eChapters

Pollination

Pollination is the act of transfer of pollen from the male reproductive organ of a plant to the female reproductive organ of same or another plant.

Pollination is of two types

5.1 Self Pollination

It is the transfer of pollen from the anther to the stigma of the same flower from where the anthers have been generated. Thus, self pollination happens to be denominated as autogamy where auto means “same” and gamy means “union”. Obviously, self pollination is found in bisexual flowers. But self pollination also occurs when pollen is transferred from one bisexual flower to the stigma of another bisexual flower of the same plant. This kind of autogamy is known as geitonogamy. So, self pollination has to be defined keeping the parent plant on the main focus not the flower. If genetical consequences are considered, self pollination promotes the occurance of purelines or homozygotes. Self pollinating species developed themselves evolutionary fit due to homozygous balance and do not exhibit significant inbreeding depression.

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.

9.2. Causes of Post-Harvest Losses (A) Primary Causes: (B) Secondary Causes: • Mechanical injury. • State of maturity. • Physio-biochemical losses. • Time of harvesting. • Microbial losses. • Storage facilities. • Physical losses. • Bruishing caused due to transportation and distribution. 9.3. Control of Post-Harvest Losses The extent of post harvest losses in vegetables can be minimized by • Careful harvesting. • Harvesting of vegetables at the right stage of maturity. • Proper sorting, grading and packing. • Careful transportation and distribution. • Adequate and suitable storage facilities. • Pre and post harvest treatment

Post-harvest deterioration primarily means the loss of commodity after harvest. It is one of the serious problems for producers, distributors and consumers. Post-harvest deterioration of perishables is the spoilage of fruits and vegetables after harvesting. Perishables are the feed commodities with moisture content between 50 and 90%. Fruits with the size of 5 g to 5 kg or more, high to very high rate of respiration, high generation of heat, soft texture, easily damageable nature and shorter shelf life are more prone to the microbial damage. The post-harvest losses are caused either by pathological, physiological and mechanical means or combination of all these. These perishables because of having minerals, vitamins, and photochemicals (essentially required for the human health) become victim to the several biotic and abiotic factors easily. Once these fruits are detached from the plant are deprived of essential ingredients as hormones, nutrients, water and other requisites. These biotic and abiotic factors apart from rendering the produce unfit for human consumption reduce the aesthetic value, substantial decrease in food value and also organoleptic quality of the vegetables. The fleshy produce are prone to the exogenous agencies such as fungi, bacteria, etc. as well as other endogenous factors such as respiration, senescence, etc. which may lead to poor quality of the produce and also affect market quality. These perishables continue to respire and may carry out various biochemical activities, leading to ripening subsequently to senescence and making them more susceptible to microbial damage. In addition, tropical conditions prevailing in India, which are characterized by high temperature conditions, are optimal for fungal and bacterial infections. In India, the post-harvest losses of fresh fruits and vegetables are estimated to be about 30%. The post-harvest losses have been recorded are 5-20% at farmer’s field due to pre-harvest infection and sorting, 15-20% due to faulty packaging, 30-40% during transportation and 30-40% during marketing.

Potato, the third most important food crop in the world after rice and wheat is becoming the main source of food and income in developing countries. India stands second in production and area of potato in world after China leaving behind the Russian Federation. In India, potato is an important component in cereal and vegetable-based cropping systems for its ability to produce high dry matter/ha in short duration and high yield compared to cereals. It is grown as mixed crop, intercrop, relay or sequential crop along with other vegetables, cereals and cash crops.

Potato is originated in South America in the high Andean hills and towards the end of 16th century it was first introduced into Europe by Spanish conquerors. In the early 17th century, it was brought to India by British missionaries or Portuguese traders. Thus, potato developed as a temperate crop and was later distributed throughout the world. Cultivated potato consists of two sub species, Solanum tuberosm ssp. andigena and S. tuberosum ssp tuberosum. Subspecies andigena is the primitive form which is adapted to shorter day length and high altitudes of mountains (above 2000). The presently cultivating tuberosum subspecies is adapted to long or short day condition of tropical regions and lower altitudes (500-200m above MSL) and is believed to be evolved from andigena types through selection.

Morphology and Floral Biology

Potato is herbaceous in nature with erect to prostrate stem. Stem is variably coloured from green, purple or mottled green or purple. Leaves are pinnate which ends in single terminal leaflet. Stolon arise from the portion of the plant below the ground. The stolon bears rudimentary leaves and tip is hook shaped. The sub apical portion at the tip of stolon enlarges to produce tubers. Hence, potato tubers are the modification of underground stem with shortened axis and poorly developed eyes. The leaf scar with a subtended lateral bud having underdeveloped internodes is referred to as the eye of the tuber. Potato is a long day plant. Moderate humidity and long day condition favours flowering. Hence flowering and fruit set is observed in hilly tracts. Inflorescence is produced terminally and is usually cymose. Flowers are bisexual, actinomorphic, and hypogynous with 5 calyx, 5 corolla and 5 stamens. The colour of corolla varies from white, pink, lilac, blue and purple. Pollen shedding is through the pores at the tip of the anthers. Mature fruit is a berry. Self-incompatibility is observed in diploid species and tetraploids are self-compatible.

Potato has special seed production problems as the quality characteristics of seed potatoes are influenced by a number of factors and important amongst them are the diseases and pests namely, viruses, fungi, bacteria and nematodes. Once the seed tuber is infected the pathogens, specially viruses, permeate through the plant system. The plant growth, therefore declines and the yield reduces progressively. It is therefore, important that seed stocks should not only be genetically pure but also should be in right physiological condition and disease free at the time of planting. Seed production technology developed for seed potato production, thus aims at producing disease free, genetically pure seed. There are now two independent channels of seed production for hills and plains.

Hill seed : The seed produced in hills (2500 metres above sea level) at suitable locations is called ‘Hill Seed’.

Plain seed : The seed produced in plains at suitable locations is called ‘plain seed’. Northern plains have emerged as an important source of potato seed production. The low aphid, plains seed is in right physiological condition at the planting time and yields higher than the traditional hill grown seed.

Once healthy seed potatoes are introduced into the system of growing them during low Aphid period accompanied by a systematic insecticide application, roguing and removal of haulms before the aphids attain critical number and the re growth is checked, the health standards for the seed crop could be maintained for a number of generations. This system of seed potato production has been designated as ‘Seed Plot Technique’.

I. FILL UPS

1. The potato is made up of _____ and _____.
2. Potato is a _____ pollinated crop
3. Potato fruit is called as_____.
4. An example of stem tuber is a _____.

Precision farming manages spatial and temporal variability within fields through targeted, data-driven interventions. Onion is particularly suited to precision management because its productivity and quality are sensitive to moisture, nutrients, environmental stress, pests and diseases. This chapter describes applications of GIS, GPS, variable-rate technology, IoT, cloud platforms, drones, remote sensing, multispectral imaging, smart sensors, artificial intelligence, automated systems and crop-response models. These technologies support soil assessment, field preparation, irrigation, fertilization, crop monitoring, stress detection, protection, yield estimation, harvesting and storage. Their potential to reduce input waste and improve profitability is considered alongside constraints involving investment costs, technical knowledge, connectivity, accessibility and data privacy.

1. PLANT DOMESTICATION AND INTRODUCTION

Domestication is the process of bringing wild species under human management. Under domestciation, the crop species have changed considerably as compared to the wild species from which they originated.

I. FILL UPS

1. _____ is required during raising of a seed crop to avoid contamination due to natural crossing.
2. _____ is another potent source of genetic contamination i.e., the plants differing in their characteristics from the seed variety.
3. Removal of off types is referred as _____.
4. _____ is the distance maintained between the seed crop and source of contaminant.
5. The isolation distance for cotton foundation seed production is _____.
6. The isolation distance for paddy is _____.

1. GENETIC PRINCIPLES

1.1. Maintenance of genetic purity during seed production

The methods suggested by Home (1953) and Hartmann and Kester (1968) may be used wholly or in part to maintain high levels of genetic purity during seed production.

The various steps suggested by Home (1953) to maintain varietal purity are as follows:

Since the dawn of civilization, the human species had an intimate association with fruits, roots, nuts and other vegetables that sustained them through the ages. This mutualism continued and flourished through domestication and organized culture of horticultural crops. Pretty long before, homestead gardening had been evolved in different parts of the globe independently to become a part of tradition in almost every society. Plant domestication by all likelihoods started around the human settlements. The obvious reasons for this were man’s need, better supply of water and organic household wastes and protection against destruction or grazing by animals, that’s why the prospective horticultural enterprise of homestead gardens all over the world is still the most enduring and sustainable form of family food production system and very important micro-units for conservation of plant genetic resources. The traditional and indigenous endeavour of the tribal people for conservation of land races also noteworthy contribution from one generation to the next. Though cereals are staples for most of the world population, there has been sustained emphasis on horticultural crops, particularly vegetables, all over the world during last few decades. The possible reasons are:

1. PPV & FR ACT

With the signing of TRIPs agreement of the World Trade Organization (WTO), India has agreed to provide protection to plant varieties. The Government of India, therefore, enacted “ The Protection of Plant Varieties and Farmers Rights Act (PPV&FR Act)” in 2001 and the Regulations for implementing the Act were formulated in 2003.

The Ministry of Agriculture, Government of India, has been identified as the nodal agency for implementing the PPV& FR Act through an Authority known as “The Protection of Plant Varieties and Farmer Rights Authority”. The Authority came into force in November, 2005.

PPV & FR act has 11 chapters, 4 schedules and 97 sections.

In order to provide for the establishment of an effective system for protection of plant varieties, the rights of farmers and plant breeders and to encourage the development of new varieties of plants it has been considered necessary to recognize and protect the rights of the farmers in respect of their contribution made at any time in conserving, improving and making available plant genetic resources for the development of the new plant varieties. Moreover to accelerate agricultural development, it is necessary to protect plants breeders’ rights to stimulate investment for research and development for the development of new plant varieties.

Pumpkin (Cucurbita maxima Duch.) is a well known and widely cultivated vegetable variety of the family Cucurbitaceae. The seed production can be done in summer season (February - March) and in rainy season (April - May). In Tamil Nadu, sowing during July – August is best for seed production.

I. FILL UPS

1. _____ vegetable is botanically called as a fruit.
2. Fruit of pumpkin is called _____.
3. The isolation distance for pumpkin foundation seed production is _____.
4. The isolation distance for pumpkin certified seed production is _____.

Purity analysis

Purity of a seed lot indicates in percentage how large a fraction is made up of pure seeds of the species in question, and how much is made up of inert matter and other seeds. Impurities may be any non seed material (leaf, flower, fruit fractions, soil etc.), small fractions of seeds of the actual species, as well as seeds of other species. Pure seed may include both dead and empty seed, plus damaged seed, purity does not tell anything about viability. The purity analysis of a seed sample in the seed testing laboratory refers to the determination of the different components of the purity viz., pure seeds, other crop seeds, weed seeds and inert matter. Each component is reported as a percentage of total weight. The objective of the purity analysis is to determine whether the submitted sample conforms to the prescribed physical quality standards with regard to physical components. Large seeds are generally easy to clean and purity analyses are therefore often omitted. However, for smaller seeds contamination with other seeds may occur e.g., during processing.

I. FILL UPS

1. _____ and _____ seeds give highest grain yield.
2. Assessment of _____ is one of the basic requirement for quality control of seed under the seed act.
3. The minimum number of seeds for germination test of _____.
4. The purity analysis in groundnut is done with working sample size is _____.

1. SEED PURITY AND ITS COMPONENTS

Seed purity analysis from the working sample taken from submitted sample is made in accordance to ISTA rules. The uncertified seed sample is generally a mixture of pure seeds, inert matter and biological impurities including genetically impure seeds of the variety.

A buyer expects to have good seed and not a mixture of pure seed with a high percentage of chaff, straw, sand, weed seeds and other crop seeds and also genetically impure or mixed seeds.

Purity analysis is a test to estimate the extent of biotic and abiotic impurities present in the seed lot of a variety.

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:

Introduction

Germination is the process by which a plant grows from a seed or similar structure. The most common example of germination is the sprouting of a seedling from a seed of an angiosperm or gymnosperm. Quick germination is the various ways and means that really fastened the process of seed germination. Through various ways, it is possible to reduce the time of germination by 70 per cent and also the success rate of germination can also be doubled.

I. FILL UPS

1. The quick viability test was developed by _____.
2. _____ is a biochemical test.
3. The indicator used for quick viability test is _____.
4. For maize seeds, the method followed for staining is _____.

The relative long periods of time required for completion of germination tests delays the seed marketing. This necessiated the development of rapid methods for estimating the germination capacity of seeds. This test was developed by Lakon (1942) in Germany.

1. PRINCIPLE

It is a biochemical test, in which living cells are made visible by reduction of an indicator dye. The indicator used is 2,3,5 triphenyl tetrazolium chloride. Within the seed tissues, it interferes with the reduction processes of living cells and accepts hydrogen from the hydrogenases. By hydrogenation of the 2,3,5-triphenyl tetrazolium chloride, a red stable and non diffusible substance, triphenyl formazan is produced in living cells (Fig. 1).

Introduction

Stored-product insects are serious pests of dried, stored, durable agricultural commodities and of many value-added food products and non-food derivatives of agricultural products worldwide. Various estimates on post harvest losses across the country revealed that there is loss of 2–12 per cent during storage exclusively by insects. Almost all the insect species may destroy 10.0 -15.0 per cent of grain and contaminate the rest with undesirable odour. The major loss is done by two internal feeders i.e. rice weevil and grain borer, which are major pests of rice, wheat and millets (Champ and Dyte, 1977). They also help in transportation of fungi (Sinha and Sinha, 1990). The losses during storage are quantity losses and quality losses. Quantity losses occur when insects, rodents, mites, birds and microorganisms, consume the grain. Infestation causes reduction in seed germination, increase in moisture, free fatty acid levels and decrease in pH and protein contents etc. resulting in total quality loss. Quality losses affect the economic value of the food grains fetching low prices to farmers (Das et al., 2013).

I. FILL UPS

1. Redgram is commonly is known as _____.
2. _____ is the second most important pulse crop after chick pea.
3. Redgram, being a _____ capable of fixing atmospheric nitrogen.
4. Pigeon pea contains_____% protein.
5. Isolation distance of redgram must be_____.
6. The spacing adopted for short duration red gram is _____.

Among abiotic stresses, low and high temperature stress is very critical for determining the agricultural production. Plants exhibit a maximum rate of growth and development at an optimum temperature or over a diurnal range of temperatures (Fitter and Hay, 1981). When ambient temperature deviates from optimal, physiological, biochemical, metabolic and molecular changes occur within plants. This is an effort of plants to maximize growth and developmental processes and to maintain cellular homeostasis during such adverse conditions. Under increasingly stressful conditions, plants experience progressively more abnormal, impaired or dysfunctional cellular and whole-plant processes until the cardinal temperatures for survival are reached (Fitter and Hay, 1981). At the extremes of the natural temperature range of a plant, the degree of physiological, cellular, metabolic and molecular dysfunction becomes so severe that it leads to death.

Growth constraints and stress result in significant crop losses and therefore the mechanisms underlying endurance and adaptation to these changes have long been the focus of intense research (Bray 2004). Kültz (2005) elaborated two types of responses to a particular kind of stress:

Ribbed gourd (Luffa acutangula (L) Roxb.) belonging to the family Cucurbitaceae is a well known vegetable variety in India. The seed production can be done in both summer and rainy season.
Method of seed production

Bitter gourd is a cross-pollinated crop which occurs through bees. Seeds should be allowed to set by open-pollination in isolation. The isolation distance maintained between the fields of other varieties and the fields of the same variety not conforming to the varietal purity requirements for certification is 1000 metres for foundation and 500 metres for certified seed production.

I. FILL UPS

1. The stigma receptivity of ribbedgourd is_____.
2. Ribbedgourd is a _____ pollinated crop.
   1. Isolation distance for foundation seed production of ribbedgourd is _____.

I. FILL UPS

1. The inflorescence of rice is _____.
2. The rice flower is called _____.
3. The stigma receptivity of rice crop is_____ period.
4. The pollen viability of rice is for _____.
5. The grain stem of rice is called_____.
6. Rice is _____ pollinated crop.

Bio-stimulants are increasingly used to improve crop performance while reducing dependence on intensive chemical inputs. They include amino acids, protein hydrolysates, humic substances, seaweed extracts, beneficial microorganisms and plant- or microbial-derived compounds. These substances can influence root architecture, nutrient assimilation, hormonal balance, photosynthesis, stress tolerance and disease resistance. This chapter examines the effects of different bio-stimulants on onion seed germination, vegetative growth, bulb development, yield, quality and storage life. It discusses their modes of action, application methods and integration with nutrient-management programmes. Bio-stimulants are presented as promising components of environmentally responsible and resource-efficient onion production, while areas requiring further research are identified.

Previous year questions

1. Introduction?

2. Role of private? Introduction

• The Indian seed industry used to be dominated by public sector seed companies. However, following the easing of government regulations and the implementation of a new seed policy in 1988, the private sector seed companies have started playing a major role in seed development and marketing.

• More recently, the government’s decision to embrace biotechnology as a means of achieving food security has attracted several leading biotechnology-focused multinational seed companies to India.

• The composition of the seed industry, by volume of turnover, has reportedly reached a ratio of 60:40 between the private and public sectors.

Root crops are cool season vegetables growing for its fleshy root developed from the tap root and hypocotyl region. They are grown during winter in tropical and subtropical condition, throughout the year in hills and spring-summer in high altitude hills. The major root crops growing in our country include carrot (Umbelliferae), radish (Brassicaceae), beet root (Chenopodiaceae) and turnip (Brassicaceae). Two distinct types viz., asiatic or tropical types and European types present in these root crops except beet root. In beet root, European or biennial types only exist. The tropical types are annuals that does not require chilling treatment for flowering. Therefore, seed production of these types is taken up in plains but European types are biennials and they require vernalization treatment after vegetative phase for flowering. Hence, the seed production of biennial types is possible in hills. The seed productions of Asiatic varieties of root crops are done in Punjab, Haryana, U.P. and parts of Rajasthan and Gujarat. Whereas, the seed production of temperate varieties is done in Saproon valley, Kullu valley, Kalpa valley of H.P., Kashmir valley of J&K and selected location of Northeast region specially Sikkim and Arunachal Pradesh. The seed production of beet root is being done in high altitude hills of J&K. All the crops belonging to this group are similar in the cultural practices though they come under different family. All root crops prefer well drained loose and friable soil. Ridge or bed planting is mainly following in all root crops. They are direct sown crops and does not respond to transplanting. They are highly cross pollinated.

The two methods of seed production following in root crops are seed-to-seed method and root-to-seed method. The first method is followed for the production of truthfully labelled seed or certified seed as the seed yield will be more, but quality remains inferior to the second method. The breeder seed as well as foundation seeds require utmost quality hence root-to-seed is preferred for its production. In this method, the matured roots are harvested and the roots are inspected for its trueness. Only true-to-type roots are selected for replanting in the field for seed production and undesirable ones are discarded. The selection and rouging in seed crop are done on the basis of foliage characters and external and internal root characters (colour, shape, size, flesh colour, core size, pungency, indistinct rings etc.). The roots after selection are prepared for replanting by cutting one-third top (shoot) portion and one-fourth to one-half root cut. the prepared stecklings are replanted to obtain good yield of quality seeds. In case of turnip and beet, after selection, the tap root and tops of the roots are trimmed without injuring the crown portion and is replanted.

I. FILL UPS

1. _____ is a multipurpose crop that has been grown for orange red dye.
2. Safflower oil contains _____ % linoleic acid.
3. Orange red dye extracted from safflower flowers is called _____.

10.2. Breeding Objectives 10.2.1. Tomato • To develop early , high yielding and consumer preference varieties / hybrids. • Large round fruit with adequate firmness and shelf-life, uniform fruit sizes shape, red colour and freedom from external blemishes or abnormalities for fresh market. • Large fruit size, high fruit quality and continuous production for home garden tomatoes. • Deep, uniformly red coloured tomatoes , pH below 4.4, high total soluble solid (4.5-7) and high alcohol solids (AIS) in processing tomatoes. • To evolve varieties / hybrid resistant to diseases like fusarium wilt, verticillum wilt, late blight, early blight, septoria leaf spot, anthracnose, bacterial wilt, bacterial canker and tomato leaf curl virus. • To develop varieties/ hybrids resistant to root-knot nematodes. • To breed varieties/ hybrids suitable for abiotic stresses like low Day (K10o C) and high temperatures (day 35+2o C) excess and moisture deficient, salt etc. • To develop varieties/ hybrids for prolonged storage and transportation

I. FILL UPS

1. The seed act was passed in the year_____.
2. _____ advise the central and state government regarding suitability of seed testing laboratories.
3. _____deals with all the problems related seed certification and to coordinate the work of state seed certification agencies.
4. _____ agencies take sample to inspect seed lot and certify seeds of any notified kind of varieties.
5. _____ initiate testing program and collaborate with state seed laboratory and designed to promote uniformity in test results between all seed laboratories in India.
6. _____ look into the grievances of certified seed producers against a seed certification officials.

Any new variety produced by the Scientist has to be multiplied to many times to meet the needs of the farmers. In order to ensure the availability of quality seeds, Government of India have enacted Seed Act 1966 and Seed Rules, 1968. The Seed (Control) order 1983 was promulgated under essential commodities act, 1955 in order to ensure the production, marketing and distribution of the seeds.

1. SEED ACT 1966

The objective of Seed Act is for regulating the quality of certain notified kind / varieties of seeds for sale and for matters connected therewith. The Seed Act passed by the Indian Parliament in 1966 was designed to create a ‘climate’ in which the seeds man could operate effectively and to make good quality seed available to cultivators. Seed Rules under the Act were notified in September 1968 and the act was implemented in October 1969. This act extent to the whole of India and it has 25 sections.

I. FILL UPS

1. A seed is defined as a _____ or a reproductive unit formed from fertilized ovule, consisting of an embryo, reserve food and a protective cover.
2. A seed is defined as a mature ovule or a reproductive unit formed from _____ consisting of an embryo, reserve food and a protective cover.
3. A seed is defined as a mature ovule, or a reproductive unit formed from fertilized ovule, consisting of an _____, reserve food and a protective cover.
4. A seed is defined as a mature ovule or a reproductive unit formed from fertilized ovule, consisting of an embryo, _____ and a protective cover.
5. Seed acts as a carrier of _____.
6. Seed must ensure high _____ (true to type).
7. Seed must be viable and have good _____ capacity

1. SEED

A seed is defined as a ‘mature ovule’ or a reproductive unit formed from fertilized ovule, consisting of an embryo, reserve food and a protective cover.

Seed is the basic input in agriculture upon which other inputs are applied. A good vigorous seed utilities all the resources and realized as a reasonable output to the grower. It is wealth to the farmer, it is the yesterday’s harvest and tomorrow’s hope. Good seed in good soil realize good yield.

Seeds exhibit a great range of variation in shape, size, colour and behaviour. The most essential factor for the success of plantation is the ready availability of quality seeds. The quality of seed is totally responsible for the future return / performance of each and every seedling.

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.

Archaeobotany

Botany as far as it is relevant in archaeology mainly denotes all types of ancient organic material (in particular ancient plant remains) collected from excavation sites. The deliberate study of the interrelationship between humans and plants and the environmental context in which this occurred has been called archaeobotany.

Introduction

Since beginning of this century genetic diversity of agricultural crop has been lost due to several reasons (Marla, 2012). Genetic erosion is caused by human intervention, mono culture, green revolution especially due to commercialization of plant breeding. So there is urgent need to collect, conserve plant genetic & genomic resource for further use.

A seed bank stores seeds to preserve genetic diversity. There are many reasons to store seeds. One reason is to have on-hand the genes that plant breeders need to increase yield, disease resistance, drought tolerance, nutritional quality, etc. of plants used in agriculture (i.e., crops or domesticated species). Another reason is to forestall loss of genetic diversity in rare or imperiled plant species in an effort to conserve biodiversity ex situ and in situ. Many plants that were used centuries ago by humans are used less frequently now and seed banks offer a way to preserve that historical and cultural value. Collections of seeds stored at constant low temperature and moisture guard against loss of genetic resources that are otherwise maintained in situ or in field collections. These alternative ‘living’ collections can be damaged by natural disasters, outbreaks of disease or war. Seed banks are considered seed libraries and contain valuable information about evolved strategies to combat plant stress or produce novel products. The work of seed banks spans decades and even centuries. Most seed banks are publicly funded and seeds are usually available for research that benefits the public.

Seed bearing plants

Seed-bearing plants are broadly categorized in two major types: the gymnosperms and the angiosperms which are together grouped in Division Spermatophyta in the older system of classification for the plant kingdom. Consequently, seed plants are presently classified into multiple phyla. Still, for the purpose of learning basic concepts, it is convenient to group plants informally as spermatophytes (sperm "seed" + phyte "plant"). The spermatophytes are the most complex and evolutionarily advanced plants. Unlike ferns and bryophytes which reproduce and disperse by unicellular spores, spermatophytes reproduce and disperse by means of multi-cellular seeds which consist a protective seed coat surrounding an embryonic sporophyte and its food supply. This group of seed plants exhibits an alternation of generations in which the sporophyte is dominant. Furthermore, the gametophyte is microscopic and heterosporous with the latter term meaning that these seed plants produce two types of spores: microspores and megaspores that give rise to separate male gametophytes (micro-gametophytes) and female gametophytes (mega-gametophytes) respectively. The megaspore is never released from the sporangium; thus, the female gametophyte develops within the sporangium while being still attached to the sporophyte.

Methods in Seed Blending

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

I. FILL UPS

1. _____ are also called ed-worms.
2. _____ nematode causes discolouration in groundnut.
3. _____ in rice is caused by Aphelenchoides besseyi.
4. The ear cockle disease is caused _____.

1. NEMATODES

Nematodes, also called eel-worms, are wormlike in appearance, but quite distinct taxonomically from true worms. They live freely in fresh or salt water or in soil. They are saprozoic and also parasitize animals (including man) and plants. Many species of nemotdes parasitize higher plants and cause disease symptoms. Plant parasitic nematodes are small (invisible to the naked eye), long, tubular, round in the cross section, unsegmented and smooth invertebrates. They inhibit different parts of plants, namely, roots, stem, flower buds and seeds. Depending on the host-parasite relationship, plant parasitic nematodes may be sedentary or migratory and ectoparasitic and/or endoparasitic in their feeding habits.

1.1. Nematodes

Seed-borne nematodes may be internal or may occur as seed infestation. Several saprozoic soil nematodes occur in beds of soil mixed with seed. Seed infestation by nematodes does not produce any specific symptoms on seed, but in those that occur as endoparasites, the floral structure may be modified into a seed gall (Anguina spp.) may produce symptoms such as discoloration of testa in groundnut (Ditylenchus destructor) or may be symptomless as in paddy kernels infected by Aphelenchoides besseyi. Neergaard (1979) listed five genera - Anguina, Aphelenchoides, Ditylenchus, Heterodora and Rhadinaphelenchus - that are seed-transmitted. Heterodora and Rhadinaphelenchus occur as endoparasites in roots, stems, and leaves. The latter also affects the growing apex, inflorescence and husks of dropped nuts.

1. MINIMUM SEED CERTIFICATION STANDARDS

In a seed quality control programme through seed certification, the minimum seed certification standards, in fact, are the minimum standard conditions which must be met. The minimum seed certification standards, thus are the standards required for the certification of seeds by the certification agencies.

The minimum seed certification standards can be broadly grouped into two groups.

Previous Year Questions

1. Different Classes of Seeds?

2. Various parameters of field & seed standards for breeder seed production?

3. Factors that affect the longevity of seeds during storage in warehouses?

4. Initial Seed Quality?

5. Seed Testing?

Different Classes of Seeds

1. Nucleus Seed: It is handful of seed maintained by concerned breeder for further multiplication. The nucleus seed will have all the characters that the breeder has placed in it and it is of highest genetic purity. The quantity of nucleus seed is in kilograms.

2. Breeder Seed (BS): Breeder seed is a seed or vegetative propagating material directly controlled by the originating or sponsoring plant breeder of the breeding programme or institution and or seed whose production is personally supervised by a qualified plant breeder and which provides the source for the initial and recurring increase of foundation seed. Breeder seed is exempted from certification. However, the breeder seed crop is being inspected at appropriate stages by a Monitoring Team consisting of breeder, representative of NSC and representative of Seed Certification Agency. The breeder seed lots are affixed with Golden Yellow tags. The genetic purity of breeder seed crop should be maintained at 100 per cent.

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.

I. FILL UPS

1. _____ is a legally sanctioned system for quality control on seed multiplication and production.
2. Certification consists of _____ phases.
3. In single application, the maximum area that can be offered for certification is _____.
4. AOSCA stands for_____.