Agricultural seed production

1. Quality Seed Production
By
Dr. S. S. Jena
ASCO, Bolangir

2. Introduction
• Seed play an important role in any technology
embedding and we have to produce pure, quality,
resistant, healthy seeds for production of healthy food
to satisfy our needs.
• The main aim of seed production is to produce
genetically pure and good quality seed.
• Variety is a group of plants having clear distinguished
characters which when reproduced either sexually or
asexually retains these characters.
• The genetic purity of a variety is lost or deteriorated
during seed multiplication.

3. What is seed?
In broad sense
• Seed is a material which is used for planting or regeneration purpose.
scientifically
• Seed is a fertilized matured ovule together covered with seed coat is
called seed or it is a propagating material.
Technological point of view
• Seed is a fertilized ripened ovule consisting of three main parts namely
seed coat, endosperm and embryo, which in due course gives rise to a
new plant.
• It also refers to Propagating materials of healthy seedlings, tuber,
bulbs, rhizome, roots, cuttings, setts, all types of grafts and
vegetatively propagating materials used for production purpose.

4. Seed Quality
• Seed quality is the sum of all properties contributing to seed
performance. The quality of seed can decide whether a
farmer’s crop will be good, bad or indifferent.
• Seed quality is determined by the following characteristics:
1. Physical Attributes
2. Physiological Attributes
3. Genetic Attributes
4. Storability

5. Seed Quality
1. Physical Attributes
 A minimum of damaged seed
 A minimal amount of weed seed or inert matter
 A minimum of diseased seed
 Near uniform seed size
2. Physiological Attributes
 Germination Percentage or Viability
The germination percentage or viability is an indicator of the
seed’s ability to emerge from the soil to produce a plant in the
field under normal conditions
 Seed Vigour
Seed vigour is the capacity of seed to emerge from the soil and
survive under potentially stressful field conditions and to grow
rapidly under favourable conditions

6. Seed Quality
3. Genetic Attributes
• Seed of the same variety
• Adapted to the local conditions
• Pest and disease tolerance
• High yielding ability
4. Storability
• Moisture content
• Temperature of the environment
• Seed treatment

7. Deterioration of variety
The several factors that are responsible for loss of genetic
purity during seed production as listed by kadam (1942) are:
1. Developmental variation
2. Mechanical mixture
3. Mutation
4. Natural Crossing
5. Genetic drift
6. Minor Genetic Variation
7. Selective Influence of Diseases
8. The Techniques of the Plant Breeder
9. Breakdown of male sterility
10. Improper / defective seed certification System

8. 1. DevelopmentalVariations
Arise when seeds are grown in:
• Difficult environment
• Different soil & fertility conditions
• Different climatic conditions
• Different photo-periods
• Different elevations
For several consecutive generations
• Solution:
Grow them in their areas of adaptation & growing season.

9. 2. MechanicalMixtures
Most important source of variety deterioration
• Take place:
• At sowing time if more than 1 variety is sown with
same drill
• During harvesting & threshing operations.
• Gunny bags, seed bins, elevators etc are contaminated
with seeds of other varieties.
• Solution:
 Rogue the seed fields
 Care during seed production, harvesting, threshing &
further handling.

10. 3. Mutations
• Not a serious factor.
• Difficult to detect minor mutations.
Solution:
• Remove mutant plant
• Increase of true to type stock eliminate the problem

11. 4. NaturalCrossing
• Most important source of deterioration
• The deterioration in variety due to natural crossing
occurs due to the following 3 reasons:-
• Natural crossing with undesirable type.
• Natural crossing with diseased plant
• Natural crossing with off-type plants
• In self fertilized crops, natural crossing is not a serious
source of contamination & variety deterioration unless:
• The variety is male sterile
• Grown in close proximity to other varieties.

12. • But in Cross fertilized crops, natural crossing is the major
source of genetic contamination.
• Genetic contamination in seed fields due to natural crossing
depends upon the following factors:
• The breeding system of species
• Isolation distance
• Varietal mass
• Pollinating agent
Solution:
• Isolation between plantation.
• Small amounts of contamination over wide distances.

13. 5. Geneticdrift
• When seed is multiplied in large areas only small
quantities of seed is taken and preserved for the next
years sowing.
• Because of such improper sub-sampling all the
genotypes will not be represented in the next generation
and leads to change in genetic composition. This is called
as genetic drift.

14. 6. Minor GeneticVariation
• Exist in the phenotypically uniform & homogenous
varieties at the time of their release.
• When it goes under seed production selective
environment pressure has been removed and starts to
show the changes and may finally affects the yield.
• Solution:
• Yield trials of lines propagated from plants of breeder’s
seed in the maintenance of self fertilized crop
varieties.
• Care during maintenance of nucleus & breeder’s seed
is necessary.

15. 7. SelectiveInfluence of Disease
• New crop varieties often become susceptible to new
races of diseases
• Vegetatively propagated stocks deteriorate
• Solution:
• During seed production it is very necessary to produce
disease free seeds/stocks.

16. 8. Techniquesof plant Breeder
• Premature release of variety
• Variety testing program
• Break down in male sterility
• Environmental conditions
• Heritable variation
• Solution:
• Careful handling and adaptation of techniques

17. 9. Breakdownof male sterility
• Generally in hybrid seed production if there is any
breakdown of male sterility it may lead to a mixture of
F1 hybrids and selfers.
10. Improperseedcertification
• It is not a factor that deteriorates the crops varieties,
but is there is any lacuna in any of the above factors
and if it has not been checked it may lead to
deterioration of crop varieties.

18. Maintenance of Genetic Purity During
Seed Production
 Use of approved seed only in seed multiplication.
 Inspection & approval of fields prior to planting.
 Field inspection & approval of growing crops at critical
stages for verification of genetic purity, detection of
mixtures, weeds and for freedom from noxious weeds &
seed borne disease Etc.
 Sampling & sealing of cleaned lots.
 Growing of samples of potentially approved stocks for
comparison with authentic stocks.

19.  Providing adequate isolation to prevent contamination by
natural crossing or mechanical mixtures.
 Roguing of seed fields prior to the stage at which
they could contaminate the seed crop
 Periodic testing of varieties for genetic purity.
 Avoiding genetic shifts by growing crops in areas of their
adaptation only.
 Certification of seed crops to maintain genetic purity &
quality of seed.
 Adopting the generation system
 Grow out test.

20. A) GENERATION SYSTEM
• Seed production is restricted to
four generations only.
• Starting from breeder’s seed, the seed can only
be multiplied up-to 3 more generations:
i.e. Foundation, Registered & certified

21. Important safeguards for maintaining
genetic purity during seed production
1. Control of seed source
2. Preceding crop requirements
3. Isolation
4. Rouging of seed fields
5. Seed certification
6. Grow-out test

22. 1) Control of seed source
• Association of Official Seed Certifying Agencies (AOSCA)
recommended 4 classes of seeds
1. Breeder’s Seed
2. Foundation Seed
3. Registered Seed
4. Certified Seed

23. • Breeder’s Seed:
• Directly controlled by the original breeder, sponsoring breeder
or institution and which provides for the initial & recurring
increase of foundation seed.
• Foundation Seed:
• Include seed stock so handled as to most nearly maintain
specific genetic identity & purity and that may be designated
of distributed by an agricultural experiment station.
• It is the source of all certified seeds, either directly or through
registered seed

24. • Registered Seed:
• It is progeny of foundation or registered seed
• It is so handled as to maintain satisfactory genetic identity &
purity and that has been approved and certified by a certifying
agency.
• This class of seed should be of a quality suitable for production
of certified seed
• Certified Seed:
• It is progeny of foundation, registered or certified seed that is
so handled to maintain satisfactory genetic identity & purity
and that has been approved & certified by certifying agency.

25. 2) Preceding Crop Requirements:
• In the field where seed production of any crop is to be
taken the same crop could not be grown in previous
season.
• Fixed to avoid contamination through volunteer plants &
also the soil borne diseases

26. 3) Isolation
• Keeping the seed production plots apart from fields of the
same crop to avoid the risk of contamination by pollen from
the neighbouring fields.
• Isolation between seed plots can be effected by distances
(spatial isolation) or time (temporal isolation).
a. Spatial isolation:
• Isolation from Natural contamination: (cross pollination)
• Higher the class of seed wider the distance (BS V/s FS)
• In hybrid seed production distance is wider than that of
varietal seed production.

27. Cont.
b. Temporal isolation
• Crop of seed production should be sown early or late by a
margin of 15-20 days than neighboring fields of same or other
variety to prevent entry of foreign pollens in the field of seed
production.
c. Physical barrier
• In surrounding of seed production plot particularly on bunds
densely planted and well heighted plants should be grown to
prevent entry of foreign pollens to the seed production crops.
• Other contamination may be due to mechanical mixture at
• Harvesting
• Sowing
• Threshing
• Processing
• Handling
• Soil

28. 4) Rouging of seed field
• The removal of off type plants is referred to as rouging
• There are three main sources of off type plants.
• Firstly the off type plants may arise due to presence of some
recessive gene in homozygous conditions at the time of
release
• Another source of off type plants is the volunteer plants
arising from accidentally planted seeds or from seed
produced by earlier crops.
• Mechanical mixtures is also source of contamination.
• Removal is necessary before pollination occurs
• Regular supervision by trained personnel is imperative.

29. 5) Seed Certification
• The principal objective of seed certification is to maintain
& make available crop seeds which are of good seeding
value and true to variety.
• Qualified & well experienced inspection is necessary.
• Seed standards are confirmed by such agencies.

30. 6) Grow-out Test
Varieties being grown for seed production
should periodically be tested for genetic purity by grow-
out tests, to make sure that they are being maintained in
their true form

32. • Variety should be adapted to photoperiod and
temperature of that area.
• Moderate rainfall and humidity is good for seed
production.
• Dry sunny period and moderate temperature for
pollination.
• General regions with extreme summer heat & very cold
winters should be avoided for seed production.
• Ample sunshine, relatively moderate
rainfall & the absence of strong winds.
1. Selection of suitable agro-climatic
region

33. 2. Selection of Seed Plot
• Seed plot should have following characters:
• Soil texture & fertility should be according to
the requirement of the seed crops.
• Should be free from volunteer plants, weed
plants & other crop plants.
• The soil should be comparatively free from
soil-borne diseases & insect pests.
• In the preceding season the same crop should
have not been grown on this land, if it is so
required by seed certification standards

34. 3. Isolation of Seed Crops
• Done by providing distance between seed fields &
contaminating field
• On a small scale i.e. in nucleus/breeder’s seed
production the isolation can also be provided by
enclosing plants in cage by enclosing individual flowers
or by removing male flower part and then by individual
artificial pollination.
• After harvesting isolation of seed produced of different
varieties is necessary to avoid mechanical contamination.
• Similarly bags or other containers used to hold the seed
must be carefully cleaned to remove any seed which may
have remained in the bags from previous lots.

35. 4. Preparation of Land
• The land for seed crop must be prepared well.
• Good land preparation helps improved
germination, good stand establishment &
destruction of potential weeds.
• It also aids in water management & good
uniform irrigation.

36. 5. Selection of Variety
a) The variety should be adapted to agro-climatic
conditions of the region.
b) The variety should really be high yielder.
c) The variety should posses other desirable
attributes, namely disease resistance, earliness,
grain quality.

37. 6. Seed Treatments
• Chemical seed treatment.
• Seed treatment for breaking dormancy due to
hard seediness

38. 7. Time of Planting
• The seed crops should invariably be sown at
their normal planting time.
• Depending upon incidences of disease & pests,
some adjustments could be made if necessary.
• At time of planting there should be sufficient soil
moisture for germination to take place.

39. 8. Seed Rate
• Lower seed rates than usual for raising
commercial crop are desirable because they
facilitate rouging operations & inspection of seed
crop

40. 9. Methods of Sowing
• Row method of sowing
• Mechanical drilling can be used
• Desired amount
• Uniform depth
• Clean equipments
• Proper distance between plants

41. 10. Depth of sowing
• Shallow plantation in case of small seeds
• Deep plantation in case of large seeds
• Deep plantation in dry soils

42. 11. Rouging
• It is wise to remove the whole plant and not just
the flower head.
• The no. of rouging necessary will vary with the
crop, cleanness of planting seed & stage of the
multiplication of the seed crop.
• Rouging in most of the field crops may be done
at any of the following stages as per needs of the
seed crop.
a)Vegetative /pre-flowering stage
b)Flowering stage
c)Maturity stage

43. 12. Pollination
• Honey bee
• Insects
• Wind and water

44. 13. Weed Control
a)The presence of weed seeds at time of crop
harvest leads to mixing of weed seeds with crop
seeds. In many instances it is difficult to remove
them during the processing of seeds.
b)The presence of weeds in the seed field or
nearby areas may serve as host to no. of
diseases. Good & effective weed control
therefore would be necessary to obtain good
seed yields & to avoid contamination

45. 14. Disease/Insect Control
• If systematic diseases agents are not checked the seed
produces will get infected with spores of disease and
produce diseased plants in the next season.
• Agents of systemic disease, leave their spores on seed
coats. If not checked this results in a greater susceptibility
to various seedling diseases which can affect the crop.
Seed yield & quality are reduced.
Management of diseases & pests in seed crops:-
a)Plant only treated seed
b)Prepare & adopt appropriate schedule of spraying for
effective disease &insect control.
c)Roguing of diseased plants & ear heads from time to time
also helps in checking the further spread of diseases.

46. 15. Nutrition
 Nitrogen, phosphorous potassium & several
other elements play an important role for proper
development of plants & seeds.
 Identify the nutritional requirement of seed
crops & apply adequate fertilizer
 Results in maximum yields, god seed quality &
better expression of plant type which facilitate
rouging & there by helps in maintaining
higher genetic purity as well.

47. 16. Irrigation
• Dried regions are more suitable for good quality,
disease free seed production in that condition
irrigation is essential to obtain good seed yields.
• Before planting & at intervals up to flowering.
• One or two irrigations beyond flowering are
desirable for may seed crop.
• In general lighter soils need more irrigation than
heavier soils.

48. 17. Harvesting of seed crops
• Optimum time of harvest is when seed is fully
mature
• When weather damage begun, seed is easily
harvested & cleaned resulting in minimum
harvest losses.
• Earlier harvesting makes combining difficult &
relative losses due to threshing & cleaning are
greater.
• Late harvesting result in increased weather
damage & losses due shattering seeds & lodging
of plants in field.

49. 18. Method of harvesting
• By hands
• Quality of seed depends upon handling of
harvested crop & the care taken during
threshing
• Maintain lot identity
• My be by machine

50. 19. Drying of seeds
• More moisture at the time of harvest
• Precautions for seed drying
a)Identity of the lots must be maintained
b)Care should be taken to ensure that
mechanical mixture does not take place
c)Drying of seeds to safe moisture limits should
be done rather quickly.
If the seeds are to be artificially dried they should
be supplied to processing plants soon after
harvesting

51. 20. Storage of raw seeds
• Short period Storage should be in stacks or bags kept in
ordinary buildings or godowns after sun drying
• Filling in neat & clean bags, if old then properly treated
before use
• Proper labeling
• The stacks of bags should be made on wooden pallets.
• Storage place should be:
• Properly clean
• Dry
• Cool
• Sprayed with malathion
• fumigated