Introduction:
Seed technology is a branch of agricultural science that deals with the production, processing, testing, storage, certification, quality control, and marketing of seeds. Its main objective is to ensure that farmers receive high-quality seeds with high genetic purity, physical purity, germination, vigor and health, leading to better crop establishment and higher yield.
Good quality seed is the most important input in agriculture because it carries the genetic potential of improved crop varieties. Modern seed technology combines principles of plant breeding, seed science, and quality assurance to maintain seed quality from production to sowing. It also supports food security, sustainable agriculture, and the rapid adoption of improved crop varieties.
Table of Contents
seed:
- Botanically seed is a fertilized ovule consisting of intact embryo, stored food and seed coat which is viable and has got the capacity to germinate.
- National (Indian) Seed Act passed in: 1966
- National Seed Corporation in:1963
Classes of seed:
- Seed are grouped in to five main classes
- Nucleus seed:
- It is the first stage or class of improved seed.
- Such seeds are the initial seed of an improved variety and are available in limited quanatity.
- It is produced directly by the originating plant breeder at research institute.
- It has highest genetic purity (about 100%)
- Breeder seed:
- It is the progeny of nucleus seed.
- It is produced under strict supervision of plant breeder at research institute.
- Breeder seed is used to produce foundation seed.
- Genetic and physical purity is almost same to nucleus seed.
- It has golden yellow colored tag.
- Foundation seed:
- It is progeny of breeder seed.
- It is known as mother seed and it is the source of registered and certified seed classes.
- It is genetically 99.9% pure. However, physical purity of 98% is permissible.
- It is mainly produced National Seeds Corporation (NSC).
- It is produced on government farms, at experiment stations, agriculture universities or on cultivator’s field under strict supervision of research scientists and expert from state seed certification agencies (SSCA).
- White tag is denoted for foundation seed.
- Registered seed:
- It is produced from foundation seed or registered seed itself.
- It has satisfactory genetic identity and purity.
- In India it is generally omitted (avoided) and certified seed is produced directly from foundation seed.
- It has purple or orange colored tag on bags.
- Certified seed:
- It is the progeny of either registered seed or foundation seed or certified seed itself.
- It has satisfactory genetic identity and purity.
- It is approved and certified by the state seed certifying agency.
- The bags are denoted blue (azure blue) colored tag.
- It is available for general distribution to the farmers for commercial crop production.
Viability of seeds:
Sees viability is defined as the capacity of the seed to remain capable of germination for some some specific period of time.
Seed viability test
- Potassium permanganent method:
- It’s qualitative test to find out whether seeds are viable.
- Tetrazolium chloride test:
- It is known as biological test.
- Sees are soaked in 0.5-2% solution 0f 2, 3, 5, triphenyl tetrazolium chloride.
- The viable or living seeds take bright red coloration and the color becomes more intense in the embryo.
- It is a quickest method of seed viability test.
- Grodex test:
- Grodex is a seed germination indicator.
- It’s a brand name of triphenyl tetrazolium bromide in powder form.
- GADA test:
- It is a biochemical method of seed storability developed by P. Linko in 1961 to measure glutamic acid decarboxylase activity in seeds, wheat and rice.
Isolation distance:
Isolation of seed crop is essential to avoid genetic and physical impurities.
Minimum isolation requirement of some crops:
| Crops | Minimum isolation distance (in m) of Foundation seed | Minimum isolation distance (in m) of Certified seed |
| Self-pollinated crops like rice, wheat, barley, oat | 3 | 3 |
| Pearl millet hybrid | 1000 | 200 |
| Maize, sorghum | 400 | 200 |
| Cotton hybrid | 50 | 30 |
| Groundnut, soyabean | 3 | 3 |
| Rapeseed and mustard | 400 | 200 |
| Cucurbits | 800/1000 | 400/500 |
| Okra | 400 | 200 |
| Tomato | 50 | 25 |
| Onion | 1000 | 400 |
Real value of seed:
- Real value: Purity % * Germination % divided by 100.
- It’s percentage of germinability of percentage of purity of seed lot of a crop plant
- It is expressed in percentage and also known as utility percentage of seed.
- Impurity percentage is called dockage.
https://agritech.tnau.ac.in/seed_certification/seed%20tech%20agri%20index/seedconcepts.html
