Seed Production Principles

1. PRINCIPLES OF SEED
PRODUCTION.
By
Sri. Roshan Parihar (Asst.Prof.)
TCB College of Agri.& Res. Station
Sarkanda ,Bilaspur,(C.G.)495001

2. • Genetic principles
• Agronomic principles

3. GENETIC PRINCIPLES
Deterioration of Crop Varieties and Methods to prevent
them
Variety: It Is a group of plants having clear
distinguished characters which when reproduced
either sexually or asexually retains these characters.
• The main aim of seed production is to produce
genetically pure and good quality seed. But why/how
the genetic purity of a variety is lost or deteriorated
during seed multiplication.
• 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 Mixtures
• 3. Mutations

4. • 4. Natural Crossing
• 5. Genetic drift
• 6. Minor Genetic Variation
• 7. Selective influence of Diseases
• 8. Techniques of the Breeder
• 9. Breakdown of male sterility
• 10. Improper / defective seed certification
System

5. • 1. Developmental Variation :Due to difficult
environment , soil and fertility condition , diff. climatic
conditions ,diff elevations, hence reco. to grown on
adapted areas and growing seacons.
• 2. Mechanical Mixtures : At the time of sowing due
to seed drill, volunteer plant of the same crops, during
harvesting and threshing operations. Seeds may get
retained on the processing equipments. Precaution of
rouging to done to prevent the mechanical admixtures.
• 3. Mutations : Not a serious cause in seed
production,vegetatively propagated crops are
genetically purified by the use of true to type stock.
• 4. Natural Crossing: introgression of genes from
unrelated stock is the main cause of natural crossing. It
occurs due to the folowing reasons.
– Natural crossing with undesirable types.
– Natural crossing with diseased types.
– Natural crossing with off type plants.

6. Seed production of hybrids may be get contaminated
with the near by variety of the same crop however
properly isolated, due to by breeding system of sp
(such as A,B line),varietal mass, wind direction and
pollinating agent.
• 5. Genetic drift : 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 allthe genotypes will not be represented in
the next generation and leads to change ingenetic
composition. This is called as genetic drift.
• 6. Minor Genetic variation: Released varieties may
have small scale of genetic variation present at the
time of release .when it goes under seed production
selective enviromwent pressure has been removed and
starts to show the changes and may finally affects the
yield. Hence seed production of nucleus seed and
breeder seed must be taken with utmost care to avoid
such

7. • 7.Selective influence of Disease: New varieties may
become susceptible to new races of pathogen and
leads to out of date byt seed programme, hence proper
crop protection must be applied to grow a healthy
crop.
• 8. Techniques of the Breeder :cytogenetical
irregularties, early or pre mature release of
varieties.release of segregatigng stock as a variety,
• 9. Breakdown of male sterility:Generally in hybrid
seed production if there is any breakdown of male
sterility in may lead to a mixture of F1 hybrids and
selfers.
• 10. Improper Seed Certification : 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.

8. Maintenance of Genetic Purity during seed Production
• Horne (1953) had suggested the following methods
for maintenance of genetic purity;
• 1. Control of seed source or Use of approved seed in
seed multiplication.
– Seed classes of breeder , foundation or certified
seeds must be used.
• 2.Preceding crop requirements :
– Providing isolation distance to prevent cross
fertilization or mechanical mixtures of other
varieties.
– Distance to be maintained for all the farm
operations for genetic purity maintenance.
– Rouging of seed fields prior to planting and during
the various stages prior to flowering.

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

10. •Providing
isolation distance
to prevent cross
fertilization or
mechanical
mixtures of other
varieties.

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What is Isolation ?
• Keeping the seed production
plots apart from fields of the
same crop to avoid the risk of
contamination by pollen from
the neighboring fields.
Isolation between seed plots
can be effected by distances
(spatial isolation) or time
(temporal isolation).

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Types of Isolation
• Types of Isolation:
• 1. Spatial Isolation
• 2. Temporal Isolation
• 3. Physical barrier

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What is Spatial Isolation
The spatial separation
required between a seed
field and other sources of
genetic and mechanical
contamination, especially
between varieties of
cross pollination.

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Spatial Isolation
•MORE THE EXTENT OF OUT
CROSSING WIDER THE DISTANCE.
• HIGHER THE CLASS OF SEED
WIDER THE DISTANCE. (BS v/s FS).
• IN HYBRID SEED PRODUCTION
WIDER THE DISTANCE THAN THAT
OF VARIETY(INBRED/PURELINE).

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2. Temporal Isolation
• CROP OF SEED PRODUCTION
SHOULD BE SOWN EARLY OR
LATE BY A MARGIN OF 15-20 DAYS
THAN NEIBOURING FIELDS OF
SAME OR OTHER VARIETY TO
PREVENT ENTRY OF FORGEIN
POLLENS IN THE FIELD OF SEED
PRODUCTION .

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3. Physical barrier
• IN SURROUNDING OF CROP OF
SEED PRODUCTION
PARTICULARLY ON BUNDS
CROP OF WELL PLANT
HEIGHT AND DENSLY
PLANTED SHOULD BE GROWN
TO PREVENT ENTRY OF
FORGEIN POLLENS IN THE
FIELD OF SEED PRODUCTION .

17. What is Roguing ?
• Roguing“The selective removal
of undesirable plants from a
seed crop on the basis of visual
field inspection, in order to
improve one or more quality
(genetic purity, disease free)
attributes of the seed lot to be
harvested"
(Laverack and Turner 1995).

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Rouging ---------
• Removal of noxious weeds
(wild oat in wheat, and
Argemone mexicana in
Brassica species) that are
liable to multiply with the
seed crop, thus affecting
future generations, may be
regarded as part of roguing.

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Rouging ---------
• Rouging at all stages of
the crop in the field is
an essential
requirement to maintain
the variety purity as it
was at the time of
release/notification.

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Rouging ---------
• Sometimes rogue
plants are not
distinguishable before
flowering, therefore,
rouging should be
done, as early as
blooming starts.

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Rouging
• Doubt ful plants too should
be rouged.
• The rogued plants should
be removed from the field
immediately after roguing
and destroyed as they may
survive for a few days and
may spread their pollen.

22. • 3.Certification of seed crop by SCA
Authorities to maintain genetic purity
and quality.
– Inspection of seed fields prior to
planting ,and approval of the Crop
at critical stages for verification of
genetic purity, detection of
mixtures, weeds and seed borne
diseases.
– Sampling and sealing of cleaned
lots.
– Adopting generation system

23. What is Seed certification
The main objective of seed certification is to
make available seeds of good quality with 100
% pure genetic purity to farmers. To achieve
this qualified and trained personnel from SCA
(SEED CERTIFICATION AGENCIES)carry out field
inspections at appropriate stages of crop
growth.They also make seed inspection by
drawing samples from seed lots after
processing.
What is seed certification ?

24. • The SCA verifies for both filed and
seed standards and the seed lot
must confirm to get approval as
certified seed.
• 4.Grow in adapted areas only to
avoid genetic shifts in the variety.
• 5. Growing of samples with
authentic stocks or Grow -out test
for Periodic testing of varieties for
genetic purity.

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GROW OUT TEST (GOT )
• Genetic purity of any variety
is confirmed by carrying out
through grow out test (GOT
i.e. growing of progenies
during off-season in the field)
and electrophoresis . These
tests are essential part of
seed certification of hybrids
and high valued seeds.

26. Electrophoresis
Genetic purity of any variety is
confirmed by carrying out
through molecular method of
protein electrophoresis . Where
protein bands are run on
agarose gel alog with the
reference band , if both test and
reference band are same then
genetic purity is confirmed.

27. SEPARATION
AND DETECTION OF PROTEINS II
SDS-PAGE

28. SDS-PAGE
(= sodium dodecylsulphate-polyacrylamide gel
electrophoresis)
-Method for separation of proteins according to
their molecular weight

29. Outline of second part of the
experiment
*Prepare polyacrylamide gels
*Add diluted samples to the sample buffer
*Heat to 95C for 4 minutes
*Load the samples onto polyacrylamide gel
*Run 200 volts for 30-40 minutes
*Stain in Coomassie Blue stain
*Destain
*Identify molecular markers, actin and myosin
in the separated proteins

31. Levels of Protein Organization
• Primary structure = linear chain of
amino acids
• Secondary structure = domains of
repeating structures, such as β-
pleated
sheets and α-helices
• Tertiary structure = 3-dimensional
shape of a folded polypeptide,
maintained by disulfide bonds,
electrostatic interactions, hydrophobic
effects
• Quaternary structure = several
polypeptide chains associated
together to form a functional protein

32. -Proteins denatured by heating
them in a sample buffer containing
sodium dodecyl sulphate (SDS)
-The proteins no longer have any
secondary, tertiary or quaternary
structure

33. -Resultant proteins take on a rod-like
shape and a uniform negative charge-to-
mass ratio proportional to their
molecular weights

34. How does an SDS-PAGE gel
work?
•Negatively charged proteins move to positive electrode
•Smaller proteins move faster
• Proteins separate by size

35. -
+
s-s
SDS, heat
proteins with
SDS

36. What is in the Sample Buffer?
*Tris buffer to provide appropriate pH
*SDS (sodium dodecyl sulphate) detergent to
dissolve proteins and give them a negative
charge
*Glycerol to make samples sink into wells
*Bromophenol Blue dye to visualize samples

37. SDS-Polyacrylamide Gel
Electrophoresis (SDS-PAGE)
•SDS (Sodium Dodecyl Sulfate)
detergent
–solubilizes and denatures
proteins
–negative charge to proteins
•Heat denatures proteins
O
S
O
O
O
-
CH2
CH2
CH2
CH2
CH2
CH2
CH2
CH2
CH2
CH2
CH2
CH3
SDS

38. Why Use Acrylamide Gels to Separate
Proteins?
• Acrylamide gel: Tight matrix
• Ideal for protein separation
• Smaller pore size than agarose
• Proteins much smaller than intact
chromosonal DNA
-average amino acid = 110 Dalton

39. Protein Size
• Size measured in daltons (Da) or kilodaltons (kDa)
• Dalton = atomic mass unit
= corresponds to mass of hydrogen
molecule (1.66 x 10 -24 gram)
= defined also as 1/16 of the mass of an
atom of oxygen
• Average amino acid = 110 Da
Average nucleotide pair = 649 Da

40. Gel Analysis
Lane 1. Kaleidoscope Markers
2. Shark
3. Salmon
4. Trout
5. Catfish
6. Sturgeon
7. Actin and Myosin Standard

41. Agronomic principles of seed prod.
Selection of a suitable Agro*
Climatic region:
1.Photoperiod.
2.Temperature.
3.Rainfall.(Moderate)
4.Humidity. (Moderate)
5.Sun Insolation.(Dry sunny days)
6.Wind velocity.

42. •Excessive dew and rain cause
hinderance in pollination.
•Too high temp cause
dessication of pollen and
resulted poor seed set.
•Hot and dry weather in case of
vegetable , legumes fail to seed
set effectively and leads to seed
less fruits.
•Vegetables requires cool
climate and low humidity for
flower and pollination.

43. • For cross pollinated crops
adequate wind velocity must
be required to complete pollin.
• Oilseed crops can tolerate high
temp. but rise of terminal heat
may leads to force maturity
resulted small seed size.
• So very cold temp also damage
seed quality in early phases of
seed maturation.

44. • Seed crops for rabi season must
not be grown on such areas
where winter rains prevailed
because it may cause seed
quality deterioration at the
harvesting time and also make
harvesting a big problem.
• Damp and humid weather
increase the disease and pest
attack on the field as well as
storage site.

45. Selection of seed plot
1.Soil texture and fertility.
2.Site free from volunteer plants,
weeds, other crop plants.
3.Site must be free from soil borne
disease and pests.
4.Preceding crop must not be
same.
5.Site must be levelled and
irrigation facilities must present

46. isolation of seed plot
1.Isolation of distance must be
maintained as per the
requirement.
2.If distance isolation is not
maintained than Temporal or
Time isolation must be practices
by altering the sowing date by
differential planting.
3.On a small scale of Nucleus or

47. • Land for seed crop must be well
prepared, well levelled so that
water stagnation must not take
place.
• Good land status enhance good
seed germination,field emergence
and stand establishment.
• Well pulverised seed bed and
trash must be picked up and
removed before sowing,
Preparation of land

48. • Variety adapted to the agro-
climatic regions.
• High yielder variety.
• Variety with exellent
features
viz.quality,earliness,resista
nce etc.
Selection of variety

49. • Seeds of appropriate class
must be brought with cash
memo.
• Check out the seals and tags
are remain intact and bags
are not torned.
• Check out the details
mentioned on the label with
full assurance.
• Cash memo must be kept with
care for further verification.
Verification of Seed source

50. • Revolving drum used for the treatment
of seeds.
• Chemical seed treatment.
• Bacterial inoculation of seeds.
a. By drum method.
b. By the use of vaccum seed treater on
USA , on which seeds are first made
permeable and then liquid suspension of
bacterial inoculation must be applied to
each seed under vaccum creation forces
the entrance of bacteria into the seed.
Seed treatment

51. • Seed treatment to break
dormancy.
a.Hard seeded crops are water
soaked.
b.Mechanical scarification must
be done for seed coat
breakage.
c.Acid scarification must be done
for crops where this the only
method applied viz.seeds
soaked in 95 % sulphuric acid
for 15-60 minutes.

52. Time of sowing / Seed rate
• Should be
sown on
normal sowing
time with
adequate
moisture
enhances
germination.
• Low seed
rates are
preferred for
easy roguing
operations
and
inspection.

53. • Broadcasting is also used.
• Seed drill method is preferred to
ensure depth for germination.
• Line sowing favours roguing,
inspection and interculture operations
by mechanical methods also.
• Small seeds are planted shallow,while
large seeds are planted deeper.
• In sandy, warm and dry soils seeds
should be sown on high depth.
Method of sowing.

54. • Vegetative stage /pre flowering
stage based on height, colour of
vegetation,leaf size,shape ,
orientation or diseased or
malformed plant.
• Flowering stage roguing based on
emergence of panicle characters
and uprooting of such plants.
Roguing

55. • Flowering stage roguing is
equally important in case of
hybrid crops. Where in a
male sterile line (A line) a
plant of male fertile line (B
line) is present. Such B Line
plants are called as POLLEN
SHEDDERS and it must be
rogued out at flowering
stage.

56. • Maturity stage roguing is
important and it leads to
removal of defective ear
heads viz. off textured, off
coloured,diseased or
malformed etc.

57. • In case of cross pollinated crops if
a bee hive is present in the close
proximity of the seed farms it
leads to higher seed set.
Supplementary pollination

58. • Weeds may increase the chances
of admixtures.
• Weed plants are the source of
disease host .
• Noxious weeds pose a serious set
back to seed purity if not
controlled.
• Weed crop compete with the seed
crop for food and space.
Weed control

59. • Seed crop must be seed treated
for systemic disease.
• As soon as pest attack seen
control must be applied to retain
the healthy plant,
• Diseased and pest infested plant
are unable to make food
efficiently and hence should be
rogued out.
Disease and insect control

60. • Seed crop must be supplied with
nitrogen to maintain their status
green.
• More nitrogen must increase the
succulence and delay the
maturity.
• When yellowing occurs on the
lower leaves and upper leaves
are green it must be supplied.
Nutrition

61. • In case of severe nitrogen
shortage leaves will turn
brown and die.
• On early stage of crop don’t
supply too much nitrogen, may
increase the height, reduce
flowering and lodging too
happen.
• As the crop proceeds toward
flowering provide the second
split of nitrogen.

62. • Along with the first split of N , P
and k must be given as a basic
dose.
• Phosphorous is associated with
root growth, straw length,fruiting ,
seed development ,plant maturity
and disease resistance.
• Pottassium is associated with
photosynthetic ability of the plant
,flowering and seed development.
• K deficiency leads to a general loss
of dark green colour, straw
weakning , severe deficiency leads
to produce bronze to yellow
discolouration along the edges of
older lower leaves.

63. • As the crop needs water it
must be supplied .
• To be supplied at all the
critical stages of crop.
• Surface irrigation method of
water application with check
basin must be used for the
judicious use of water.
Irrigation scheduling of seed crops

64. Assessment of Harvesting time
• Harvesting time is one
of the important factors
that influence the
planting value of seeds.
• The moisture content of
seeds is an important
consideration in deciding
the time of harvesting.

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HARVESTING----2
Early harvest (pre-mature)
causes:
1. High number of partially
filled and immature seeds
with high moisture
content.
2. Seed quality such as
longevity and field
emergence depressed.

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Maximum
germination and
vigor is recorded
at physiological
maturity
(Harrington
1972).

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HARVESTING
Physiological maturity
denotes the stage of
development when the
seed reaches its maximum
dry weight and marks the
end of the seed-filling
period.

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HARVESTING-6
Optimum time or stages
of harvest in some crops grown for seed
Crop Time / Stage of harvest
• Rice 27 Days After Anthesis
• Sorghum 30-35 Days After Anthesis
• Sorghum 35-40 Days After Anthesis
(late varieties)

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H A R V E S T I N G -5
OPTIMUM STAGES OF HARVEST IN SOME CROPS GROWN FOR
SEED PRODUCTION
• Arhar 25 Days After Anthesis
• Mungbean 25 Days After flowering
• Toria 70-100 Days After Sowing
• Soybean 100-104 Days After Sowing
• Cotton 55-60 Days After anthesis

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Threshing 1
• Before the threshing of
harvest of seed production
plot threshing floor/
thresher must be clean
thoroughly to avoid any
physical impurities and or
admixture of seeds of any
crop and weeds.

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Threshing II
• Threshing of
harvest of seed
production plot
Should be done first
then commercial crop.

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Storage of produced seeds --------
•Before storing,
seeds must be sun
dried properly to
maintain moisture
content of seeds.

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Storage of produced seeds --------
Packing material used
for seed storage plays
important role to
maintain seed’s
longevity during
storage.

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Storage of produced seeds --------
Under ambient conditions
(room temperature) use of air
permeable containers viz.
cotton
cloth or gunny begs, as
compare to
polythene bags, is better.
These should be stored in dry
and cool place.

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Storage of produced seeds --------
• In storage optimum
condition conditions
particularly temperature
and RH% must be
maintained.
• Preventive control
measures against
storage pest must be
taken.

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Storage of produced seeds --------
• Herrington (1959) proposed
thumb rules for safer storage of
seed by maintaining temperature
and RH% in storage as;
1.“ THE SUM OF TEMPERATURE (0F)
and RH% IN STORAGE MUST BE
100±2 ”
Examples inculdes such as 50 % RH
and temp at 50 (0F) or 60 % RH and
40 (0F) are found suitable for
maintain seed quality of maize for a
period of one year or more.
2. 1 % Reduction in moisture content
of seed doubles the seed longevity.