eChapters

Flowers are the reproductive structures of Angiosperms. The apical shoot meristem of the vegetative plant continues to produce new leaves and vegetative buds, which may develop into branches, but after sometime, the meristem, instead of producing leaves and branches, becomes transformed into specialized reproductive structures called flowers. The transformation of vegetative shoot apex into re-productive structure is called flowering. The process of flowering is controlled by two main important environmental factors, i.e., (i) the duration of light received by the plant called photoperiod and (ii) the low temperature treatment given to the seed or the plant referred to as vernalization (Figure 6.1).

The term ecology was first of all proposed by zoologist H. Pietir in 1865. It was derived from the Greek word ecologic means oikos = living place and logos = study and some definitions of ecology presented below:

1. According to Ernst Haeckel, 1869 “The total relations of the animal to both its organic and inorganic environment is called as ecology”.
2. E. Warming 1895 “Ecology is the study of animals and plants in relation to their environment”.
3. According to Odum 1963 “Study of structures and functions of nature is defined as ecology”.
4. Krebs 1985 says that the “Ecology is the scientific study of interaction that determine the distribution and abundance of organisms”.

The life of insects is dependent on the adaptability of the environment, if the environment is unfavourable then the insect population ceases and vice-versa. This insect move one place to another to get the favourable environment so that they can pull on their life activities properly. There is a deep relationship between the living community and non-living environment. Both are affecting each other greatly. This inter-relationship between living community and non-living environment is called as ecosystem. The term ecosystem was first used by A.G. Tansley as early as 1935 and he defined, “Ecosystem is the system of resulting from the interaction of all the living and non-living factors of the environment”.

Fruits provide a suitable environment for seed maturation and often a mechanism for the dispersal of mature seeds. By anatomical definition, fruit is a mature ovary, and therefore, includes carpel tissues in part or in whole. However, many fleshy fruit species develop mature fruit tissues by including extra-carpellary floral components. The examples include strawberry, pineapple, mulberry and pome fruit (apple, pear, etc.) in which the receptacle, bracts, calyx and floral tube (the fused base of floral organs), respectively constitute majority of mature fruit tissues. Even species with fruit derived from carpel tissue exclusively can display a range of developmental programs, spanning the relatively uniform single expanded carpel or drupe of stone fruit to the differentiated carpel tissues, giving rise to the peel (flavedo) and multi-carpel flesh as observed in citrus and banana. Although genetic selection of agriculturally valuable fruits is being done since centuries but most of the information about how fruits develop, how this development is coordinated with embryonic development and seed formation and the molecular, cellular and physiological events that control fruit growth and differentiation are still lacking. In the following sections, the various aspects controlling fruit setting and development have been discussed.

Many insect can be observed at any hour of the day. This is proper understanding of the taxonomy and biology. The insect collection, storage and preservation are useful technique of their culture. The best period for collection is from early spring to late rainfall and the best time of the collection of most of the species is during the daytime. The insect are polyphagous and therefore, plants provide one of the best collecting places. Insect can be picked, swept off the plant with the help of a net. Different species feed on different kinds of plant, one should therefore, examine all sorts of plant, flowers weed shrubs and trees. Few insect are only found in the stem, bark, wood, fruit or roots etc. Some species can be found in the leaf mud and litter on the surface of the soil, particularly in woods or areas where the vegetation is dense, others can be found under stones bark etc. other house hold insects may be observed feeding on clothing, furniture, grain, food and other parts of Plant and House and some are aquatic insects.

In addition to pathogenic diseases, numerous abiotic disorders may also arise during growth, development and post-harvest storage of solanaceous vegetables. The physiological disorders of vegetables that have been included in this chapter are directly or indirectly associated with genetic, cultural, nutritional, physiological and environmental factors, and in most of the cases, the definite cause of disorder is not well understood due to the association of numerous factors together. These disorders may be related to colour, shape and form/condition of the produce. The genesis of physiological maladies was earlier poorly understand due to complexity in their characteristic symptoms but at present is relatively more transparent. The characteristic symptoms of abiotic disorders discussed below have not been attributed solely to a single agent or to a single cultural or environmental factor. The environmental factors correlated with the incidence of these disorders include high light intensities and low or high temperature of that growing area. For many abiotic disorders, very limited research work has been done, and the causes are poorly understood both in terms of why cultivars differ in susceptibility and why certain environmental factors predispose the plants or parts of the plant to the disorder. The growers feel concerned with the incidence of abiotic disorders as these cause huge economic loss. Therefore, the control of these abiotic disorders is essential for profitable production of solanaceous vegetable crops. In this chapter, emphasis has been given on practical aspects of diagnosis and potential control measures.

The original divisions of the class insecta are a matter of dispute and it is not easy to decide which division to use many, different original order and groups are recognised by different experts and which one is best will no doubt remain problem. The words taxonomy, systematics and classification have been used alternatively for the same subject by various scientists. However Simpson 1964 has attempted to segregate these. According to him classification is the order of animals into groups on the basis of their relationship that is association of contiguity similarity or both. Systematic is the scientific study of the kinds and diversity of organism and of any and all relationships among them, while taxonomy is the theoretical study of classification including its bases, principal procedures and rule. All animal species are segregated into small and large groups on the basis of their comparative similarities and dissimilarities. The largest group is called phyllum as followed by class, order, family, genus-species and sub-species respectively. The Phylum, class, order, genus, species etc. The division of class insecta into primitive wingless insects, the apterygota and the secondary winged-insects the pterygota and included some orders. The class insecta may be divided into two subclasses.

Fresh fruits are an important component of our diet since they provide essential nutrients like minerals and vitamins and are often attractive to the consumer because of their taste, texture, colour, aroma and flavour. Fruits of different species are botanically different, and they may be derived from various parts of the flower, including the pericarp, mesocarp and receptacle. Growth of fruit tissues is initiated shortly after fertilization and accompanied by the accumulation of food reserves donated by the parent plant. Fruit ripening corresponds to a number of physiological, structural and biochemical changes, which make the fruit attractive to the consumers. These changes include physical changes, viz. the changes in colour, texture, taste, aroma and flavour, and the metabolic changes such as changes in the level of enzymes and gene expression. The varieties of mechanism, which exist in different fruits to bring about a series of these changes to make them attractive for consumption, have been summarized in Table 9.1.

Because of the variety of ways in which these quality attributes are generated, there are significant differences existing in enzymes involved in ripening of different types of fruit. Once initiated, these physiological and biochemical modifications continue until the fruit is in peak condition for consumption. If the fruits are not harvested at appropriate stage of maturity, these changes continue and make them more susceptible to mechanical damage, infection and senescence. Since harvesting fruits at right stage of their maturity is critical, it is important to understand the biochemistry of fruit ripening process fully. This chapter will highlight the biochemical and metabolic changes involved during fruit ripening to make the fruit acceptable for potential consumers. Some of the possible genetic manipulations, which can be done to delay the onset of these ripening related changes, are given in later part of the chapter.

Efficiency of pest control by insecticides is dependent on the correct type of pesticide formulation applied at the proper time and correct dosage, besides the good equipment. Equipment used to apply insecticides must be suited to the crop (or other situation in which the pest is to be controlled), to the scale of operation, and to the formulation of chemical to be applied. In the long run, it is good economy to buy the best equipment available.

Application equipment of high quality means not only good, durable construction but also good design that gives it a professional appearance. Because it is desirable and often necessary to utilize pesticides in a variety of ways, various types of dispensing equipment have been developed. This equipment is placed in the following categories: (1) Sprayers, (2) Dusters, and (3) Granule Applicators. In addition, specialised equipment of various sorts (such as mist machines and fog generators) are available for particular purposes. Since detailed consideration of pesticide application equipment is out of the scope of this book, only a brief consideration is given here to some important features of the main types of equipment.

Most of the plants undergo a period of rest, and in this period, the growth activities temporarily halt. The whole plant looses its aerial parts and undergoes a rest period in the form of rhizome, corm, or tuber. Researchers who study fruit trees use the term rest for dormancy (Samish, 1954). This period is sometimes called as quiescence. The term rest and quiescence can be included under common category dormancy. Some workers differentiate the term dormancy and rest period (Burton, 1964). Wareing and Co-workers (Robinson and Wareing, 1964; Wareing et al., 1964) isolated dormancy inducing substance in sycamore seedlings (Acer pseudoplatanus) which was named as dormin. Further, analysis of this substance by Cornforth et al. (1965) reveals that dormin was identical to Abscisin-II (a substance speeding the abscission of the young flowers of Lupinus luteus and have antiauxin effect).

Dormancy can be defined as an arrest in development of buds, seeds, embryos, or spores under conditions otherwise suited for growth (Taylorson and Hendricks, 1977). It is a survival strategy (exhibited by many plant species), which enables them to survive in climates where part of the year such as winter or dry seasons is unsuitable for growth. The dormancy may be due to the factors within the dormant organ or seed itself and it is called spontaneous dormancy. This type of dormancy is found in seeds, buds and perenating organs like tubers, bulbs, bulbils, corms and rhizomes. In some weeds, dormancy is caused by high or low temperature and this type of dormancy is called as imposed dormancy. Seeds normally germinate in darkness but are inhibited by light are considered to become dormant after exposure to light (Bewley and Black, 1982; 1985). Seeds that require light for germination are said to be photo dormant.

Plant hormone is an organic compound synthesized in one part of the plant body and translocated to another part where in very low concentration it causes a physiological response. However, this definition could not demarcate the vitamins and other growth influencing substances from hormones. For this reason, the term Phytohormone was introduced with included vitamins, growth hormones and flowering hormones. Phytohormone can be defined as an organic substance produced naturally in higher plants, controlling growth or other physiological functions at a site remote from its place of synthesis and active in minute amounts, whereas, an organic substance, which promotes growth, i.e., irreversible increase in height or volume, when applied in low concentration to the shoots of plant is known as growth hormone.

The plant hormones are naturally occurring as they are synthesized by the plant. On the other hand, there are several manufactured chemicals, which often resemble the hormones in physiological action and molecular structures, are called growth regulators. Generally, there are five classes of phytohormones.

The phytohormones universally present in all plants are classified as under:

The insect larva after the complete development emerges out from the egg by rupturing the egg shell chorion. It passes through several stages called as instars. Each instar is separated by a moult; the growth from larva to adult involves some degree of morphological changes or metamorphosis. The egg hatches into 1st instar larva which later moults to the second instar larva and so on until at a final moult the adult imago stage. The insect moult takes place after attaining adult except in the insect apterygote insect. In family pantatomide full insect moulting occurs. Many insects especially those with a small number of instars (mosquitoes) and (chrysocoris stolli) insect moulting occurs as Ist, 2nd, 3rd, 4th and 5th imago instar and then after sometime adults insect emerges.

Metamorphosis of Insect: The development process by which first instar immature stage is transformed into the adult is called metamorphosis, which means literally change in the form. The developing stage is morphologically different from the adult. The degree of difference varies from slight to extreme with many intermediates stage. E.g., Cockroaches, Butterfly, Chrysocoris stolli Wolf. The insect may be grouped on dependance of degree of metamorphosis as:

Water is the most abundant compound on the earth but its sufficient availability is always a big constraint in crop production, particularly in arid and semi-arid areas since agriculture is the last priority for good quality water due to severe competition with public health and industrial demand, hence, the judicious and efficient use of water for irrigation in agriculture needs through knowledge of soil-plant-water relationship. The integrated approach for water management in rain fed areas or irrigated agriculture in soil-plant-atmosphere system helps in the selection of suitable crops and varieties and also helps in improving the crop yield and water use efficiency in relation to water supplying capacity of soil profile depending on its texture and rhizosphere depth. Similarly, atmospheric demand of evapotranspiration by various weather parameters via temperature, relative humidity, radiation, rainfall and wind speed is highly variable during the crop season depending on geographical location and is highly area specific. In irrigated area, the saving of irrigation water through improved management practices will further help in extending the irrigated areas with same amount of water, which will further boost agricultural production and sustainability.

Most of the earth’s total water is contained in oceans (96%), a small portion (2%) as snow and ice and the rest (2%) in the water bodies of the continents. Oceans, lakes, rivers and other water bodies of the earth are called hydrosphere. Continuous circulation of water between hydrosphere, atmosphere and lithosphere is known as hydrological cycle (Figure 12.1). Schematic diagram illustrating the earth’s water cycle– the hydrological cycle.

Measurement of soil moisture content is one of the most routinely done soil characterization. Knowledge of soil moisture is essential to understand the behaviour of soil as a medium for plant growth. Moreover, this property of soil helps to explain other processes of the soil. There are several methods of measuring soil moisture content. The most commonly used methods are gravimetric and tensiometric. The standard gravimetric method is quite accurate and simple but is time consuming, cumbersome and destructive. Furthermore, due to relatively small soil samples that are taken, the variability between replicates is great.

Gravimetric Method

Equipment needed includes zip-loc bags or aluminium moisture boxes and soil sampling tools. Soil sampling tools can be a soil probe, auger, or even a post-hole digger. Balance and scale should have accuracy to 0.1 gram. Proper sampling of the field is important to obtain a representative sample of the field. The soil sample should be collected from the field at a minimum of three locations, and the sample locations chosen should represent the entire field. Sampling from the small areas of low spots or ridges that do not represent majority of the field should be avoided. If there are major changes in soil classification within a field, the field should be divided into sub-sites and samples are collected accordingly.

Drought is one of the most frequent and widely spread stress factors that limit the production of vegetables in the world. Nearly every piece of cultivated land including those in the irrigated areas could be subjected to drought. However, the frequency, duration, severity, timing and extent of drought vary greatly from region to region.

The stress caused by deficit water in the living plant system, which is capable of inducing a potential injury, is called drought stress. Drought can also be defined as scarcity of water for plants and can be due to soil, atmospheric and physiological factors. In our conditions, the great damage to the production of vegetables is brought about by soil drought, which occurs when rapidly available water is spent from zone of the active rhizosphere. That particular moment represents the beginning of drought and as the water reserves in the soil become closer to the lower limit of optimum moisture, the drought becomes more intensive. Under such conditions, plants survive on the limited water available in the active rhizosphere and deeper soil layers, and this water is used to maintain essential life processes at the expense of crop yield.

The lack of precipitation causes drought; the area of cultivable soil in our country under irrigation is very small and so is the possibility to diminish the negative consequences of occasional shortage of precipitation. Aiming to reduce damage caused by drought, a huge number of research-experiments on drought, especially on tolerance has been conducted worldwide. Here, the attempts have been made to review the work done on drought tolerance by national and international centers.

Stress is usually defined as an external factor that exerts a disadvantageous influence on the plant. Under both natural and agricultural conditions, plants are exposed to unfavourable environments that result in some degree of stress. Water deficit, chilling and freezing, heat stress and heat shock, salinity, oxygen deficiency and air pollution are major stress factors restricting plant growth. Stress is measured in relation to plant survival, plant processes, growth and crop yield. An environment, which is stressful for one plant, may not be stressful for another, e.g., pea and soybean that grow best at 20 and 30°C, respectively. As the temperature increases, the pea shows sign of heat stress much sooner than soybean, thus, soybean has greater heat stress tolerance.

To the farmers, the plants those survive in an adverse environment are called hardy plants and those, which do not survive under a particular adverse environment, are called susceptible or tender plants. So based on reactions of several plants to the environment, particular plants are selected for a region and also the farmers to suit the nature of a crop adopt different seasons of planting. Biologists have adopted the term stress for any environmental factor potentially unfavourable to a living organism. The ability of the plant to survive the unfavourable factor is due to its stress resistance. There is an equal and opposite reactions for every action. Stress is the action, whereas, strain is the reaction. A body of a plant subjected to stress is in a state of strain. External force of a particular stress causes disturbances in the body of the plant leading to a change in either shape or size and also may lead to internal disturbances, which affect physiological processes. Up to a point, a strain may be completely reversible. When the stress is released at this stage, the plant becomes normal without exhibiting any strain, which is known as elastic strain. Beyond this point, the strain will be partially elastic and irreversible partially, and then we say, it reaches permanent set and it is known as plastic strain.

Growth is a characteristic of life of any living being, and it continues until the end of organism. It is expressed in height, weight, volume, size, shape, number and area in every biological system. The shape and size of the plants are because of their continued cellular development and differentiation. Growth, which is quantified mathematically in terms of time, is termed as growth rate, and this gives a valuable information documenting growth as influenced by various abiotic, edaphic and biotic factors.

Principles

Various growth indices are better indicators of plant or crop performance under a specific treatment. Growth indices can be calculated from pot culture or field grown plants. Growth curve can be fitted using these values to predict productivity.

Requirements

Greenhouse or field-grown plants, scale, tags, hot air oven, electronic balance and leaf area meter are the basic requirements for recording the data on different parameters of growth.

The ultimate aim of production, handling and distribution of vegetables is to satisfy the consumers, and it is well known fact that consumer satisfaction depends on quality of the produce what he gets (Shewfelt et al., 1997). The term quality implies the degree of suitability of produce for a particular use. Quality can be expressed as an absence of defects or degree of excellence of the produce in respect to appearance, i.e., size, shape and colour. Quality is a bundle of attributes that are inherent in the produce and can readily be quantified throughout handling and distribution. It may also be defined as a series of attributes selected based on accuracy and precision of measurement. For grades and standards, the definition of quality is institutionalized so that it may have the same meaning for every one using it. Combination of characteristic features of the produce itself is termed as quality and that the consumer’s perception and response to those characteristic features should be referred to as acceptability.

Quality of produce encompasses sensory properties, such as appearance, texture, odour, aroma, taste and flavour that are readily perceived by the human senses and hidden attributes, such as safety, chemical constituents, nutritive values, mechanical properties, functional property and defects that require sophisticated instruments to measure (Abbott, 1999). Combination of sensory and instrumental measurements of quality attributes provides an estimate of customer acceptability. In a long chain from producer to the actual consumer, each passes judgment and each has his own set of acceptability or quality criteria, often biased by personal expectations and preferences. The component attributes of quality vary with context. The choice of what to measure, how to measure it and what values acceptable to the consumer are determined by the person requiring the measurement, with consideration of the intended use of the produce. Quality can be measured, and it relates to consumer acceptability.

Locusts are injurious to man as it destroys several human commodities. Locusts are phytophagous and feed on several plants cultivated by man. The locusts are insects belonging to the order orthoptera. The most popular insect is grasshopper. The only difference between the two types of insects is that locust can exist in two different behavioural states whereas grasshoppers do not. When the population density is low locusts behave as individuals, much like grasshopper. As the population density is high locusts gregariously behave as band of nymphs or swarms of adults. The changes in body shape and colour and in fertility, survial and migratory behaviour are accompanied by phase change. The most important locust species is the desert locust (Schistocerca-gregaria). The international pest influences various parts of Asia, Africa and Europe. Other locust species are highly injurious to mainkind like Bombay locust and Indian migratory locust (Locusta- migratoria) found all over India in its solitary phase. The monsoon months in July and August suitable are for locust multiplication conditions. The new generation produced migrate eastward into the Indian desert areas in May and June.

Vegetables form an important component of our daily diet as they provide necessary nutrients to the diet and they add colour, texture and flavour to it. Vegetables contain very high content of water (about 78 to 98%) and are reasonably good source of starch, sugar, cellulose, hemicellulose, pentosans and pectic substances. They also contribute minerals, vitamins and indigestible fibers to our diet. The yellow, orange and dark green leafy vegetables are rich source of carotenes- the precursors of vitamin A. Non-volatile acids, such as citric, malic, oxalic and succinic acids, contribute to their flavour. The very strong flavour characteristics of some vegetables like onion, garlic, cabbage, cauliflower, etc. are due to certain sulfur containing volatile compounds. However, vegetables, in general, are poor source of protein and amino acids.

India has made significant progress in the production of vegetables since independence because its diverse agro-climatic zones ranging from tropical to temperate allow the production of a wide spectrum of vegetables.At present, the country is producing about 108 million tonnes of vegetables and considered the second largest producer in the world (Venkatesan et al., 2006). Currently, the plant breeders are focusing their efforts to produce high yielding varieties having resistance against diseases and herbicides and tolerance against drought and salinity. Therefore, the physical aspects of quality, i.e., shape, size, texture, colour, tenderness, etc. are given due priority in the breeding programme with no emphasis to the biochemical and nutritional quality parameters, which include dry matter, proteins, vitamins, sugars, flavouring compounds, alkaloids, flavonoids, etc. However, under present set up of World Trade Organization (WTO), the country will have to compete with quality conscious European and developed countries, and with inferior quality product, it would not be possible to penetrate the foreign market. Therefore, breeding programme in a country like India with future-plans of globalization of agriculture produce must be aimed at achieving good nutritional quality. In different types of vegetable, a varied set of biochemical parameters determines the quality. In this chapter, the methods for qualitative and quantitative determination of these parameters in vegetables have been described.

In India, the total losses of vegetables due to inadequate post-harvest handling, transportation and storage facilities have been estimated at least 25-40%. However, in some vegetables, the post-harvest losses may be as high as 80-100%. Being highly perishable nature of the vegetables, the losses always increase as the produce moves from harvesting to the consumer. Vegetables with a loss of as little as 5% in fresh weight show shrivelled, wilted and staled appearance, which makes the vegetable tissues tough, non-crispy and unpalatable, and eventually, lowers their saleability and consumer acceptability considerably.

Improper harvesting, handling, transportation, storage and distribution of vegetables result in significant post-harvest losses. In such situations, the reduction in post-harvest losses of perishables becomes more essential in countries like India. If these losses are minimised by handling and storing the produce carefully, the following gains can be realised:

DEFINITION

Pheromones are chemical produced as messengers that affect the behavior of other individuals of insects. The term pheromone was introduced by Peter Karlson and Martin Liischer (1959) and is based on the Greek pherein (to transport) and hormon (to stimulate) is a chemical that triggers a natural behavioural response in another member of the same species. There are alarm pheromones, food trail pheromones, sex pheromones. And many are others that affect behaviour or physiology. Their use among insects has been particularly well documented, although many vertebrates and plants also communicate using pheromones. Pheromones are chemicals released by an organism into its environment enabling it to communicate with other members of its own species.

Vegetables consist of a large group of plants consumed as food. These represent complex commodities those include roots, stems, leaves, petioles, bulbs, tubers, corms, rhizomes, flowers buds, immature flowers, seedlings, immature and mature fruits and immature, partially mature and mature seeds of plants (Walker, 1988). Vegetables form an important part of human diet, providing essential minerals, vitamins, fibers and very special phytochemicals and they add a variety to the human diet (Singh, 2007). The consumption of vegetables has increased significantly since the consumers have now become more health-conscious (Cruess, 1958; Brackett, 1987a). Vegetables are cultivated in open fields, greenhouses and soil free hydroponic systems. In terms of retail, vegetables can be sold in a fresh or minimally processed form to provide a ready to eat product.

Vegetables are derived from various parts of plants, and it is sometimes useful to associate different vegetables with the parts of plant they represent. The vegetables based on their parts used as food are given below in Table 20.1.

COMMON INSECT PESTS AND THEIR CONTROL

Since, insects are the most successful and one among the strongest rivals of man in the competition of existence. Due to their immense tendency of producing numerous viable propagules (eggs) i.e., their high fecundity, their population graph takes a sharp peak in a very short span of time.

A time reaches when the population of an insect type reaches to the level where from it starts causing inconvenience or injury to man, plants, domesticated animals and other human belongings, at such a juncture they are termed as insect pests.

Many, workers are of the view that “insects capable of causing 5 or more than 5% of damage to the crops, stored products, domesticated animals and other human dependences will be termed as pests”. Thus, if an insect causes a loss of less than 5% will not be considered as a pest. Moreover insect pests which cause a damage of 5-10% are said to be minor pests and those which cause a loss of more than 10% of yield are said to be major pests.

Plant tissue culture is the cultivation of plant cells, tissues, or organs on specially formulated nutrients media under the right environmental conditions. A whole plant can be regenerated from a single cell. The history of plant tissue culture has been long and started with Haberlandt in 1902 when he proposed the culture of single plant cells, his experimentation never resulted in success. White (1943) became successful in culturing plant cells for the first time, however, Morel (1960) at the Institut National Recherche Agronomique in Versailles near Paris was first to demonstrate meristem culture technology. He successfully introduced tissue culture technology to the orchid industry and produced disease-free plants of grape. By the 1970s, plant tissue culture had become a formidable technology. Plant tissue culture technique has been around for more than 30 years and considered as an important straightforward technology for the production of disease-free high quality planting material and the rapid production of many uniform plants. Its application requires a sterile workplace, nursery, greenhouse and trained manpower.

Plant tissue culturing techniques have been especially important in the agricultural community over the past many years. During this time, plant tissue culture has effectively moved from the confines of small laboratories and has taken its place among broad scale techniques employed by agricultural industry.

Silk is a way of life in India. Over thousands of years, it has become an inseparable part of Indian culture and tradition. No ritual is complete without silk being used as a wear in some form or the other. Sericulture and Silk Textiles Industry is one of the major sub-sectors comprising the textiles sector. Sericulture is an agro-based cottage industry. Sericulture refers to the mass-scale rearing of silk producing organisms in order to obtain silk. Sericulture is an agro-based labour intensive industry. The major activities involved in a sericulture industry are:

1. Cultivation of silkworm food plants
2. Rearing of silkworms for the production of raw silk
3. Reeling the cocoons for unwinding the silk filament and
4. Other post-cocoon processes such as twisting, dyeing, weaving, printing and finishing.

Vegetables play an important role in human nutrition and health making them important in Indian agricultural economy. The productivity of vegetable crop is seriously affected by several biotic and abiotic stresses and makes the economic conditions of the Indian marginal farmers worst. Under Indian conditions, 25-40% of the total vegetable produce is going waste due to lack of post-harvest storage and processing facilities in the country. Conventional plant breeding methods have improved vegetable crop plants bringing together a wide array of genes responsible for novel productivity and quality traits. However, sometimes, genes needed for crop improvement are not available in the existing germplasm. In genetic engineering, individual genes affecting the traits of economic importance are introduced in commercial cultivars. It is a targeted approach to improve the crop plants, which attempts to avoid the transfer of large blocks of genetic material. It requires identification and cloning of desirable gene and its subsequent transfer in plant species for improvement. Transgenic technologies offer many scientific advantages in breeding for improved vegetable crop quality and performance. However, very few genetically engineered horticultural crops have been released to farmers. As of 2005, one thousand million acres of transgenic crops have been planted globally covering 40% of the United States land area out of which 75% of the area is devoted to cotton, 50% to corn and 85% to soybeans in the United States of America (ISAAA, 2006).

We live in a knowledge economy, where ideas generated by talented people and the inventions they make are the new currency. Research and innovation are now seen as the key differentiating factors determining the market value of a product or service. The emphasis today has graduated from cost arbitrage and quality deliverables to Intellectual property (IP) creation and research and development. Intellectual or Intangible property is the creation of human mind. An intellectual property under protection by law is intellectual property right (IPR). Intellectual property is an important business asset giving significant competitive advantages. Intellectual properties are protected by giving time bound restriction to inventor, owner, author, originator, or plant breeder to use, sell, share, or distribute intellectual asset. These are exclusive rights to the owner and give ability for a lawsuit against others for infringement of IP owner. It is also a marketable asset, which can be licensed out to a third party bringing income to the business in the form of license payments and royalties. Intellectual property rights are legal rights, which result from intellectual activity in the industrial, scientific, literary and artistic fields. These rights give statutory expression to the moral and economic rights of creators in their creations. Intellectual property rights safeguard the creators and other producers of intellectual goods and services by granting them certain time-limited rights to control the use made of those productions. These rights also promote creativity, dissemination, application of their results and encourage fair-trading, which contributes to economic and social development.

Seed

• 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 is a mature integumented megasporangium or mature ovule consisting of embryonic plants together with store food material covered by a protective coat.
• Seeds are fertilised, mature ovules, the result of sexual reproduction in plants. Not all plants produce seed (some produce spores or reproduce vegetatively) but most of the higher plants produce seed.
• It is the product of the ripened ovule of gymnosperm and angiosperm plants which occurs after fertilization and some growth within the mother plant.
• The formation of the seed completes the process of reproduction in plants (started with the development of flowers and pollination), with the embryo developed from the zygote and the seed coat from the integuments of the ovule.

History and development of seed Industry in India can be discussed under two heads

1. Pre-independence development.
2. Post-independence development.

Generation system of seed multiplication is nothing but the production of a particular class of seed from specific class of seed up to certified seed stage. The choice of a proper seed multiplication model is the key to further success of a seed programme. This basically depends upon,

• The rate of genetic deterioration
• Seed multiplication ratio
• Total seed demand (Seed replacement rate)

Variety is a group of plants having clear distinguished characters which when reproduced either sexually or asexually retains their characters. The genetic purity of a variety or trueness to its type deteriorates due to several factors during the production cycles. The factors that are responsible for loss of genetic purity during seed production are :

• Developmental Variation
• Mechanical Mixtures
• Mutations
• Natural Crossing
• Genetic drift
• Minor Genetic Variation
• Selective influence of Diseases
• Techniques of the Breeder
• Breakdown of male sterility
• Improper/defective seed certification System

Seed Production

Systemized crop production is known as seed production. In seed production adequate care is given from the purchase of seeds upto harvest adopting proper seed and crop management techniques. The benefits of seed production are

• Higher income
• Higher quality seed for next sowing

The important events involved in seed development and maturation include

• Pollination
• Fertilization
• Development of the fertilized ovule by cell division
• Accumulation of reserve food material
• Loss of moisture content

• The seed production of varieties and hybrids should be carried out carefully by following various techniques in the region where they are well adopted.
• The various factors affecting quality seed production includes,
  1. Agro climatic factors / Ecological factors - edaphic and climatic factors
  2. Production factors
  3. Post harvesting handling of seed
  4. Seed quality control factors

Harvesting is one of the agronomic management practices that require technical knowledge on maturation of the crops. This knowledge is much important in seed production than in commercial production.

Physiological maturation

• It is the stage of accumulation of maximum dry matter within the seeds. The moisture content of the seed at this stage will be in decreasing order (25-30%) and is expressed with maximum dry weigh of seed, germination and vigour potential. The physiological maturation is represented for individual seed and this maturation will not be the same for the population, due to differential flowering habit.
• The attainment of physiological maturation is represented by sigmoid curve of growth pattern. The physiological maturation can be represented both as duration and visible symptoms.

Removal of seeds from dry fruits is known as threshing while that of wet fruits is known as extraction. Threshing involves beating or rubbing the plant material to detach the seed from its pod or fruit. The detached seed is then winnowed to remove chaff, straw and other light material from the seed.

Threshing / extraction methods

1. Mechanical threshing

• Various types of threshing machines with adjustable cylinder speeds are available for extraction of vegetable seeds.
• Care must be taken to avoid damage to the seed during mechanical threshing, by properly adjusting the speed of the beaters, the width of the gap between the beaters and the concave, the airflow and the sieve sizes.

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 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.

Seed certification

It is a legally sanctioned system for quality control and seed multiplication and production. It involves field inspection, pre and post control tests and seed quality tests. As per Indian Seed Act seed certification is voluntary and it is not compulsory. The seed that is sold in the market is of two types certified seed or truthfully labelled seed. Whereas truthfully labelled seed is one which is being produced and marketed by the producing company by maintaining the labelling standards.

Plant breeding/genetic improvement aims at altering plant genotypes in a way that they suit human needs for food, feed and industrial raw products and support sustainable plant production. In that sense, plant breeding may be regarded as the evolution of plant type by the will of mankind. Plant breeding/genetic improvement is important because an improved cultivar is the most-economic and least laborious input for farmers.

Plant breeding is one of the early accomplishments of humankind. Many of the cultivated plants are the result of slow and involuntary improvement from wild progenitors by human being over centuries. In fact, the process of domestication of wild plants is one of the most fascinating chapters in the history of humankind. Concept of plant breeding came in the being through domestication as it involved selection of the most desirable types. Among the ancient domesticates, some of the vegetable crops are front-runners, like peas, radish, muskmelon, watermelon, etc. Other present day popular vegetable crops were domesticated later in the Neolithic times. Some species including certain vegetables are still undergoing the domestication process. However, for all practical purposes, the breeders have given up domestication of wild relatives of the cultivated species. Today, breeders often incorporate important characters, like resistance to biotic stresses, adaptability to environments, etc. to the cultivated forms from their wild relatives.

Selection from the available variations is the oldest and the most effective breeding procedure. However, genetic recombination at present forms the basis of modern plant breeding approach. In this respect, Josef Kolreuter’s extensive crossing experiments between 1755 and 1806 were essentially the first attempts to scientifically-reconstruct naturally occurring species and types by combining their characters. Any way, no matter what method is adopted in the breeding approach, it inevitably involves selection, which is the most difficult part of overall breeding process.

The industrial revolution in Western Europe and concomitant flourish of capitalism and increasing commercial agricultural production stimulated breeding activities as a profitable venture of capitalistic economy. Throughout the 19th century, thousands of large and small seed companies were developed in Germany, England and the United States out of this impetus.

Dietary constitution of Indian people is mostly cereal based. However, the cereals supply chiefly carbohydrates. Therefore, there is deficiency of protein, minerals and vitamins, especially vitamin A, riboflavin, vitamin C, etc. in the diet. The dieticians advocate the intake of 125 g leafy vegetables, 75 g other vegetables and 100 g root and tuber vegetables (total 300 g) everyday because vegetables provide all the nutrient components like carbohydrates, protein, fat, minerals, vitamins and water along with roughages, which are the essential constituents of a balanced diet.

India has attained food security by increased cereal production due to green revolution. In case of vegetables, although there has been increase in production from 15 million tonnes during 1950 to 94 million tonnes in 2005 but still more vegetables are needed to meet the minimum requirement of at least 250 g per day per capita. There has also been increasing demand for fresh export and for processing industries. Moreover, there is a pressure for increasing vegetable supply caused by constantly increasing population in a world of limited acres.

Addition of new agricultural land is of course not possible. In this situation, plant breeding can be expected to contribute substantially to greater vegetable productivity. This can be accomplished not only by the breeding of basically higher yielding varieties but also by the development of varieties that help to stabilize production through resistance to various biotic and abiotic stresses.

Seed sampling

Seed sampling is to draw a portion of seed from seed lot that represents the entire seed lot. Seed lot is a uniformly blended quantity of seed either in bag or in bulk.

Vegetables are cheaper source of carbohydrates, proteins, minerals, vitamins and dietary fibers, and hence, assume a place of very great importance in the diet of individuals. All kinds of vegetable are grown almost universally. India occupies the prime position in the production of vegetable crops and is the second largest producer of vegetables in the world. The area and production of vegetables in India have been increasing during the post-green revolution period, and the country is heading towards another revolution in the form of Golden Revolution. However, there is an utmost requirement for genetic improvement of vegetable crops in terms of productivity, qualitative characters and resistance to biotic and abiotic stresses. For any genetic improvement programme, the presence of genetic variation is pre-requisite and mutation is the ultimate source of this heritable variation.

Mutation technique that holds promise of generating a much wider desirable variability than classical breeding has been refined. Out of 2275 mutant varieties worldwide in all crops, as many as 66 mutants are in vegetables. In terms of percentage, China, India, USSR, The Netherlands, The United States of America and Japan account for 26.8, 11.5, 9.3, 7.8, 5.7 and 5.3%, respectively of mutagen varieties in all crops. Such varieties are 3% in case of vegetables. After mutation treatment by a mutagen to a specific plant, DNA alterations (deletion, duplication, inversion, translocation, or transposition of larger DNA fragments, or simple basic pair changes) occur and lead to the DNA sequence change. Hence, new characteristics of that plant are established. In fact, induced mutations supply us with many new plant lines, which may be used as primary materials for crop breeding. Hence, mutation breeding seems to be an effective and ultimate option to improve vegetable crops in the shortest possible time. A large number of new promising varieties in different crops, including vegetables, have successfully been developed worldwide using various mutagens (Chopra, 2005).

Vegetables have always been looked upon as an essential part of diet and are necessary for human health and well-being. Vegetables supply many kinds of nutrients, e.g., carbohydrates, proteins, minerals, vitamins, fibers, phytochemicals, etc. and also add flavour, colour and crispness to foodstuffs. For developing modern day vegetables, breeders have utilized an understanding of genetic principles and applied them for the improvement of these crops. They often make crosses (hybridization) between a crop plant and a related or wild species (a wide cross) enabling valuable genes to be used for genetic improvement of the crops. Over the last few decades, molecular breeding is supplementing plant breeder’s efforts for accelerated genetic enhancement bringing about a revolution in this area. This approach demands efficient procedures for the routine introduction of foreign DNA into plant genomes and utilizing them for the production of novel types of vegetable. In this chapter, attempts have been made to review most of the available molecular breeding techniques, which can routinely be employed in various aspects of vegetable improvement.

Cultivars are developed by selecting for desired traits or by removing undesirable traits that are controlled by genes (the blueprint for all characteristics in living organisms) from existing varieties or breeding lines. The plant species, varieties and clones are identified or selected by their physical features since olden times. However, these traits would change with respect to environmental and climatic conditions. The biochemical parameters like enzymes, proteins, alkaloids, etc. are also likely to change due to the stages of development of plant tissue. Successful selection strategies are dependent on the breeder’s ability to distinguish genetic effects from environmental effects on a visible or measurable trait. Therefore, the scientists resorted to use ‘genetic marker’, i.e., any stable and inheritable variation that can be measured or detected by a suitable method and can be used subsequently to detect the presence of a specific genotype or phenotype, which otherwise is very difficult to detect. Presently, the breeders and scientists all over the world are pursuing mostly DNA or molecular markers.

Hybrid vigour is used as a synonymous of heterosis. In 1910, the term heterosis was first used by Shull who defined this phenomenon as the stimulus of heterozygous, and in his word, it has been the “interpretation of increased vigour, size, fruitfulness, speed of development, resistance to insect-pests and diseases or to the climatic rigors of any kind manifested by the out breeding organism as compared with corresponding inbreds as a specific result of the unlikeliness in the constitution of uniting parental gametes”. This definition is often interpreted as not implying a genetic basis for heterosis, because the definition basically describes the phenotypes that result from the crossing of two different inbred lines. Generally, heterosis is manifested as an increase in vigour, size, growth rate, yield, or some other characteristics but in some cases, the hybrid may be inferior to the weaker parent. This also represents as heterosis (average heterosis), and if heterosis is estimated over the superior parent, such an estimate is sometimes referred to as heterobeltiosis, hence, authors feel “heterosis refers a biological phenomenon in which the F₁ population obtained by crossing of the two genetically dissimilar gametes or individual shows increased or decreased vigour over better parent or over the mid-parental value. Earlier, Power (1944)also suggested that the term heterosis should be used only when the hybrid is either superior or inferior to both the parents. Other situation should be regarded as partial or complete dominance. It can be easily explained with the help of Table 5.1.

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.

Diseases of plants are produced by a variety of organisms from plant and animal kingdoms viz., fungi, bacteria, viruses, nematodes and insects. The diseases reduce total biomass (dry matter) production and consequently yield of the crop by general stunting, damage to the leaf tissues, fruits and seeds or by killing the plants. The degree of damage would depend upon the intensity of infection but both need not be proportional. One serious effect of disease is the disappearance from cultivation of otherwise excellent but susceptible varieties.

Vegetable crops have been found to be highly susceptible to biotic stresses from the disease causing microorganisms and insects-pests. The ability of pathogen and insect-pests to attack and proliferate in the host plant is highly specific. There are wide differences in the host plants in response to the attack by pathogens and insects. Although control of the diseases and insects by the use of chemicals is possible to certain extent but indiscriminate use of fungicides or insecticides over the crop has several disadvantages. Besides increasing cost involved in chemical control, residual toxicity of the chemicals such as fungicides, antibiotics and insecticides in food chain and development of resistance against pathogens and insect-pests to different chemicals are serious problems.

Genetic improvement of host plants conferring resistance to diseases and insect-pests is considered to be the best approach in the management of diseases and insect-pests, and this is more particularly true in case of vegetable crops. Indiscriminate use of chemicals in the vegetable sector has led to health hazard. This has resulted in switching towards organic vegetables. However, cost of production of organic vegetables naturally will not permit the common people to consume these products. Therefore, the best option is to induce resistance in the host varieties. The resistant varieties could in turn be an important component in the organic vegetable farming, thereby reducing cost of production to certain extent.

Concern for improvement of nutritional quality of vegetables has arisen in the context of providing nutritional security to our ever-increasing population. Nutritional security denotes the consumption and physiological use of adequate quantities of safe and nutritious food by every member of the family and encompasses the process of equitable distribution among members of household and communities (Nandi and Bhattacharjee, 2002). This would entail the need to ensure a varied food intake, comprising all the essential macro-and micronutrients (protein, carbohydrates, minerals and vitamins), plant pigments (lycopene, beta-carotene, anthocianin, lutein, capsanthin, zeaxanthin, etc.) and other functional phytochemicals (secondary metabolites, like flavonoids, isothiocyanates, glucosinolates, etc.) through a diversified diet. In this regard, production and consumption of vegetables that are the valuable source of micronutrients, beneficial phytonutrients and highly functional phytochemicals hold the key in assuring nutritional security.

Implication of vegetables in diet has been well conceived among the high-income group in the world since human health in recent years has assumed an unprecedently important status. Increased interests in nutrition, fitness and beauty have exaggerated concerns over diet and human health. A new diet-health paradigm is evolving which places more emphasis on the positive aspects of diet. Foods have now assumed the status of functional foods, which should be capable of providing additional physiological benefits, such as preventing or delaying the onset of chronic diseases as well as meeting basic nutritional requirements so with high-income elasticity, the demand for vegetables and perception of diversified diet have been growing steadily, hence, both access and consumption of vegetables have been increasing in the urban and peri-urban population groups. However, meeting the requirements for macro- and micronutrients for most of the population groups in households and communities of South Asia, Latin America and African countries seems far off because of meager presence of vegetables in the diet. In south Asia where meat intake is low, ascorbic acid emerges as one of the most important enhancers of iron absorption. This is attributed to the fact that foods containing vegetables may provide an optimal mix of minerals, vitamins, antioxidants, dietary fibers and other non-nutrients bioactive compounds.

Seed germination

It is defined as the emergence and development from the seed embryo, of those essential structures, for the kind of seed in question, indicates its ability to produce a normal plant under favourable conditions. The seedlings devoid of an essential structure; showing weak or unbalanced development; decay or damage affecting the normal development of seedling are not considered in calculating the germination percentage.

India is contributing about 10% of the world’s vegetables, and in terms of production, the country stands second after China. The existing area under vegetable cultivation in India is around 6.89 million hectare with a production of about 96.54 million tonnes. There will be a demand of 151-193 million tonnes of vegetables in India by 2030 (Dhaliwal et al., 2006). There are extensive crop losses in vegetable crops due to increased insect infestations. Since vegetables are grown round the year, there is carry over of insect-pests across the seasons and also from sowing until harvesting. Vegetables also invite more pest problems because of their cultivation under high fertility conditions leading to high plant succulence. High yielding varieties and hybrids are further more prone to the attack of insect-pests. Insect infestation affects the quality and market value of vegetables adversely and it is estimated that 30-40% of the total production is lost due to the attack of pests (Lal et al., 2004). A large number of pesticides are being used repeatedly to manage the insect-pests in India. Indiscriminate use of pesticides has led to many problems like toxic residues in edible parts of the vegetables, adverse effects on non-target organisms and beneficial insects, resurgence of secondary pests and development of resistance in major pests to pesticides and also environmental pollution. Therefore, latest approach has been to minimize the use of highly toxic insecticides by integrating different strategies of pest control like use of biological control agents, pesticides of plant origin, insect resistant varieties and other cultural practices. In this chapter, efforts have been made to highlight the distribution, host range, identifying characters, biology and nature of damage of important insect-pests of vegetables and also the methods of their management crop or pest wise.