This document provides information about forest tree seeds. It discusses the basic structure and parts of a seed, including the embryo, endosperm, and seed coat. It describes different types of seeds and patterns of seed germination. Key factors that influence seed germination like water, temperature, light, and oxygen are outlined. The document also discusses seed dormancy, methods to break dormancy, sources of seeds, seed collection and processing procedures, storage methods, certification, and common tests for seed quality including tests for genuineness, purity, moisture content, and viability.

1. FOREST TREE SEEDS

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: