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 refersto 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.
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