Textbook Of Seed Science & Technology

Introduction

Seed technology is defined as “that discipline of study having t.o do with seed production, maintenance quality and preservation (Cowan, 1973).

Feistritzer (1975) has defined seed technology as the method through which the genetic and physical characteristic of seeds could be improved. It involves such activities as variety development, evaluation and release, seed production, seed processing, seed storage, seed testing, seed certification, seed quality control and seed marketing etc.

So seed technology in widest sense, includes development of superior crop plant varieties, their evaluation and release, seed production, seed processing, seed storage, seed testing, seed certification, seed quality control, seed marketing, seed distribution and the related research on these aspects,

The major goal of seed technology is to increase agricultural production through the spread of good quality seeds of high yielding varieties. To achieve this goal, the quality seeds must be rapidly multiplied and supplied to the farmers at proper time with the reasonable price.

Seed quality is the degree of excellence in regard to the physical and genetical characters. High quality seed lots posses high genetic purity and high germination percentage and minimum inert, weed and other crop seed and are free from diseases and pest attack. If it is lacking in any of these qualities, it is said to be low quality seed lots. Only good quality seeds expected to respond well for fertilizers and other inputs used. Among the various inputs, seed is the basic and cheapest input. Good Agriculture depends on the multiplication of good quality seeds of high yielding varieties. If quality is not maintained it proves the words of Sudir sen as “what are known as seeds of hope may turn into seeds of frustration”.

Significance of a good quality seed

– Good quality seeds of improved varieties ensure higher yield atleast10-12%

– Ensures genetic and physical purity of the crops

– Gives desired plant population

– Able to withstand the adverse conditions much better

– Seedlings will be more vigourous, fast growing and can resist pest and disease incidence to certain extent

– Ensures uniform growth and maturity

– Development of root system will be more efficient that aids absorption of nutrients efficiently and result in higher yield.

– It will respond well to added fertilizer and other inputs.

Goal of seed technology

1. Rapid multiplication

2. Timely supply

3. Assured high quality seed

4. Reasonable price

In brief the role of seed technology in Agriculture sector is timely supply of quality seeds for reasonable price.

Characteristics of good quality seed

1. Improved variety : The variety must be superior to existing ones. It must be the latest variety suited to the area in regard to the production potential and other desirable characteristics.

2. Genetic purity : Genetic purity of seeds refer to trueness to type. If the seed possesses all the genetic qualities that breeder has placed in the variety, it is said to be genetically pure.

3. Physical purity : Physical purity of a seed lot refers to the physical composition of seed lots. Freedom from inert matter, broken grains, soil and dust particles, chaff etc., so also weed seeds and other crop seeds.

4. Seed germination and vigour :

Seed germination refers to ability of a seed when planted under normal sowing conditions to give rise to a normal seedling. Vigour refers to potential of the seed to give rise into a normal plant under wide range of environmental conditions.

5. Planting value :

Planting value is the real worth of a seed lot for raising the crop. It is determined by calculating pure live seed percentage

6. Seed health

Health of seed refers to the presence or absence of disease organisms /insect pests on seeds.

7. Seed moisture

Seed moisture is the most critical factor in the maintenance of seed germination and viability during storage.

8. Seed size, weight and specific gravity

The seed size, weight and its specific gravity has been found to have positive correlation with seed germination and vigour in many crops.

9. Seed colour

Seed colour often reflects the conditions during seed maturation. Good normal colour and shine are the indications for good quality seed.

Differences between Seed and Grain

Seed

It should be a viable and vigorous one It should be physically and genetically pure Should satisfy minimum seed certification standards

It can be treated with pesticide /fungicide to protect seed against storage pests and fungi

Respiration rate and other physiological and biological processes should be kept at low level during storage

Should be compulsorily certified production

It should satisfy all the quality norms

Seed can be utilized as grain provided if it is not treated with poisonous chemicals

Grain

Need not be a viable one No such requirement

No need of certification

It should never be treated with any chemicals, since used for consumption

No such specifications are required.

No such condition in grain

No such quality norm is required

Grain never can be converted into seed.