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The basic aim of seed legislation and its subsequent enforcement is to regulate the quality of seeds sold to farmers. So long as Agriculture remains tradition and static, there is little justification for regulating seed quality. However with technological advancement and the systematic application of science to Agriculture, it becomes compulsory to regulate the quality of seeds through seed legislation and its subsequent enforcement to ensure that seed buyers are not made to run undue risks.

TYPES OF SEED LEGISLATION

Seed legislation can be broadly divided into two groups.

1.    Sanctioning legislation

2.    Control legislation

Sanctioning Legislation

Which authorizes, establishes or otherwise legally sanctions such activities as formation/establishment of advisory bodies, seed certification agencies, seed testing Labouratories, foundation and certified seed programmes, recognition of seed certification agencies of foreign countries, appellate authority etc.

Seed multiplication and production was controlled by a legally sanctioned system called Seed Certification. Seed certification procedures and designed to ensure physical and genetic purity, freedom from weed seeds and diseases and good germinability of the certified seed. Seed certification is done by the Seed Certification Agency (SSCA) of the concerned state or by NSC.
 
Objectives of Seed Certification

The objective of seed certification programme was formulated by Douglas, 1971
 
i)    to ensure genuineness and quality of seed.
ii)    The identification and their rapid increase of new varieties under accepted names.
iii)    The systematic increase of superior varieties
iv)    Continuing supply of quality material and their maintenance.

Seed Storage is an essential process during seed production programme. The purpose of seed storage is to preserve planting stocks from one season to next planting season.Seed storage starts from the moment of maturity and extend until its planting, in the next season.
 
PRINCIPLES OF STORAGE

Primary aim of storage is simply to prevent deterioration of quality seed. The management objective during the storage period is to reduce metabolic activity to such a low level that the seed is sufficiently stable with minimal deterioration. The two alternative methods are

1.    Reduction of moisture content to a safe level and cooling of the seed.
2.    Modification of atmospheric condition of the storage system.

Types of storage

There are four types

1.    Storage of commercial,  truthfully labelled and certified seed.

2.    Storage of carry-over seeds.

3.    Storage of foundation seed stocks and enforcement seed samples.

4.    Storage for germplasm seeds.

Seed Testing
1.    Sampling

2.    Determination of Heterogeneity

3.    Purity analysis

4.    Germination Test

5.    Seedling Evaluation

6.    Quick Test for Viability

7.    Estimation of Seed Moisture

8.    Grow Out Test

9.    Seed Health Test

Seed processing, drying, cleaning and upgrading

Seed processing refers to all the steps necessary for preparation of harvested seed for marketing namely handling, drying, shelling, preconditioning, cleaning, size grading testing, and packaging etc.

Layout for seed processing plant

Layout plan for construction of seed processing plant should be carefully planned to ensure that thorough seed cleaning, upgrading, seed treatment and other seed processing operations are carried out efficiently without mixing and damaging seed lots with minimum equipment, personnel, time and at minimum cost.

The following factors should be considered while planning and designing the processing unit:

Need to know Physiological maturity (PM), Harvestable maturity (HM) and harvesting method

·    If these factors are considered, the harvest produce will have the maximum seed quality characters in terms of germination, vigour and storability.

 The maturity is of two types depending on the purpose. If the crop is for grain production it is enough to harvest the crop during harvestable maturity. But when the crop is meant for seed purpose it is advisable to harvest the crop during physiological maturity.

A hybrid is the first generation progeny of a cross between two genetically different identical inbred lines. The individual lines are known as inbreds.  Ineffective cross-pollination is a major constraint in a commercial production of hybrid seeds in many crop species. In such crops manual pollination is the way to produce hybrid seeds. Eg. Cotton. In the case of rice it is highly self-pollinated crop and cross-pollination is a big problem. The increased vigour, uniformity and yield of F1 hybrid have been exploited in most crops where the pollination system allows for convenient and economic cross hybridization.  This system is called breeding tool in exploiting the hybrid vigour.

The term heterosis from Greek means hetero different, osis-condition was coined by skull (1914).

Heterosis or hybrid vigour, refers to the increase or decrease in vigour of off spring (hybrid) over parents. Usually, theses two terms are used synonymous.   But hybrid vigour refers to increased vigour; Heterosis both increased and decreased vigour.

Superiority of the hybrid as hybrid vigour and the mechanism by which this superiority is developed is heterosis (Rangaswamy, 1998).

Seed Production Technology

1.    Paddy
2.    Sorghum
3.    Bajra        
4.    Maize              
5.    Blackgram    
6.    Soyabean                
7.    Cowpea             
8.    Redgram 
9.    Groundnut
10.    Sunflower
11.    Castor       
12.    Gingelly
13.    Tomato
14.    Brinjal
15.    Chilli
16.    Bhendi

The degree of excellence in regard to the physical and genetical characterstics of seeds is called as Seed quality. Seed lots having high genetic purity and high germination percentage and minimum inert, weed and other crop seed and are free from diseases and pest attack, it is said to be a high quality seeds. 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.
 
Viability: It is the ability of embryo to live, grow and develop into a seedling under favorable conditions. The seeds attained maximum viability at physiological maturity stage. Later on seeds start to loss viability.

Multiplication and distribution of high quality seed of improved varieties is a crucial step in agricultural production of any country.

When an entry is identified by the workshop of the concerned project, the breeder begins the seed multiplication of the strain in the following crop season. The seed produced by the breeder after a strain is identified, but before it is released as a variety is termed as the “stock seed”. This seed is known as breeder seed after it is released and notified. In the crop season following notification foundation seed of newly released variety is produced. In the second crop season following the release of variety, certified seed of the variety is produced. Thus the farmer is able to obtain certified seed of a newly released variety for commercial cultivation only in the third crop season following in the notification of the variety. However the seed of such variety reach the farmer even before its release through mini-kit trials. Many other farmers would obtain the seeds from those farmers who conducted the mini kit trials and so on in the next two years. Thus an outstanding variety is likely to reach many farmers even before its certified seeds have been put on sale.

Seed

A true seed is defined as a fertilized mature ovule consisting of embryo, stored material and protective coats. The seed strictly speaking is an embryo a living organism embedded in the supporting or the food storage tissue.

A seed stands for any of the following used for sowing or planting.

1.    Seeds of food crops including edible oil seeds and seeds of fruit and vegetables.
2.    Cotton seeds
3.    Seeds of cattle fodder
4.    Jute seeds
5.    Seedlings, tubers, bulbs, rhizomes, roots, cuttings, all type of grafts and other vegetative propagated material for food crops or cattle fodder.

Seed technology is defined as “that discipline of study having to 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 Sampling

The size and quantity of seed sample required for seed quality testing remains small as compared to the seed lot hence, representative samples are randomly drawn for this purpose. The process of obtaining a uniform and representative sample from a seed lot for seed quality testing is called seed sampling. The samples are prepared in accordance to ISTA rules to ensure that small size sample should represent truly and in the same proportion all constituents of seed lot.

Mini seed testing lab analytical register

Seed storage is the preservation of viable seeds from the time of collection to the required for sowing. It is important to get adequate plant stands in addition to healthy and vigourous plants.

Objectives

i. To maintain initial seed quality during storage period by providing suitable conditions.

ii. To maintain the seed germination and emergence rates.

iii. To prevent the seed deterioration during storage period.

iv. To maintain the physical and physiological seed qualities.

The seed moisture content is the amount of water present in the seed. It is generally expressed in percentage of dry and wet seed weight. It is the loss in weight of the original sample when it is dried. High moisture content in seed sample favors the mechanical damage, seed longevity, incidence of disease and insect pests.

Objective

i. To know the moisture content of seeds by suitable methods
ii. To suggest the seed drying.

Seed Viability Test

Germination test for a seed lot is a pre-requisite to know its potential of emergence under field condition. However, this test requires few days to weeks and a month in some cases. Tetrazolium test gives quick information on seed viability or germinability. It makes possible to distinguish red coloured living parts of seeds from the colourless dead ones. Staining of seeds determines  viability.  Completely  stained  seeds  are  viable  while,  partially and comparatively unstained seeds are non-viable. This test is not valid as compared to seed germination test.

Seed Germination Test

Germination is the process of emergence and development of seed embryo into a plant under favourable environmental conditions of water, soil, sunlight and temperature. The best example of germination is the sprouting of a seedling from a seed of an angiosperm plant. It reflects the ability of seed to produce a normal plant under favourable environmental conditions. The germination rate of a particular seed lot is a key indicator of its performance in the field.

Physical purity test determines the proportion of pure seed, other crop seed, weed seed, inert matter, moisture and germination components in the seed lot by weight in percentage in accordance to prescribed Seed Standards. It thus, helps in improving the plant stand, raising a pure crop by eliminating other crop seeds, weed seeds and disease free-seeds. Seed must not be sold until the percentage of pure seed, other crop seed, weed seed, and inert matter are in accordance to seed physical purity standards. Physical purity test is required for seed certification or seed law enforcement and it is a pre-requisite for ger- mination test.

1. Isolation distance

Seed
The seed, in botany is a mature ovule, consisting of an embryo together with a store of food all surrounded by a protective coat and bear ability to develop a new plant on optimum conditions of soil, moisture and light. It usually develops after the fertilization on an egg cell by male generative cell from a pollen grain. Seeds of some species develop without the intervention of the male cell, formed entirely of ‘mother’ tissue. Such seeds are called apogamic seeds. In seed technology, the seed is seed or any vegetatively propagated material produced from seed crop in accordance to Indian seed standards and has potential to develop new crop in presence of soil, moisture and light.

Notified Varieties of Different Seed Spices

India is famous as the ‘Land of Spices’ world over. Spices are nature’s gift to humankind for flavoring our food. They are also used as preservative and in pharmaceuticals. India is the largest producer, consumer and exporter of seed spices and their value added products. About 63 different spice crops are cultivated in the country. Among them, seed spices are annual herbs, whose dried seeds or fruits are used as spices. These crops share 21.87% in terms of quantity and 7.42 % in terms of value to total spices export in the country. The country grows a wide variety of seed spices like coriander, cumin, fenugreek and fennel as major crop, while, dill, nigella, ajwain, anise, celery, caraway, parsley, black cumin and few other are categories as the minor seed spices.

Storage of paddy seed lots after harvesting is one of the crucial aspects of processing shopfloor. Paddy due to increased mechanised harvesting may loose vital seed quality parameters. Since seed growers cannot buy a combined harvester themselves-they resort to hiring of this machine. Sometimes in the hurry of completing harvesting they harvest the crop at un-safe moisture content. This un-safe moisture content may go up to 50-60% also. Harvesting of seed crop with high moisture has adverse effect on storability. Ensuring safe seed moisture is very critical especially during rabi-summer seed production cycle. Most of the growers depend on sun drying for reducing the seed moisture. But paddy should not be dried >3% in one cycle. Follow tempering and convection cooling after every cycle and repeat the cycle till seed attains safe moisture content (14%).

The management of storage in open and closed storage is critical before start of any seed processing activities. When seed lots reach the shop floor, they need to be stored properly. Unlike commercial produce seed lots cannot be stored in bulk. These need to be stacked lot wise and there is problem of “stackburn”-resulting from successive layers in building a bag stack. In crops like soyabean-”stackburn” can have detrimental effect on seed quality. The quality parameters like germination and viability can get lost instantly if not properly stacked on the pallets.

To assess the quality of the seed is necessary before it is shipped for packaging and made available to the farming community. To assess certain routine seed quality parameters which are statutory for labelling seed sampling and testing are very critical. Seed testing is not only a mandatory trade requirement but also decides the market potential of a particular product in the market and safeguard the brand image of the company. Seed sampling for labelling and other trade requirements is done at processing plant. The reliability of seed testing is depends on the accuracy with which the sample represents the lot and precision of the laboratory test. In many cases variations in the test results are due to variation in the sampling. Hence, seed sampling is one of the important activities of the shop floor or processing unit.

There are stages in seed supply chain where seed losses happen at harvesting and post harvest stage. These losses may occur due to higher moisture at harvest, due to harvesting methods, processing methods, at seed storage, during transport etc. Estimation of these losses is an important function of seed inventory management. Estimating seed losses help to improve processing and seed distribution efficiency. These simple statistical tools will help to measure quantitative post harvest seed losses. Seed testing can be used for measuring qualitative post harvest seed losses.

The “falling number” is a measurement used by plant breeders and grain quality specialists to determine the soundness of wheat, which is primarily influenced by the degree of sprouting in a grain sample. Hagberg Falling Number is the full name of this international standard of sprout measurement.  The term “falling numbers” refers to the amount of time it takes for the Hagberg steel ball in this sprout analysis tool to fall through a flour/water slurry that has been heated to release the starch from water. 

PPEs are the personal protection equipments which protect the personnel against some hazards in the shop floor. PPEs form important aspects of Environment (safe disposal of treated chemicals, dusts coming out of processing), Safety (to seed storages) and Health (personnel) (ESH) strategy of any shop floor.

NAME OF THE UNIT: 

    1.    Location of Seed Storage 
    2.    Date of Inspections/visit

Seed processing efficiency (SPE) is one of the important aspects in seed processing. It will help in measuring the potential of the shop floor. It will also help in standardizing activities like screens and improving physical purity. SPE will help to improve the quality of the seed material and help in utilizing the machines at their optimum capacity. SPE may vary among the different crops and even among the varieties.
 
To quantify SPE we need to pass the test sample (bulk-pre processed) through the target machine and enter the details in a processing register. To quantify the SPE we need to follow these mathematical formulae:

According to Harrington’s rule (1960) of thumb, for storage, every one percent increase in moisture content, the seed life is halved far seeds of moisture content of 5-14%. For temperature, every 5^ºC rise in temperature, between 0-50 ^ºC, the seed life is halved.

Mechanical damage in oil seeds like soya bean can be induced at any time during harvesting, handling, conditioning and sowing operations. There is relationship between moisture and mechanical damage. In general the low moisture containing seeds are more prone for mechanical damage than the high moisture containing seeds. In this experiment we look for this relationship by measuring seed quality parameters like germination and leakage (electrical conductivity).

The moisture content is the amount of water in the seed and is usually expressed as a percentage. It can he expressed on either a wet weight basis (where it is expressed as a percentage of the fresh weight of the seed) or on a dry weight basis (where it is expressed as a percentage of the dry weight of the seed). The seed moisture content is the most vital parameter, which influence the seed quality and storage life of the seed. Seed moisture content is closely associated with several aspects of physiological seed quality. For example, it is related to seed maturity, optimum harvest time, mechanical damage, economics of artificial seed drying, seed longevity and insect & pathogen infestation.

Fumigation is a method of pest control that completely fills an area with gaseous pesticides to suffocate or poison the pests within. It is utilized for control of pests in buildings, soil, seed, and grain produce. It is also used during processing of goods to be imported or exported in order to prevent transfer of exotic organisms. Fumigants are chemical compounds in gaseous form that enter the body of insect through the spiracles spread all over via trachea and tracheoles. The important fumigants are Methyl bromide, Ethylene dibromide, Aluminium phosphide, Ethyl formate, Hydrogen cyanide, Chloropicrin etc.

These materials include barrier coated paper bags, barrier laminated film bags, jute bags, PP woven box bag and cotton bags.
 
A: Paper Bags
    1.    Coated paper:  bags provide a barrier for leaking or staining of the product. This can be done by a greaseproof or claycoated kraftpaper.
    2.    Open-Mouth sacks:  can be manufactured using different types of paper. Simple kraftliner, glossy claycoated and lacquered outerliner are possible. These sacks can be supplied with liners and printed up to 8 colours.

The objective of seed pelleting is to provide an opportunity to package effective quantities of materials such that they can influence the micro-environment of each seed.
 
Process of Pelleting

Seeds are introduced into a coating drum or pan that resembles a cement mixer. An amalgam of pelleting materials (clays, limestone, calcium carbonate, talc, vermiculite) and cementing adhesives (gum Arabic, gelatine, methyl cellulose polyvinyl alchol) are used to form the pellet and other compounds such as inoculants, fungicides, etc. May be added to enhance seed performance.

Objective

    1.    Design drum priming (2-3 kg and drying unit with house hold or commonly available materials.
    2.    Standardization of time for seed priming for different crops.

Probable drum priming unit components

A] A vertical drum which need to be rotating
B] A motor which will rotate
C] A desktop assembly
D] A simple two way seed drier (Fig not given here)

Seed Priming is the process of controlled hydration of seeds to a level that permits pre-germinative metabolic actively to proceed, but prevents actual emergence of the radical. It is done to increase the speed and uniformity of germination particularly under adverse conditions of temperature, moisture and salinity conditions. In this condition, seeds go through all the essential preparatory processes of germination but prevent cell elongation and radical emergence. During the waiting period at the osmotic barrier the ‘slower’ seeds tend to catch up with the ‘faster ones’ so that the subsequent germination is more uniform, than that of untreated seeds. The duration of priming varies with the crop as well as method of priming such that priming is allowed for I and II stage of seed imbibitions without allowing radical protrusion.

Seed is the primary and essential starting point of a wide range of crops, including the majority of vegetables except those vegetative propagated (e.g- potato and sweet potato). Seedling emergence and field stand establishment is one of the problems facing the growers, especially in early planting where adverse conditions are prevailed (low temperature and high soil moisture). Seed germination and seedling emergence are affected by many factors such as: seed genotype, seed quality (seed viability and seed vigor) and the environmental conditions (moisture and temperature) prevailing during seed germination and subsequent seedling emergence, assuming that the seed is not dormant.

Objective: To study the seed treatment methods and equipments A key factor in achieving the few potential of good quality seed is the blanket treatment of the seeds with agrochemical in order to control or prevent diseases in the  crops.

Drying is an important unit operation in seed processing in order to maintain seed ability and vigor . it is advocated that seeds should be harvested soon after they attain physiological maturity to obtain better quality seeds and to minimize field losses. The traditional method of sun drying is inadequate, uncontrolled and time bound, which may not meet the high demand of quality seeds in time. Hence artificial drying, the effect of certain drying parameters like seed moisture content, drying air temperature, airflow rate, depth of seed loading and time of exposure on drying characteristics and viability of seeds are to be determined for safe and economical drying of seeds.

The use of seed processing equipments helps in improving the seed quality by inducing uniformity of physical properties of seeds. This help in achieving optimum plant population and desired economic yield. In certain crops like soya bean, standard seed processing may not give desired seed quality because of sensitivity towards moisture. As general practice seed need to be dried to its safe moisture content of 9 before processing. But in case of soya bean lower seed moisture may result higher mechanical damage after standard seed processing. Drier seed are more vulnerable for mechanical damage. In this practical w try to explore the importance of moisture in seed processing and also need of alternative processing equipments like spiral graders to minimize mechanical damage.

This practical in continuation of the practical no.10 explore the effects of screen sizes on different varieties. The screen sizes vary not with crops but with varieties also. To know the effect of screen sizes among the varieties we need to take the top and middle screens as standard or as recommended. These methods can be applied to any crop and to different varieties.

Seed size is an important parameter of seed vigor as it in influences the performance of seed in soil. Seed bulk at harvest contains a wide range of seed sizes but these may not all be of equal value for sowing. Farmers have always realized the necessary of using uniform seeds for good viability to obtain high emergence and growth. This will also help in getting optimum plant population and higher yields.
 
The influence of seed size on seedling vigor and crop productivity has already been proven since the days Hannaford who was considered as father of seed processing. To achieve uniformity in seed size this optimum sieve/screen size is very critical for optimum seed recovery and economical seed yield. Though the screen sizes are standardized for different crops but vary with different varieties. The shop floor should continuously explore and fine tune screen sizes for different varieties.

9.1 Magnetic seed separator

These machines use a magnetic force to separate damaged seeds or other particles from the good seeds. This is used to solve special problems in seed lots that can not be taken out with our other basic seed cleaning equipment. Most of the time it is used for vegetable and field seeds that have problems in seed damage (fish mouth in cucumber or melon seeds / cracked radish or cabbage seeds), insect damage (beetle holes in cotton seeds) or contamination with soil or plant parts (white plant parts in onion seed) etc.

The processing operations are carried out based on the principle of physical differences found in a seed lot.

Mechanical damage is inflicted on seeds during harvesting, threshing drying, processing and handling. Injury may occur from any kind of physical abuse. Threshing abuse probably is most serious but, seed conditioning and handling also contribute to seed injury. High temperatures during drying or drying too quick or excessively can cause injury. Susceptibility to mechanical injury increases as the moisture content of the seed decreases. Effect of all individual impacts received by the seed appears to be cumulative in total seed damage. Cereals are largely immune to mechanical injury presumably because of the protective outer structures, the palea and lemma. Large sized legumes are more suscepitable. Small seeds tend to escape injury during harvest and seeds that are spherical tend to suffer less damage than elongated or irregularly shaped ones.

Methods in Seed Blending

For good seed blending there are three methods and details of which given as below:

The physical properties of seeds are a basic activity for designing processing equipments and precision planters. Since these characters vary with crop or variety, one needs to have the data handy to be used on shop floor. This data also helps to quantify processing efficiency, presence of dormancy and suitability for seed treatments for all existing and new crops or varieties.