Seed production and its management in wheat

1. By: Mulusew Fikre
EGS Wheat Seed Production and Quality Control
By: Talila Garamu
Email=talilagaram@gmail.com
Mobile phone =+251917639222
(M.Sc Seed scientist and Agronomist )
October 6 2022
Assala

2. Presentation outline
Introduction
Definition of terminology
 Seed Quality Components
Seed class Production
Principles of wheat seed production
Seed Quality Control
Seed Production Planning software

3. Introduction
In Ethiopia Grain crops that are widely produced in the
country include cereals, grain legumes and oil crops.
Agricultural production and productivity are lagging, which
has resulted in food and nutrition insecurity
To alleviate food insecurity and malnutrition through
increasing productivity, development of improved varieties of
seed crops along with improved crop management and
protection packages for enhancing productivity of food and
forage crop.

4. Introduction……
In Ethiopia production and supply of improved agricultural
technologies is inadequate in the country.
The limitations are, in part, related to low availability of improved
seeds of the important food, forage, and cash crops.
Scarcity of environmentally friendly, sustainable, and affordable
fertilizer is also a problem that constrains the efforts being made
to enhance yields of crops.
Insufficient availability of technical skills is another important
factor that limits production and use of technologies in agricultural
productivity

5. Introduction…..
 To increase production and productivity grain crop, forage
crop and etc
 Improved Seed is a vital input. So, farmers should get
improved seeds

6. What is EGS seed production??
 EGS which encompasses breeder, pre-basic and basic
seed.
 Is the critical connection between breeding activities and the
eventual production and distribution of varieties to
farmers(Cramer, L. (2019).

7. A. Botanical definition-
It is a matured ovule consisting of an embryonic plant together
with a stored all surrounded by a protective.
Definition of seed

8. B- Agricultural definition
The living organ
of the crop in
basic from that
is used for
propagation.
Any part of a
crop from
which a new
crop will
grow.
Is a dispersal
/reproductive unit
which can be a true
seed single seeded
fruit or multiple
seeded fruit with
accessory structures
cuttings bulbs or
tubers etc

9. Botanical
seed
Tuber
Corm
Rhizomes Cuttings
layering
C. Generally Seed is generative or vegetative
part of a plant that is used as preparative material.

10. What is improved variety?
 Improved variety is a variety that contains certain desirable
traits that are improved through breeding over their parents or
existing standard checks
High and quality yield
Desirable agronomic traits like lodging resistance, suitability
for machine harvesting, etc.
Biotic and a biotic stresses resistance/tolerance
Better adaptation to different environments, growing
conditions, farming system, etc.
It should have a maximum of 13% moisture content, high
germination percentage and real value [purity (%) X
germination(%)/100]

11. Grain VERSUS Seed

12. Differences between grain and seed
Seed and grain production appears similar, but there are key
fundamental differences
GRAIN SEED
Quantity based Quality based
Consumption Planting
Output Input
Farmers Growers
Fulfilled grain quality standards Fulfilled seed quality standards
Market price Premium price

13. Germination
Vigor Health
Genetic Moisture
Physical purity Size Uniformity
Labeled
Seed
quality
is
a
multiple
concept

14. 2. Seed Quality Components
 Seed is the repositories of the genetic material responsible
for restoration of heritable features of the newly incoming
generation.
 Factors which may influence the survival, health, agronomic
fitness and productivity of the plants which comes from the
seed parents, should be taken into consideration during
production and processing of seeds for final use.
 Some of the basic parameters of quality seeds are (Gregg
and van Gastel, 2000, FOA, 2015).

15. Seed Quality Components
GENETIC SEED QUALITY
Varietal purity and identity
PHYSICAL SEED QUALITY
Species purity (crops)
Analytical purity (inert matter)
Size, (Uniformity)
PHYSIOLOGICAL SEED QUALITY
Viability, Germination, Vigor(Moisture )
SEED HEALTH QUALITY
Seed-borne pests, parasitic weeds

16. GENETIC SEED QUALITY
 Inherent varietal characteristics;
Good product quality and yield
Resistance to biotic stress
Resistance to abiotic stress
Response to modern inputs
Suitability for mechanization

17. GENETIC (VARIETAL) SEED QUALITY
Good product quality and yield
Resistance to biotic stress
Resistance to a biotic stress
Response to modern inputs
Suitability for mechanization
Inherent varietal characteristics

18. PHYSICAL SEED QUALITY
A. Analytical purity
 Basic seed quality component
 Composition of seed lot (pure seed, other crop seed, inert
matter)
 Nature of contaminants in a seed lot
 Determination is based on weight

19. A. Purity Analysis
 Is to determine the composition by weight of the variety
and contaminants in the sample.
 Components of Purity Analysis;
Pure seed
 It includes all botanical varieties of wheat.
Other crop seed
 It refers to the seeds of crops other than the wheat seed
examined, for example, barley, and field peas
Weed seed
 It includes seeds of those species normally recognized as
weed or specified under seed regulations as noxious weeds

20. Purity Analysis….
Inert matter
 It includes seed like structures, stem pieces, leaves, sand
particles, stone particles, empty glumes, lemmas, chaff,
awns, stalks longer than florets, and spikelets.
Analytical purity
Seed samples are analyzed and the proportion
expressed in percentages
Pure seed = X
Other crop seed = Y
Inert matter = Z
Weed seed = w
Purity (%) = X x 100
X+Y+Z+W

22. B. Seed size:
It is important that seed be large, plump and well developed
to retain adequate food supply to young germinating plant.
If the seeds are small or shrunken, they may not contain
enough stored food to give the plant a vigorous stands.
Plants grown from poorly developed seeds may thus be
stunted in early stage of growth and never recover
sufficiently to produce normal plants.

23. C. Uniformity
Seeds consisting of partly or fully developed and small or,
weak grains will have a tendency to be affected in their
vigor and development by some strong plants and thus
reduce the stand.
The plants from the inferior or week seeds may be more
subject to attacks of disease and insects and in most cases
may mature later than stronger seeds.

24. PHYSIOLOGICAL SEED QUALITY
Germination capacity
Proportion of seed producing normal seedlings
Potential field establishment under favorable condition
Higher germination lowers seed rate and cost

25. 2. PHYSIOLOGICAL SEED QUALITY
Germination capacity
Hundred seeds of 2-4 replicates tested
under favorable conditions and classified
into:
• Normal seedlings = W
• Abnormal seedlings = X
• Fresh un-germinated seeds = Y
• Dead seeds = Z
Germination = W x 100
W+X+Y+Z
Real Value = Purity x Germination
100

27. PHYSIOLOGICAL SEED QUALITY
Seed Vigor
Germination and seedling establishment under a wider range
of environment
Faster growth and establishment
Better competition with weeds
Disease escape and better yield

28. Seed Moisture Content
Influences seed quality during:
 Harvesting/cleaning (mechanical damage)
Seed storage (heating, germination)
It is important for producers, processors and store
managers
 Harvesting decisions
 Drying and cleaning
 Pricing for payment
 Storage management

29. SEED HEALTH QUALITY
 Seed serve as a vehicle for dissemination of diseases and pests
 Infected seeds may fail to germinate, reduced emergence or
reduce productivity
 Freedom from plant pathogens and pests is essential
 Lower disease risk
 Limit disease spread

30. Significance of Quality seed production
Enhanced
productivity,
Higher harvest index,
it means higher grain
yield but low biomass
yield
Higher profit
Reduced risks from
pests and other biotic
factors
Direct benefits of quality
seeds to farmers include:

31. 3. Seed class/ Generation of seed
Breeder seed
class of seed produced under the supervision of a plant
breeder as originator
Pre-basic seed
• is the progeny of breeder seed
Basic seed
• is the progeny of Pre-basic seed.
Certified seed
• is the progeny of Basic seed

32. Breeder seed
 Breeder seed is the offspring of a nucleus seed that is
typically replicated over a greater area of the field under
the direction of a plant breeder and monitored by a
breeder and internal quality monitoring committee
 The breeder stage seed is the initial seed in the
multiplication generation system.
 The breeder seed is the source of the first seed, as well
as the subsequent rise in Pre basic/basic s seed
production

33. SEED QUALITY CONTROL

34. 3. Agronomic Principles EGS of seed production

35. REQUIREMENTS FOR SEED PRODUCTION
A. FIELD REQUIREMENTS
B. MANAGING SEED PRODUCTION FIELDS

36. A. FIELD REQUIREMENTS

37. 1. Agro-climate Condition
A wheat variety grown for seed production must be
suitable to climatic and photoperiodic conditions
prevailing in specific location.
Areas with moderate rainfall, humidity, absence of
strong winds and temperatures with sufficient dry
sunny period for seed harvesting are suitable for wheat
seed production.
Soil neither acidic nor alkaline

38. Moderate rainfall and
humidity .
Well adapted to the photoperiodic
and temperature conditions of the
growth areas
Extreme heat and cold
avoided Except adapted
crops
Selection of suitable
Agro-climatic region

39. 2. Site Selection
 Isolation Distance.
 For cross pollinated crops, fields for seed production must
also be selected after considering the possibility of genetic
contamination by out crossing (for seed production purpose)
 Field should be rotated for 1 to 3 seasons.

40. Site selection
 Seed production should be undertaken where edaphic,
climatic, and biological (disease and pest) conditions are
favorable for good crop production.
 Each variety should be produced in areas where it is best
adapted to grow for getting quality seeds of the required
quantity
 The presence of irrigation water and irrigation facilities is
very important to avoid risks of moisture shortage at any
stage of crop growth

41. Selection of the
location
Have
good soil
texture
and
fertility.
Land slope
with in 2-8
range
Free from
volunteer
weeds
and other
crops.
Free
from soil
borne
diseases
and
insect
pests
The
previous
crops
should
not be
same
crop
Adequate
isolation
distance

42. Inappropriate land selection

43. 3.Variety selection
 The first requirement for seed production is that the seed to be
multiplied must be from an improved variety that is officially
released (recommended) for wider cultivation.
 Not only seed producers but also seed certifying agencies
should verify and assure varietal identity and whether the
variety grown is from an approved seed source.
 If need be, the terms on which the seed is granted to the
producer and all documents including procurement invoices
should be checked and confirmed.

44. Selection of variety
Selected
Variety
Grain quality
&others
Adopted to
agro-
climatic
condition
Earliness
Disease & pest
resistance
High yielder

46. Selection of Seed and variety
Seed purity: The seed used for raising a seed crop should be of
known purity, appropriate class and invariably obtained from
authorized official agency.

47. Seed colour of the varieties

48. 4. Land Preparation
 A good effective depth with a fine tilth to ensure seed-soil
contact.
 Good seed-soil contact ensure good crop emergence and
stand which are the basis for good yields Favorable physical
properties: good internal drainage, an optimal moisture
regime,
 Chemical properties: sufficient and balanced quantities of
nutrients (NPS and other micro-nutrients/trace nutrients)
 Biological properties: good level of organic matter, and with
beneficial micro-organisms

49. Ploughing
 1-2 month before planting, According to the agro ecology of
the area
 Plough the field two times, which will make the soil loose and
make easy for aeration and root growth. In the first time,
plough the field 5-8 cm deep and second time 10-15 cm
deep ploughing should be done.
 In case, there is big size of soil clods present in the field after
first ploughing, the breaking of those clods should be done
manually with the help of spade before those clods become
hard.

50. Ploughing….
 Make sure that the seed bed is free from weeds and
remove volunteers of the same crop (if any) before sowing;
 When irrigating wheat field, the deep plow the soil and
make it fine and Pre-sowing irrigation is necessary for
uniform germination.
 Give a light shallow disking after pre sowing irrigation
 Leveling of the seedbed is important provide uniform stands
and facilitate rouging.

52. Preparation of land:
The land must be well prepared.

53. Good land preparation helps in improved & uniform
germination resulted in good stand establishment

54. 5. Time of sowing
Seeds should be sown at their normal planting time.
It depends on
Agro ecology,
Soil type, and
Variety of seed
If sowing is delayed then more seed rate is required as
compared to timely sown crop because germination and
growth of late crop is not as good as timely sown seed.

55. Time of sowing…….
In moisture stress areas, plant should be done as fast as
possible
In waterlogged Vertisols, planting is done late in the season.
Poorly drained plots are not advisable for wheat seed
production
However, delayed sowing can cause the crop not to mature
well before the end of the rainy season.
It pest and disease attack is severe on late-planted crops.
Seeds from late-planted crops are shriveled and have low
vigor

56. 6. Method and depth of sowing:
Row planting (20cm between row recommended)
Broad casting
Broadcasting method of sowing requires more seed
rate as compared to row sowing.
Sowing Depth
Seed sown in rows at right depth (2-10cm) is easily
manageable and reduces the nutrient competency

57. 6. Determine Seed rate
 The optimum seed rates for wheat depends on type of
Wheat Variety
Morphology of the wheat
Fertility status of the Area
Tillering ability,
Germination percentage,
Method of planting

58. Determine Seed rate:
Lower seed rate than usual to facilitate rouging
operation/seed inspection Size of the Cultivars:-
Crop varieties having tillering characteristics require less
seed rate as compared to non tillering.
Dwarf cultivars require more seed than tall because plant
population of tall cultivars is more subjected to lodging.
Amount of Moisture Available: for better moisture less seed.

59. Seed rate Vs Seed Multiplication ratio (SMR)
 Seed Multiplication Ratio (SMR) is the ratio of yield
and seed rate per unit area.
 influenced by the soil fertility and agronomic management
 SMR=Seed yield/seed rate
 For seed production fields, use lower seed rate;
for higher multiplication factors, but to lower yield per
unit area.
adequate production of the ultimate certified seeds

60. Cont…..
 Increase the multiplication factor;
 Improve seed quality because a lower number of plants per unit of
land receive better nutrition,
 lead to rapid seed increase i.e., more seed harvested per kilogram of
seed planted, and farmers will benefit from the improved variety
earlier.
 lower seed multiplication ratio is a challenge for adequate production of the
ultimate certified seeds
 Planting early generations when extensive agronomic practices are used,
but certified seed is planted at the normal or slightly lower seed rate.

62. 7. Fertilizer application
Fertilizers should be applied to achieve maximum crop
production. But the right way is first carry out soil analysis
and establish what is lacking and how much to add.
Adequate N, P, K and other blended essential minerals are
crucial for proper plant growth.
Split applications of N are general advocated to avoid
lodging of crop due to excessive vegetative growth.

63. Stage of fertilizer application fort the seed production
NPS and other blended fertilizer were applied at the
plating for the increasing the germination capacity
and improve the soil fertility of the soil.
UREA were applied at the different growth stage
Planting stage = 1/4 of the urea
Tillering stage = 2/4 of urea for increasing the
tillering capacity
Booting stage = ¼ of the for panicle elongation

64. Factors determining level of fertilizer application
Crop Types:- Different kinds of crop require different amount of
nutrient. The leguminous crops require less N than the cereals.
Soil fertility:- More fertile soils require less nutrients to produce a
good crop.
Growth stage- At earlier and midst age nutrient requirement is more
than the later stage of crop growth.
Moisture status:- If soil moisture status is good then response of
fertilizer application is more so more fertilizer can be applied as
compared to rain fed or dry land condition.

65. Fertilizer deficiency
How to know the nutrient deficiency of the crop???

66. • Visual deficiency symptoms
• Plant tissue analysis
• Soil test
• Crop response to fertilizer
The four methods of identifying nutrient
disorders in crop plants are :

67. B. Managing seed production fields

68. 1 Isolation Distance
 The isolation distance required varies with the type of crop
and seed class
 However, the distances may be reduced if there are physical
barriers like forest to prevent easy movement of pollen from
another field with a different variety or varieties of the same
crop species to the seed production field.
 Different planting dates (time isolation) may also be used if land
is scarce to avoid distance isolation provided that there is no
overlapping between the flowering times of the two varieties.

69. Prevent both out crossing and mechanical mix-up in
open-pollinated crops and mechanical impurity in self-
pollinated crops.
According to Ethiopian seed standard isolation distance
were depend on the
Crop type
Seed class
Pollination types

71. Rogueing
Is the removal of all undesirable plants.
when it does not conform to the varietal description.
It is the process of removal of voluntary plants, off types,
other crop plants, pollen shedders, and objectionable weed
Is to assure the desired varietal, genetic and physical
purity in the seed production field
Reducing the incidence of seed transmitted diseases

72.  The number of rouging varies with the crop, purity of the
source seed and the stage of the multiplication of the seed
crops.
 The best periods for rouging wheat are at heading and
maturity.
 This is because; off-types and other varieties of the same
species are most easily identified.
Rogueing….

75. 3. Crop Rotation
For controlling disease and pest, wheat should not be
planted in the same plot and crop rotation should be
adopted in every 3 years for seed production.
If farmers cultivate wheat every year, virus and other
soil borne diseases will be increased. Hence, wheat
produced from such field could not be used as seed.

76. 3. Crop Rotation….
Rotation of wheat with non-cereal crops could provide
several benefits to the subsequent wheat crop
It improves soil-structure, add organic matter, and reduce
weed, disease and insect pest problems.
Soil fertility enhanced if the preceding crop legume.
For example, a precursor mustard increases wheat yield
substantially with this crop also improves soil structure,
suppresses weed and breaks soil-borne disease cycle

77. 3.4 Avoiding mechanical mixture
Clean machines, equipments and threshing ground between
different varieties of the same crop
Threshing floor should be preferably cemented to keep
contamination by inert matter, weed seeds and other crop/
variety seed to be minimum

78. 5 .Weed management
 Weeds compete with the crop plants, carry diseases and
harbor insects. Weeds can significantly lower the crop yield
and seed quality.
 To produce high quality seed thorough control of weeds on the
wheat seed plots,
 Depending on the level of weed infestation, weeding a wheat
seed farm should begin
1st weeding two weeks after sowing or even earlier, ,
2nd weeding at 4–5 weeks, and
3rd weeding at 7–8 weeks,

79. Basic Principle of control weed
1. Prevention;
 It encompasses all measures taken to prevent the
introduction and/or establishment and spread of weeds.
 No weed control programme is successful if adequate
preventive measures are not taken to reduce weed
infestation.

80. 2. Eradication
 Eradication means complete elimination or removal of all
live weeds/wild plants/plants including their seeds and
vegetative propagules from certain area.
 Eradication is very difficult to achieve or hardly achieved in
terms of complete exhaustion of seed bank and vegetative
propagules of weeds from soil.

81. 3. Control
 Unlike weed prevention, control is exercised normally
after the weed problem arises/exists or known to users
from previous history of weed infestation in a certain
area/crop field.

82. Methods of weed Management
1. Preventive methods
2. Physical methods (Hand pulling/hand weeding ,Hand
hoeing, tillage ,mowing and slashing, flooding, mulching and
etc )
3. Cultural control a good crop is the best weed killer.
 Cultural/ecological methods exploit crop’s competitiveness,
growing environment and management practices towards
producing a good/healthy crop.

83. 4. Biological control
 It is the control of an organism (weeds, insects or pathogens
in agriculture) employing another living organism.
 They have just prey-predator relationship.
 The biological agents normally employed for the purpose
could be parasites, predators (insects, mites), pathogens
(fungi, bactieria, viruses), deleterious Rhizobacteria (DRB),
herbivorous fish, other animals (ducks and geese, snails)
and botanical agents (competitive plants, crops or weeds).

84. 5. Chemical method of weed control
 A proper technical know-how is a pre-requisite for
successful adoption of chemical method of weed control
the so-called herbicide technology.
 Herbicide selectivity and its dose, time and method of
application are of paramount importance/consideration
before applying to a crop.

85. 5.1 Herbicide classification
i) Based on time of application
a) Pre-planting: Pre-planting herbicides are applied in
finally-prepared levelled soil one day before or just
before planting of a crop followed by stirring/wrecking of
soil by hoe or by some secondary tillage implements to
ensure incorporation of the herbicide.

86. b) Pre-emergence: are applied 1-2 days after planting or
immediately after planting of a crop but before the
emergence of crop. Although the emergence of crop is
taken into consideration, the emergence of weeds is
equally important for designating many herbicides pre-
emergent.
c) Post-emergence/post-transplanting: are applied
after the emergence of a crop and weeds both, although
on principle it is after the emergence of crop.

87. ii) Based on selectivity
a) Selective: kills selectively a particular species/group of
plants (weeds) in a mixed stand/population of plants (crop
and weeds).
 All pre-planting, pre-emergence and post-emergence
herbicides meant for application in crops are selective ones.
b) Non-selective: kills indiscriminately species/group of plants
irrespective of weeds and crop.

88. iii) Based on spectrum of weed control
a) Narrow-spectrum: Narrow-spectrum herbicides control
a particular group of weeds (grasses, broad-leaved or
sedges).
b) Broad-spectrum: Broad-spectrum herbicides control a
wider array of weeds constituting grasses, broad-leaved
and/or sedges.

89. iv) Based on surface/site of application
a) Soil-applied/soil-active: are applied to soil or active
through soil and kill germinating or sprouting weed
seeds, rhizomes, stolons, tubers, corms, etc. All pre-
planting and pre-emergence herbicides.
b) Foliage-applied/foliage-active: Almost all post-
emergence herbicides, which are usually applied to the
canopy/foliage of plants on principle could be foliage-
active ones.

90. v) Based on mode of action
a) Contact: Control weeds by means of contact with
germinating seeds, radicles/roots and/or plumules /shoots/
foliages. However, they are not purely contact in nature.
They have at least some degree of mobility, may be
restricted within a leaf, a petiole etc.
b) Translocated/systemic: They move from the site of
application (soil, plant foliage) to site of action, where they
inhibit/jeopardize a particular or a number of bio-chemical
reactions and bring about the ultimate herbicidal effect.

91. Controlling plant disease requires an understanding of the
agents that cause disease as well as an understanding of
how plants are affected by disease and disease triangle .
Diseases are Caused by Infectious plant pathogens include
fungi, bacteria, nematodes, viruses, and parasitic plants.
6. Disease and insect pest Management

92. Disease triangle

93. Leaf rust
Stem rust
IDENTIFICATION:
 Lesion color
 Shape and
distribution of
lesions
 Parts of the plant
affected
Leaf /brown/rust Stem /black/ rust Stripe/yellow/ rust

94. Common bunt
is a seedling-infecting pathogen that has spores that are carried
on the outside of the seed coat or are present in the soil.
Using fungicide seed treatment and varieties that are disease-
free are effective Management option

95. Management Option
Applying a fungicide at early flowering if wet weather
prevails before and during flowering;
Using crop rotations
Avoiding over irrigation during full heading and especially
flowering

96. Management of the disease include
fungicide seed treatment and using disease-free
seeds

97. Wheat field free of Weed
Insect and Disease

98. Pest management in wheat
 Use of resistant varieties-
 Chemical control (fungicides, insecticides, herbicides)
 Use of cultural practices to control of diseases, weeds and
insects-sowing date, legume crop rotation, tillage frequency
 Biological control: In wheat, Trichoderma species have been
reported to be effective in controlling wheat diseases such as
fusarium head blight, septoria and tan spot.
 Insect predators and parasites
 Use of integrated pest management (IPM) approaches

99. A successful IPM depends on four basic techniques
 Scouting.: Regular and random visual observations provide
early warning to disease problems
 Disease Identification: The first and most important step is
to identify the problem; misdiagnosis results in use of improper
control.
 Timing: Improper timing of control measure will result in
disease control failure; the control measure must be timed
correctly to the stage of disease development.
 Record: Brief accurate records are a good tool for disease
control decisions

100. Harvesting of seed crops
Harvesting of the crop is highly determined by the
moisture contents of crop
If seed harvested with high moisture content and do
not dry them immediately, the high seed moisture will
cause the seed to heat, molds will grow, and the seed
will die very quickly.
If the seed are badly spoiled, they cannot even be
used for grain.

101. Harvesting…..
 Most seed crops are harvested when the seed are at
"harvest maturity.
 For most grain crops, this is around 12-14% moisture
content; for oily seed such as soybean, groundnut or
cotton, this is around 8-10% moisture.
 However, for wheat the best moisture content varies
from 14 to 17%

102. Harvesting….
 Harvesting of seed crop at right time can help;
 Maintain quality
 Minimize damage and loss of seed
 Seed reach in maximum germination capacity and
vigor when they attain physiological maturity.

103. Seed processing and storage

104. Seed processing …..
 Seed processing, is the preparation of harvested seed
for marketing and/or dissemination to farmers.
 Raw seed usually constitutes unwanted components
like impurities both in physical and genetic terms.
 It includes reception seed, drying, cleaning,
grading, treatment, weighing, packaging and storage

105. Seed processing…….
Some seed-processing operations particularly for
breeder seed may be done manually.
The raw seed for processing, up on receipt, should
be weighed and assigned a seed lot number for
future traceability.
The initial moisture content of the seed highly
influences the viability of the seed and drying must
be started within a few hours after harvesting and
threshing and continue until the required optimum
moisture level is achieved

106. Seed processing …..
Optimum moisture content reduces the deterioration
rates during storage, prevents attack by moulds and
insects and facilitates processing.
 In order to preserve seed viability and vigor, it
necessary to dry seeds to safe moisture content levels
as early as possible without heaping wet seed pods.

107. Seed processing…..
 Seed moisture content is basically determined as percent
water content of the seeds.
 It is measured either by drying seed samples in an oven or
with the help of moisture testers.
 The oven method involves weighing the seed samples and
drying them to a constant weight in an oven.
 The dried seeds are weighed again and any loss in weight
represents the weight of water lost due to drying.
 Then the percentage moisture content is estimated as
follows:

108. Were as W1=seed weighted before drying
W2=seed weighted after drying

109. Seed Cleaning
 After being harvested, seeds have to be cleaned to
remove inert matter, weed and other crop seeds,
seeds of other varieties of the same crop, and diseased
and damaged seeds.
 Cleaning enhances seed quality like purity, germination
and health provided that the right machines are used
and right operations are followed.

110. Seed Cleaning ……..
 Seed cleaning is primarily based on differences in physical
properties between the desirable seed and
contaminants.
 Cleaning is possible because seeds are different in
physical properties like size, weight and shape.

111. Seed Cleaning ……..
 Use of graded seeds is also obviously an important
requirement where sowing is done using seed drills and
planters.
 Seeds should be properly graded before being distributed to
the farmers.
 Purity, particularly genetic purity, i.e. the seeds that are
genetically pure and resemble the characteristics
described for that particular variety, should be tested before
storage

112. Steps of seed cleaning
 Involves two steps,
A. Pre-cleaning is the rapid removal of materials that
are either substantially larger or very light and much
smaller than the crop seed. It may also include the
removal of awns or beards – stiff bristles growing from
the ear of cereal grains (e.g. wheat, barley, rye and
many grasses).
B. Basic cleaning; It removes all the undesirable
materials from the seed and improves the physical
purity of the seed lot.

113. A. Pre-cleaning
The objective is not to obtain quality seed,
Facilitate subsequent operations by reducing the size
of seed lots,
Simplifying the cleaning process,
Decreasing seed loss during cleaning, and
Removing particles that may be problematic during
interim storage (e.g. mould-inducing green material
and live insects from the field).

114. B. Basic Cleaning
Is the most important step in the seed cleaning process.
It involves the use of mainly the air-screen cleaner
which is widely used to achieve a high level of physical
purity.
It is based on screens and a stream of air, and
separates the seed lot into various quality fractions
based on size (length, width and thickness), weight and
density.

115. Weighing, packaging, and storage
Package the cleaned seed in a suitable material (e.g.
polypropylene or jute).
Pack the seed in different quantities appropriate for sowing
a specific area of land to help farmers to affordably decide
how much seed to purchase.
Same-sized and same-type containers must have the same
weight to simplify the inventory control of seeds in storage

116. Labelling
Once packaged, the bags should be labelled to mark that
the seed has passed the quality control tests.
For certified seed lots, the certification agency normally
provides official labels.
Once packaged and labelled at the processing plant, the
seed is transported directly for sale or held in storage
until needed.

117. Seed storage
Seed storage is the preservation of seeds under
controlled environmental conditions that maintain seed
viability for a given period of time.
Storage is part of post-harvest operation to maintain the
viability, germination, and vigour of seed in good
condition from harvesting to planting.
Seed is usually stored by the growers (after harvest on
the farm), processors (before or after processing),
distributors (at the distribution/sales points) and by the
farmers (before planting).

120. .

121. SEED QUALITY CONTROL

122. 1. Field Inspection
 Field inspection Field inspection for pre-basic, basic and
certified seeds is normally performed by seed certification
agencies (not by the producer) in Ethiopia.
 The grower should be trained on the preconditions that
may lead to acceptance or rejection of the field and the
seed.
 The main objective of field inspection is to examine the
seed production field and determine its suitability for
seed certification

123. Inspectors must know;
Varietal characteristics,
Common diseases,
Pests and weeds with practices and
Conditions for production of high quality seeds of the
crop.
Methodology of field sampling and specific field
tolerance level for the contamination( seed standard)

124. Field Inspection……
Observation were made;
seed source,
Field requirements
Crop history
Isolation Distance
presence of off type plants
 presence of plant of other varieties and crop
species
Presence of objectionable weed
Presence of disease and other plants

125. SEED QUALITY CONTROL
 Field inspection
Quality standard are more rigid as we move from
certified seed to other seed classes
Three inspections in case of cross- and often-cross
pollinated crops (one before flowering, one at flowering
and one before or during harvesting) and
 Two in case of self-pollinated crops (one each before
and during flowering) are recommended for certified
seeds.

126. Time of Field inspection for the wheat field
 Inspection before flowering is done to
 Confirm proper isolation distance and absence of
volunteer and off-type plants
 To ensure absence of off-types with different flower
colors as described for the variety.
 Inspection is made before or during harvesting
 To check and assure whether the seed maintained its
originality as described for the variety

127. Steps of field inspection
A. Taking Field Overview;
Walk through the field to view the general condition of the
whole field.
A rough estimation of the field size and shape should be
taken before making the inspection.
 One variety is rejected in the field if;
If the varietal identity does not match the varietal
descriptors.
In case most of the crop (one-third or more) has lodged
No isolation distance, crop uniformity, crop condition,
disease.

128. SEED QUALITY CONTROL
Figure. Some of the possible travel
patterns for field inspection

129. SEED QUALITY CONTROL

130. 2. Seed Quality Inspection
Seed quality can be determined by the internal quality
assurance system seed producer and/or seed
certification laboratories.
Quality components such as physical purity, moisture
content, germination and vigor have to be tested before
distribution to the users.

131. Methods for seed sample
 Seed sampling is drawing a portion of seed lot that
represents the entire seed lot
 Primary sample: A small portion taken from one location in
the lot;;
 Composite sample: A mixture of all the primary samples
from the lot;
 Submitted sample: This is the sample submitted to the
testing station, comprising the composite sample reduced as
necessary;;
 Working sample: A reduced sample taken from the
submitted sample in the laboratory, used in a given quality
test. Seed sampling is drawing a portion of seed lot that
represents the entire seed lot;

132. SEED QUALITY CONTROL

133. SEED QUALITY CONTROL

134. SEED QUALITY CONTROL

135. SEED CERTIFICATION

136. SEED CERTIFICATION

137. Lot reference construction
Example: LRN= 2008/04/HB/2-8/ c1/ 01/ 01
` 1 2 3 4 5 6 7
1-production yr/Baraa Oomishamee
2-producer ID
3- crop type
4- field number
5- seed class
6- processing site
7- lot number

138. SEED CERTIFICATION

139. Ethiopian seed standards

140. Tag type
Seed tag were prepared based
on the seed class of seed

141. Tags used for the Pre-basic seed

142. Tags for the Basic seed

143. Tags used for the Certified seed

144. Planning for seed production
In planning phase, one has to have adequate
information on the type of seed required to produce in
order to make maximum benefit out of it.
Depending upon the type of seed demand and its
premium, some seed farmers may have a tendency to
produce

145. Planning for seed production ……
 In planning phase;
Careful selection of areas suitable for seed growth ,
Use of good agronomic practices,
Seed drying,
Processing and
Storage require skilled manpower and
A reliable quality control program.

146. Planning for seed production ……
 The planning of seed production based on:
seed rate
seed yield of the parental components
reserve factor..hyperlink.xlsx