Determinants of quality seed

A. Seed purity

• The seed should be pure (true to type), with high sowing quality, good yield potential, evenness in growth pattern and maturity.

Effects of impure seed

• It may cause difficulty in scheduling field operations and adopting suitable cultural practices.
• It may be difficult to protect plant from insects, pests, diseases, weeds and climatic hazards.
• It may be difficult to obtain quality and quantity of economic and biological yield of crops.
• It may not be suitable for seed multiplication and seed preservation for the future cropping.
• It may cause difficulty in grading, storage, consumption and marketing.

Requirement for the determination of seed purity

a. Improved variety:

• The variety must be truly superior to the existing one.
• It must be latest and best suited to the areas in regards to production potential and other characteristics.
• Such seeds have at least 10-15% more genetic potential and are resistant to insect and diseases, well adopted to the agro-climatic conditions and cropping system of the locality, high in response to better conditions of growth.
• They have a wide range of adaptability, tolerance to adverse conditions.
• Their quality is acceptable to the local market and consumers.

b. Genetic purity

• There should not be any genetic deterioration in the variety.
• If the seed possess all the genetic qualities that the breeder has place in the variety, it is said to be genetically pure.
• Genetic purity is directly responsible for higher yields.
• There should not be off type plant and no varietal mixture.

c. Physical purity

• Physical purity of the seed lot refers to the physical composition of seed lots. It must be clean and processed, free from inert matter (dirt, grit, chaff, adhered soil, sticky substances such as pulp of fruits), weed seeds (noxious and objectionable weed seeds) and other crop seeds or seeds of other variety.
• Higher the content of pure seeds, the better would be the seed quality.

B. Physiological quality

• Quality seed should have high germination capacity and seed vigor.
• It should have bold and plumpy grains.
• It must be dried to proper moisture content.
• The seed size, weight and specific gravity have been found positive correlation with seed germination and vigor in many crops.

C. Pathological quality

• The quality seed must be free from diseases (pathogen spores in or on the seed).
• Seed should be treated with proper chemicals.

D. Other characteristics

• Seed color often reflects the condition during seed maturity.
• Good normal color and shine have been regarded as invaluable quality guides by the farmers from the time immemorial.