Genetic ,agronomic principles, deterioration of crop varieties, isolation, types, rouging, seed certification, GOT, Gel electrophoresis, seed prod agronomy,

1. Sub.:- Principles of Seed Technology
Course No. :- APB- 5221
Credit hours:- 3(1+2)
Lecture Topic :- General Principles of seed production.
Presented by:-
Indira Gandhi Krishi Vishwavidyalaya
Raipur, C.G.
Presented by:-
Lt. Roshan Parihar, Asstt. Professor (GPB)
Deptt. of Genetics & Plant Breeding
BTC College of Agriculture & Research Station
,Sarkanda, Bilaspur,(CG)-495001

2. • Genetic Principles• 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.
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• 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 typegenetically 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 all the genotypes will not be represented
in the next generation and leads to change in genetic
composition. This is called as genetic drift.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 environment 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
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 :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 WHEREIN THE FIELD WHERE
SEED PRODUCTIONSEED PRODUCTION
OF ANY CROP IS TOOF ANY CROP IS TO
BE TAKEN THE SAMEBE TAKEN THE SAME
CROP COULD NOTCROP COULD NOT
BE TAKEN THE SAMEBE TAKEN THE SAME
CROP COULD NOTCROP COULD NOT
BE GROWN INBE GROWN IN
PREVIOUS SEASON .PREVIOUS SEASON .

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

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

12. Types of IsolationTypes of Isolation
•• Types of Isolation:Types of Isolation:
•• 1. Spatial Isolation1. Spatial Isolation
•• 2. Temporal Isolation2. Temporal Isolation
•• 3. Physical barrier3. Physical barrier
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•• 3. Physical barrier3. Physical barrier

13. What is Spatial IsolationIsolation
TheThe spatialspatial separationseparation
requiredrequired betweenbetween aa seedseed
fieldfield andand otherother sourcessources ofof
geneticgenetic andand mechanicalmechanical
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fieldfield andand otherother sourcessources ofof
geneticgenetic andand mechanicalmechanical
contamination,contamination, especiallyespecially
betweenbetween varietiesvarieties ofof
crosscross pollinationpollination..

14. Spatial IsolationIsolation
••MORE THE EXTENT OF OUTMORE THE EXTENT OF OUT
CROSSING WIDER THE DISTANCE.CROSSING WIDER THE DISTANCE.
•• HIGHER THE CLASS OF SEEDHIGHER THE CLASS OF SEED
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•• HIGHER THE CLASS OF SEEDHIGHER THE CLASS OF SEED
WIDER THE DISTANCE.WIDER THE DISTANCE. (BS v/s FS).(BS v/s FS).
•• IN HYBRID SEED PRODUCTIONIN HYBRID SEED PRODUCTION
WIDER THE DISTANCE THAN THATWIDER THE DISTANCE THAN THAT
OF VARIETYOF VARIETY(INBRED/PURELINE).(INBRED/PURELINE).

15. 2. Temporal Isolation2. Temporal Isolation
•• CROP OF SEED PRODUCTIONCROP OF SEED PRODUCTION
SHOULD BE SOWN EARLY OR LATESHOULD BE SOWN EARLY OR LATE
BY A MARGIN OF 15BY A MARGIN OF 15--20 DAYS THAN20 DAYS THAN
NEIBOURING FIELDS OF SAME ORNEIBOURING FIELDS OF SAME OR
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NEIBOURING FIELDS OF SAME ORNEIBOURING FIELDS OF SAME OR
OTHER VARIETY TO PREVENTOTHER VARIETY TO PREVENT
ENTRY OF FORGEIN POLLENS IN THEENTRY OF FORGEIN POLLENS IN THE
FIELD OF SEED PRODUCTION .FIELD OF SEED PRODUCTION .

16. 3. Physical barrier3. Physical barrier
•• ININ SURROUNDINGSURROUNDING OFOF CROPCROP OFOF
SEEDSEED PRODUCTIONPRODUCTION
PARTICULARLYPARTICULARLY ONON BUNDSBUNDS
CROPCROP OFOF WELLWELL PLANTPLANT
HEIGHTHEIGHT ANDAND DENSLYDENSLY
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CROPCROP OFOF WELLWELL PLANTPLANT
HEIGHTHEIGHT ANDAND DENSLYDENSLY
PLANTEDPLANTED SHOULDSHOULD BEBE GROWNGROWN
TOTO PREVENTPREVENT ENTRYENTRY OFOF
FORGEINFORGEIN POLLENSPOLLENS ININ THETHE
FIELDFIELD OFOF SEEDSEED PRODUCTIONPRODUCTION ..

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

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

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

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

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

22. 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
What is seed certification ?
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.

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

24. • 4.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 bornemixtures, weeds and seed borne
diseases.
– Sampling and sealing of cleaned
lots.
– Adopting generation system

25. 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)
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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 . Whereprotein 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 IIPROTEINS 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
& Proteins
*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

30. Commassie blue staining of 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 electrodeto 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 chargegive 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
CH2
CH2
CH2
CH2
CH2
CH2
CH3
–solubilizes and
denatures proteins
–negative charge to
proteins
•Heat denatures proteins
O
S
O
O
O
-
CH2
CH2
CH2
CH2
CH2
CH2
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• 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= 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.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 seedvegetable , 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 maturitymay 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 makeharvesting 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 borne3.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 not2.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
Breeder seed production barrier

47. • Land for seed crop must be well
prepared, well levelled so that
water stagnation must not take
place.
Preparation of land
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,

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

49. • Seeds of appropriate class
must be brought with cash
memo.
• Check out the seals and tags
are remain intact and bags
Verification of Seed source
• 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.

50. • Revolving drum used for the treatment
of seeds.
• Chemical seed treatment.
• Bacterial inoculation of seeds.
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.

51. • Seed treatment to break
dormancy.
a.Hard seeded crops are water
soaked.
b.Mechanical scarification must
be done for seed coatbe 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
• Low seed
rates are
preferred for
easy roguingtime with
adequate
moisture
enhances
germination.
easy roguing
operations
and
inspection.

53. • Broadcasting is also used.
• Seed drill method is preferred to
ensure depth for germination.
• Line sowing favours roguing,
Method of sowing.
• 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.

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

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 Lineline) 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.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
leads to higher seed set.

58. • Weeds may increase the chances
of admixtures.
• Weed plants are the source of
disease host .
Weed control
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.

59. • Seed crop must be seed treated
for systemic disease.
• As soon as pest attack seen
control must be applied to retain
Disease and insect control
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.

60. • Seed crop must be supplied with
nitrogen to maintain their status
green.
• More nitrogen must increase the
Nutrition
• 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.

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, reduceincrease 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 plantphotosynthetic 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.
Irrigation scheduling of seed crops
critical stages of crop.
• Surface irrigation method of
water application with check
basin must be used for the
judicious use of water.

64. Assessment of Harvesting time
•• Harvesting time is oneHarvesting time is one
of the important factorsof the important factors
that influence thethat influence the
planting value of seeds.planting value of seeds.planting value of seeds.planting value of seeds.
•• The moisture content ofThe moisture content of
seeds is an importantseeds is an important
considerationconsideration in decidingin deciding
the time of harvestingthe time of harvesting..

65. Early harvest (pre-mature)
causes:
1. High number of partially1. High number of partially
filled and immature seedsfilled and immature seeds
with high moisturewith high moisture
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with high moisturewith high moisture
content.content.
2. Seed quality such as2. Seed quality such as
longevity and fieldlongevity and field
emergence depressed.emergence depressed.

66. MaximumMaximum
germination andgermination and
vigor is recordedvigor is recorded
at physiologicalat physiological
maturitymaturity
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at physiologicalat physiological
maturitymaturity
(Harrington(Harrington
1972).1972).

67. HARVESTINGHARVESTING
Physiological maturityPhysiological maturity
denotes the stage ofdenotes the stage of
development when thedevelopment when the
seed reaches its maximumseed reaches its maximum
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development when thedevelopment when the
seed reaches its maximumseed reaches its maximum
dry weight and marks thedry weight and marks the
end of the seedend of the seed--fillingfilling
period.period.

68. Optimum time or stages
of harvest in some crops grown for seed
Crop Time / Stage of harvestCrop Time / Stage of harvest
•• Rice 27 Days AfterRice 27 Days After AnthesisAnthesis
•• Sorghum 30Sorghum 30--35 Days After35 Days After AnthesisAnthesis
•• Sorghum 35Sorghum 35--40 Days After40 Days After AnthesisAnthesis
((late varietieslate varieties))
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((late varietieslate varieties))
•• ArharArhar 2525 Days AfterDays After AnthesisAnthesis
•• MungbeanMungbean 25 Days After flowering25 Days After flowering
•• ToriaToria 7070--100 Days After Sowing100 Days After Sowing
•• Soybean 100Soybean 100--104 Days After Sowing104 Days After Sowing
•• Cotton 55Cotton 55--60 Days After60 Days After anthesisanthesis

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

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

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

72. Storage of produced seeds --------
Packing material usedPacking material used
for seed storage playsfor seed storage plays
important role toimportant role to
maintain seed’smaintain seed’s
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maintain seed’smaintain seed’s
longevity duringlongevity during
storage.storage.

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

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

75. 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
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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.