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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.

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.

Abstract

Although  people have harvested seeds and fruit from trees for centuries, only after World War II, the science and theories of forest genetics begin to be seriously applied to and practiced in operational forestry around the world. The genetic improvements, or gains, need to be captured, packaged, and mass produced so that these gains could be deployed in operational forestry systems. This can be accomplished through seed orchards which is a link between tree breeding and silvicultural activities. Seed orchards are by far the most frequently used sexually reproducing forestry production populations in the world. Apart from the genetic improvement, seed orchards are also used for the production of seed that is well adapted to specific environments. Seed orchards can be categorized according to the generation of breeding or the type of plant material used.

During processing seeds are cleaned, dried, and graded which are then treated with specific fungicide and insecticide. Seed at this stage is at best quality, which are then packaged into various packaging materials in a specific weight. Packaging or bagging of processed and treated seed is a requisite for easy handling of the bulk seed. Seed packaging can be defined as filling with seed, weighing and sealing the container whereas seed package as storage container where the seeds are kept for marketing or shipping or till the next sowing time.

The Packaging of Seed Involves

1. Filling bags/ containers of uniform size with seeds of known weight.

2. Providing leaflets inside the package with information about any specific cultural practices needed.

3. Attaching labels or certification tags having information regarding all the quality parameters.

4. Temper-proof sealing of the bag.

5. Storage or transportation of the bags.

Seed Packing

Seed packaging is the process of filling, weighing and sewing of bags with seed. The choice of packaging materials and amount of seeds to be packed depends on kind of seeds to be packed, duration of storage, storage environment, the seed moisture content, the cost of seed, the cost of packaging material, the geographical area where the seeds will be stored.

1. SEED PATHOLOGY

The area of science that studies the relationship between pathogens and seeds is seed pathology.

2. TYPES OF PATHOGEN

Diseases of plants are caused primarily by three types of pathogens: bacteria, fungi, and viruses. Despite that fungi comprise the largest group of pathogens, the bulk of seed-specific diseases are caused by bacteria or viruses. This is due to the fact that bacteria and viruses are more adopt at entering and then travelling through the veins of the plant, a phenomenon known as ‘systemic infection,’ and from the vascular system may make their way into the developing embryos of seeds.

Fungi, in contrast, tend to be restricted to the outer layers of the plant, where they initiate infection by means of air-borne spores and then proceed to spread by attacking nearby cells of the outer layers. Fungi are much less likely to enter the vascular system of the plant, and thus infect seed mostly when they either ‘crawl’ all the way to seed on the outside of the plant, or else send out spores that land on the seed. In either case, the fungal spores are on the outside of the seed, in the layers of the seed coat, spores on the seed coat are more prone to either dry up and die, or else to get sloughed off with the seed coat during seed germination, thereby failing to cause disease on the next generation of plants.

I. FILL UPS

1. The area of science that studies the relationship between pathogens and seeds is _____.
2. The diseases that are caused by fungal pathogens in residues and on the soil surface are defined as _____.
3. The establishment of a pathogens in any part of the seed is referred as _____.

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.

Much of the success on modern agriculture dependson the availability of high quality seeds with good genetic potential and proven performance in germination, emergence, and vigorous Vegetative growth.

Seed: Seed is a fertilized mature ovule containing an embryonic axis (embryo), stored food material (endosperm) and a protective covering (seed coat or testa).

Seed structures: Living embryo, the most important part of seed, consists of two structures (i) embryonic axis and ( ii ) cotyledon(s). Theembryonic axis is composed of three parts namely

(i)radical (embryonic root), the hypocotyls (point of attachment of cotyledons) and (iii) plumule (theshootapex with the first true leaves). Thethree parts of embryonic axis are easy to identify in dicots, but in monocots (especially in the family Gramineae) their identification is difficult. In monocots, there is only one cotyledon, which is reduced and modifiedto form the scutellum. The basalsheath of cotyledon is elongated to take the shape of coleoptile,while in somecases (e.g., maize), the hypocotyls is modified to form mesocotyl. The base of hypocotyls sheathing the radical is termed as coleorhiza.

Seed development: Thereare manyvariations in the pattern of seeddevelopment when the entire plant kingdom is considered. However, the general processof This includes seed development is almost similar.

I. FILL UPS

1. _____ is basically a critical assessment of effective seed requirement.
2. _____ is the ratio of seed yield per seed generation.
3. The quantity of quality seed that have replaced the actual seed requirement of the location is _____.
4. SRR for hybrid seeds is _____
5. Seed multiplication ratio for groundnut _____

1. INTRODUCTION

Indian population is estimated to increase to about 1400 million by 2025. Consequently, India’s requirements for food grains and other food products to feed the increasing population will continue to rise. The food grain requirements are estimated at 350 to 370 million tonnes by 2025. The demand pattern for agricultural commodities for the domestic market will also shift as a result of increasing incomes and faster urbanization. Compared to 26% increase in 1991, the urban population is projected to increase by 42% in 2020. For competing in the global market, the product pattern will shift to high value commodities like fruits, vegetables, floriculture, dairy products, meat and marine products. In such a future scenario, it is necessary to increase agricultural production through improved cropping system, judicious use of agro-inputs and wide use of modern agricultural technology. It is also important to augment and streamline the existing marketing system including handling, transportation, storage, processing and distribution.

4.1. Seed policy

4.1.1. Seed policies formulated for governing seed quality control system

Significant transformation took place in the traditional variety improvement and seed production programmes in the sixties and modernized with initiation of hybrid development programme in maize, sorghum and pearl millet, as well as with the introduction, breeding and release of semi dwarf high yielding varieties of wheat and rice. To support the release of varieties and their quality seed production Indian Parliament enacted Indian Seeds Act in 1966. Subsequently, National Seeds Corporation was launched by Government of India for scientific growth of seed industry in the country. All these developments led to the green revolution and country attained self-sufficiency in food crops.

I. FILL UPS

1. The Seeds Act was passed in the year _____
2. Seed Control Order was passed in the year _____
3. The New Policy on Seed Development was passed in the year _____
4. Seed Act came into force in _____
5. In _____ year, Seed Rules were formed.
6. In _____ year, Seed Certification Agencies and Central Seed Certification Board were formed.

1. INTRODUCTION

Seed is the most important determinant of agricultural production potential, on which the efficacy of other agriculture inputs is dependent. Seeds of appropriate characteristics are required to meet the demand of diverse agro-climatic conditions and intensive cropping systems. Sustained increase in agriculture production and productivity is dependent, to a large extent, on development of new and improved varieties of crops and an efficient system for timely supply of quality seeds to farmers..

Abstract

Seed priming is the innovative way of ensuring optimum germination and plant stand under moisture deficit situations. It enables the seed to tide over initial stress from biotic and abiotic factors. Higher yield with better quality seed are reported. The seeds of agronomic and horticultural crops are significantly affected by ageing and deterioration. Reversal or rejuvenation of aged seeds is therefore of primary interest. Experiments related to reversal of seed deterioration effects due to ageing relying heavily on accelerated ageing (AA) of seeds and their priming using various priming agents especially osmotic substances. Repair during germination is a hypothetical event supported by some investigators and questioned by others. Repair includes the spontaneous reorganization of plasma membrane phospholipids, which occurs during seed hydration. Alternatively or additionally, metabolic repair might occur. Experimental evidence for repair in imbibed seeds has been elusive. Priming reduced electrolyte leakage as well as lipid peroxidation in seeds implying the activation of membrane repair processes. Priming was also associated with increased levels of antioxidants like ascorbic acid and tocopherols particularly the latter and the activities of enzymes SOD, CAT POX involved in the mitigation of oxidative damage. In comparison with the priming of unaged seeds, the aged seeds experienced a diminution of response in terms of changes in the levels of antioxidants and scavenging enzymes. Thus, seed priming technique under climate extremities seems the best and economical means to sustain higher crop yields. The technique needs to be popularized among the farmers practicing agriculture and horticulture under rainfed situation so as to sustain production under climatic adversaries and enhance livelihood security and more profitability at the farm.

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 Processing

Seed processing may be understood to comprise all the operations after harvest that aim at maximizing seed viability, vigour and health. It includes cleaning, drying, seed treatment, packaging and storage.

Seed processing is specialized activity and also a tool to improve seed quality further to an acceptable standard. Seed quality parameters like germination, vigour or genetic purity can be improved using processing. Say a seed lot having a minimum standard of 90% germination, but the competition in the market offering seed quality 92 or 95 % then to meet the market demand we can process the seed lots using re-milling or re-conditioning techniques. Also sometimes simple techniques like liquid density separation which uses specific density of the seed to separate good seed from inferior quality can be considered. Various case studies on processing to improve seed quality are given here.

1. SEED PROCESSING

1.1. Purpose

Seed processing is necessary in order to dry the seeds to safe moisture level, remove or reduce to the extent possible the various undesirable materials, weed seeds, other crop seeds, deteriorated or damaged seeds, uniform size grading and seed treatment to upgrade the overall seed quality.

1.2. Physical characteristics that aid in grading and upgrading

The threshed produce are pre-cleaned either manually or mechanically and are graded using different, but optimum sieves of specified sizes. This grading bring homogeneity in the lot which aids in obtaining uniformity among the population in the subsequent sowing.

Different kinds of seeds can be separated when they differ in one or more physical characteristics. Physical characteristics normally used to separate seeds are size shape, length, weight, colour, surface texture, affinity to liquids, electrical conductivity, etc.