eChapters

6.1 Introduction

All separation procedures depend mainly on some physical characteristics of the compounds. It is relatively easy to separate compounds that have significantly different physical characteristics by simple techniques such as solvent extraction. If the various compounds are similar to each other in their molecular size, any slight difference in any one of their physical properties is exploited to achieve separation. The separation and purification of plant constituents is mainly carried out using one or other, or a combination of chromatographic techniques: Paper Chromatography (PC), Thin Layer Chromatography (TLC), Column Chromatography (CC), High Performance Liquid Chromatography (HPTLC), Optimum Performance Laminar Chromatography (OPLC), Gas Liquid Chromatography (GLC) and High Performance Liquid Chromatography (HPLC). One further technique, which has fairly wide application in phytochemistry, is electrophoresis.

7.1 Introduction

For qualitative and quantitative analysis of phytochemicals, chromatography can be used. Gas chromatography is a powerful means of performing qualitative and quantitative measurements of complex mixtures of volatile substances, which are vaporizable without decomposition.Gas Chromatography-Mass Spectrometry (GCMS) system is a widely used instrument for qualitative and quantitative analysis of solid, liquid, and gaseous samples. Samples are converted into gaseous ions and then separated on the basis of their mass-tocharge ratio. This technique is capable of providing information about 1. the qualitative and quantitative composition of both inorganic and organic analytes in complex mixtures; 2. the structure of a wide variety of complex molecular structures; 3. isotopic ratios of atoms in samples; and 4. the structure and composition of solid surfaces. High performance liquid chromatography (HPLC) is a physico-chemical separation technique for the qualitative and quantitative analysis of mixtures consisting of compounds soluble in solvents, e.g. all organic compounds and inorganic ions. Advances in the applications of thin-layer chromatography (TLC) and high-performance thin-layer chromatography (HPTLC) for the separation, detection, and qualitative and quantitative determination of compounds has also increased.

8.1 Introduction

After isolation and purification of the compound, it has to be identified. It is necessary to find out the class of the compound first and then to find out the specific compound within the class. The class of compound is usually determined from the colour tests, solubility, Rf properties and UV spectral characteristics of the compound. Further identification within the class depends on measuring physical properties and spectral measurements and then comparing these data with those in the literature. The physical properties include melting point (for solids), boiling point (for liquids), optical rotation (for optically active compounds) and Rf. The spectral measurements include Ultra Violet (UV) , Infra Red (IR) , Mass Spectrum (MS) and Nuclear Magnetic Resonance (NMR). Data on X – ray crystallography of the compound are also useful for identification of the compound.

On completion of the analysis of the spectra obtained, the pieces that have been identified are listed. Then the pieces, the MW and / or molecular formula are checked and the pieces are refined to fit. Finally, the pieces are assembled paying particular attention to ¹H-NMR chemical shifts and coupling patterns. The answer should be checked with the ¹H-NMR data very carefully and it is probably the most critical test to pass. The ¹H-NMR spectrum is potentially the most useful for assembling the structure of the compound.

A known compound can usually be identified on the basis of the above mentioned physical and spectral characteristics. For final confirmation, direct comparison with authentic compound (if available) should be carried out Authentic compounds can be obtained from commercial companies. In the absence of authentic compound, the data from literature can be carefully compared for the identification of the isolated compound. If a new compound is present, all the above data are sufficient enough to identify it. However, data on chemical degradation or laboratory synthesis of the compound are necessary to confirm the identification of the new compound.

9.1 Introduction

Phytochemicals are the individual chemicals from which the plants are made. Phytochemical is simply a word that means plant chemicals. Plants have the ability to synthesize mixtures of structurally diverse bioactive compounds with multiple and mutually potential therapeutic effects. The plants have the capacity of manufacturing the secondary products. Phytochemicals with antioxidant properties tend to be brightly colored because they contain chromophores, ie, a series of alternating single-bonded and double-bonded carbons. Isoprene is often the building block of such units. The darkest green vegetables contain the most chlorophyll, and vegetables with the most chlorophyll require the most antioxidants. Green will mask the other colors, when other-colored antioxidant phytochemicals are present. Hundreds of phytochemicals are currently being studied. Many are believed to have a major positive impact on human health (Duke and Sternberg, 2005). Important plant secondary metabolites have been isolated over a period of time from natural sources. The phytochemical may belong to the following categories : Terpenoids, Phenolic compounds, Alkaloids, Glycosides, Carbohydrates, Lipids, Proteins, Nucleic acids, etc. Some of the phytochemicals from the plants are listed in Table 9.1 and structures of some of them are given in Fig.9.1.

10.1 Introduction

The following plants have been worked out in the laboratory of Prof. N. Raaman: Cynodon dactylon, Artemisia pallens, Leptadenia reticulata, Clausena dentata, Tylophora indica, Aristolochia bracteolata, A. indica, Cissus quadrangularis, Hypericum mysorense. and Solanum trilobatum. Out of some of the data of these plants have been included in the previous chapters. In this chapter, compound isolation (CD1) from Clausena dentata (worked by Dr. R. Kamaraj) and characterization of the compound are given in detail.

10.2 Preparation of extracts from Clausena dentata

The dry powder of stem bark (2.5 kg) was first soaked, at room temperature, in hexane (1:4 w/v) for 24 h. The extract was suction filtered using Whatmann filter paper. This is repeated for two more days and similar extracts were pooled together and concentrated at 40°C under reduced pressure using Buchi R - 153 Rotavapor. The residual plant material was extracted successively with chloroform and methanol in the same manner as followed for hexane. All the concentrates were subjected to column chromatography to isolate the active principles.

Agroforestry is a new name for a set of old practices. The general concept of agroforestry is to integrate trees and agriculture so as to create a more diversified landscape, while providing the producers with new environmental and economic benefits. In other words, agroforestry is a method of farming that allows trees and shrubs to grow along with crops and/or livestock, therefore blending agriculture and forestry in the same production system. In fact, man's association with forest is much older than with agriculture. First man was a food gatherer and hunter in forests. Then he realized that the seeds of the fruits he collected germinated, grew into plants and bore the fruits again and thus man started to cultivate foods. Man's desire to live in a community created settled agriculture.

The pressure on the agricultural lands has increased manifolds due to the increasing population, expansion of urban area and the industrialization process. The environment has also been disturbed. Soil is losing its productivity and the biodiversity is threatened. Farming community is trying all means to increase the land productivity. Chemical fertilizers and pesticides are applied in higher proportion, causing environmental pollution hazards. Under all these circumstances agroforestry has shown that besides sustainable agriculture it can also help promote a better environment. Trees have always played an important role in mankind's survival. This relatively young science known as agroforestry was brought from the realm of indigenous knowledge into the forefront of agricultural research three and half decades ago and was promoted widely as a sustainability-enhancing practice that combines the best attributes of forestry and agriculture.

The words ‘system’, ‘sub-system’ and ‘practice’ are commonly used in agroforestry literature. In a broad sense, a system is defined as a group of associated elements forming a unified whole and working together in a well defined regular relation for a common goal. An agroforestry system refers to a type of agroforestry land-use that extends over a locality to the extent of forming a land utilization type of the locality. Sub-system and practice are lower-order terms in the hierarchy with lesser magnitudes of role, content and complexity. However, these terms are used loosely, and almost synonymously.

Classification of agroforestry systems is necessary in order to understand and provide a practical framework for evaluating systems and developing action plans for their improvement. Any classification scheme should satisfy the following criteria (Nair, 2008).

The word 'social forestry' was coined by Westoby and used in the ninth Commonwealth Forestry Conference at New Delhi in 1968. In India the term was first used by the National Commission on Agriculture, Government of India in 1976, to denote tree raising programmes to supply firewood, small timber and minor forest products to rural population. Prasad (1985) defined social forestry as forestry outside the conventional forests which primarily aims at providing continuous flow of goods and services for the benefit of people. This implies that the production of forest goods for fulfilling the needs of the local people is social forestry. Thus, conceptually it deals with the people to produce goods such as fuel, fodder, small timber, etc. to meet the needs of local community particularly the underprivileged section (Shah, 1988).

Management approaches to soil, including problems of soil degradation and low soil fertility, have recently undergone major changes. The earlier concept was to concentrate on achieving high levels of production from the more fertile areas, leaving the marginal lands for extensive use only. Steeply sloping and highly drought-prone areas were mostly left without any cultivation as production from these areas was hardly cost effective. Soil constraints were to be overcome by inputs like improved crop varieties, fertilizers, chemical control of pests and diseases, and the use of irrigation.

The approach of use of newly developed high yielding crop varieties, improved agronomic management practices, use of chemical fertilizers, efficient water management and timely plant protection measures has been successful in achieving large increases in crop productivity in recent years. On the other hand, continuous application of fertilizers at higher rates leads to environmental problems. Yield responses to fertilizers have declined because of soil physical degradation and micronutrient deficiencies. Above all, large numbers of poor farmers simply can neither afford high levels of fertilizers and other purchased inputs, nor do they have the capital to take on the risk involved in their use. Increasing the area under irrigation has also run into severe constraints in the form of limits to available freshwater resources.

Agroforestry systems are not simply systems where trees and crops or animals give useful products to the farmers, rather systems where trees and crops and/or animals interact. Interaction literally means influence or mutual or reciprocal action. So component interaction refers to the influence of one component of a system on the performance of other component as well as the system as a whole.

In agroforestry systems, trees are grown in close proximity to crops and pasture. Their performance would largely depend on their ability to share various growth resources in a given environmental situation. Various interactions take place between the woody trees and herbaceous plants (crops or pastures) which is referred to as tree-crop interface. These interactions take place through the media of soil and microclimate and may exert favourable or adverse effects on the crop. Study of interaction helps to know how the components of agroforestry utilize and share the resources of the environment, and how the growth and development of any of the components will influence the others. Interaction occurs both above and below the ground and includes a complex set of interactions relating to radiation exchange, the water balance, nutrient budget and cycling, shelter and other microclimatic modifications.

The success of an agroforestry system relies heavily on exploitation of the component interactions. In an ideal relationship, production of trees as well as crops or grasses in combination could be comparable to their sole performance. Agroforestry could be even more advantageous if the production of associated components is increased due to influence of trees. This is possible because trees are capable of improving productivity of soil in many ways. A large number of trees are known to fix nitrogen symbiotically. Nevertheless, instances of crop inhibition in association of trees are not uncommon. Such inhibitions are primarily caused by shade effect as well as competition for belowground resources such as nutrients and water. In some cases inhibitory effect may also result from allelochemicals secreted by some of the tree species.

Farmers have been growing trees for different purposes for thousands of years. Tree species that are grown to provide more than one significant function are called multipurpose trees. These functions may be productive such as producing fuelwood, timber, fibre, fodder, food, medicine, etc. and/or protective such as soil conservation, shade, shelterbelt, microclimate amelioration, land sustainability, biodiversity preservation, etc. All trees are multipurpose; some, however, are more multipurpose than others. Tree species can be multipurpose in two ways.

1. A single tree can provide more than one function. For example, Gliricidia sepium is grown as living fences that provide fuel, fodder and green manure for agricultural crops - all at the same time.
2. Trees of the same species, when managed differently, can provide different functions. For example, Leucaena leucocephala is managed so that some trees will mainly yield wood while others mainly produce leaf fodder.

Farmers can grow multipurpose trees (MPT) in various combinations with other crops, as in agroforestry, in block plantations of trees or in naturally regenerating tree farms. In certain cases, multipurpose trees are grown and managed for only one purpose. For example, Gliricida sepium is grown only to provide shade in coffee plantations. The same species may be planted in some other places and is managed differently for a very different use.

Trees that provide materials for propagation are called mother trees. Selection of mother trees is important because the young trees will be expected to inherit the favourable characteristics from the mother tree, such as fast growth, upright or spreading shape of the tree crown, good flowering and fruiting, and tolerance of diseases or pests. There may be sexual propagation by seed or vegetative propagation by using other parts of the tree. The genetic make-up of the seeds differs due to recombination of the genes, resulting in seedling variation. Thus, all the seedlings may look like the mother tree in some respects, but no two seedlings are the same. In case of vegetative propagation through cutting, layering, grafting or budding, the genetic make-up of the young tree is exactly the same as that of the mother tree. Consequently, all new trees grown vegetatively from one mother tree have the same set of gene pairs and therefore the same characteristics; they form a so called clone. Differences between plants of a clone can only be caused by different growing conditions.

Agroforestry is a land use system that involves two or more plant species at least one of which must be a woody perennial. When perennial woody and herbaceous components are grown together on the same piece of land their performance would largely depend on their ability to share various growth resources in a given environmental situation. Due to difference in growth pattern and resource requirement of the components in agroforestry situation, a close interactive relation is obvious. Thus, careful management practices for the components are required to establish a successful agroforestry system. The characteristics of the trees and crops, and their interactions, can be modified with good management practice in order to take advantage of the positive characteristics and minimize the effects of the negative ones. Effective and efficient agroforestry management may be divided into two groups - tree management and agricultural crop management.

Ecology of a place is influenced by a number of biotic and abiotic factors. An agroecological zone is broadly homogeneous in climatic and edaphic factors, but not necessarily contiguous, where a specific crop exhibits roughly the same biological expression. On the other hand, the characteristics of an agroecological zone influence the crops and cropping patterns of the zone. Thus, there are considerable variations in the types and management practices of agroforestry systems being followed in different agroecological zones.

AGROFORESTRY FOR HUMID AND SUBHUMID TROPICS

Humid and subhumid tropical regions have much variation in biological, social and economical parameters. The characteristics of humid tropics include high mean annual rainfall of more than 1500 mm, dry season of less than four months in a year and mean annual temperature of more than 22oC. Rainfall usually exceeds the evapotranspiration. However, demographic pressure has caused excessive deforestation and overgrazing which developed soil related problems like low soil fertility, low organic matter, high acidity and high rainfall erosivity. The agroforestry practices designed for this region should aim for improved fallows, soil fertility improvement and conservation, food production, etc. Thus, the common agroforestry systems in this zone are taungya, homegardens, alley cropping, plantation-crop combination, windbreaks, silvipastoral systems and various intercropping systems. Shifting cultivation is a common practice in tropics which should be discouraged as it causes environmental degradation and ecological imbalance, soil erosion and soil nutrient loss.

A watershed is a geohydrological unit or all the land and water area bounded by a divide which contributes runoff to a common point. Watershed is considered to be synonymous with ‘catchment basin’ and ‘drainage basin’. In watershed management approach, development is not only confined to agricultural lands but also covers the area, starting from the highest point of the land to the outlet of the natural stream. Watershed management becomes increasingly important as a way to improve livelihood of people while conserving and regenerating their natural resources.

Watershed management is the process of creating and implementing plans, programmes and projects to sustain and enhance watershed functions that affect the plant, animal and human communities within a watershed boundary. It implies the judicious use of all the resources i.e. land, water and vegetation in an area to prevent soil erosion, improve water availability and increase food, fodder, fuel and timber on sustained basis.

India shares 17.4% of the world population, while its land is only 2.4% of the total geographical area of the world. Naturally, the pressure on the land is often beyond its carrying capacity. Therefore, the productive lands, especially the farmlands in India are in the constant process of various degrees of degradation and are fast turning into wastelands. At present, approximately 63.85 million hectare area of the land is lying as wastelands in India (NRSA, 2005). Out of these lands, about 50% lands are such non-forest lands, which can be made fertile again if treated properly. In the last 50 years India’s lush green village forests and woodlots have been deforested to the maximum. To restore this ecological imbalance by developing the degraded non-forest wastelands, Government of India had created the Department of Wasteland Development during July, 1992 under the Ministry of Rural Development, which has been subsequently reorganized and renamed Department of Land Resources, with a broader mandate.

National Wasteland Development Board was established in 1985 mainly to tackle the problem of degradation of lands, restoration of ecology and to meet the growing demands of fuelwood and fodder at the national level. The Board was reconstituted in August, 1992 and was made responsible for development of wastelands mainly in non- forest areas in totality by involving local people at every stage of development. It aims at creating a scenario where the Government acts as a facilitator and the people at the grass root level become the real executioner of the programme. The degradation of environment in the fragile Indian subtropical ecosystem is basically attributed to the following factors.

Human societies over the ages have depleted natural resources in different ways and degraded their local environments. Indiscriminate cutting down of trees and accelerating the construction works lead to global warming and climate change. Climate scientists believe that human-induced deforestation is responsible for 18-25% of climate change. Accumulation of greenhouse gases in the lower atmosphere is the main cause of global climate change. The concentration of these gases in the earth’s atmosphere is increasing, mainly due to deforestation and the combustion of fossil fuels which release carbon dioxide.

The earth receives heat energy constantly from the sun through radiation. Some of the heat is absorbed and some is reflected. Carbon dioxide works like an invisible blanket that wraps around the earth and traps the heat inside, similar to the function of a greenhouse. A greenhouse is a structure that is used in colder climates to grow plants. Even when outside temperatures drop below freezing point, greenhouses are still warm enough inside to grow plants. Greenhouses are made of glass, which allows solar radiation to enter. The heat is trapped inside the greenhouse, allowing plants to grow all the year round. Increasing concentrations of carbon dioxide in the earth’s atmosphere insulate it like a greenhouse, leading to a gradual warming of the earth’s atmosphere. Carbon dioxide is the major greenhouse gas, but there are others as well, including methane and nitrous oxide.

In agroforestry systems the various components like tree, crop and pasture exist in different proportions and orientations. It is difficult to find out which agroforestry system is the best suited for a given land situation. Similarly, it is to be decided which technologies are required for refinement and improvement of the existing agroforestry practices. But without sufficient knowledge of the existing system in a particular land situation, it is very difficult to set the research priorities for modification and development of this system.

Diagnosis and Design (D & D) is a systematic and objective methodology developed by International Centre for Research in Agroforestry (ICRAF) to initiate, monitor and evaluate agroforestry programmes. D & D is based on the philosophy that knowledge of the existing situation (diagnosis) is essential to plan and evaluate (design) meaningful and effective programmes in agroforestry research for development. The methodology plays a strategic role in all the phases of the agroforestry research process. D & D in agroforestry is unique and it has been specially developed for the following purposes.

Agroforestry systems are more complex than the agricultural systems. The long-term nature of trials involving woody species and the varying objectives of agroforestry trials demand that adequate caution be exercised in their design. Several characteristics of the trees like slow growth, long term effects on their surroundings, long life, age of trees, the area over which the influence of trees extend, etc. complicate the issue of designing experiments for these systems. Agroforestry experiments are often established on marginal sites which include sloping lands, and sites with infertile and degraded soils. It is thus difficult to find homogeneous sites of such problem areas, especially sloping lands where plots along contour lines are long and linear. Germplasm of many agroforestry tree species are usually collected from different origins which lack uniformity. Therefore, experimental materials in an agroforestry experiment may not be of uniform quality.

There are several features of agroforestry systems that require some modification of the methods usually used in agricultural experiments. Important issues related to agroforestry experiments include

Economic analysis provides a rational basis for making decisions in allocating scarce resources among various options to achieve competing goals. If resources were not limiting, there would be no need for economic consideration.

PRINCIPLES OF ECONOMIC ANALYSIS

Optimization criteria

The additional return obtained from using one additional unit of an input should be considered to optimize net income from several possible production options. If option ‘x’ gives a higher return to land than other options, then additional units of land should be allocated to option ‘x’.

Agricultural extension is a term that has long been used to describe a non-formal educational system aimed at improving the livelihood of farmers. Extension education aims at three main types of behavioural changes in relation to knowledge (things known), attitudes (things felt) and skills (how to implement the things). This can be achieved through persuasion and motivation for the changes. The core activities in extension are education and training. Extension is now being regarded as a much wider task of integrating indigenous and new skills and techniques, derived from study or research, into an overall framework of discussion and cooperation between the people and the extension organisation. The extension worker is primarily engaged in the ‘selling’ of ideas to bring about changes in the knowledge, attitudes and skills of the individual. Functions of extension in a broader sense include

Horticulture word derived from Latin word: Hortus meaning ‘Garden’ and cultura means ‘cultivation’.

Father of horticulture: Thomas Andrew Knight, John Lindley, Liberty Hyde Bailey.

1^st artificial hybridization in fruit crop in world: T. A. Knight.

Father of vegetables: L. H. Bailey.

1^st book in horticulture: Fruit growing in India: W.B. Hayes (1945) & related to litchi.

Export growth of fresh fruits and vegetables in term of value is 14% and of processed fruits and vegetables is 16.27%.

Contribution of horticulture sector to agriculture GDP (2013-14): 29%.

India is largest producer of Coconut, Cashew, Tea and Spices.

1. GENERAL POMOLOGY

Word pomology: Derived from Greek word ‘pome’ meaning development of fruit from inferior ovary and ‘logos’ meaning to study.

Father of systematic pomology: De Candolle.

Temperate fruits are popularly known in India as hill fruits or cold region fruits.

India ranks 1^st in productivity of grapes, banana and papaya.

Ratio of Chlorophyll a to chlorophyll b is highest in C⁴ plants.

Gibberellic acid is enhanced by exposing plants to red light.

The life line tree of ‘Thar Desert’ is Prosopis cineraria.

Grape of the desert is Salvadora oleoides.

1. General Olericulture

Olericulture is Latin term ‘Olerus’ meaning herb.

China, India, USA, Turkey and Italy: Major vegetable producers.

Indian subcontinent has 80 species of major and minor vegetables apart from several wild species consumed as vegetable.

About 175 different types of vegetables are grown in India, includes 82 leafy vegetables and 41 root (tuber and bulb) crops.

Cucurbits, taros, yams, brinjal and okra have rich diversity in Indian gene centre.

USA is leading importer of cucumber and gherkins, assorted canned vegetables and other dehydrated vegetables from India.

Germany leads in import of preserved onion, green pepper in brine and dehydrated onion flakes/powder.

Singapore leads in import of dried asparagus; Japan in dehydrated garlic flakes; UAE in dehydrated garlic powder; Bangladesh in peas and Switzerland in dried mushrooms including morels.

Mizoram is the largest producer of chow chow.

1. GENERAL FLORICULTURE

Development of Floriculture’ was recommended by Dr. P.P. Trivedi committee.

India ranks 2^nd in flower cultivation next to China.

The production of loose flowers almost tripled between the 8^th Plan and the 11^th Plan.

The annual domestic demand is valued at around 60 billion USD.

About 2,33,000 hectares across the country was used for floriculture, producing 17,29,000 metric tonnes (MT) of loose flowers and 76,732 lakh cut flowers.

India has exported 22,947.23 MT of floriculture products to the world for worth of Rs. 460.75 crores in 2014-15.

The share of exports of dried flowers and plant parts are 45%, flowering plants (22%), fresh foliage (13%), fresh cut flowers (10%), live plants (7%) and bulbs and tubers (3%).

India’s share in global floriculture trade- 0.6%.

1. GENERAL INFORMATION

International Group for the Genetic Improvement of Cocoa (INGENIC) formed in 1993.

Central Coconut Research Station (presently CPCRI) was established in 1940.

Central Plantation Crops Research Institute (CPCRI), Kasargod, Kerala established in 1970.

CPCRI hosts International Coconut Gene Bank for South Asia under the umbrella of Coconut Genetic Resources Network (COGENT) of the Biodiversity International.

National Active Germplasm Site for coconut: CPCRI.

United Planter’s Association of Southern India (UPASI) started in 1893.

Branch of International Rubber Association was established in 1948 at Kottayam, Kerala. It was renamed as Indian Rubber Institute in 1987.

Rubber Research Institute of India, Kottayam established in 1995.

1. GENERAL INFORMATION

Asian continent, particularly India is known as “Land of Spices”.

Spice crops are largely grown in tropics between 20⁰N and 20⁰S.

Term ‘spice’ was derived from Latin ‘Species aromatacea’ means ‘Fruits of the earth’.

Spices and condiments are grouped under food adjuncts.

India is largest producer of spices and oleoresin.

Home of spices/ Spice bowl of India: Kerala.

1. GENERAL INFORMATION!

Major constraint of medicinal plants: Lack of genuine planting material.

Maximum number of medicinal plants belong to family Asteraceae.

Maximum demand in world market: 1. Senna leaves 2. Isabgol seeds 3. Cassia tora seeds.

India is largest producer of 1. Kewada oil 2. Senna 3. Davana oil 4. Isabgol.

India is 2^nd largest producer of 1. Opium latex 2. Jasmine concrete 3. Tuberose concrete

India is 3^rd largest exporter of periwinkle.

Thailand is largest exporter of sarpagandha leaves.

China is largest producer of 1. Geranium oil 2. Citronella oil.

1. GENERAL INFORMATION

India’s exports of Processed Food was Rs. 31563.43 Crores in 2014-15, which includes products like Mango pulp (Rs. 841.39 Crores), Dried and Preserved vegetable (Rs. 847.11 Crores), Other Processed Fruit and Vegetable (Rs. 2,569.93 Crores), Pulses (Rs. 1,209.51 Crores), Groundnuts (Rs. 4,675.35 Crores), Guargum (Rs. 9,480.00 Crores), Jaggery and Confectionary (Rs. 1,161.81 Crores), Cocoa Products (Rs. 848.62 Crores), Cereal Preparations (Rs. 3,038.79 Crores), Alcoholic and Non-Alcoholic Beverages (Rs. 2,231.58 Crores) and Miscellaneous Preparations (Rs. 2,437.77 Crores).

Economics

The term “Economics” is derived from the Greek words ‘OIKOS’ and ‘NOMAS’ or ‘NEMEIN’. ‘Oikos’ means house hold and ‘Nomas’ or ‘Nemein’ means management. So in its original sense economics means house hold management; i.e. satisfying as many wants of the house hold or family as possible by allocating the limited resources at the disposal of the family wisely among different wants. In the modern and practical sense Economics means management of day to day problems arising from unlimited wants and limited resources by wisely allocating limited resources to satisfy maximum wants. In other words economics is the study of how man manages his limited resources as it satisfies as many wants as possible.

Goods and services are created through process of production. After production they have to be transferred or moved from the original producers to the final consumers. This involves the creation of market and the undertaking of number of activities such as buying, assembling, transportation warehousing, risk bearing, financing, selling etc. This constitutes the subject matter of marketing. Hence there is the need for the study of market.

What is market?

Market is derived from the Latin word “Marcatus” meaning trade, merchandise, ware, traffic or place of business. In the ordinary language, market is a place where buyers and sellers meet personally and make their purchases or sales. But in the language of economics, market need not be a place but it may be an area or region meant for potential exchange between a group of buyers and sellers interested in negotiating the terms of purchase and sale of goods and services and such negotiations may be done face to face at a certain place or may be done through other means of communication such as mail, phone, cable, television or through business middle men. What ever may be the means of communication there will be free exchange or perfect communication between buyers and sellers so that a fairly uniform price prevails for a particular commodity over the whole area at any given time.

Popularly the term management is used to refer to the group of managerial personnel of an enterprise. But the use of the term management in this sense is not correct, because the managerial personnel of an enterprise are usually designated as ‘managers’, ‘executives’ or administrators. Strictly speaking the term management refers to functional concept of management. Management refers to the sum total of all those functions or activities, which relate to the laying down of policies, plans and purposes, securing men, money, machinery needed for the achievement of the organisational objectives, putting all of them into operation and supervising and checking their performances in order to ensure the productive use of human and material resources for the maximum benefit or profit of the organisation, its employees and society in general.

Management is the sum total of five principal functions namely planning, organising, staffing, directing and controlling. The functional areas of management include: a) Financial management, b) Personnel management, c) material management, d) Production management, e) marketing management and f) Office management.

Book Keeping

What is book keeping?

Book keeping is defined as;

1. The art of recording business transactions (pecuniary transactions) in a regulator and systematic manner.
2. Book keeping is the science and art of correctly recording in books of accounts all those business transactions that result in the transfer of money or money’s worth.
3. Book keeping is an art of recording day to day business transactions in a set of books in a most systematic manner.
4. It is the process of analysing, classifying and recording transaction in accordance with preconceived plan.

Agricultural crops are being affected by a wide range of organisms such as insects, mites, fungi, bacteria etc. Another important and unseen enemy is known as plant parasitic nematodes. The study on nematodes is known as Nematology.

Nematology is an important branch of biological science, which deals with a complex, diverse group of round worms known as Nematodes that occur worldwide in essentially all environments. Nematodes are also known as eelworms in Europe, nemas in the United States and round worms by zoologists. Many species are important parasites of plants and animals, whereas others are beneficial to agriculture and the environment. Nematodes that are parasites of man and animals are called helminths and the study is known as Helminthology. The name nematode was derived from Greek words nema (thread) and oides (resembling). This book focuses primarily on plant parasitic nematodes, their morphology, anatomy, nematological techniques, taxonomy, classification based on their feeding habits, symptom of damage to crops, interaction with other microorganisms, biology of important nematodes viz., Meloidogyne, Heterodera, Rotylenchulus, Tylenchulus and Radopholus and nematode pests of important crops and their management.

Annual crop losses due to these obligate parasites have been estimated to be about $78 billion worldwide and $8 billion for U.S. growers. The estimated annual crop loss in Tamil Nadu is around Rs. 200 crores.

The soil in a hectare of agroecosystem typically contains billions of plant parasitic as well as beneficial nematodes. The damage to plants caused by nematodes is often overlooked because the associated symptoms, including slow growth, stunting and yellowing can also be attributed to nutritional and water related disorders.

In light of the high population of nematodes, N.A. Cobb (1915) who is considered to be the father of American Nematology, provided a dramatic description of the abundance of nematodes. He stated, “if all the matter in the universe except the nematodes were swept away, our world still would be dimly recognisable. We would find its mountain tops, valleys, rivers, lakes and oceans represented by a film of nematodes.” The Papyrus Ebers suggested a knowledge of the human intestinal parasite, Ascaris lumbricoides and the tissue parasite, Dracunculus medinensis. In early Egyptian writings also these two human parasites have been described. In 1956, Borellus recorded his observations “Vinegar eels” the microbivorous or free living nematode occurring in most vinegar at that time. The statement “sowed cockle, reaped no corn” in Shakespeare’s “Love’s Labour’s Lost”, act 4, scene 3, as suggested by Thorne (1961) possibly the first record of plant parasitic nematodes in 1549. The nematode that Thorne suspected to be in that reference actually was described by Needham in 1743. Subsequently, discovery of microscope and developments in various disciplines of science led to the discovery of plant parasitic nematodes and the disease caused by them. Some of the important milestones on the history of plant nematology are listed below in chronological order.

Eventhough nematodes occupy nearly every habitat on earth, they are remarkably similar in morphology and life stages. Despite their structural complexity, certain basic principles are common to all nematodes. Nematodes are triploblastic, bilaterally symmetrical, unsegmented, pseudocoelomate, vermiform and colourless animals. The plant parasitic nematodes are slender, elongate, spindle shaped or fusiform, tapering towards both ends and circular in cross section. The length of the nematodes may very from 0.2 mm (Paratylenchus) to about 11.0 mm (Paralongidorus maximus). Their body width vary from 0.01 to 0.05 mm. In few genera, the females on maturity assume pear shape (Meloidogyne), globular shape (Globodera), reniform (Rotylenchulus reniformis) or saccate (Tylenchulus semipenetrans). The swelling increases the reproductive potential of the organism. Radially symmetric traits (triradiate, tetraradiate and hexaradiate) exist in the anterior region. The regions of intestine, excretory and reproductive systems show tendencies towards asymmetry. The nematodes have one or two tubular gonads which open separately in the female and into the rectum in the male which also have the copulatory spicules.

The free living saprophytic nematodes are generally larger in size. The animal and human parasitic helminths may have length of few centimetres to even a meter or more. The helminth parasitising whale fish is about 27 feet long. The study on these animals and human parasites are known as Helminthology.

Life cycle of nematode has six stages. The egg stage, first stage juvenile (J₁), second stage juvenile (J₂), third stage juvenile (J₃), fourth stage juvenile (J₄) and the adult stage.

The first four stages are the immature stages and are known as juvenile stages. The female lays eggs in soil or in plant tissues, singly or in groups as egg mass that hatch out into juveniles which are almost similar to adults appearance. The first moult occurs within the egg shell and the second stage juvenile comes out by rupturing the egg shells as J₂. In case of Xiphinema index, the juveniles are reported to emerge from the egg before the first moult. The juvenile cuticle is shed after each moult.

The egg

The nematode eggs are oval in shape. The eggs are covered by three membranes, the external protein layer which is the secretion of uterus wall, the middle chitinous layer or the true shell secreted by egg itself and the inner lipid layer (vitelline layer). The chitin content in the egg shell vary in different species of nematodes.

Plant parasitic nematodes cause serious problems in sustained crop production. For a successful management of nematodes, their morphology, biology and host - parasitic relationship should be thoroughly studied. A thorough study is achieved only when its taxonomical position is known. Thus, in a simple way taxonomy can be defined as the theroretical study of classification of an organism.

The systematic arrangement of organisms into groups on the basis of their relationship is termed as classification.

Nematodes are placed in the group invertebrate, Kingdom Animalia.

Hyman (1951) revised the phylum Aschelminthes and included six classes viz., Rotifera, Gastotricha, Echinodera, Priapulida, Nematoda and Nematomorpha.

Sampling for nematode population estimation

Sampling for nematode communities has been the basis for the development of appropriate control strategy. The major purposes of sampling for nematodes include population estimation for general detection, advisory or predictive programme, disease diagnosis and also for research purposes.

Plant parasitic nematodes are usually confined to top 20-25 cm soil and may vary depending upon the soil type, moisture content, host plant and climatic condition. Surface soil do not harbour any nematode. The roots and rhizosphere of severely infested plants do not harbour numerous nematodes as the nematodes tend to move to adjacent healthy plants. Hence soil and root samples need to be collected from plants showing partial symptoms. Samples should not be collected from dead or wilted plants.

The nematode feeding on plant can be divided into above ground feeders and below ground feeders.

I. Above ground feeders

a) Feeding on flower buds, leaves and bulbs

Seed gall nematode : Anguina tritici

Leaf and bud nematode : Aphelenchoides

Stem and buld nematode : Ditylenchus

Most of the plant parasitic nematodes affect the root portion of plants except Anguina spp., Aphelenchus spp., Aphelenchoides spp., Ditylenchus spp., Bursaphelenchus cocophilus and B. xylophilus. Nematodes suck the sap of the plants with the help of stylet and causes leaf discolouration, stunted growth, reduced leaf size and fruits, lesions on roots, galls, reduced root system and finally wilting. Symptoms of nematode diseases can be classified as

Symptoms produced by above ground feeding nematodes
Symptoms produced by below ground feeding nematodes

Plant parasitic nematodes favour the establishment of secondary pathogens viz., fungi, bacteria, virus etc. The nematodes alter the host in such a way that the host tissue becomes suitable for colonization by the secondary pathogens. Even though the nematodes themselves are capable of causing considerable damage to the crops, their association with other organisms aggravate the disease. The nematodes cause mechanical wound which favours the entry of microorganisms. In some cases, the association of nematode and pathogen breaks the disease resistance in resistant cultivators of crop plants.

Nematode - Fungus Interaction

Nematode - fungus interaction was first observed by Atkinson (1892) in cotton. Fusarium wilt was more severe in the presence of Meloidogyne spp. Since then the nematode - fungus interations had received considerable attention on important crops like banana, cotton, cowpea, brinjal, tobacco and tomato. Some examples of nematode - fungus interaction are given in the following table.

Rice

Plant parasitic nematodes cause serious damage to rice crop. Thirty two species belonging to 13 genera were observed in association with the crop. Among them few are considered to be important. They are the rice white - tip nematode (Aphelenchoides besseyi), rice stem nematode (Ditylenchus angustus), rice root nematode (Hirschmanniella oryzae), root-knot nematode (Meloidogyne graminicola) and the cyst nematode (Heterodera oryzicola).

The white-tip nematode (Aphelenchoides besseyi)

The yield loss due to the white-tip nematode is estimated to be as much as 17.4 to 54.1 per cent. The nematode is distributed in India, Bangladesh, Sri Lanka, Japan, Indonesia, Taiwan, Former USSR, Italy, Cuba and Madagascar.

Citrus (Citrus spp.)

Citrus is an important fruit crop and ranks third in area which is followed by mango and banana. They are grown in 105,396 hectares in India. Among the oranges, mandarin oranges, limes and sweet oranges are very popular while lemons, grape fruits, pummelos, sour and bitter oranges are of minor importance. The Citrus spp. are grown in larger extent in the states of Maharashtra, Karnataka, Kerala, Tamil Nadu, Andhra Pradesh, Punjab, Haryana, Rajasthan, Assam, Orissa and Bihar.

Nematode menace in citrus gardens are very much realised. In 1912 the citrus nematode, Tylenchulus semipenetrans was reported from California and found to cause ‘slow decline’ disease. More than 30 genera of plant parasitic nematodes are associated with the Citrus spp. Among them, Tylenchulus semipenetrans, Radopholus citrophilus, Meloidogyne spp. Pratylenchus spp. Xiphinema spp. and Hoplolaimus spp. are often associated with the crop.

Potato

Potato is one of the most important vegetable crop grown in India. It thrives best in cool climate. Therefore it is a summer crop in the hills and a winter crop in plains.

Twenty seven species of nematodes have been reported on potato among them the cyst nematodes (Globodera rostochiensis and G. pallida) and the root-knot nematodes (Meloidogyne incognita, M. javanica and M. hapla) are important in India.

Cyst nematodes (G.rostochiensis and G. pallida)

In India, the cyst nematode menace on potato was first reported by Dr. Jones during 1961 from Nilgiri Hills.

Geographical distribution

The potato cyst nematode is distributed in Central, South and North America, Europe, Iceland, Western USSR and South Africa.

In India it is distributed in Nilgiri and Kodai Hills and in New Delhi.

Crossandra

Crossandra (Crossandra undulaefolia) is one of the important commercially grown flower crop in Tamil Nadu. In recent years there is a marked decline in the cultivation of this crop in Madurai, Dindigul, Coimbatore, Salem, Thiruvannamalai and Tiruchirappalli districts. The common problem with the crop is death of plants in patches during the second and third year. This is due to the nematode-fungal complex disease in the crop.

Investigations revealed the association of root-knot nematode, Meloidogyne spp. and the root-lesion nematode, Pratylenchus delattrei with the crop along with fungal patheogen, Fusarium solani.

Root-knot nematode

Both M. incognita and M. javanica are reported to cause damage and yield loss to the crop. The affected plants exhibit stunted growth, yellowing of leaves and also have chlorotic symptoms. The nematode in association with R. solani causes serious damage to the crop. The infested plants show root galls.

Black Pepper

Black pepper (Piper nigrum) is indigenous to the tropical forests of Western Ghats of South India. The crop is grown in Kerala, Karnataka, Tamil Nadu, Andra Pradesh and Assam.

The root-knot nematode, Meloidogyne incognita and the burrowing nematode, Radopholus similis are important pests of this crop. The root-knot nematode infested vines show yellowing of lower leaves and the leaves loose natural luster. The yellowing of leaves gradually progresses upwards. The affected vine leaves become flaccid and wither. The infested plant root show root galls of varying sizes.

The burrowing nematode also causes serious damage to the vine. Var der Vecht (1950) first reported slow wilt in this crop due to R.similis infestation in Indonesia. The nematode in association with Fusarium and Rhizoctonia causes serious damage to the crop.

Nematode Control

Plant parasitic nematodes can be controlled by several methods. The nematode control aims to improve growth, quality and yield by keeping the nematode population below the economical threshold level. The control measures to be adopted should be profitable and cost effective. It is essential to calculate the cost benefit ratio before adopting control measures.

The nematode control methods are

1. Regulatory (Legal) control
2. Physical control
3. Cultural control
4. Biological control
5. Chemical control

Nematode associated with insects are referred as entomophilic, entomogenous and entomophagous nematodes. Generally they belong to the superfamilies Tylenchoidea, Rhadbitoidea, Oxyuroidea and Mermithoidea of the phylum Nematoda.

Nature of parasitism

Christie (1914) divided the nematodes associated with invertebrates into three groups.

• Those nematodes which live in the alimentary tract of he invertebrates.
• Those nematodes which are more or less closely related to free living species and often have a combination of saprophagous and parasitic habits.
• Those nematodes which parasitizes the body cavity or tissue of their host.

Entomophilic nematodes are group of parasites that cause debilitation, sterility or death of insects. Entomophilic nematodes vary greatly in size and shape having the insects as intermediate or as definite hosts. Many group of insects are parasitised by nematodes.

Model organisms are widely used in biological researches to describe basic biological processes. When selecting living organisms as models to work with, a wide range of characteristics are used which include: 1) rapid development with short life cycles, 2) small adult size, 3) ready availability and 4) tractability. Being small, growing rapidly and being readily available are crucial in terms of housing them, given the budget and space limitations of research and teaching laboratories. Tractability relates to the ease with which they can be manipulated. Many model organisms have been used including fruit fly, Drosophila melanogaster, the most obvious organism used for teaching Mendelian genetics and developmental biology; Escherichia coli, a favoured organism for molecular biological studies involving recombinant DNA technology. Research into the molecular and developmental biology of C. elegans was begun in 1974 by Sydney Brenner and it has since been used extensively as a model organism.

C. elegans is a popular research organism as it possesses all the characteristics mentioned, yet shares many essential biological properties with humans. For instance, researchers who study apoptosis (programmed cell death) use C. elegans as an experimental organism in the hope of finding treatments for certain types of human cancers, such as leukaemia.

C. elegans is easy and inexpensive to maintain in laboratory conditions with a diet of E. coli. Embryogenesis occurs in about 12 hours, development to the adult stage occurs in 2.5 days and the life span is 2-3 weeks. The short, hermaphroditic life cycle (~3 days) and large number (300+) of offspring of C. elegans allows large-scale production of animals within a short period of time. Since C. elegans has a small body size, in vivo assays can be conducted in a 96 well microplate. Laboratory stocks of C. elegans can even be stored in liquid nitrogen for 25 years without losing their viability. The transparent body allows clear observation of all cells in mature and developing animals. Furthermore, the intensively studied genome, complete cell lineage map, knockout (KO) mutant libraries and established genetic methodologies including mutagenesis, transgenesis and RNA interference (RNAi) provide a variety of options to manipulate and study C. elegans at the molecular level and for a more detailed presentation of genetic and genomic resources.