In broad sense, seed is a material which is used for planting or regeneration purpose. However scientifically, Seed is a fertilized matured ovule together covered with seed coat is called seed or it is a propagating material i.e., part of agriculture, sericulture, silviculture and horticultural plants used for sowing or planting purpose.
Seed may be defined as “Structurally a true seed is a fertilized matured ovule, consisting of an embryonic plant, a store of food and a protective seed coat, a store of food consists of cotyledons and endosperm”
Definition of seed
However, from the seed technological point of view seed may be sexually produced matured ovule consisting of an intact embryo, endosperm and or cotyledon with protective covering (seed coat). It also refers to propagating materials of healthy seedlings, tuber, bulbs, rhizome, roots, cuttings, setts, slips, all types of grafts and vegetatively propagating materials used for production purpose.
Thus seed is the most vital and crucial input for crop production, one of the ways to increase the productivity without adding appreciably to the extent of land now under cultivation by planting quality seed.
Characteristics/attributes of quality seed;
1. It must be genetically pure:
Breeder/nucleus: 100 %
Foundation seeds: 99.5%
Certified seeds varieties: 98%
Certified hybrid seeds:95%
Certified hybrid cotton: 90%
Certified hybrid castor: 85%
2. It should have required level of physical purity:
All crops: 98%
1. Free form other crop seeds (number/kg): designated inseparable crop seeds are the plants seeds cultivated crops found in the seed fields and whose seeds are so similar to crop seed that is difficult to separate them economically by mechanical means, cause physical admixtures with the crop seeds only when these crop mature approximately at the same time when seed crop matures. Ex. In barley: oats and wheat seeds
2. Free from objectionable weed seeds: these are seeds of weed species which are harmful in one or more of the following ways;
a. The size and shape of weed seeds are similar to the crop seed and difficult to separate them by mechanical means
b. Weeds growth habit is determinate type and compete with the crop for all resources
c. Weed plant parts are poisonous or injurious to human and animals
d. Weed platns also serves as alternative hosts for pests and diseases
Ex. Bersem: chicory
Paddy: wild paddy (Oryza sativa var. fatua)
Cucurbits: Wild cucurbits spp.
Lettuce: wild lettuce
Bhendi: wild Abelmoscous spp
Wheat: Convolvulus arvensis (Hirankuri)
3. Free from designated diseases: it refers to the diseases specified for the seed certification which may cause contamination of seed lot
Ex; loose smut of wheat (Ustilago tritici)
Kernal smut of sorghum (Sphacelotheca sorghi)
Grain smut of pearl millet (Tolyposporium penicillariae)
Ergot of bajra (Claviceps microcephala)
Early blight of tomato (Alternaria solani)
Little leaf of brinjal (Datura virus-2) etc.,
4. High germination and vigour
5. Optimum moisture content
Cereals: 10-12 %
The importance of quality seeds has been recognized from the time immemorial. The old scripture, Manu Smriti says “Subeejam Sukshetre Jayate Sampadyathe” i.e., Good seed in good soil yields abundantly. Seed quality has been treated as sacred, being an important factor in the improvement of agriculture and agrarian societies. The Rigveda, 2000 BC indicate the importance accorded to seed and the mother earth. 5th century Kautilya Artha Shasthra, surapalas vrikshayurveda mentioned importance of seed and mentioned about seed treatments to ensure good germination. Seed dressing with milk, vidanga, cowdung, honey to protect the seed during germination.
Although the importance of seed was recognized in ancient agriculture, the need for organized seed production was identified only at the beginning of 20th century when Royal commission of Agriculture (1925) recommended spread of improved varieties and seed distribution.
Importance of quality seed:
1. Seed is a vital input in crop production;
• It is the cheapest input in crop production and key to agriculture progress.
• Crop status largely depends on the seed materials used for sowing
• Response of other inputs in crop production depends on seed material used
2. The seed required for raising crop is quite small and its cost is so less compared to other inputs
3. This emphasis the need for increasing the areas under quality seed production
4. It is estimated that good quality seeds to improved varieties can contribute about 20-25% increase in yield.
The advent of modern plant breeding methods and biotechnological advances in seed industry plays a significant role in developing of high yielding varieties and hybrids.
Role of improved seeds:
1. Carrier of new technology
2. Basic tool for a secure food supply
3. The principle means to obtain crop yields in less favourable production area
4. Medium for rapid rehabilitation of agriculture after natural disasters.
Difference between seed and grain:
Seed & Grain
It should be a viable
Need not be a viable
It should have maximum genetic & physical purity
Should satisfy minimum seed certification standards
No such requirements
Treated with pesticide /fungicide to protect seed against storage pests and fungi
Not treated with any chemicals, since used for consumption
Respiration rate and other physiological and biological processes should be kept at low level during storage
No such specifications
Production is technically organized
It should satisfy all the seed quality attributes
Benefits of using quality seeds
1. They are genetically pure (true to type).
2. The good quality seed has high return per unit area as the genetic potentiality of the crop can be fully exploited.
3. Less infestation of land with weed seed/other crop seeds.
4. Less disease and insect problem.
5. Minimization of seed/seedling rate i.e., fast and uniform emergence of seedling.
6. They are vigorous, free from pests and disease.
7. They can be adopted themselves for extreme climatic condition and cropping system of the location.
8. The quality seed respond well to the applied fertilizers and nutrients.
9. Uniform in plant population and maturity.
10. Crop raised with quality seed are aesthetically pleasing.
11. Good seed prolongs life of a variety.
12. Yield prediction is very easy.
13. Handling in post-harvest operation will be easy.
14. Preparations of finished products are also better.