The document outlines the importance of seed quality testing, which involves various methods to assess purity, germination, viability, vigor, and moisture content of seeds. It describes the history of seed testing in Nepal, the different types of tests conducted, and the importance of quality seeds in enhancing productivity and income for farmers. Key attributes and testing methods are highlighted, emphasizing that accurate sampling and testing are crucial for maintaining seed quality.

1. SEED QUALITY TESTING
Prepared By:
Ganesh Lamsal
HRT-01M-2018

2. CONTENT
 Introduction
 Importance of quality seed
 History and regional seed testing laboratory
 Seed Sampling method
 Purity test
 Seed germination test
 Seed Viability test
 Seed vigour test
 Moisture determination
 Conclusion

3. INTRODUCTION
 Seed: “Seed is a matured ovule having embryonic plant, food
substance and protective cover or seeds or germ which can be
used in sowing or planting to produce crops by reproducing in a
sexual or asexual mode” (Seed Vision 2013-25).
 Quality seed: Seed possessing quality factors like genetic purity,
trueness to type with high degree of physical purity, uniformity,
high germination potential, optimum moisture and vigor, freedom
from diseases and pests and noxious weeds.

4. IMPORTANCE OF QUALITY SEED
 Alone can increased productivity by 15-20% (Joshi,
2015)
 Decreased the seed requirement rate
 Can be stored for longer period of time.
 Increased income

5. QUALITY SEED ATTRIBUTES
Four quality attributes
1)Physical Attributes
2) Physiological Attributes
3) Genetic Attributes
4) Seed Health Attributes

6. WHY SEED TESTING ?
 Seed testing is the cornerstone of all other seed technologies.
 Provides essential information for determining the quality of
seed.
 Concern with parameters such as germination, physical purity
and moisture content.
 Means to regulate the use and maintenance of seeds.
 Required to assess the seed quality attributes of the seed lots
which have to be offered for sale.

7. History and Regional Seed testing laboratories
 In Nepal, 1st
seed testing laboratory was established in 1962 under
Agronomy Division of Department of Agriculture (DOA) then it
got accredited to the International Seed Testing Association
(ISTA) in 1964.
 Currently 5 regional seed testing laboratories in Nepal (Source:
Krishi Diary, 2073).
 Regional seed testing laboratory at Jhumka, Hetauda, Bhairawa,
Nepaljung, Sundarpur.

8. Seed sampling
 Primary sample: small portion of seed drawn from
different container of seed lot
 Composite sample: primary samples combined
together
 Submitted sample: sample prepared for seed testing
to be submitted to seed testing lab
 Working sample: sample prepared from submitted
sample for carrying specific seed test

9. Seed lot and its sizes
Seed lot: huge quantity of seed combined together and bagged with lot number. Seed
lot must be of same variety, same seed class, same quality standard, same moisture%,
and no heterogeneity.

10. Sampling intensity

11. Sampling instruments
Sleeve type trier
Nobble trier for jute bags

12. SAMPLING METHOD FOR WORKING SAMPLE
Sampling method is used to make homogenous sample and reduce the
sample size without any bias.
1) MECHINICAL METHOD:
a) Boerner divider
 It consists of a hopper, a cone and series of baffles
directing the seeds into 2 spouts.
Disadvantage: difficult to check for cleanliness.
Fig.1: Boerner divider

13. ……………sampling method…………………..
b) Slot divider
 It is a sample divider built on the same principles as the
Boerner divider.
 Here the channels are arranged in a straight row.
 It is suitable for large seeds and chaffy seeds.
Figure 2. Slot divider

14. ………sampling method…………………..
c) Centrifugal or Gamet divider
 Seeds fall on a shallow rubber spinner which on
rotation by an electric motor
 Approx. equal quantities of seed will fall in each spout.
Figure 3. Gamet divider

15. ……………sampling method………….
2) Hand halving method
 Whole submitted sample is spread over the large sheet of paper.
 Divided into 4 equal portion and each portion is again divided
into four quarters.
 Out of 16 quarters, every alternate portion combined together.
 Process repeated till required sample size is obtained.
 Eg: carrot

16. ……………sampling method………….
3) Spoon method
 Practice for small seeded sample.
 Seed lot to sample poured and spread uniformly over the tray.
 With spatula on one and and spoon in another hand, pick the
small portion of seed from random palces on the tray until
required quantity of sample is obtained.
 Eg. Onion, Brassica

17. SEED TESTING PRACTICE
1. Purity testing
2. Germination testing
3. Viability testing
4. Seed vigour testing
5. Moisture content

18. 1. PURITY TEST
 It conforms to the prescribed physical quality standards.
 The working sample is weighted and separated into its components
on purity board and magnifying glass (diaphnoscope).
 The ISTA purity values results are expressed as % of pure seeds,
other crop seeds, weed seeds and inert materials.
 the percentage in weight of all components are added up to get
purity %.
 Check the tolerance of calculation that is permitted.

19. Instrument used for Determining Purity
Figure 4. Purity Work Board Figure 5. Seed Blower
 Blower is used to separate pure seed from inert material and other
crop seed
 purity work board helps for easier counting of pure seed , inert
material and other crop seed percentage in the given sample.

20. 2. SEED GERMINATION TEST
 Estimate the maximum number of seeds that will produce a normal
seedling.
 Germination tests shall be conducted with a pure seed fraction.
 The test is conducted under favorable conditions of moisture,
temperature, suitable substratum and light if necessary.
 No pretreatment is given except for those recommended by ISTA.
 Test carried out on 4 × 100 seeds as certification set out in replicates of
25, 50 or 100 seeds.
 Reporting: normal seedlings out of 400 on test are counted and
expressed in %

21. Methods used for determining seed germination.
 Sand germination method
 Petridish method
 Roll towel method
 Paper germination method

22. 22
Figure 6: Sand germination
Figure 7: Petridish germination
Figure 8: Roll towel method
Figure 9: Seed germinated on
paper

23. Germination test using paper

24. Between paper(BP)

25. Pleated paper (PP)
For seeds with multigerm eg, spinach, beet

26. Pre treatments for breaking dormancy
 Pre-chilling: 5-100
C for 3-7 days may be needed , eg brassica, onion
 Pre-drying: 30-450
C for 3-7 days, eg: rice
 Pre-washing: pre-soaked in water, eg: bean
 0.2 % KNO3 : eg: tomato
 GA: 200-1000ppm
 Scarification: mechanical (piercing, rubbing)
 Acid Scarification: H2SO4/HNO3

28. 3. VIABILITY TEST
 Tetrazolium test :
 It is done to determine seed viability, which may be expected to germinate.
 Very rapid (<24 hr.) and useful also for dormant seeds.
 Tetrazolium react with enzyme dehydrogenase which is present in the seed
and indicate whether the seed is ‘living’ or ‘dead’.
2,3,5-triphenyl + Dehydrogenase Triphenyl formazan + HCl
tetrazolium chloride (red and insoluble)

29. ……viability test ………………
 Tetrazolium salt solution of 0.5 % is used for bisected
seed or embryo and 1% solution for whole seed .
 Dead seed remains colorless even after dipping in
tetrazolium salt solution.
Limitation:
 too high values of vitality, no separation of
abnormal.
 does not detect the presence of pathogen or phytotoxic
effect.
Figure : Stained embryos
after tetrazolium test

30. 4. SEED VIGOUR TEST
o Vigour tests are not a replacement for germination tests,
however they provide additional information.
o It is the ability to germinate rapidly and to tolerate various
environmental factors which may be negative.
o Better vigour is correlated with field condition under unfavorable
environment condition.
o Method used to determine seed vigour:
o 1) Hiltner/ Brick gravel test 2) Paper piercing
test
o 3) Accelerated aging test 4) Conductivity

31. ……………..seed vigour …………..
1) Hiltner Test (Brick gravel test)
 Under unfavourable conditions only high vigour seed can form good
seedling
 100 seeds are placed upon sand inside the box.
 After placing seed, 2-3 mm layer of porous brick gravel is spread over
the seeds.
 The box is kept in the germinator at appropriate temperature.
 Seedlings which have emerged through the brick gravel layer are
counted.
 Then % of emerged seedlings are used to compare seed vigour of
different lots.
 Eg. Bean

32. ……………..seed vigour …………..
2) Paper piercing test
 The seeds are placed on 1.5 cm moist sand in a
tray or sand box.
 Then covered with special filter paper, followed
by 2 cm of moist sand.
 After this, the sand boxes/trays are kept in a
germinator at 20°C for 8 days.
 After then taken out and seedlings emerging
above the paper are counted.
Figure: Seedlings at paper
piercing test

33. ……………..seed vigour …………..
3) Accelerated aging test
 This test is conducted with the stress of high temp.
and moisture.
 The given weight of seeds is placed in a small box
with a screen tray that suspends the seeds over a
reservoir of water.
 These boxes are then placed in an aging chamber at
40 to 43 °C for 72 hrs.
 At the end of the period, the seeds are planted and
tested for germination under the standard
conditions.
Figure: The accelerated
aging test is conducted by
placing seeds in a plastic box
with a water reservoir and
holding them at 40 ºC for
72 hours.

34. ……………..seed vigour …………..
4) Conductivity test for pea
 The electrical conductivity test has been
widely tested in agriculture but has not
been adopted as routine practice.
 2-5 gm seeds are soaked in 100 ml water at
250
C for 10-12 hours
 Deteriorated or dead seeds leak electrolytes
more readily than high-vigor seeds.
 This greater leakage causes the water to
have a higher conductivity which can be
measured with a conductivity meter.
Figure: Electrical conductivity to
determine seed vigour

35. 5) Controlled deterioration test for
brassica sps
 First initial weight and MC is determined
 Environment is adjusted to raise to 20%MC, weighting is done at intervals
till the seeds attain desired weight of seeds at 20% MC.
 Immediately this is paked in aluminium pouch and sealed, not allowing to
equilibrate with ambient RH and kept at 720
C for 24 hours.
 Now, packets are floated into water bath at 450
C for 24 hours and allow to
cool for 5-10 minutes
 After this, seeds undergo standard germination test on Whatman paper or
filter paper
 Count the seedlings germinated

36. 5. Moisture test
 First tests conducted when seed sample is arrived at the seed lab.
 The seeds will likely gain or lose moisture in exchange with the
ambient air.
 The standardized laboratory test : oven method (ISTA 1996).
 It is expressed as a percentage of the weight of the original sample.
Method of determination of seed moisture
1. Air oven method
2. Moisture meters

37. ………moisture determination………
1) Air oven method :
 Materials req.: Grinder, Container, Oven, Desiccator, Analytical
balance
 Grinding : For leguminous seeds, coarse grinding is recommended
Fine seeds doesn’t need any grinding operation.
 Pre drying : For which grinding is necessary and the moisture content is
> 17%
 Weight of the submitted sample
o 10 g for species that have to be ground.
o 5 g for all other species.
o The sample should be submitted in polythene bag of 700 gauge.

38. Two types of Air oven Method
 high constant temperature(130±30
C for 1 or 2 hours):
seeds with non-volatile materials eg; carrot, tomato,
bean, cowpea, pea
 grinding into 4 mm for legumes and 0.5-1 mm for
cereals
 Weight and put in oven at 130±30
C for 1 or 2 hours
 Remove the dishes and note down the weights.

39.  Low constant temperature (103±20
C for 17 hours) , seeds
with volatile materials eg; onion, cauliflower, BLM, radish
 Griend into 4 mm for legumes and 0.5-1 mm for cereals
 Weight and put in oven at 103±20
C for 17 hours
 Remove dishes and note down weights

40. …………moisture determination………….
2) Moisture meter
 The principle involved in these moisture meters is
that wet grains are good conductors while dry
grains are less conductors of electricity.
 So, the MC is directly proportional to the
electrical conductivity of the seed.
 It consists of a compression unit to compress the
sample to pre -determined thickness.
 The test seed taken in a test cup and is
compressed.
 Then press the push type switch till the reading
comes in the display.
Figure: Moisture
meter

41. Moisture
meter

42. Calculation of moisture content
 Formula for samples not requiring pre-drying
 %MC=
 Formula for samples requiring pre drying
 %MC=S1+S2-
 Where: S1=% MC at first stage of drying, S2= %MC at
second stage of drying

44. CONCLUSION
 Purity, moisture, viability, vigour and germination are the
important seed quality testing parameters
 SQCC is the body responsible for quality control of seed and
5 regional labs test the seed quality in Nepal.
 Sampling is very crucial and sample should be prepared
without bias.
 Quality seed helps to increase productivity, decrease seed
rate requirement, improves storage capacity and ultimately
increases farmers income.