eChapters

Introduction

In general economic model, technological change in agriculture is expected to cause the commodity supply curve to shift down and out against a stationary demand curve, giving rise to an increase in quantity produced and consumed, and at a relatively lower price. Agricultural economists have used supply and demand models of commodity markets to represent agricultural research impacts, beginning with Schultz (1953) and Griliches (1958), with important subsequent contributions by Duncan and Tisdell (1971), Akino and Hayami (1975), among others. Such a model is explicitly used in many studies. However, low crop productivity, food insecurity, hunger and malnutrition; inadequate farming knowledge and skills, implements and inputs are characteristic of smallholder agriculture in developing countries including India. Many researchers argue that conservation agriculture can guarantee higher crop productivity, food security, improved net income of the farmers and environmental protection, better than the traditional systems of cultivation practices.

Introduction 

Conservation tillage has been defined based on percent cover of the soil surface with crop residue (CTIC, 2000). Quantifying crop residue cover on the soil surface is important for improving estimates of surface energy balance, net primary productivity, nutrient cycling, and carbon sequestration. Quantifying crop residue cover is also an important factor in controlling soil erosion and evaluating the effectiveness of conservation tillage practices (Barnes et al., 2003). Collecting this information by conventional method of survey and line transact are time-consuming, labor intensive, costly and can involve destructive sampling (Morrison et al., 1993). Moreover, field data are limited because they provide point, rather than area information. Remote sensing technique revealed as promising tool in providing such spatial data over a large area in a time and cost-effective manner.

Soil microorganisms are believed to play a major regulatory role in organic carbon dynamics, as key architects in nutrient transformation, and physical engineering of soil structure. The microbial populations of the soil alone encompass an enormous diversity of bacteria, algae, fungi, protozoa, and actinomycetes. Microbial diversity is being regulated by substrate and water availability, temperature, climatic regime and soil structure, which is considered as a transformation agent for soil organic matter and a labile pool of organic and inorganic nutrients. Extensive cultivation with repeated tillage operation often disrupts soil aggregates stability and destroys aggregates carbon and therefore, soil lose their physical properties and nutrient supplying capacity in a long-run.

Soil and nutrients are important factors for sustainable crop production in agriculture. Water erosion contributes more than 60% to the area under soil degradation in India. Soil erosion has been a serious threat to sustainable agriculture. However, soil and water conservation measures plays important role in improving the productivity of natural resources. India presently supports 17% of the global population with a geographical area of 329 Mha on merely 2.5% world’s land area and 4% fresh water resources. The net cultivable area in the country is about 140Mha is remaining constant or even squeezing from the pressures of urbanization, industrialization, infrastructure development and to house the ever increasing population. The loss of productive soil is another concern. The loss of fertile top soil by water erosion is estimated to be about 5334 Mt per year with it nearly 8.4 million tonnes (mt) of nutrients was estimated in eroded soil still holds true about in i.e. 2.5 mt nitrogen, 3.3 mt phosphorus and 2.6 mt potassium per hectare is lost due to ill soil and water management practices (Dhruvanarayana and Ram Babu, 1983).

Abstract

Modern agriculture has disturbed the age-old balance of host-pathogen system resulting diseases occur at regular interval leading to enormous loss to the agricultural production, which is estimated to be 10-25% or less during normal years but may extend up to 100 % during epidemic. Broadly, there are two breeding approaches adopted for disease resistance which includes conventional and molecular one. Conventional approach includes pureline, pedigree, backcross, recurrent selection and interspecific hybrids through which various resistant varieties has been developed. However, after sometime there is sudden outbreak of diseases due to continuous sowing of these varieties which results in the advancement in molecular biology and with the discovery of trait linked markers it paved a new pathway to look a new corner to develop varieties which are disease resistant. Molecular approach consists of gene pyramiding through which two or more genes providing resistance to different types of diseases is introgressed in a particular variety, gene deployment and multiline varieties which consists of heterogeneous population formed by mixing the cultivars to differ in the ability of disease resistance and reduces the rate of epidemic development. With the help of makers in marker assisted breeding using foreground, recombinant and background selection several linked markers are identified which provides resistance against disease like in wheat stem rust, leaf rust etc.

Introduction

With the change in global scenario there is increase in pressure of meeting the food requirements of rapid growing population but due to scarcity of resources it is becoming very difficult to meet the needs of present population but even if there is so much problem still nature has provided solution to sort out from it through hybrid seed production through male sterility. As male sterility is a condition in which pollen grain is either absent or non-functional in the pollen grain. Its first case was reported by Koelreuter in 1763. Later many scientist have reported about its role in hybrid seed production. Mainly the male sterility is characterized by malformation of androecium, lack of normal anther sac, inability of pollen to mature or to release from the anther sac and inability to develop normal microspore or pollen. Due to such malformation male sterility is characterized into phenotypic male sterility, genotypic male sterility and chemically induced male sterility. Later in 1998, Kaul further generalised the phenotypic male sterility into structural, sporogenous and functional male sterility. In case of structural male sterility stamens are completely absent or if present then it is either malformed or modified into other floral part. While in case of sporogenous male sterility a case of abnormal microsporogenesis has been reported. In functional male sterility pollen development is normal but its function is impaired.Genotypic male sterility which is further classified into genetic, cytoplasmic and cytoplasmic genetic male sterility.

Introduction

Agriculture is one of the promising sectors which offers marvelous potential for sustainable growth and play a key role in the economy of the country. Many of the foods that are already common in our diet are obtained from plant varieties that were developed using conventional genetic techniques of breeding and selection. Increase in the world population and limited food supply strained researchers to introduce and advance agriculture management and modern technologies along with conventional practices to attain highest possible crop productivity. Agricultural technology is based on the domestication of wild plants to create the crops that we have come to depend upon. Humans invented agriculture approximately 10,000 years ago when they began to harvest and cultivate specific plants to produce food. The improved plant traits selected by early agriculturalists were transmitted genetically to succeeding generations of plants. Both public institutions and private companies are now involved in crop genetic improvement.

Abstract

Abiotic stresses have been a serious challenge for sustainable agriculture particularly vegetable cultivation characterized by decreased endurance against stresses like drought, temperature fluctuation and salinity. In India, drought and salinity being major abiotic stresses affect an area of 16% and 4.28%, respectively. Plant Breeders have to face many impediments while developing stress tolerant varieties. Developing tolerant varieties is quite difficult as tolerance varies with the developmental stages and has complex inheritance. This can be understood well by studying ontogeny of plants. Drought varies in time of occurrence, severity and duration. Field screening for tolerance is very difficult because of various interactions like drought × high temperature, high temperature × salinity interactions etc. Artificial screening in different stresses could be an alternative approach. The varieties developed with higher inputs at research stations fail to perform at farmers’ fields due to high genotype × environment interactions. Cultivated species have less genetic variability for abiotic stress tolerance but tolerance can be enhanced by using diverse and heterogeneous population. Though wild species possess genes for tolerance but these genes are closely linked with the undesirable gene(s) e.g. in tomato where S. cheesmanii, S. peruvianum, S. pimpinellifolium and S. sitiens have undesirable traits which affect yield and quality adversely.

Abstract

Brassica vegetables belonging to family Brassicaceae are one of the most important groups of cool season vegetables. Initially, these crops were confined to Europe and other temperate regions. But, after the Second World War, their cultivation has spread to tropics and sub tropics as well. All the members of this group have originated primarily from the common ancestor wild cabbage (Brassica oleracea var. oleracea) and are fully cross-compatible with each other. In general, these are highly cross pollinated crops and have shown preponderance of non-additive gene action for most of the economic traits thereby suggesting the relevance of heterosis breeding. In the absence of appropriate genetic mechanism for the production of hybrid seed with ease at relatively lower cost, heterosis in a crop is of no practical value. Fortunately, the presence of natural genetic phenomenon of sporophytic self incompatibility and male sterility (particularly CMS) in brassica vegetables has proved instrumental in commercialization of hybrid seed production.

Introduction

India is a rich center of plant diversity due to varied climatic conditions as well as soil qualities which provide a better platform for the diverse plant groups. In India around 45000 plant species are spread over the area (Mayers, 1988). These plant species multiply and produces the new plant. The multiplication of plants is termed as propagation and the art of propagation is as old as civilization of human being. The history of civilization began with the propagation and growing of plants. Plant propagation was in practice in pre-historic period. However, the propagation process has got commercial popularity only recently. The success in plant propagation depends on a thorough knowledge of the growth of plants, choice of suitable method and technical skill. In nature, plants multiply naturally to perpetuate themselves. Now-a-days, propagation practices have been totally modernized and became advanced from field to in vitro. Variation in plant propagation can be observed in the nature like some plants are producing many seeds for future generation with their unique type of dispersal mechanism. Among a large

Abstract

A perennial plant or simply perennial is a plant that lives for more than two years. The term is often used to differentiate a plant from shorter-lived annuals and biennials. The term is also widely used to distinguish plants with little or no woody growth from trees and shrubs, which are also technically perennials. in vitro technologies are continuously expanding in the field of biology. Plant tissue culture has become a general title for a very broad subject. Commercial use of micropropagation is still limited, because of its relatively high production cost resulting mainly from high labor costs, low growth rate in vitro, and poor survival rate of the plantlets during acclimatization. Micropropagation of woody perennials is essential due their importance in production of secondary metabolites, which are playing a vital role now a days. Stages of micropropagation i.e mother plant selection, establishment of the aseptic culture, multiplication, root regeneration and transfer to the natural environment, which are systematically reproduced in many protocols which will aids in micropropagation studies of many woody perennials. Thus the review of present study attempts to provide a comprehensive account on micropropagation of woody perennials complementing conventional programmes for improvement.

Abstract

Plant research often involves growing new plants in a controlled environment. These may be plants that we have genetically altered in some way or may be plants of which we need many copies all exactly alike. These things can be accomplished through tissue culture of small tissue pieces from the plant of interest. The latest list of ISO recognizes 109 spices, but only a few are important commercially such as black pepper, cardamom, ginger, turmeric, large cardamom, cumin, coriander, fennel, fenugreek, garlic, saffron and celery. They are extensively used in flavouring food and confectionery, perfumery and soaps and also as colouring materials. Many of these groups of crops have medicinal properties and are used in many Ayurvedic and Unani medicines. Inspite of the rich diversity and importance, the productivity of spices is low in India. Spices are an important group of economic plants with large genetic diversity in the Indian subcontinent and need to be conserved through in- vitro methods. Conservation of the germplasm using traditional method of field maintenance is problematic, normally labour intensive and also face risk of germplasm loss due to pest/pathogen attack or natural disasters. To minimize the problems of their conservation and increasing interest has been shown to use plant tissue culture. In vitro conservation of germplasm has been reported in various crop species including the spices black pepper, cardamom, ginger, turmeric, large cardamom.

Introduction

Healthy seeds and seedlings are the first and essential requirement for achieving full yield potential of any vegetable crop. In recent years, vegetable growers have become highly conscious of the importance of quality seeds or seedlings. A major portion of the area under vegetable cultivation in India is now sown with hybrid seeds, which are costly but give higher yields and quality produce. In view of the high cost of seeds, some vegetable crops like tomato, brinjal, capsicum and cucurbits are being transplanted after growing nursery under protected conditions to achieve maximum germination count and healthy plant establishment. Raising of seedlings in plug trays or portrays is one such technology that achieves the above requirement. This technology is fast emerging as agro enterprise in India for its obvious advantage to both the nursery grower and the farmer. Soil-less substrate consisting of coco-peat and vermiculite is filled in plug trays and one seed is manually placed in each cell of the plug tray. However, manual seeding is labour-intensive operation requiring about more labour and time consuming. Mechanized precision seeding of plug trays is, therefore, necessary to enhance the capacity of rapidly growing nursery industry in India.

Introduction

Controlled perpetuation of plants is known as plant propagation. Plant propagation can be broadly classified in two types: sexual and asexual. In sexual propagation, the fusion of male and female gametes gives rise to a new plant, whereas in asexual propagation which is also known as vegetative propagation, the development of new plants takes place without the fusion of male and female gametes, that is, the new plant develops from vegetative plant parts. Various techniques of asexual propagation are adopted in plant propagation, such as: grafting, budding, layering, cutting, etc. So far cutting and layering are concerned; the new plants are developed on their own root system, but in grafting and budding on the others’ root system. It means that in these two techniques (grafting and budding), two plant parts are joined to form new plants; the one which forms the root system is known as rootstock and the one forming the shoot system is known as scion. Plant propagation is both a science and an art. The science of plant propagation requires knowledge of plant physiology, nursery cultural practices, and characteristics of the particular plant that you want to grow. The art of plant propagation cannot be taught in a book or classroom, however, because it consists of specific technical skills that must be acquired through innate ability or experience and often requires a certain feel.

Object: Preparation of solutions. 

Material required: Volumetric flask, measuring cylinder, beakers, pipettes, balance, distilled water and chemicals. 

Theory: The use of solution is common in experimental procedures of plant physiology. It is very important for a student to be familiar with their preparation. The substance dissolved in a solution is called solute and the medium in which it is dissolved is known as solvent. Solutions of two liquids (e.g. alcohol in water) and solid in liquid (e.g. NaCl in water) are most common. Solutions are thus a homogenous mixture of a solute in a solvent. 

Object: To demonstrate the phenomenon of osmosis using potato osmoscope. 

Material required: A potato tuber, sugar solution, beaker, water, petridish, knife, measuring cylinder, and stand.

Theory: Osmosis is a phenomenon in which water molecules diffuse through the semi permeable membrane from region of its higher concentration to the region of lower concentration.

Object: To demonstrate the phenomenon of endosmosis and exosmosis by using grapes and raisins.

Material required: Grapes, raisins, beaker or petridish, water and sugar solution.

Object: To demonstrate the process of diffusion.

Material required: Beakers, copper sulphate, distilled water and sugar solution.

Object: Methods of measurement of water status and water saturation deficit in plant parts. 

Material required: Leaf samples, leaf borer, water, petridishes, forceps, oven and blotting paper. 

Theory: Plant water status strongly influences plant growth and biomass production through its effects on leaf and root expansion and on photosynthesis. Therefore, measurement of plant water status is an important component of understanding plant processes and maximizing yield under different ecosystems. 

Method: Plant water status can be measured and computed by any one of the following methods

Object: Estimation of water potential of plant tissue by Chardakov’s method.

Material required: Test tubes, sucrose or polyethylene glycol (PEG) 6000, methylene blue and dropper.

Principle: Concentration of the solution in which a plant tissue is immersed changes. If the solution is hypertonic (with lesser yw) the tissue loses water and the solution becomes dilute. If the solution is hypotonic (with higher yW) the tissue absorbs water and the Solution becomes concentrated. If the solution is isotonic (with yw equal to the tissue sap) the tissue neither loses nor absorbs water and the solution concentration does not change. Thus the yw of this solution gives the yw of the tissue.

Objective: Estimation of photosynthetic pigment from plant leaves.

Material required: Plant leaves, test tube, test tube stand, spectrophotometer, balance, centrifuge machine, mortar and pestle, acetone and distilled water.

Theory: Photosynthetic pigments, namely, the chlorophylls are present in green leaves and shoots of plants. There are at least five types of chlorophylls in plants. Chl’a’ and ‘b’ occur in higher plants, ferns and mosses. Chl ‘c’,‘d’ and ‘e’ are found only in algae and in certain bacteria. Chlorophylls are extracted from plant leaves. The absorption peaks of chl ‘a’ at 663 nm and ‘b’ at 645 nm are characteristic measures from which amount of chlorophylls can be calculated.

Object: Measurement of absorption spectrum of chloroplastic pigments.

Material required: Spectrophotometer, plant leaves, ethanol, electric balance, beaker, test tubes and water.

Object: To demonstrate chlorophyll fluorescence.

Material required: Spectrophotometer, fresh green spinach, mortar, pestle, acid washed sand, acetone, funnel, filter paper and test tubes.

Principle: Chlorophyll molecule absorbs light in the blue (450nm) and red (660nm) region and get into excited state and emits an electron. The electron drops back to the ground state within 10-9 seconds and some energy (which is not used in biochemical reaction) are given out as the observed fluorescent far red light.

Procedure and observation: Take some soft green spinach leaves. Grind these with a pestle -mortar in acetone adding a pinch of acid washed sand. Make a fine paste. Filter to get a clear solution in a test tube. Take the test tube in bright sun light.

Object: Measurement of leaf area by graph paper method.

Material required: leaves, graph paper and pencil or pen.

Object: Estimation of stomatal index and stomatal frequency with replica method.

Material required: Leaf sample, blue/red correction fluid, transparent finger nail polish, brush glass slide and microscope.

Principle: The number of stomata per unit area of the leaf is called as Stomatal Frequency. The stomatal index is defined as the percentage number of Stomata as compared to all the epidermal cells in a unit area of leaf i.e.

Object: Demonstration of leaf anatomy or structure of C₃ and C₄ Plants (demonstration by already prepared slides).

Material required: Already prepared slides of corn and wheat leaves and microscope.

Object: To demonstrate that water is lost from a living plant during transpiration. 

Material Required: A potted healthy plant, a bell jar, a rubber sheet or oil cloth, a glass sheet and grease.

Theory: Transpiration: Loss of water in the form of water vapour from the internal tissues of living plants through aerial parts of the plant is known as transpiration.

Object: To measure rate of transpiration of potted plant by gravimetric (Lysimeter) method. 

Material required: Potted plants, Polythene sheet, Platform and electric balance etc.

Method: Select same size and same type well watered potted intact plants. Seal the pots and the root system with a sheet of polythene so that the water loss to the atmosphere occurs only from the shoot system not from the soil (To check evaporation losses). Immediately record the weight of the potted plant and keep them in different environment such as (1) warm environment (2) cool environment (3) Calm environment.

Object: To measure the rate of transpiration by using Ganong’s potometer

Material required: Ganong’s potometer, beaker, wax or vaseline, stop watch and twig or a branch of a plant.

Theory: The amount of water absorbed is almost equal to the amount of water transpired. The difference between the two amounts is negligible. 

Method: Potometer consists of wide mouthed tube fitted with a hard cork in which a twig or branch of a plant is inserted. Other end of tube is dipped in beaker. One half of the tube is graduated. The apparatus is filled with water using the reservoir. An air bubble is inserted in the tube as shown in figure.

Object: To find out the relation between transpiration and absorption. 

Material Required: Wide mouthed glass bottle, with a narrow graduated side tube, split rubber cork, water and a plant with intact root system.

Theory: The loss in weight of plant indicates the amount of water transpired. And fall in water level of the side tube indicates the amount of water absorbed. This shows that amount of water transpired is normally equal to the amount of water absorbed by the plant roots.

Object: To demonstrate unequal transpiration by the two leaf surfaces from four leaf method. 

Material required: four leaves of china rose or any dorsiventral leaves, two stands, thread and grease or vaseline. 

Theory: Transpiration is a process in which loss of water occurs in the form of water vapour from the aerial parts of the living plant. 

Method: Take four leaves of equal size from a plant (e.g. China rose). Now apply or smear the vaseline on the four leaves as follows:

Object: To demonstrate that light and carbon dioxide are essential for photosynthesis (Moll’s half leaf experiment). 

Material Required: A potted plant, a wide mouthed bottle, caustic potash, splits of rubber Cork and vaseline etc. 

Object: To demonstrate that O₂ is evolved during photosynthesis. 
 

Material required: Hydrilla plant, beaker, test tube, funnel, pond water and pyrogallol. 
 

Theory: Oxygen is a byproduct of photosynthesis, which is evolved in presence of light and chlorophyll during photosynthesis.

Object: To demonstrate anaerobic respiration. 

Material required: Soaked pea or gram seeds, mercury, test tube stand, forceps and KOH pellets. 

Theory: Generally, plants at certain stage have the capacity to respire in absence of oxygen i.e. anaerobic respiration. In this process, oxidation of carbohydrate takes places, ethyl alcohol and CO2 being end products and only a little amount of energy is liberated-

Object: To demonstrate that oxygen is used up during respiration. 

Material required: A conical flask, some germinating seeds, glass tube having two bends at right angles, mercury, beaker, small tube and caustic potash (KOH).

Theory: Plants at some stage have a capacity to respire more rapidly in presence of oxygen i.e. aerobic respiration. In this process, oxidation of carbohydrate occurs resulting in conversion of carbohydrate into carbon dioxide (CO₂) and water with release of large amount of energy.

Object: To determine respiratory quotient of different types of respiratory substrates.

Object: To demonstrate the optimum conditions for seed germination. 

Material required: Beaker, glass slide, bean seeds, thread and water.

Theory: Germination is a process by which the embryo in the seed becomes activated and begins to grow into a new seedling under favorable conditions. Food is stored in the seeds in dry conditions but the developing embryo cannot utilize this dry food. Food can be utilized in liquid form only and seeds can utilize only dissolved oxygen. Excess water stop germination because once all the dissolves oxygen is utilized by the seed, further germination is not possible as the life supporting oxygen is lacking. Suitable temperature is necessary because low temperature retards the embryo activity and high temperature destroys the delicate embryo tissue. Seed usually germinate between 0oC to 50oC temperature and the optimum temperature is lies between 25 to 30oC. During germination rapid cell division takes place. Energy is required for cell division. This energy is obtained from oxidation. The oxygen is required for oxidation is supplied by the air.

Object: Breaking of seed dormancy to facilitate germination.

Material required: Seeds, water, sharp needle, sharp razor, sandpaper, acids, Potassium nitrate and gibberellic acid. 

Definition: Inability of a viable seed to respond the favorable environmental conditions for germination is known as dormancy.

Object: Determination of the viability of seeds by tetrazolium test. 

Material required: Healthy seeds, tetrazolium solutions, beakers, water and petridishes. 

Theory: Viability of seeds shows their potential towards germination.

Object: To demonstrate the measurement of growth in plants with the help of Arc auxanometer. 

Material required: Potted plant, Arc auxanometer, rope and weight.

Theory: Growth is a permanent change in plants with respect to its size, form, weight and volume.

Object: Growth analysis: Calculation of growth parameters. 

Material required: Primary data collected from individual plants or derived from whole canopies. 

Theory: The growth analysis study provides information on the growth of plants or of a plant community in a precise way with the available’ raw data. The study also provides precise information on the nature of plant and environment interaction in a particular habitat.

Object: Yield estimation of kharif crops.

Material required: Polythene bags, balance, gunny bags or baskets, pans and harvesting equipment like sickle, knife etc.

Theory: Yield is the ultimate objective of cultivating agricultural plants. Different plant parts constitute the economic yield in different crops, like grain in cereals, pulses and oil seeds, vegetative parts or fruits in record yield at the correct maturation stage. Do not allow excessive wilting or drying of the material. Estimate yield in a sufficiently large sample. Materials required only a representative crop to estimate yields. (Do not select plants of any particular type. Do not damage any plant part vegetable crops; bark or out growth in fiber crops (jute, cotton); and the entire plant in fodder crops. The yield per unit area (per M₂ or ha) is the product of yield per plant multiplied by the number of plants per unit area. It is, therefore, essential to know the yield components per plant as well as per unit area.

Object: Effect of ethylene on regulation of stomata.

Material required: Plant leaves, ethaphon, ACC, double distilled water, measuring cylinder, beaker and electric balance.

Theory: Ethylene is a plant hormone that regulates many aspects of growth and development. Despite the well-known association between ethylene and stress signalling, its effects on stomatal movements are largely unexplored. Here, genetic and physiological data are provided that position ethylene into the Arabidopsis guard cell signalling network, and demonstrate a functional link between ethylene and hydrogen peroxide (H₂O₂). In wild-type leaves, ethylene induces stomatal closure that is dependent on H₂O₂ production in guard cells, generated by the nicotinamide adenine dinucleotide phosphate hydrogen (NADPH) oxidase AtrbohF. 

We are entering an era when certain environmental conditions will exert a degree of concern which has never been before encountered by man in the course of human history.

The survival of human beings depends on the realisation that they have to live in harmony with the various elements of the environment which are interconnected.
    
(i)     An understanding of the components and processes which takes place in the environment.
    
(ii)     The relationship between different abiotic and biotic components and the assessment of resources with reference to needs of people in a region is essential for their survival.
    
(iii)     A reduction in rate of growth of population in developing countries and a reduction in consumption of resources by developed countries would lead to a balance between population and resources. In this manner, the awareness of the problems faced by environment would enable people to take appropriate decisions. This makes the earth habitable for future generations.

“Natural” means an ecosystem not influenced by man and resources means that reserve stock of supply which living things can take from nature for sustenance of life. In reference to man, natural resources can be defined as those natural reserve stocks of supply which man utilizes for his sustenance and welfare. The reservoirs of natural resources are the sun,  the  atmosphere,  the  lithosphere  and the  hydrosphere.  Natural resources include energy, air, water, soil, minerals, plants and animals. The nature of resource depends upon many factors such as scientific and technological development of the society, profession of that particular society, and culture.

Conservation has always been one of the most important applications of ecology.Unfortunately, the term “conservation” suggest “hoarding”, as if the idea were simply to ration static supplies so that there would be some left for the future. In the eye of the general public the “conservationist” is too often presumed to be an antisocial person who is against any kind of “development”. What the real conservationist is  against  is unplanned  development  that breaks  ecological  as  well as human laws. The true aim of conservation, is two fold–
    
(1)     To ensure the  preservation of a  quality  environment that considers esthetic and recreational as well as product needs; and  
    
(2)     To ensure as continuous yield of useful plants, animals and materials by establishing a balanced cycle of harvest and renewal.

Any living organism in its natural habitat is called a wildlife. It may be plant animal or a microbe. The significance of wild life lies in setting up the balance of population in nature by maintaining food chains and food webs. It acts as the gene banks in relation to breeding of plants and animals for introduction of desirable characters such as high yield of economic product and resistance to diseases. The scientists are performing studies to screen and select useful genes in economically important organisms.

Air is one of the most important constituents of man’s environment. It is calculated that a roan breathes about 22,000 times a day inhaling about 16 kg of air by weight. Air is present everywhere and its entrance from one place to another cannot be checked. Clean and pure air is very essential for the health and survival of man.

The ‘greenhouse effect’ earns its name from the rough similarity between the way it works and the way the glass of a greenhouse works. Glass too, is transparent to short-wave radiation but opaque to long-wave radiation, so the greenhouse traps heat.
Carbon dioxide plays a critical role in controlling the Earth’s climate because as an aerosol it absorbs and reflects or scatters incoming radiation on the one hand and absorbs and reradiates outgoing infrared radiation on the other. This latter phenomenon results in what is popularly called the Greenhouse Effect, an analogy to what happens in a greenhouse.

El Nino is the name given to the occasional development of warm ocean surface waters along the coast of Ecuador and Peru. When this warming occurs the usual upwelling of cold, nutrient rich deep ocean water is significantly reduced. El Nino normally occurs around Christmas and lasts usually for a few weeks to a few months. Sometimes an extremely warm event can develop that lasts for much longer time periods. In the 1990s, strong El Ninos developed in 1991 and lasted until 1995, and from fall 1997 to spring 1998.