Seed production technology

1. Production of genetically pure and otherwise good quality
pedigree seed is an exacting task requiring high technical
skills and comparatively heavy financial investment. During
seed production strict attention must be given to the
maintenance of genetic purity and other qualities of seeds in
order to obtained new superior crop plant varieties. In other
words, seed production must be carried outunder
standardized and well-organized condition.

2. GENETIC
 Avoid Deterioration of
varieties
 1.Developmental variation
 2.Mechanical mixture
 3.Mutation
 4.NaturalCrossing
 5.Minor GeneticVariation
 6. Selective Influenceof
Diseases
 7.TheTechniques of thePlant
Breeder
 Maintenance of genetic
purity
AGRONOMIC
 Selection of aAgro-
climatic Region
 Selection of seed plot
 Isolation of Seed crops
 Preparation of Land
 Selection of variety
 Seed treatment
 Seed plantation
 Farm operations
 Harvesting of seeds
 After harvest care

4. 1. Developmental variation
2. Mechanical mixture
3. Mutation
4. NaturalCrossing
5. Minor GeneticVariation
6. Selective Influence of Diseases
7. TheTechniques of the PlantBreeder

5. 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.

6. 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.

7.  Not a serious factor.
 Difficult to detect minor mutations.
Solution:
 Remove mutant plant
 Increase of true to type stock eliminate the
problem

8.  Most important source 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.

9.  But in Cross fertilized crops, natural crossing isthe
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.

10.  Exist in the phenotypically uniform &
homogenous varieties at the time of their
release.
 During later production of cycle variation lost
due to selective elimination by environment.
 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.

11.  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.

12.  Premature release of variety
 Variety testing program
 Break down in male sterility
 Environmental conditions
 Heritable variation
 Solution:
 Careful handling and adaptationof
techniques

13.  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.

14.  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.

15.  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

16. 1. Control of seed source
2. Preceding crop requirements
3. Isolation
4. Rouging of seed fields
5. Seed certification
6. Grow-out test

17.  Association of Official Seed Certifying
Agencies (AOSCA) recommended 4 classes of
seeds
1. Breeder’sSeed
2. FoundationSeed
3. RegisteredSeed
4. CertifiedSeed

18.  Breeder’sSeed:
 Directly controlled by the original breeder,
sponsoring breeder or institution and which provides
for the initial & recurring increase of foundation seed.
 FoundationSeed:
 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

19.  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.

20. IN THE FIELD WHERE SEED PRODUCTION
OF ANY CROP IS TO BE TAKEN THE SAME
CROP COULD NOT BE GROWN IN
PREVIOUS SEASON .

21.  From contamination.
 Natural contamination: (cross pollination)
 Other contamination may be due to
mechanical mixture at
 Harvesting
 Sowing
 Threshing
 Processing
 Handling
 Soil

22.  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.

23.  The principal objective of seed certificationis
to maintain & make available crop seeds
which are of good seeding value and true to
variety.
 Qualified & well experienced inspectionis
necessary.
 Seed standards are confirmed bysuch
agencies.

24. 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 trueform

26.  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

27.  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

28.  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.

29.  The land for seed crop must be preparedwell.
 Good land preparation helps improved
germination, good stand establishment &
destruction of potential weeds.
 It also aids in water management &good
uniform irrigation.

30. 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.

31.  Chemical seed treatment.
 Seed treatment for breaking dormancy due
to hard seediness

32.  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.

33. Lower seed rates than usual for raising
commercial crop are desirable because they
facilitate rouging operations & inspection of
seed crop

34.  Row method of sowing
 Mechanical drilling can beused
 Desired amount
 Uniform depth
 Clean equipments
 Proper distance betweenplants

35.  Shallow plantation in case of smallseeds
 Deep plantation in case of largeseeds
 Deep plantation in dry soils

36.  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

37.  Honey bee
 Insects
 Wind and water

38. 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

39.  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.

40. 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.

41.  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 intervalsup
to flowering.
 One or two irrigations beyond floweringare
desirable for may seed crop.
 In general lighter soils need more irrigation
than heavier soils.

42.  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.

43.  By hands
 Quality of seed depends upon handlingof
harvested crop & the care taken during
threshing
 Maintain lot identity
 My be by machine

44.  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

45.  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