This document outlines the key steps involved in seed processing, which includes pre-conditioning, cleaning, and grading. Pre-conditioning involves removing plant parts from harvested seeds through shelling. Cleaning is done using air screens and vibrating screens to remove external materials like trash and stones. This is mostly done using an air-screen cleaner. The final step of grading further separates seeds by size, shape, and other physical properties using different machines like specific gravity separators or spiral separators to obtain high quality seeds free of impurities. Seed processing helps improve planting conditions, seed quality, and applies treatments to prevent disease.

1. Principles of Seed
Technology
Topic - Steps involve in seed processing
Submitted to- Submitted by
Dinesh

2. Outline
• Introduction
• Advantages
• Seed processing steps
① pre conditioning and precleaning
②Cleaning
③Grading and cleaning

3. Introduction
• Seed processing is a vital part of the seed production
needed to move the improved genetic materials of the
plant breeder into commercial channels for feeding the
rapidly expanding world population. The farmer must
get the quality seed that is free from all undesired
materials because farmers entire crop depends on it.
• Seed processing is that segment of the seed industry
responsible for upgrading seed (Fig. 1), improving
planting condition of seed, and applying chemical
protectants to the seed.

4. Advantages
• Make possible more uniform planting rates by proper
sizing
• Improve seed marketing by improving seed quality
• Prevent spread of weed seed
• Prevent crops from disease by applying chemical
protectants
• Reduces seed losses by drying
• Facilitate uniform marketing by providing storage from
harvest time until the seed is needed for planting.

5. Steps involve in seed processing
• Step 1- Pre-conditioning and pre-cleaning
• Step 2- Cleaning
• Step 3-Cleaning and Grading

7. Step-1 -Pre conditioning and pre
cleaning
• Pre conditioning:- Isolation of seed from plant parts
with which it was harvested. e.g. Shelling
• Pre cleaning:- Removal of external materials like
trash, stones, clods which are either in larger size or
lighter in weight. No pre cleaning is required for
hand harvested and winnowed seeds

8. Seed Scalper
It removes the larger
inert matter from the
seeds. If it contains a
single sieve it is called as
scalpers, two sieves –
rough cleaners. The unit
consists of a vibrating or
rotating screen or sieve
having perforation large
enough to allow the
rough seed pass through
readily.

9. Debearders
The machine has horizontal
beater with arms rotating
inside a steel drum. When
the seeds pass through it
do the action of rubbing
the seeds and clip the
seeds of oats, debeard
barley, thresh white cap in
wheat, remove awns and
beards, de hull some grass
seeds and polish the seed.

10. Other equipments

11. Step-2-Cleaning
• The second stage of cleaning is carried out with air
blasts and vibrating screens and is applicable to all
kinds of seeds. It is essentially the same as scalping
but more refined. It is performed mostly by one
machine known as air-screen cleaner.

12. Air-Screen cleaner cum
grader
The air-screen machine is
the basic cleaner in most
seed processing plants.
Almost all seed must be
cleaned by air-screen
cleaner before specific
specifications can be
attempted. Machine size
varies from small, two-
screen farm models to
large industrial cleaners
with 7-8 screens

13. Step-3- Cleaning and Grading
• To obtain quality seed, it is necessary to clean the seed
obtained from the farm to get rid of inert materials,
weed seeds, other crop seeds, other variety seeds,
damaged and deteriorated seed. Different kinds of
seeds can be separated when they differ in one or more
physical characteristics. Physical characteristics
normally used to separate seeds are size, shape, length,
weight, colour, surface texture, affinity to liquids,
electrical conductivity, etc. The problem lies in
identifying the most important property and use the
machine that separates seed using the identified
property.

14. upgrading
• Seed lots require further cleaning treatment to
remove adulterants that are similar to pure seed in
size and shape, to be separated by air screen
cleaner. Removal of seeds larger or smaller than
required size (sizing) and removal of cracked,
damaged or otherwise defective seeds (grading) is
accomplished in this final stage of processing.

15. Some of the identified properties and machines
operating by following the properties are listed below:

16. Specific Gravity
separator
This method makes
use of a
combination of
weight and surface
characteristics of
the seed to be
separated

17. Spiral
separator
The separator, which
classifies seed
according to its
shape and rolling
ability, consists of
sheet metal strips
fitted around a
central axis in the
form of a spiral.

18. Other useful equipments
• Colour separator
• Magnetic separator
• Intended cylinder etc.
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