eChapters

INTRODUCTION

While the world has been changing during the last few years both politically and economically in unexpected and remarkable way, food security remains an unfulfilled dream of billions of people. With the world population crossing six billion marks, the demand for food grains is increasing at an alarming rate. Increasing population, on the other hand, has led to decrease in cropping area. In order to meet the global food demand we have to increase the productivity. Insects have always been a major cause of yield-loss in agriculture. They account for 20-30% of crop-loss. Several approaches e.g. physical, chemical and biological have been used with varying degree of success to reduce such losses.
 
The insect pest management is one of the most important yield destabilizing factors in almost all the crops. While for some insects, genetic sources of resistance are available in the respective plant germplasm, for many others germplasm is almost devoid of effective resistance genes. It is because of this factor that conventional breeding strategies have not been successful in breeding insect pest’s resistant varieties. The only means available at present for managing the insect is extensive application of insecticides and pesticides. Excessive usage of the pesticides causes, on one hand, environmental pollution and on the other, it forces the insects to develop resistance against these chemicals. Application of the pesticides also imposes additional economic burden on the farmers.

INTRODUCTION
 
In India tremendous progress has been made in agriculture. In absence of check on population growth, it may cross 1.5 billions by 2030. As a consequence per capita availability of land 0.13 ha will further reduce to 0.1 hectare in 2020 A.D. The demand of growing population for food and fibre require country to produce higher yields from presently cultivated land. Currently an average of 2790 calories of food available each day for every human on the planet, (23 per cent more than in 1961 and enough to feed every one). The production targets and required yield to feed the ever increasing current population with present available resources will require the growth rate of 2.35 and 2.2 per cent in rice and wheat, respectively and as high as 4.45 and 3.38 per cent for pulses and oil seeds, respectively. This requires national average yield to be increased by 30-50 per cent, which is not a cakewalk. India will require producing additional 5-6 million tones annually to keep pace with ever-increasing national food and nutritional requirements. Recurrent famines, starvation death and lack of resources led to green revolution, which as of now has turned our begging bowl to agriculturally advanced cereal exporting country.

Introduction

Advent of agriculture in India dates back to around 2000 BC, the period of Indus Valley Civilization. South and East Asia also witnessed the start of agriculture around the same time. The crops were grown only during the monsoons. Winters served as a closed period for crops as well as for the pests. Even at that time a number of insect pests were known to cause serious damage to different crops. Agriculture has been revolutionized during the few decades since World War II (Kupatt et al., 2005). Introduction of high yielding varieties and associated technology resulted in tremendous increase in the production from the same piece of land. The results of these changes include a dramatic reduction in time and resources needed to provide an unprecedented quantity of quality food and fiber. The initial introduction of plant protection agents as wonder material did not lasted long, as very soon their ill effects on human health and environment were witnessed.

INTRODUCTION

The first significant economic contribution of host plant resistance in agriculture was made in 1890 when European grape vines were successfully grafted on resistant root stock to save the French Wine industry from viteus vilifaliac (Fitch). Studies from the past century have led to the development of resistant varieties in about 15 crops to about 50 key insect pests. During the last 20 years alone, more than 500 insect resistant cultivars of rice, maize, cotton, sorghum, alfalfa and wheat have been developed and released world wide (Dhaliwal and Arora, 2001). The insect resistant varieties are grown on millions of ha. annually and help the farmers to save billions of dollars in insecticide costs (Dhaliwal and Arora, 2001). The role of Host Plant Resistance in Integrated Pest Management is discussed below.

Introduction

Humans have inhabited the earth for nearly 2 million years. For over 90 per cent of this period, the maximum population numbered about 200,000 and the growth rate was only about 0.01 percent per year. The use of fire and the development of tools were the first major changes affecting human population growth which increased to about 5 million individuals about 100,000 years ago. The population remained fluctuating about this mean value for the next 90,000 years depending upon the food supply. Up to this time people were hunterer-gatherers and depended exclusively on the natural ecosystem for their food. Then about 10,000 years ago, humans began to cultivate crops for food. With established agriculture came an increased and stable food supply. This contributed to an increased growth rate of the human population (Dhaliwal et al., 1998).

INTRODUCTION

Management of several of the important insect-pests of crops is becoming increasingly difficult owing to a number of factors by which pests have been able to offset the effect of control interventions. Several of the present day pest management problems may be ascribed to the excessive and indiscriminate use of chemical pesticides during the last about three decades. Routine application of insecticides for controlling insect-pests, without taking into consideration whether economic damage to the crops is being inflicted by the pest or not, has resulted into several problems like pest resistance, pest resurgence, pest replacement, killing of natural enemies of pests, presence of toxic residues in food, and soil and environmental pollution, etc., apart from increase in the cost of plant protection. Entomologists have been trying to find solution to these problems through integrated pest management of which monitoring of insect activity through regular surveys is an important component. In fact, knowledge of insect activity is indispensable since pest management system can not operate without accurate estimates of pests and natural enemies population or without reliable assessment of plant damage and its effect on yield.

Introduction

The history of Integrated Pest Control goes back much farther than the mere coining of the term in the early fifties and the subsequent elaboration and clarification of the concept. The origins are deeply rooted in the evolution of pest control practices as developed by Entomologists and Plant Pathologists in the Nineteenth Century.

Human history is a series of attempts to gain increasing control over the environment. At first this control was minimal to the degree that poor shelter and unstable food supplies imposed severe population constraints. The gradual gain in man’s capacity to control his environment parallels the gradual rise of civilization. But as man aggregated into villages near rivers and planted crops near by, he encountered increasingly severe attacks by pests on the crops. For thousands of years, man could do nothing about these pests but appeal to the power of magic and a variety of gods. For the most part, early humans had to live with and tolerate the ravages of plant diseases and insects, but gradually they learned how to improve their conditions through “trial and error” experiences. These improvements included the beginnings of pest control or pest management, the most preferred term today.

Words like rDNA (recombinant DNA) technology, cloning, genetically modified organism (GMO), living modified organism (LMO) and transgenics are of today’s common knowledge. However rather than scientific interest, debates on biosafety issues have made these terms more agnized among general people. Global, sectorial and individual protests against transgenic plants and animals are enunciated allover the world raising issues and concerns over risks and health hazards of using these organisms. Despite these protests and concerns, commercial use of transgenic organism as food, feed or other purposes are increasing at an exponential rate. Although there is not much scientific evidence where transgenics have caused havocs on ecological balance or human health, the biosafety issues need to be solved to provide a safer environment rather than be sorry and lament in the future for today’s mistakes. One of the major problems in supporting use of GMOs lies in the incapability of biosafety science to draw reliable and widely acceptable conclusions for labeling a safe tag on these organisms and their derivatives.

Food is the basic requirement for maintaining the life process. Plants supply the bulk of foods required for human and animal. With limited cultivable area and ever increasing pressure of human population, the demand for food is constantly rising which can not be alone met by conventional plant breeding technologies. Novel techniques like plant genetic engineering are gaining momentum for production of superior plants or yield enhancement of a species.  It has been observed that the most commercially successful application of recombinant DNA technology is in genetic engineering of plants, which led development of multinational seed companies deriving monetary benefit from genetically modified crop and food products. From production of herbicide resistant or insect pest tolerant plants to alter the inherent quality composition of human food, plant genetic engineering has established firmly the commercial viability of recombinant DNA technology.

Preternatural development of recombinant DNA technology has established genetic engineering in animals the most important field in application of biology for human benefit, from production of genetically modified animals to providing crucial technologies to medical science sector. On the basis of the nature of the target tissues, genetic engineering may target single cell line, particular tissue sectors or the organism as a whole. The purpose of transformation may be basic research involving elucidation of gene function, study effect of directed mutations, examination of physiological and developmental processes in animals or may be target oriented, such as production of proteins or metabolites in large quantities in a cell line, incorporating rDNA in the germline cells, gene therapy, use of rDNA in disease diagnostics, or production of transgenic animals for specific purposes.

Molecular markers or DNA markers are considered to be one of the most successfully applied component of molecular biology techniques that have relevance in almost every sphere of biology, from paleobotany to transgenic technology. In true sense, a marker is a characteristic of an individual that differentiates the individual from others. Morphological descriptions like cotyledon colour of Pea, eye colour of Drosophila, shape and size of fruits in summer squash etc. are examples of typical morphological markers. However, a single morphological marker is not sufficient for describing the uniqueness of an individual, for many pea plants will have green cotyledon or many Drosophila may have red eye. To define the uniqueness of an individual, we have to find a number of marker traits characteristic of that individual. Unfortunately, morphological variations are not sufficient to differentiate between a large number of individuals, or between groups or sub groups within a species, simply because the level of polymorphism is low. Besides, morphological characters or phenotypic expressions are affected by environmental changes, so stability of expression is low and sometimes uncertain.

While structural genomics aims to describe the protein structures coded by the genes present in the genome, functional genomics deciphers meaning of the coded information at transcriptome, proteome and interactome level. In the previous chapter we have seen how a gene can be identified by creation of mutants, genetic and physical mapping, and by sequencing the gene. Another source of possible gene structures come from genome sequence information, which by using computational algorithms identifies a number of ORFs that have the structural configuration of a gene. A third option of identifying a gene is identification of differences between wild type and mutant at RNA level, by analyzing the transcriptome. If we are able to identify differences in RNA expression pattern between these two, the information can be used to search back the gene sequences responsible for the differences. From proteome analysis inferences on expression of proteins and their interaction in the functional network of the cell with other proteins, DNA, RNA and cellular 

The primary target of genomics is identification and characterization of genes and gene products. Starting point of genomics may be a whole genome sequence, from which gene and protein structures can be predicted by computational and bioinformatics approaches (in silico genomics), or genes can be identified step by step starting from identification of a phenotype by induction and detection of mutation, construction of a genetic map demarkating the position of the character, physical location, identification of the gene, cloning and characterization of the gene or genome sequence by sequencing followed by expression analysis to correlate the phenotypic expression (in vivo genomics). Alternatively, genes can be identified by developing knockout mutants by random or site directed disruption of a reading frame and then determining the protein product as well as phenotypic expression.

One of the primary targets of genome analysis is to manipulate it at the level of genes, the units of inheritance. Genes, as explained earlier have distinct positions and sequence configurations in the genome which are expressed in the form of RNA or proteins controlling the functionality and identity of an organism. To understand the function of a gene several methodologies may be adopted. As genes have conserved sequences like promoters preceding the reading frame, initiation sequences, exon-intron junctions and end sequences, these features can be used to screen genome sequence to identify the regions containing genes. An open reading frame (ORF) is the sequence of a gene for which functions have been assigned, i.e., the sequence codes for a protein or RNA. On the other hand, an unassigned reading frame (URF) is a sequence which has structural features of a gene, but no function has yet been assigned to it.

The information that drives the process of life is encoded in the genome of the organism. Structurally defined, a genome is an organization of genetic information consisting of nucleic acids (deoxyribonucleic acid or ribonucleic acid). Arrangement of nitrogenous bases in the nucleic acid codes the information for execution of cellular processes. Four types of bases (Adenine, Guanine, Cytosine and Thymine) are present in deoxyribonucleic acid (DNA) while in RNA Uracil replaces thymine group of any three bases on transcribed RNA represent a codon. With four types of bases, sixty four types of codons can be formed. Genetic information encrypted in these codons is released in the form of arrangement of polypeptides consisting proteins via mRNA intermediate. This universal process of flow of genetic information from DNA to RNA to protein is known as the central dogma of life. The whole set of information coded in 64 codons, out of which 61 codes for one or more amino acids (building block of polypeptides/proteins) and three indicating where to stop is called the book of life or genetic code.

Process of life of an organism is defined, driven and depicted by its genetic constitution, or the genome. A genome is a collection of genetic material present in the cell as nuclear or organelle DNA. To be precise, it is the sum of all single copy genetic materials present in the cellular subcompartments. Thus a diploid organism having two copies of each chromosome contains genetic material constituting two copies of the genome, while a gamete of the same organism contains single copy of the same. Organelle genome is shared by chloroplast and mitochondria. In these two organelle genetic material is present in single copy per organelle, although many copies of organelle ensures that a cell harbours many copies of mitochondrial or plastid genome. Unraveling the structure and function of the genome is, therefore, the central objective of biological science. Technologies that would help to understand the basis of genetic, biochemical and physiological processes are pivotal to execute the knowledge for the betterment of mankind and environment.

Medicinal and aromatic plants have been known for millennia and are rich source of therapeutic and cosmetic agents for the prevention of health diseases and critical skin ailments. India is the rich source for the medicinal and aromatic plants and export many plant parts for the research work to the many countries as raw materials. The major market in the world for essential oils is the United States, followed by Japan and Europe. However, production continues to be concentrated in Europe, with seven of the world’s largest essential oil processing firms. In the United States, the major users of essential oils are the soft drink companies. Japan accounts for 10 % of the world demand. The Canadian market is domi­nated by the United States perfume and flavouring industry. France is dominating the world perfumery market, and Switzerland is one of the leaders in the pharma-ceutical field. Britain and India are known to feature strongly in the flavouring sector. The essential oil industry is characterised by a number of difficulties, including lack of stable quality, inconsistent supplies, and variability of active ingredients owing to environmental effects. Even though according to World Health Organization, herbal medicines are lucrative globally and represent a steady high market value in every year.

Agarwood Oil

Biological Source : Wood of Aquilaria agalloch, Aquilaria crassna, A. Khasiana.
Family : Thymelaeaceae
Common names : Agarwood, Aloeswood, Eaglewood, Gaharu or Oudh.

Plant Introduction : Aquilaria is a fast-growing, archaic tropical forest tree, which occurs in South and Southeast Asia, from the foothills of the Himalayas to the rainforests of Papua New Guinea. Agarwood is a fast growing, evergreen tree, that normally grows to 18 - 21 m but sometimes up to 40 m in height. It bears sweetly-scented, snow-white flowers. The trees occasionally become infected with a parasite mould and begin to produce an aromatic resin in response to this attack. As the fungus grows, the tree produces a very rich, dark resin within the heartwood. The tree grows in natural forests at an altitude of a few meters above sea level to about 1000 meters, and it grows best around 500 meters. It can grow on a wide range of soils, including poor sandy soil. Seedlings need a lot of shade and water. Trees grow very fast, and start producing flowers and seeds as early as four years old.

A concentrated, hydrophobic liquid containing volatile aroma compounds obtained from aromatic plants is referred to as essential oil. It is so-called to indicate that the oil is the fragrant essence of the plant from which it is extracted generally through various distillation methods. The economics working behind essential oils has three components. First, the cultivation of herbs and plants used to extract essential oils; second, the actual process of extraction of the oils; and, third, the marketing and actual sale of these oils. But the major emphasis is often given to the agrotechnology, since the crop yield and yield of the essential oil depends on the quality of cultivation. The cost of cultivation of herbs in the developing countries per hectare is estimated at US $ 600 to 1100. This cost mainly comprises labour cost and as such this industry is uniquely suitable only for developing nations. The revenue from essential oils after the extraction per hectare is estimated to be around US $ 2500 to US $ 6500. According to industry sources, more than 3,500 essential oils are known. Out of these, some 400 are used for commercial purposes on a regular basis. These are obtained mostly from agricultural plants, some from wild plants that may be seasonal or perennial. Oil can be extracted from any part of plants—from leaves, flowers, fruits, roots etc. Whatever the source of essential oils, they have complex compositions, containing alcohol, aldehydes, ketones, phenols, esters, ethers and turpenes in varying proportions.

Plant oils are obtained from their plant hosts through a variety of processes commonly called Extraction process. Essential oils are extracted from different parts of the plants. The quality and quantity of the oil is mainly depends on the method of extraction and the quantity of the raw materials used. For example, Lavender is extracted from its flowers, Orange from the rind of its fruit, Frankincense from the resin of its tree, Cinnamon from its bark, Pine from its needles, clove from flower buds and so on. Production of a good quality essential oil, the cultivation factors also play a vital role like soil quality, climatic and geographic conditions etc. As example, Jasmine flowers must be picked by hand at dawn on the very first day they open. A Sandalwood tree must be 30 years old and 30 feet high before it is ready to produce its best quality oil. Further the quantity of the plant materials are also matters for the price and quality of the essential oil. As an example, it takes roughly 12,000 Rose blossoms to produce 5 ml of Rose. Whereas it take 100 kilos of Lavender leaves to produce 3 liters of Lavender. As a result Rose is roughly 24 times more expensive than Lavender.

The concern for nature and the focuss for all things which are basic and natural has been spearheading to a green movement of everything natural and nature-based consumer products all over the world. God has given diseases and remidies also in the nature only we have to properly find out. In today’s world of consumer boom, the role of essential oils has increased many folds. Uptil now known applications of essential oils, more and more areas are opening up which will benefit the industry. Use of essential oils in therapeutics is becoming popular in India, China, Japan and European countries. Aromatherapy involves the use of essential oils and aromatics derived from plants to cure diseases. These plants are known as aromatic plants. Aromatic plants possess odorous volatile substances which occur as essential oil, gum exudate, balsam and oleoresin in one or more parts, namely, root, wood, bark, stem, foliage, flower and fruit. The characteristic aroma is due to a variety of complex chemical compounds. The term essential oil is concomitant to fragrance or perfumes because these fragrances are oily in nature and they represent the essence or the active constituents of the plants. They are called volatile or ethereal oils as they evaporate when exposed to air at ordinary temperatures. Essential oils are highly concentrated, low volume, high value products.

The North Eastern Region of India possesses unique potential for fishery activities. The region represents all agro-climatic zones ranging from warm water drainage system to cold water conditions facilitating freshwater fishing and is identified as the hot spot of freshwater biodiversity. So far about 267 fish species have been reported to be present in the region, which is approximately 33.13% of the total Indian fresh water fishes (Munilkumar and Nandeesha, 2007). The total land coverage of the region is 2.55 lakh sq. km. which is about 7.76% of the country, out of which 70% is hilly terrain (Mahanta and Tyagi, 2003). The main fishery resources of the region comprises of rivers (18,968 km), reservoirs (8,019 ha), beels/lakes (1,48,491 ha) and tanks and ponds (42,782 ha) (Ghosh and Ponniah, 2008).

The North Eastern Region of India with its large fish eating population, needs planned sustainable development of its existing as well as potential fishery resources. A challenging environment for fisheries development prevails in the region by way of very high demand and price of fish. Given the socio-economic conditions and vast fishery resources of the region, there is a strong chance for diversion of work force to productive sectors like fisheries thus transforming the economy of the region and further socio-economic development.

Introduction

Aquaculture has been shown to offer high potential to fill the gap between supply and demand for fish and fish products to mitigate the problems of malnutrition with ever increasing world population. Globally, aquaculture has been growing rapidly in the last decade, approximately at 10-15% per year. The total aquaculture production, which was 26.7 million metric tonnes in 1996 increased to 37.5 million metric tonnes in 2001, in which tropical countries have been particularly contributing well, with the Asian component exceeding 80% (Ayyappan and Jayanthi, 2004).

The country has varied and enormous aquatic resources (coastline: 8041kms, EEZ: 2.02 million sq. km., river & canals: 171334 km., brackish water area: 1.422 million ha., reservoirs: 2.050 million ha., ponds: 2.855 million ha., beels & oxbow lakes: 0.788 million ha) (Gopakumar, 2000). The North-Eastern region of India is endowed with rich diversity of aquatic and biotic resources, which needs judicious and scientific exploitation for diversification of farm practices so as to mitigate the problem of demand and supply of quality food.

Introduction

Pearls have been favourite jewel of humanbeing since ancient times. Pearl is a natural gem and is produced by living organisms, the pearl oysters and mussels (Molluscs), unlike other precious stones. It is perhaps, the only gem that does not require the treatment by lapidary. According to our Indian system of gemmology, of the nine maharatnas (Heera, Mukta, Manikya, Pravala/Munga, Gomeda, Indra-neela, Vaidurya, Pushyaraga, and Panna) pearl (Mukta) is only next to diamond (Heera). The science of pearl culture has not been widely popular, however, the art and trade form has reached the zenith.

With the turn of the last century, the demand for pearls increased, but their supplies from the existing fishing grounds have diminished due to overexploitation and pollution. Such a situation necessitated tremendous research attention in the following decades with support from state and trade sectors, the world over. This led to the evolution of culture pearl technology as a booming aquaculture enterprise in Japan and China. These two countries have a monopolistic control over pearl trade.

The aquaculture sector showed an overwhelming growth of 468% during the last two decades and is presently playing a key role in the changing Indian economic growth. The contribution from aquaculture is 21.6% by volume and 49.3% by value to the total fisheries exports. Inland fisheries sector had shown consistent growth of over 5% per annum over the period of 1999-2005. High demand of aquaculture products in the world has forced the aquaculturist to change the culture system from extensive to intensive. This has led aquaculturist to lose millions of dollars due to fish mortalities associated with fish disease and related conditions. Out break of disease has been considered as a major stumbling block in intensive aquaculture practices.

Disease is a very complex interaction between three important factors, namely the susceptible fish, the disease causing agents (pathogen) and the environment. These three factors are most important and must be considered in any fish disease outbreak. The environment in which the causative agent of diseases and their host fish interacts, may favour one or the other. Changes in the environment, whether natural or artificial, may shift the balance from one side to the other and will often determine whether the host will survive or succumb. Understanding and managing the stress and their causative factors are thus the key factors for successful aquaculture.

Introduction

Packing and transportation forms an important component in fish trade whether live fish, fish seed, fresh fish, iced fish or dried fish. There are few reasons necessitating packing and transportation.

    ·    The movement of fry/juvenile for stocking into farms or restocking into natural environment.
    ·    The movements of fish to markets for sale selling/consumption.
    ·    The movements of ornamental aquarium live fish for trade.
    ·    The movement of aquatic animals for research purpose.

Availability of quality fish seed is the critical and basic input for successful fish culture operations. Till the sixties, a major part of the seed required for culture was being collected from the riverine sources, which had several disadvantages. Indian major carps viz. Catla, Rohu & Mrigal and Chinese carps viz. Silver carp & Grass carp mature in the pond but do not spawn or lay eggs in standing waters. Usually they breed or spawn naturally in flowing rivers during monsoon months. In artificial breeding, certain inducing agent (hormone) is injected to fish for successful spawning.

In India, the first successful induced breeding of carp was achieved through use of pituitary hormone in 1957. Increased seed production of fish today is a direct result of improved technologies of breeding, hatching and rearing.

Three decades ago, earthen “pit” hatcheries were used for hatching eggs around bunds. Today large commercial hatcheries exist, where all activities such as raising of brood stock, breeding and fry rearing can be undertaken. This has certainly marked the growth of the industry. Commercial Chinese hatchery facilitates not only large-scale production of fish seeds but also improves the survival percentage of seed.

Background

In simple term, what agriculture is to land aquaculture is to water and can be defined as the art, science, and business of cultivating plants and animals in water. Considering scope of inland aquaculture in the present discussion would be limited mostly to grow desirable fish/prawn (hence forth termed as fish) in fresh water ponds and to some extent to their seed production in hatcheries. The important activities in aquaculture includes deliberate interventions during the rearing process or life cycle of the stock, management of the culture system and production process so as to increase survival and production of stock. Since, the main goal of aquaculture is to maximize the fish production per unit land/water resources per unit time which primarily depends on the degree of management and intervention. The important forms of intervention and management practices are regular stocking, fertilization, feeding, liming etc. The degree of care taken or effort put in these aspects would determine the level of production.

Fish culture is an age old tradition modified and improved by several scientific inventions. Farmers can easily take up fish culture in village ponds, tanks or any water body and can improve their financial position substantially. Pond aquaculture is the most common method of fish culture throughout the world. For successful aquaculture of fish, molluscs, crustacean and even aquatic plants, the water and soil in which fish are grown should have favourable conditions for their growth which, in turn, is intimately linked with several physical, chemical, biological characteristics of water and management practices adopted. Physical and chemical characters of the soil and water will affect the primary and secondary production of water bodies.

The survival and production of fish in a pond is dependent on the primary and secondary production. Primary production depends on the water quality parameters. Phytoplankton make carbohydrate using sunlight and releases oxygen. This is the major source of energy and oxygen in the ecosystem. Zooplankton which feed on the phytoplankton form major source of food for the fishes.

Fish production of the country has improved considerably in the post-independent India with the total production going up from 7.52 lakh tons in 1950-51 to 90.4 lakh tons in 2010-11, with an average growth rate of 4.35% per year after 1990. The real jump has come from inland aquaculture sector. Production from inland waters which used to be less than 30% of the total till sixtees, gradually rose at a fast pace and crossed the 50% mark by the end of 20th century. The present contribution of inland sector to the country’s total fish production of 52.09 lakh tons is 58% recording an average annual growth rate of 8.4% per year after 2011.

This increase in contribution from inland sector is because of the quantum jump in production from freshwater aquaculture, made possible mainly due to development of technologies of hypophysation of Indian Major carps and composite fish culture during late fiftees and sixties respectively. Development of these two technologies, along with their wide extension through Fish Farmer’s Development Agency, initiated by Govt. of India in latter part of 1970s, have in fact revolutionised freshwater aquaculture scenario of the country. It is presently contributing to over 70% of the total fish production  from inland resources of this country.

Introduction

In present times aquaculture is being practiced using both conventional or non-conventional methods with considerable variations. Aquaculture can be termed as – extensive, semi-intensive and intensive based on operations and involvements. An increase in the intensity of aquaculture requires an increase in capital as well as operational costs.

Here we will examine the three main levels of aquaculture used in various habitats and later consider the conventional methods of aquaculture.

Different Levels of Aquaculture

Fish culture practices can be classified into three different kinds or levels on the basis of the intensity of aquaculture in terms of capital as well as operational costs. The chances of crop failure often increase with increasing intensity of aquaculture, which may involve: 

Fish is the most important source of protein for the people of Northeastern India where almost 100% people are fish eaters. So fish culture is very popular in this region. There is a huge demand for fish here and the most popular aquaculture practice is pond culture. The state of Tripura particularly progressed well in fish production and became self sufficient in fish seed production. The state is blessed with 22,895 ha of water bodies where more than 50% (12,895 ha) of area is used for aquaculture purpose. Composite fish culture and integrated aquaculture are very common here. These fish ponds are very productive both in eco-physiological and faunistic point of view. Most of the farmers have a pond area of less than one hectare for fish culture and are unable to go for any supplementary feeding. Average fish productivity is estimated as 1800 kg/ha. Preliminary experiments conducted in the Institute showed that timely application of the fertilizer and/or restricted supplementary feeding improves total production.

Introduction

In recent years aquaculture has become the fastest growing food production sector in the world with 10% annual growth rate in comparison with 3% for livestock and 1.6% for capture fisheries. FAO (2000) estimates that by 2030, over half of the fish consumed by the world’s people will be produced by aquaculture. It is not only the demand for animal protein but the high returns associated with aquafarming when compared with agriculture or animal  husbandry that has accelerated the growth of aquaculture. Thus, in the last two decades aquaculture with greater emphasis on shrimp farming made fast strides among Asian countries including India. The culture of carps in freshwater and shrimps in brackishwater are the two main culture practices followed in India. During nineties around 10% of 2.7m ha. brackishwater area has been put under farming along with a number of other supporting and ancillary units viz.; hatcheries, feed mills, processing and packaging industry etc.

Health care is an important way of making sure that rabbits stay productive. Every rabbit keeper should know how to recognize and, if possible, prevent and cure illnesses which can affect rabbits.

It is always better to prevent disease incidence than to let animals get ill and then try to treat them. Allowing rabbits to get sick is expensive for several reasons, sick animals stops growing and reproducing so money is lost with this decrease in production, some disease results in the death of rabbits, replacing the dead rabbits is expensive , treatment for the ill rabbits is usually expensive.

Normal Physiology
Rectal Temperature    :    38.6 to 40.1ºC (AV: 39.5ºC)

Food, furs, research, hobbies, pets – these are the major uses of rabbits around the world. It should be noted that rabbit production for meat and wool has become increasingly important in the last few years.

Angora wool rabbits are a commercial rabbit which is raised for its fine wool and meat as well, but primarily raised for wool production. Cooler climate is most conducive to raising this breed of rabbit. Angora rabbit does not differ from other breeds of rabbit except for its unusual length of valuable fur(wool). This modifies its raising compared to other rabbits.
 
The term ‘Angora’ qualifies those mammals which are covered with fur or wool composed of very soft hair of more than normal length – double or more than double the normal length.

Important by product from Rabbit are meat, wool, fur and skin. It can be made highly profitable if products are properly processed and marketed. Many rabbit products are wasted because people do have not enough knowledge about processing.
 
Slaughtering: Know when and how.

Skinning

Familiar with how to remove skin and carcass preparation. How the skin has to be processed and how the products which can be obtained from skin.

Manure collection and preservation.

Slaughtering : It depends on demand, type of animal where meat is consumed more, it can be achieved in 2 methods.

Sanitation in the Rabbitry is the best disease-prevention system. Daily cleaning of cages or hutches, containers and surrounding is the easiest way to ensure sanitary condition and hence control disease. The most common diseases found in rabbits are cocciodosis. Pasteurella type pneumonia and enteritis. There are generally caused by lack of sanitation in the rabbitry. With strict sanitation practices such as cleaning all cages and water containers everyday, removal of manure, soiled bedding. Contaminated feed and collecting roughage from uncontaminated areas can drastically reduces chances of any disease in the rabbitry.

Rabbits are produced for meat, wool and research and as pets or for a hobby. Meat production is the most important commercial aspect of rabbitry. The domestic rabbit is primarily herbivorous and will consume most types of grains, oil seed cakes, brans, greens and hay. Diets provided, whether home grown or commercially prepared, consist almost entirely of ingredients from plant sources. Although, the producers / farmers mostly rely on home grown feeds, a good portion of the rabbit feed presently used is commercial pelleted feed. Since the rabbit can utilize a certain amount of forage, it has a place in food production by making use of some non-competitive feeds.

Definitions

Pen Enclosure for housing rabbits that allows for freedom of movement by rabbits and allows for the provision of a variety of environmental enrichment strategies. Cage Fully enclosed container for housing rabbits which, because of its size, restricts freedom of movement by rabbits and limits the provision of environmental enrichment strategies. Cages are usually constructed from metal or plastic, with solid or mesh sides.

A suitable site for housing is very important. It is better to select a site which has good drainage, adequate shade like under trees, and with sufficient surrounding space from strong winds. Basically the shelter must protect rabbits from extreme temperatures and predators like snakes, mongoose, dogs and other animals.

Rabbits can be raised inside the building also or outside in hutches with a protective roof. A hutch is a small building containing cages for housing a few rabbits (6 to 12) a back-yard scale. They are generally made of wood or stone one and chicken wire mesh. The floor may be made of a stronger ranger mesh or soil floor bedded with straw. Hutches can also be constructed with local building materials such as tree and woven split bamboo, etc.

Introduction: Most young rabbits will be used for meat and skins; some will be kept for breeding. Whatever they are used for, the rabbit keeper will benefit if they are well cared for.

Handling of Rabbits: There will be times in any rabbitry when the animals will have to be picked up, e.g. when a doe is moved to a breeding hutch or when young rabbits are weaned.

When it is necessary to pick up a rabbit for any purpose, the aim should be to cause it no discomfort and to prevent it struggling. So it must be handled gently but firmly. There are three ways to hold a rabbit according to its size. 

Breeds of Rabbit

There are many breeds of domestic rabbits in the world and all have different qualities. Out of the number of breeds and varieties about 38 breeds and 87 varieties are recognized and well established world wide.

For commercial purposes, the most important differences between rabbits are their size, colour breeding ability and suitability to the climate. Examples of several different breeds of rabbits are given below. Some of these might be used for improving local rabbit herds.

Brief History

Fondness of man for rabbits is well established by its appearance in the Aesop’s fables and Vishnu Sharma’s ‘Panchtantra, both of which date back to 2nd century B.C. However, domestic rabbits are descendents of wild species of Western Europe and North Western Africa where Oryctolagus still exists. Interestingly, it was the Romans who first raised rabbits in leporaria (enclosed warrens) as a game animal. Like Spaniards, Romans also ate fetuses of newborn young ones whom they called laurices. These leporaria ultimately paved the way for development of game parks in the Middle Ages. The monks ate laurices during Lent because they were an aquatic dish.

Rabbit domestication dates back no farther than the previous millennium. It were the Phoenicians who are said to have discovered the wild rabbit Oryctolagus cuniculus of Southern Europe and North Africa when they reached the shores of Spain about 1000 B.C. In Roman times, the rabbit was still emblematic of Spain. The Roman spread the rabbit throughout the empire as a game animal. Like the Spaniards, the Romans also ate foetuses or new born rabbits, which they called laurices. It then becomes a practice that the rabbits were kept in leporarian, stone –walled pens or parks for hunting purposes. These leporaria ultimately paved the way for the development of game parks in the middle Ages. The monks ate laurices during lent because they were an aquatic dish. In France, only the lord of the manor could maintain a warren.

Preference of herbicides for weed management in Agriculture and Horticulture

Weeds are unwanted and undesirable plants which interfere with the utilization of land and water resources and pollute atmosphere with their allergic pollen thus affecting human welfare adversely.  They are the plants out of place, growing where we want other plants or no plants at all.  They compete with desirable and beneficial vegetation reducing the yield and quality of the produce.  The effect of weeds in agriculture or horticulture is greatest.  There is a scanty reliable study of worldwide damage to crop yields due to weeds.  Whether the data are available or not, it is well known that losses caused by weeds exceed the losses from any category of agricultural pest, viz., insects, nematodes, diseases, rodents etc. Weeds account for 45% while insects 30%, diseases 20% and other pests 5% of the total annual loss of agricultural produce186.

Introduction

India has a big challenge in fruit production in the current backdrop of decreasing per capita land holding and static fruit productivity. In recent years, China has surpassed and secured top position in the fruit production in the world accounting for 4,44,651 mt production followed by India and Brazil.  Now Chinese share in the fruit production is around 13 per cent while India contributes 10.2 per cent, Brazil 8 per cent and USA 6 per cent of total fruit production.

India is bestowed with a wide variety of agro-climatic conditions and enjoys an enviable position in the horticultural map of the world. Almost all types of fruit crops (tropical, sub-tropical and temperate) are grown in one or other part in the country.  The major tropical and sub-tropical fruits grown in India include mango, banana, papaya, orange, mosambi, guava, grape, pineapple, coconut, sapota, ber, pomegranate, litchi, aonla, bael, jackfruit etc.  Cashew nut cultivation has a big potential and its production, productivity and export has increased significantly in recent decades. Indian grape has recorded highest productivity per unit area in the world. The productivity of fruit per unit area in India has increased nearly from 10 t/ha to 12 t/ha in almost one decade.  However, the average productivity in most of the fruit crops is far below than satisfactory except grape and banana in few states.  It is paradox to record that India’s contribution in the overseas market is almost (0.11 per cent) negligible (Chadha, 2000). However, other countries like Mexico, Philippines and Venezuela, which produce far less, export 4 per cent of their total production.

Introduction

To keep pace with the ever-increasing demand for crop yield by the exploding population, use of chemical fertilizers and pesticides in agricultural production has become indispensable.  Production cost of agriculture has skyrocketed owing to the abandoning of green, organic farmyard manure and use of chemicals. However, the problems associated with chemical pesticides are abundant. The excessive application of chemical fertilizers causes soil sealing, fertility diminishing and residual problems. The leftover chemical fertilizers and pesticides have seriously affected the quality of agricultural products, people’s health and caused environmental pollution.  The over use of fertilizers has also damaged the soil’s original micro-ecological balance and deteriorated the diseases spread by soil.  While some pesticides must be abandoned because of their unacceptable non-target effect, there will always be a need in agriculture for safe and selective chemicals to limit the effects of pests.  More significantly, it is becoming increasingly more difficult and expensive to find new kinds of synthetic chemical pesticides.  Implications of chemical pesticides in ecological, environmental and human health problems have increased public awareness and concern regarding the continued use of agrichemicals that are damaging to human or  environmental health thereby obviating the search for effective alternative approaches which have minimal deleterious effects, more environmentally friendly, and will contribute to the goal of sustainability in agriculture.  In this line Plant growth-promoting rhizobacteria (PGPR) present immense potential and promise as effective substitutes for chemicals.  PGPR enhance plant growth and survival, control soil-borne fungi, and induces systemic resistance to phytopathogens and is used as inoculants for biofertilization, phytostimulation and biocontrol.

Introduction

After water, nitrogen is the most critical nutritive element for crop productivity and human efforts to produce food and energy have greatly changed the nitrogen cycle of the earth. Sustainable cropping systems throughout history and across the world have relied on the combination of a cereal with an N-fixing legume. In recent history, cereals have dominated global agriculture, while legume areas and productivity have stagnated or even declined. An atmosphere around us contains nearly 78% nitrogen, which is in free form. Hence it is not available to plants. At present, India produces around 206 million metric tones of foodgrains for its growing population, increased foodgrain cannot be produced unless we carefully make use of biological nitrogen. Biological nitrogen fixation is the key to sustain agricultural productivity through the application of biofertilizers in the field. However, there is an urgent need to transfer this technology on the field to farmers and industry by producing these fertilizers on large scale.

INTRODUCTION

One of the most dangerous ecological crises being faced by all living organism now-a-days is the pollution of the environment. It is easier to describe pollution rather than to define it. It is presumed that the environment in past was more or less pure. But due to various activities of man such as industrialization, urbanization, agricultural practices etc, composition of the environment gets changed which is called environmental pollution. Any substance that creates pollution is called ‘pollutant’. There are different types of pollution among which pollution caused by toxic level of heavy metal pollutants is called heavy metal pollution.

Heavy metal pollution is a problematic field of research and is gaining immense importance now-a-days. We have 104 elements in the periodic classification of which 80 are metals. According to Passow et al. (1961), heavy metals are those having densities more than five (5 g cc^-1) and atomic weight twenty three. The term ‘heavy metal’ is imprecise but is widely used although others such as ‘toxic metal’, ‘trace element’ are possible alternatives. Sources of these heavy metals are varying; some of these are encountered in water, air effluent, solid waste and sewage. They are emitted out from various sources e.g. waste water from electroplating industry (Cr, Ni), air emission from fluorescent lamps (Cd, Be), paint pigment waste (Pb, Cr), auto-exhaust emissions (Pb, Te) etc.