Good quality
seeds are those which are of same variety and contain little to no impurities
and shows a good performance in the field.
Following criteria can be used to describe
the quality of good seed;
1. Varietal
characteristics
2. Seed lot
characteristics
3. Seed
viability
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| Seeds of pulses |
1. VARIETAL
PURITY CHARACTERISTICS
Varietal
purity is mainly defined as the genetic or cultivar purity and can be described
by its physical & chemical traits and crop attributes.
a) Seed factors
True varietal
seeds can be characterized by its specific traits such as the length, width,
shape, size, color and aroma.
b) Chemical
analysis
A range of
chemical tests can also be used to differentiate between varieties.
Factors such as alkali digestion, color, amylase content, gel consistency
and protein helps to discriminate between varieties.
c) Crop factors
Physical
characteristics of crops are normally constant that includes plant height, time
to reach maturity, plant color and plant growth habits. Minor changes may occur
especially in severe environmental growing conditions.
2. SEED LOT
CHARACTERISTICS
The
characteristics of seed lot are:
à Amount of
impurities
à Seed size
à Damaged,
deformed or diseased seed
A brief explanation
of each is given below:
a) An impurity refers
to any contamination in the true seeds through weed seeds, other crops seeds,
and inert material such as dirt or twigs, stones etc.
b) Seed size is generally a desirable seed characteristic. Seed size represents that the seed has the capacity
to produce vigorous seedlings when conditions become favorable.
c) Damaged or infected seed: Good quality
seed should be free from diseased seeds, insects and other desirable materials.
Seeds should also be free from a variety of mechanical injury that decrease
germination and seedlings vigor.
3. SEED
VIABILITY
Seed viability
should be estimated to a large level from its;
à Seed moisture
level
à Germination potential
à Seed vigor
a) Moisture content: imposed an
influence on the life and vigor of seed. Moisture contents of the stored should be less than 14% and rather
less than 12% to increase the shelf life and storage times of seed.
b) Germination percentage: Total number
of alive seeds are expressed by germination percentage. It is determined
through tests and counts of the number of seeds that germinate under controlled
conditions.
c) Seed Vigor gives a reliable approximation of the field performance, and afterward, the
value of field planting. Whereas the rate of germination varies among varieties,
seeds should absorb moisture and produce a root within 2 days and the first leaf within 4 days. If these conditions are fulfilled then the seed is thought to have been germinated.
Seed
vigor is the ability of germinating seeds to grow continuously and survive. Seeds having low vigor usually produce fragile/weak seedlings that are vulnerable
to environmental stresses. Whereas, a high vigor in seeds can be estimated
to give early and consistent stands which provides the competitive advantage
against various environmental stresses to growing seedlings.
