Determine seed quality
Identify problems and causes.
Take decision regarding seed storage or other processing.
Determine if seed meets desired quality and requirement.
Provide basis for price.
Seed quality is determined by :
Source of seed
Size and weight of seed.
Degree of maturity and age of seed.
24. TEST OF GENUINENESS
Tests the true identity of seed.
Three basic way:
1. Identification of parent tree and certification of seed
lot.
2. Using analytical key and comparison with other.
3. Identification of seeding.
In addition:
External appearance.
Internal appearance.
25. TEST FOR MOISTURE CONTENT
Amount of moisture in the seed.
Essential for seed storage, longevity.
Moisture content = M3-M1 * 100/ (M2-M1)
M1= weight of container and cover (g)
M2 = weight of Container ,cover, content (g)
M3 = Weight of container, cover and content after drying (g)
26. TEST FOR PURITY
Percentage weight of clean
seed.
Purity = (weight of clean seed/
weight of impurity+ clean seed)*100
Number of clean seed per unit weight:
No. of seed per kg
= (no. of pure seeds in sample/
Grams of pure seeds in sample)* 1000
27. TEST FOR VIABILITY
Dried and cleaned seeds need to be tested for
germinability.
1. Direct inspection and cutting test.
External and internal characteristics are considered.
Seed kernel firm, plump, sweet smell, white colored
sound seed.
Foul, rancid colored, shriveled, discolored cotyledon
rotten seed
Suitable for quick assessment.
28. 2. Physical test
a. Oil spot test:
b. Flotation test:
c. X-ray:
d. Chemical stains:
3. Germination test
More reliable method
Test made in container, i.e. in petri dish.
Sample should be large enough. (i.e. more than 100)
Seed in container must be placed in moist sand, peat or filter
paper and lightly covered with same medium.
At the end number of seed germinated should be recorded.
29. Results are expressed in several ways-
Germination percentage:
Germination energy:
Germinative capacity:
Other germination parameters: