Seed Processing
Seed Processing :: Importance
TNAU Seed Centre


The process of removal of dockage in a seed lot and preparation of seed for marketing is called seed processing. The price and quality of seed is inversely related to dockage, which should not exceed a maximum level permitted for different crops for seed certification.
Due to the operation of processing the level of heterogeneity of seed lot gets narrowed down. The heterogeneity occurs in a seed lot due to following reasons:

  1. Variability in soil for fertility, physical, chemical and biological properties
  2. Variability in management practices (irrigation, application of nutrients etc.)
  3. Variability in ability of the seedling for utilizing the inputs
  4. Variability in pest and disease infestation
  5. Position of pod or fruit in a plant or the position of seed in a pod.

Principle of seed processing

The processing operations are carried out based on the principle of physical differences found in a seed lot.

Physical difference

            Suitable machineries

Seed size – varied from small to bold

Air screen cleaner cum grader

Density- ill filled, immature to well  matured light weight to dense seed

Specific gravity separator

Shape – round to oval and different shapes              

Spiral separator

Surface texture – smooth to wrinkled and rough

Roll mill / dodder mill

Colour of the seed – light color to dark color

Electronic color sorter

Conductivity of seed – low to high

Electronic separator

Requirement in seed processing

  1. There should be complete separation
  2. There should be minimum seed loss
  3. Upgrading should be possible  for any particular quality
  4. There should be more efficiency
  5. It should have only minimum requirement

Types of materials removed during seed processing

  1. Inert materials
  2. Common weed seeds
  3. Noxious weed seeds
  4. Deteriorated seeds
  5. Damaged seeds
  6. Other crop seeds
  7. Other variety seeds
  8. Off-size seeds

Sequence of operation in seed processing

Sequence of operations are based on characteristics of seed such as shape, size, weight, length, surface structure, colour and moisture content.  Because each crop seed possesses particular seed structure, the sequence of operation will be perfomed with proper equipments. It involves the following stages,

  1. Drying
  2. Receiving
  3. Pre-cleaning
  4. Conditioning
  5. Cleaning
  6. Separating or Upgrading
  7. Treating (Drying)
  8. Weighting
  9. Bagging
  10. Storage or Shipping

The flow charts illustrating the types of materials removed from harvested produce during processing.

  Harvested seed

Receiving   The field run produce after threshing is received in the processing plant.

Seed movement /basic steps in seed processing plant



Seed Treatments
Seed Certification
Seed Storage
© All Rights Reserved. TNAU-2008.