eChapters

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.

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.

Objectives

• Better understand the monohybrid cross.
• Calculation of monohybrid phenotypic, genotypic and testcross ratios.

Principle

Monohybrid cross deals with the study of inheritance of one pair of contrasting characters. The alleles of contrasting character selected in the monohybrid cross will show exact dominance and recessive relationship. It is also defined as a cross is made between two true-breeding parents differing for a single trait, producing an F₁ generation. These plants are intercrossed to produce an F₂ generation. Monohybrid crosses study led to the Mendel’s law of segregation. Monohybrid cross was first produced in pea by Mendel to explain the “law of segregation”. When parents with distinct phenotypes are crossed, in F₁ generation, only one type of plants appears phenotypically. However, segregation can be observed in F₂ progeny and the population can be divided into two phenotypes classes. After counting the individuals. It is observed that 75% of them express the dominant phenotype and 25% of them express recessive phenotype.

Objectives

• Better understand the various types of gene interaction.

Introduction

Gene interaction is the phenomenon of two or more genes that affect each other’s expression in different ways in the development of a single character of an organism. It is the modification of normal phenotypic expression of gene due to interaction between alleles or non-alleles. In such situation, two or more than two genes may interact to give rise to a particular phenotype

Plant genetic resources (PGR) are the genetic material of plants which are of value for present and future generations of humankind. Often used as a synonym to plant germplasm, it can be defined as a seed, a plant or plant part including cell cultures, genes and DNA sequences that are held in a repository or collected from wild as the case may be and that are useful in crop breeding, research or conservation because of genetic attributes. The term is used to describe a collection of genetic resources for an organism or genetic material which forms the physical basis of inherited qualities. In brief, germplasm is the sum total of the hereditary materials in a species. Germplasm is the foundation and lifeblood of plant breeding without which plant breeding activities cannot be conducted. Germplasm is the genetic material that can be used to perpetuate a species or a population. The base germplasm can be improved for better performance of the crop. In the initial stage of a breeding programme, breeder evaluates the available germplasm lines and makes a selection from them for further test and final release to the farmers. Later on, the germplasm serves as a source of the parental lines which are used to initiate another phase of the breeding programme. Besides, using the base germplasm, breeders generate new variability using a variety of breeding methods such as crossing parental lines and developing new lines, induced mutations and more recently gene transfer. This new variability is again subjected to appropriate selection methods leading to identification and further evaluation of new and promising genotypes for release as cultivars. Generally, germplasm includes following types:

Phenotype is a result of gene products brought to expression in a given environment. Genes specify the structure of proteins. All known enzymes are proteins. Enzymes perform catalytic function, causing the splitting or union of various molecules. All of the chemical reactions which occur in the cell constitute the subject of intermediary metabolism. These reactions occur as stepwise conversions of one substance into another, each group being mediated by a specific enzyme. All of the steps which transform a precursor substance to its end product constitute a biosynthetic pathway. Several genes are usually required to specify the enzymes involved in even the simplest pathways. Before gene-enzyme relationship could be postulated, soon after rediscovery of Mendelian principles of inheritance, it was discovered that genes were not merely separate elements producing distinct individual effects, but they could interact with each other to produce completely novel phenotypes. The simplest example of gene interaction could be the fact that allele A could be characterized by phenotype A, and the allele B by the phenotype B and an organism having both alleles A and B at the same time might show phenotype C. The occurrence of such interactions means that the phenotype we observe is not present in the genes themselves but arises from a complicated developmental process resulting from a biosynthetic pathway as illustrated below (Stansfield, 1969)

Linkage

When two or more genes are located on the same chromosome, they are said to be linked. Genes on different chromosomes are distributed to the gametes following the law of independent assortment. However, genes located on the same chromosome, tend to stay together during gamete formation. For example, results of test-crossing dihybrid individuals will produce different results depending upon whether the genes are linked or are located on the same chromosome. This is illustrated as follows:

Abstract

Spot blotch of wheat is devastating disease as one of the yield limiting factor especially in north eastern plains zone and also in north western plains zone of India. Chemical fungicides play an important role in controlling the spot blotch in India due to non availability of spot blotch resistant commercial varieties. To identify the suitable chemicals method and time of application, various fungicides thiram 37.5% WP, carboxin 37.5% WP +, propiconazole 25% EC, tebuconazole 25% EC and mancozeb 75% WP) were evaluated either as seed treatment or foliar sprays or in combination under artificial epiphytotic in vivo conditions for two crop seasons. Seed treatment (ST) by thiram + carboxin @ 2.5 g/kg of seed along with Foliar spray (FS) of propiconazole @ 0.1% at boot leaf stage on Flag-1 leaf followed by second spray at 20 days interval (two sprays) resulted in best management of spot blotch in severe conditions. It was found that the fungicide treatment not only reduced the spot blotch disease but also increases the grain yield.

Abstract

Mushroom production is emerging as an added dimension in agriculture diversity; its cultivation lies on the utilization of agricultural wastes rich in proteinaceous materials. Five different substrates such as wheat straw, maize cob, paddy straw, banana pseudo stem, and lentil straw were used with suitable supplements to evaluate the average period of spawn run, pin head initiation, time taken for harvesting of flushes, fruit yield during both crop season 2014 and 2015. In 2014, highest fruit yield (380.3 g/ 500g) were recorded when wheat straw supplemented with rice bran (2% of the substrate weight), corn flour @ 25 g/kg prepared straw and gypsum @ 20 g/kg straw among various used substrates. This treatment also resulted better in respect of time taken for spawn run (9.3 days), pin head initiation (11.7 days), time taken for harvesting of flushes (I^st flush- 20.5, II^nd flush-26.7, III^rd flush- 32.9). The second best treatment was paddy straw when supplemented with rice bran (2% of the substrate weight), corn flour @ 25 g/kg prepared straw, and gypsum @ 20 g/kg. The lowest fruit yield (193.6 g/500g), time taken for spawn run (15.9 days), pin head initiation (22.4 days), time taken for harvesting of flushes (I^st flush- 27.9, II^nd flush-37.1, III^rd flush- 44.7) were recorded with banana pseudostem (chopped) when supplemented with rice bran (2 % of the substrate weight), corn flour @ 25 g/kg prepared straw and CaCO₃ gypsum @ 20 g/kg straw. The same experiment was repeated during the year crop season 2015. Surprisingly wheat straw supplemented with rice bran (2% of the substrate weight), corn flour @ 25 g/kg prepared straw and gypsum @ 20 g/kg prepared straw was found again superior over other treatments with more or less similar performance. Similarly more or less same performances were resulted in rest of the treatment too. The incidence of mould infection in mushroom was also noticed in accordance with the kinds of substrates used during both crop season 2014 and 2015. Lowest incidence of mould i.e. green mould (5.13 %), black mould (3.10 %) and blue mould (2.42%) was observed on wheat straw when supplemented with rice bran (2% of the substrate weight), corn flour @ 25 g/kg prepared straw and gypsum @ 20 g/kg straw, green mold (3.13 %), black mold (3.10 %) and blue mold (2.42 %). Similarly more or less same pattern of mould incidence was reported in the crop season 2015.

RAPD stands for Random Amplification of Polymorphic DNA. It is a type of PCR reaction, but the segments of DNA that are amplified are random. The scientist performing RAPD creates several arbitrary, short primers (8-12 nucleotides), then proceeds with the PCR using a large template of genomic DNA, hoping that fragments will amplify. By resolving the resulting patterns, a semi-unique profile can be gleaned from a RAPD reaction.

No knowledge of the DNA sequence for the targeted gene is required, as the primers will bind somewhere in the sequence, but it is not certain exactly where. This makes the method popular for comparing the DNA of biological systems that have not had the attention of the scientific community, or in a system in which relatively few DNA sequences are compared (it is not suitable for forming a DNA databank). Because it relies on a large, intact DNA template sequence, it has some limitations in the use of degraded DNA samples. Its resolving power is much lower than targeted, species specific DNA comparison methods, such as short tandem repeats. In recent years, RAPD is used to characterize, and trace, the phylogeny of diverse plant and animal species.

In 1985, Sir Alec Jeffreys developed restriction fragment length polymorphism (RFLP), which quickly became the standard technique for DNA testing throughout the 1980s. RFLP provided the world with the first form of genetic testing based on DNA, the body’s genetic material.

Definition : RFLP analysis is a difference in homologus DNA sequences that can be detected by the presence of fragments of different lengths after digestion of the samples in question with specific restriction endonucleases (RE).

A restriction fragment length polymorphism , or RFLP, (commonly pronounced “rif lip”), is a variation in the DNA sequence of a genome that can be detected by breaking the DNA into pieces with restriction enzymes and analyzing the size of the resulting fragments by gel electrophoresis. It is the sequence that makes DNA from different sources different, and RFLP analysis is a technique that can identify some differences in sequence (when they occur in a restriction site). Though DNA sequencing techniques can characterize DNA very thoroughly, RFLP analysis was developed first and was cheap enough to see wide application. Analysis of RFLP variation was an important tool in genome mapping, localization of genetic disease genes, determination of risk for a disease, genetic fingerprinting, and paternity testing.

Genetic Mapping

Perhaps one of the most powerful applications of markers is genetic mapping. This technology allows researchers identify markers located within or very close to genes of interest. With this it is possible to trace these genes through generations of crosses.

If the trait in question is complex and multigenic, mapping will also be of tremendous help to dissect the various genes or loci that contribute to the overall characteristic. Determining the amount of impact each locus delivers is a process called Quantitative Trait Loci or QTL mapping.

1. House Plant

The screwpines or kewda plants are characteristics of many tropical regions with long ringed trunks, bracing roots and crowns of Dracaena-like foliage. The young plants are amongst the most popular foliage plants for home decoration as the plants do not flower at early stages (Wickham, 1950). They are also grown as pot and tub specimens for green house, residence, veranda and lawn decoration where their stiff clustered foliage gives them a formal decorative character. They may be kept as indoor ornamental foliage plants in the warm and semi light places of a house. (Wickham, 1982a).

2. Fence

The plant is useful for binding the soil, so checks soil erosion and not browsed by the cattle due to its spiny leaves; hence sometimes used as fence around the crop field in the coastal districts of Odisha, Andhra Pradesh, Tamil Nadu, Kerala and Gujrat. The plants are often used for hedges as in the Casuarina plantations at Puri of Odisha (Haines, 1961a) (Fig. 17).

I. General information

1. Japanese flower arrangement is called as Ikebana
2. Meaning for Ikebana is flowers kept alive
3. Western style of flower arrangement involves symmetrical arrangement of flowering plants in a vase
4. Ikebana style possess asymmetric flower arrangement
5. Tatebana is a type of flower arrangement in which flowers are placed in standing arrangement and are of tall nature
6. Basic lines of Japanese flower arrangement are heaven, man and earth
7. ‘Shin’ in Japanese flower arrangement represents Heaven
8. ‘Soe’ in Japanese flower arrangement represents Man

Climatic conditions prevalent in rainfed areas

Weather, which is part of climate, plays an important role in crop planning in dry farming area. Out of the several elements of weather, rainfall has key position in success of dry farming. In dryland areas, South West Monsoon brings the bulk of rainfall. The South West Monsoon is followed by North East Monsoon which supplements to South West Monsoon are the main source of rainfall. There are four types of rainfall characterized by the nature in different parts of India. Generally, the rainfall is scanty, erratic and ill distributed.

1. Rainfall

The monsoon period is not one of continuous rains in any part of the country. Meghalaya that is uncommon in the behavior of monsoon in the country. There are at least four variations in rainfall.

1.The commencement of rains may be quite early or considerable delayed according to the dates of monsoon for central Maharashtra zone is 10th June but is started as early as 28th May 1925 and its onset was delayed upto 26th June 1954 according with the date of onset of monsoon in Rajasthan is between June 21 to 30 but is started as late as up to end of July 1987 to 1992.

2.There may be prolonged breaks in rainfall. These breaks in monsoon rains can be different duration. The breaks of 5-7 days may not be all serious concern but breaks of longer duration of 2-3 weeks created the situation of plant water stress leading to reduction in agricultural production. Another important point is the physiological properties of soil and available water holding capacity in the relation to the breaks and drought, some of the soils e.g. deep black soils have capacity to store more than 300 mm of water per meter depth where as the desert soil can ensure only 100 mm. The impact of drought is felt more quickly in the soil having less water holding capacity but in sols with high storage capacity 15 days dry break may not affect the crop where as the soils of less storage capacity show wilting symptoms in and dry break such breaks cannot be predicted for a given season in advance. The drought caused due to this break is therefore of different magnitude and severity.

In dryland areas, moisture conservation accounts prime most important concept for maximizing productivity of dryland crops. Varied topographic and agro- climatic conditions ranging from arid to semi-arid climates with high evaporation because of varied temperature regimes permit the cultivation of drought resistance crops. Reducing the cost of cultivation without compromising the socio-economic status of farmers is prime importance. Conservation of moisture by reducing the weed menace is great task performed by the dryland farmers. Under such situations, effective utilization of dryland tools and implements used are of a primitive nature throughout the dryland farmers for higher factor productivity. Traditional farm tools and implements for self-sustenance have been adapted through experience over generations to meet emerging socio- economic and farming challenges.

Relatively small yields consequently larger areas must be farmed for a given return and the successful exploration of dryfarming requires the adoption of methods. The methods which enable farmers to do the maximum effective work with the smallest expenditure of energy. The type of soils and topographic conditions largely influence the type, size and shape of particular tillage tools/ implements among the dryland farmers. The following is a list of local tools/ implements found in the various dryland regions.

Introduction

In order to keep pace with the development there is rise in energy use but it has adverse effects on climate due to greenhouse gas emissions from burning of fast depleting fossil fuels. In this context, we need to harness and use more and more renewable forms of energy, especially solar energy that is plentiful on most part of India. Also, at several locations harnessing wind power and utilizing biomass could be effective alternatives. Solar based devices may also work in an integrated manner with small wind turbines as hybrid devices. At present, about 20% of the country’s installed electricity generation capacity is contributed by renewable sources e.g. wind, solar, bioenergy, hydro etc., which is about 71.325 Giga Watt (GW) as on 30^th June, 2018. In agricultural sector, energy is directly used for pumping irrigation water, operating different mechanized farm implements/tools and processing of foods. Share of agricultural sector in total energy consumption is about 7-8% and further increase in energy use from its present value of 1.6 kW ha^-1 to 2.5 kW ha^-1 is expected to meet the production target of next 20 years.

Introduction

In Indian Thar desert regions, excessive heat is the major problem that causes human and animal thermal discomfort. Space cooling is, therefore, the most desirable factor for the inhabitants. Various examples of dwellings responsive to climatic constraints are found in vernacular architecture throughout the world. Compact cellular layout with minimum external surface exposure to the sun, whitewashed surfaces to reduce absorptivity, blind external facades, courtyards, vegetation to provide humidity and shade, and heavy buildings constructed from high thermal capacity materials are common passive features in most of the arid regions. Wind towers for cooling ventilation are well known in Iranian and Middle East architecture, which along with cooling of the air by earth and water evaporation keep the building comfortable in hot periods. Building underground to take advantage of the large thermal storage capacity of the earth is also used in Tunisia and central Turkey.

Introduction

Solar refrigeration technology engages a system where solar power is used for cooling purposes. It offers a wide variety of cooling techniques powered by solar collector-based thermally driven cycles and photovoltaic (PV)-based electrical cooling systems. Cooling can be achieved through four basic methods: solar PV cooling, solar thermal cooling, solar thermo-electrical cooling and solar thermo-mechanical cooling. The first is a PV-based solar energy system, where solar energy is converted into electrical energy and used for refrigeration much like conventional methods. The second method utilizes a solar thermal refrigeration system, where a solar collector directly heats the refrigerant through collector tubes instead of using solar electric power. The third one produce cool by thermoelectric processes. The fourth method converts the thermal energy to mechanical energy, which is utilized to produce the refrigeration effect.

The performance of solar refrigeration systems is determined based on energy indicators of these systems. The COP (coefficient of performance) can be calculated as follows:

Introduction

Considering the accountable post-harvest losses which is approximately 30-35 percent, food processing becomes an extremely important sector for preventing the losses and feeding the growing population. The Indian food industry is poised for huge growth, as currently valued at US$ 1.3 billion with compound annual growth rate of 20 per cent per year, increasing its contribution to world food trade every year. In India, the food sector has emerged as a high-growth and high-profit sector due to its immense potential for value addition, particularly within the food processing industry. Increasing population of the country and high cost of fuels have also created a demand for new alternate sources of energies for post-harvest processing of foods. Solar food processing technologies may become a viable option that provides good quality foods at low or no additional fuel costs. The energy policy of the developing countries now focuses on the clean renewable energy to create a further reduction of the petroleum import and to alter the utilization of petroleum energy toward the utilization of solar energy. It is an interesting fact that most of the developing countries fall in the climatic zone where the insolation is considerably higher than the world average of 3.82 kWh m-2 (Majumdar 2015). The daily horizontal insolation of India is approximately 5.80 kWh m-2 (Visavale 2009, Visavale et al. 2011). Solar dyers are an alternative to traditional drying technique and a contribution towards the solution of the problems of the open sun drying from perspective of renewable and clean energy. The International Energy Agency (IEA) declared in its 2011 solar energy perspectives executive summary (SEP 2011): “Solar energy offers a clean, climate-friendly, very abundant and inexhaustible energy resource to mankind, relatively wellspread over the globe. Its availability is greater in warm and sunny countries that will experience most of the world’s population and economic growth over the next decades.

Pteridophytes such as ferns belonging to several families, selaginellas popularly called ‘club mosses’ belonging to Selaginellaceae and the Lycopods which resemble both these, belonging to Lycopodiaceae are shade loving plants adapted to cool and moist or hot and humid ecosystems of tropical to temperate climates. They are mostly epiphytic or lithophytic and are grown as foliage ornamentals in a fernery or in shaded areas in gardens. Many are favoured indoor plants.

Popularly grown ferns, lycopods and selaginellas of gardens are listed below:

Adiantum capillus-veneris

Adiantaceae

Common Maidenhair fern

Plants are shade loving bushy lithophytes and have delicate looking thin black stems carrying light green oblique-ovate fronds. They are pot grown as ornamental foliage plants.

Adiantum decorum

Syn. Adiantum raddianum

Adiantaceae

Maidenhair fern

2.1 INTRODUCTION

With increasing population, urbanization and continuous depletion of natural resources, there has to be a paradigm shift in farmer’s perception from production to productivity and to profitability. In the present scenario, the major challenges arising are shrinking land and depleting water and other related resources in agriculture. There is need for promoting farmer friendly location specific production system management technologies in a concerted manner to achieve a vertical growth in horticulture production duly ensuring quality of produce and better remuneration per unit of area with judicious use of natural resources. In this endeavour, precision farming aims to have efficient utilization of resources per unit of time and area for achieving targeted production of horticultural produce. With the revolution in information technology, now it has become possible to focus on the positioning of agricultural tools with high degree of accuracy and sophistication for maximizing returns. The combination of information technology and use of hi-tech equipments made it possible for the introduction of precision farming. It is a comprehensive system designed to optimize agriculture production through the application of crop information, advanced technology and management practices. With recent advances in geographic information systems, it has become possible to focus on site specific crop production technologies so as to harness the potential of horticulture through innovative technologies in a sustainable manner.

5.1 INTRODUCTION

Drought and rampant poverty, the double plague of arid region, present a scenario of misery and insecurity across the region where agriculture is the main livelihood and chief source for subsistence of the rural people. The conditions of low and erratic rainfall, extreme temperature conditions, high evapo-transpiration, scarce water resources, infertile and saline soils with ill-defined profile development threaten sustainable agriculture. Sustainable productivity is difficult to achieve by monoculture of either seasonal or forage crops. Thus cropping system approach for agricultural production is of far greater significance in these regions. Traditionally efforts have been made by the native people, obviously to achieve sustainable production ensuring ecological stability, to grow several species together, e.g. pearl millet, moth bean, cluster bean and gram between the natural stands of khejri (Prosopis cineraria), bordi (Zizyphus rotundifolia), lasoda (Cordia myxa), pilu (Salvadora oleoides), and ker (Capparis decidua). The perennial species also provide fodder for sheep and goats during scarcity periods.

Fruit based cropping system is now considered to be the most ideal strategy to provide food, nutrition and income security to the people (Chundawat, 1993, Chadha, 2002, Awasthi and Pareek, 2008). Integration of annual crops with fruit trees yields multiple outputs that ensure production and income generation (Randhawa, 1990 and Osman, 2003) in a sustainable manner. Natural resources (land, solar radiation, water, soil etc.) as well as socio-economic inputs (labour, credit, power, and market infrastructure) are efficiently utilized. Crop productivity under tree canopy is enhanced due to improved soil fertility (Young, 1989) and ameliorative influence of shade by reducing understorey temperature and evapotranspiration (Bunderson et al., 1990). Incorporation of fruit trees into the cropping system is more remunerative. It increases the resilience of the system over time. It enables to i) maximize system productivity on annual basis, ii) utilize resources with high efficiency through due consideration of various interactions and direct, residual and cumulative effects occurring in soil-plant-atmosphere continuum, iii) intensify input use vis-à-vis quality of environment, and iv) impart sustainability of farm resources and environment in long term perspective. The type of horticulture based cropping system in arid region has been discussed in this paper considering these issues.

20.1 INTRODUCTION

With rapid increase in area under micro irrigation, now fertigation is getting momentum in many states in the country. At present, most of the soluble fertilizers are imported in the country. Hence, these are very expensive and beyond the reach of common farmers. It is interesting to record that for number of nutrients, which are becoming constraints in most of the Indian soils, soluble formulations have yet to be developed. This calls for some alternative options. As an alternatives liquid manures like cow urine, biogas slurry, or fermented manures etc can be sprinkled on the soil, applied with irrigation water or diluted and sprayed as foliar fertilizers (Frank et al; 2005).To our understanding, organic fertilizers /organic liquid manures referred now as bio-enhancers are essential to maintain the activity of microorganisms and other life forms in the soil. These are prepared locally, can resolve number of apprehensions and will be helpful in boosting production and mitigating number of nutritional disorders in most of soils and crops. It is interesting to record that these can be prepared at the farm with some infrastructure facilities and hands on training. Most of these formulations are used through irrigation. These organisms (bacteria and moulds) improve the soil health by solubilzing the complex organic substrates into simple forms and make it available to the plant, resulting in increased productivity. If these are integrated with micro irrigation techniques after proper filtration their efficacy can further be improved.

Cow dung and urine are important component in organic farming. Cow dung is rich source of microbial consortia Actinomycetes, which are helpful in control of many plant diseases. A potential species Streptosporangium psedovulgare of Actinomycetes and four strains of Bacillus subtalis have been identified at CISH, Lucknow (Pathak et.al., 2009).These showed anti pathogenic potential against anthracnose gummosis, stem end rot and dieback pathogens. These were observed to attack mycelia cell wall and finally the host cell degenerates completely. Organic liquid manures play a key role in promoting growth and providing immunity to plant system ( Sreenivasa et al., 2010).

24.1 INTRODUCTION

Citrus fruits occupy third position after mango and banana in the country and ranks 6^th in the world citrus production. The productivity, however, is only about 40 percent of that in Spain, Brazil, USA or Japan (8.4 t/ha) only. Of the total production, mandarin contributes more than that of sweet orange in which major chunk of 57.72 per cent was shared by Maharashtra, followed by 19.81 per cent by Madhya Pradesh state. At present, the Brazil is the largest producer of citrus, followed by USA. There are number of issues which need to be addressed to make fruit quality comparable to the international standards. Post harvest losses of fruits are also enormous mainly due to unscientific method of harvesting, lack of utilization of post-harvest handling techniques due to which 25 - 30 per cent losses occur in developing countries in comparison to 5 - 10 per cent in developed countries. Synergistic effect of pre-harvest practices and post harvest handling is the key to get the fruit of high quality and enhanced shelf life.

Recent trends are emerging as use of less chemicals and Good Agricultural Practices (GAP) during cultivation. Maintenance of quality standards and regulations up to retail market level is of utmost importance. Whereas, in marketing sector, now-a-days participation of private players on large scale in retail marketing of produce is noticed.

Value chains have become the centre of considerable academic and practical interests. Part of the reason for the rapidly growing interest in value chains in the citrus sector has been the result of changes in global retailing. In a large number of countries, supermarkets chains now dominate food retailing. Supermarkets have increasingly integrated their operations involving many aspects of the post farm gate operations. Value chain management is one of these. Some identified issues relates to supply chain bottlenecks resulting in farmers experiencing gluts of commodities, processors not being able to procure sufficient raw materials for their plants, retailers not getting sufficient products to meet the demand of consumers, and exporters are unable to meet foreign consumer requirements. Lack of innovation that affects the entire chain, an example being the introduction of plastic crates for a fruit processor involves a vast number of actors in the chain to coordinate their efforts.

Different types of greenhouses or protected structures are designed to meet the specific needs. They can be classified based on shape, utility, construction, cladding material, net houses and technology adopted.

A. Classification based on shape of greenhouse: Greenhouses can be classified based on their shape or style. For the purpose of classification, the uniqueness of the cross section of the greenhouses can be considered as a factor. As the longitudinal section tend to be approximately the same for all types, the longitudinal section of the greenhouse cannot be used for classification. The cross sections depict the width and height of the structure and the length is perpendicular to the plane of cross section. Also, the cross section provides information on the overall shape of the structural members, such as truss or hoop, which will be repeated on every day. The commonly followed types of greenhouse based on shape are lean-to, even span, uneven span, ridge and furrow, saw tooth and quonset.

Lean-to type greenhouse: A lean-to design is used when a greenhouse is placed against the side of an existing building. It is built against a building, using the existing structure for one or more of its sides. It is usually attached to a house, but may be attached to other buildings. The roof of the building is extended with appropriate greenhouse covering material and the area is properly enclosed. It is typically facing south side. The lean-to type greenhouse is limited to single or double-row plant benches with a total width of 7 to 12 feet. It can be as long as the building it is attached to. It should face the best direction for adequate sun exposure. The advantage of the lean-to type greenhouse is that, it usually is close to available electricity, water, and heat. It is a least expensive structure. This design makes the best use of sunlight and minimizes the requirement of roof supports. It has the following disadvantages:

Planning

A greenhouse, is basically the purpose of providing and maintaining a growing environment that will result in optimum production at maximum yield. The agriculture in the controlled environment is possible in all the regions irrespective of climate and weather. It is an enclosing structure for growing plants, greenhouse must admit the visible light portion of solar radiation for the plant photosynthesis and, therefore, must be transparent. At the same time, to protect the plants, a greenhouse must be ventilated or cooled during the day because of the heat load from the radiation. The structure must also be heated or insulated during cold nights. A greenhouse acts as a barrier between the plant production areas and the external or the general environment.

Site selection and orientation

A greenhouse is designed to withstand local wind, snow and crop loads for a specific cropping activity. In this way, the structure becomes location and crop specific. The building site should be as level as possible to reduce the cost of grading, and the site should be well aerated and should receive good solar radiation. Provision of a drainage system is always possible. It is also advisable to select a site with a natural windbreak. In regions where snow is expected, trees should be 30.5 m away in order to keep drifts back from the greenhouses. To prevent shadows on the crop, trees located on the east, south, or west sides should be at a distance of 2.5 times their height.

Greenhouses should provide a controlled environment for plant production with sufficient sunlight, temperature and humidity. Greenhouses need exposure to maximum light, particularly in the morning hours. Consider the location of existing trees and buildings when choosing your greenhouse site. Water, fuel and electricity make environmental controls possible that are essential for favourable results. For this reason, use reliable heating, cooling and ventilation.

The greenhouse temperature requirements depend upon which plants are to be grown. Most plants require day temperatures of 70 to 80 degrees F, with night temperatures somewhat lower. Relative humidity may also require some control, depending on the plants cultured. Some plants grow best in cool greenhouses with night temperatures of 50 degrees F after they are transplanted from the seeding tray. These plants include azalea, daisy, carnation, aster, beet, calendula, camellia, carrot, cineraria, cyclamen, cymbidium orchid, lettuce, pansy, parsley, primrose, radish, snapdragon, sweet pea and many bedding plants. Some plants grow best in warm greenhouses with night temperatures of 65 degrees F. These plants include rose, tomato, poinsettia, lily, hyacinth, cattleya orchid, gloxinia, geranium, gardenia, daffodil, chrysanthemum, coleus, Christmas cactus, calla, caladium, begonia, African violet, amaryllis and tulip. Tropical plants usually grow best in high humidity with night temperatures of 70 degrees F.

The popularity of greenhouse-grown produce continues to rise as it provides a variety of produce during the “off” season. Greenhouses are good for healthy plant nursery production and other a number of crops for profit. Though the greenhouse farming in India like in other countries is progressing but there are certain problems and constraints as stated below.

1.Greenhouse production generally is highly technical and requires constant and continuous attention during cropping period. Relevant information about the crop environmental requirement such as right temperature, humidity etc is essential.

2.Knowledge about the right type of inputs for greenhouse production is a must which is not easily available.

3.Greenhouses cultivation increases the land, water and fertilizer productivity along with reduction in pesticide use. But such interventions are associated with very high initial cost. Although, it is linked with several Government Schemes in India and have 50-90% of subsidies depending on intervention, status / socio-economic condition and policy of State and Central Government.

4.Uninterrupted and regular power supply is required for operating cooling and heating system of the controlled environment greenhouses which necessitate a back-up power pack which is also expensive and underutilized.

INTRODUCTION

Potato ranks third among the major food crops after wheat and rice in the world. It is most important and versatile food of the world. India is second largest potato producer next to china.Potatois bulky and watery in nature and requires lot of energy for production and processing. It is a shortduration crop of 90-120 days, having highest yield per ay per unit area as compared to other major crops. Being a relatively short duration crop in the plains of India, its mechanization assumes a special importance in order to accomplish various farmoperations inverylimited time foritshigherproduction.Manualproduction of potato is time consuming and tedius job, it requires about 1600-2000 man-hours per hectare. With the rising cost of production and depleting energy reserves, increase in crop productivity with minimum input of energy and cost one of the paramount concerns (Garg and Singh 2002). Sustenance of agriculturalproductivitygoes handin handwith mechanization of differentfarm operations, which aims at achieving timeliness of operations, efficientuseof inputs safety and comfort of farmers, reduction in cost of produce and drudgery of farmers (Verma et. al, 1992).With the emergence of new crop rotations and enhanced cropping intensity, many farmers experience scarcity of time and labour. Mechanization plays an important role in timely completing farm operations involved in potato production. It implies a resource management strategy to increase productivity and economic returns. Efforts have been made at various levels to mechanise both production and processing. Various mechanical tools, implements and machinery have been developed for land development, fertilizer application, planting, weeding, harvesting, preparation for storage and on-farm processing of potato (Singh and Gulati 2014).

INTRODUCTION

Potato plays a vital rolein foodsecurityworldwide. It is the third most important food crop, afterrice and wheat. It is a nutrient-rich crop which provides more calories,vitamins and nutrients per unit area than any otherstaple crops. FAO declared potato as the crop to address future global food security and poverty alleviation during2008. In Indian agriculture, potatoplays a very important role as it alone contributes about 21 percent of the total vegetable area and 26 percent of total vegetable production of India (DAC&FW, 2017a). As per FAOSTAT data for the year 2017,India with48.6 million t is ranked second in potato productionin the world, onlybehind Chinawith 99.2 million t (Figure 1).

Abstract

Lianas are slightly lesser known angiosperms, grows typically in the form of climbing vines mostly in tropical and subtropical forests. Such plants are characterized by scandent thick stems, woody stem in nature and vary in shape and size. They depend on supports in the form of trees, fence and usually climb upward towards the sunlight as they needed for their survival. Keeping the importance of lianas in forests and household, this study was conducted to document the liana angiosperms growing in Western Himalaya along with their medicinal potential for human and animals. This study reveals a total 64 lianas species belonging to 24 families recorded from Jammu and Kashmir, Ladakh, Uttarakhand, Himachal Pradesh and Punjab. This investigation also provided with medicinal potential of these species, which is used as ethnomedicine by local people living in the interior regions of hills and mountains of Himalaya. In this communication, we highlight lianas as an example of an underestimated forest element that, on the one hand, is a key component in and around forests. This study also helps in conservation of endangered liana species in Himalaya.

Abstract

Keeping in view the increasing demand of off-season and high value vegetables in several big cities of the country, there is an urgent need for diversification from the traditional agriculture by production of high value vegetable crops under different protected conditions for increasing their productivity and quality not only for getting high returns but in a Horti-Business / Veggie-business model. Nursery raising under protected cultivation is highly suitable for such Horti-business model or can be adopted as an agri entrepreneur business in major vegetable growing areas of the country by unemployed youths who are graduates in agriculture or post graduates in horticulture. Low cost protected technologies like plastic low tunnels or walk in tunnels, shade net houses can be used for off season vegetable cultivation for getting high returns. Similarly, insect proof net houses can be used on a large scale for safe vegetable cultivation by way of minimizing the use of pesticides in vegetable cultivation and virus free quality seed production in large number of vegetables in a horti-business model. Some of the technologies like low pressure drip irrigation and low cost nursery raising technology can also be replicated in other parts of the country even among the resource poor and tribal farmers.

Environmental management systems (EMSs) such as ISO 14000 are seen as mechanisms for achieving improvements in environmental performance and for supporting the trade prospects of “clean” firms. The potential advantages of EMSs are clear, but the adoption of ISO 14000 is very recent, and practical issues are emerging, among them the need for an emphasis on performance improvement and for simplification of certification; the potential for regulatory streamlining; and the trade consequences. This chapter outlines the key elements of an EMS and discusses these issues.

The Benefits of an EMS

An environmental management system (EMS) is a structured program of continuous environmental improvement that follows procedures drawn from established business management practices. The concept is straightforward, and the principles can be easily applied, given the necessary support. There has been increasing interest in the potential value of EMS approaches, ofwhich the recently released ISO 14000 series is the most widely known.

The first steps in the control of industrial pollution have been the creation of the necessary regulatory framework and the specification and design of control equipment to reduce emissions. These efforts have been broadly successful in improving the performance of many polluters, but in other cases, investments in pollution equipment are wasted because the equipment is not operated properly. Attention, in the World Bank and elsewhere, is turning to support of regulatory and end-of-pipe approaches through incentives, production efficiencies, and management improvements a range of measures often grouped under the broad banner of cleaner production and eco-efficiency.

18.1 Introduction

Recycling of industrial wastewater is not only environmentally beneficial, but it is typically more cost effective than conventional treatment and discharge. Through application of stream segregation and appropriate treatment technologies, high purity water is produced for continuous reuse where by metals are recovered and solid wastes reduced. Recycling of industrial effluent by chemical treatment includes many separation methods for getting pure waters. It is very essential to discuss about reverse osmosis, filtration, adsorption evaporation etc. This chapter includes the discussion about the methodology of chemical treatments.

18.2 Conventional Treatments

The oldest and most widely applied method of wastewater treatment involves the addition of chemicals and applications of aerators etc. to alter the make-up constituents of a waste. Although generally downsized, the process continues to play an important role in newer systems used today. Automated controls and advanced instrumentation have improved this technology in recent years. (Tomer et.al., 1997)

20.1 Introduction

High levels of energy and materials consumption in industrial countries are the driving force behind the decline in virtually all major life support systems on Planet Earth. Over the last decade an increasing number of scientists and other thoughtful people have come to conclude that modern levels of materials and energy consumption are having a destabilizing influence on the world’s ecosystems.

Energy consumption contributes directly to climate change by adding carbon-based molecules to the atmosphere in excess of naturally occurring amounts. Carbon molecules, primarily carbon dioxide from burning petroleum products, trap radiant heat and keep it from escaping from the Earth’s atmosphere. The resulting warming of the air is changing our global climate.

Materials consumption contributes indirectly to climate change because it requires energy to mine, extract, harvest, process, and transport raw materials, and more energy to manufacture, transport and, after use, dispose of products.

All the materials used in products, only 1% is used in products ‘durable’ enough to still be in use six months later, according to industrial ecologist Robert Ayres. This wasteful consumption of materials wreaks havoc on our land, water resources and their ecosystems. What’s seldom appreciated is that it also wreaks havoc on our atmosphere and contributes to climate change. Waste prevention and recycling are critical to stopping climate change.

Squashes and Pumpkin (Cucurbita, spp, 2n = 2x = 40) are the words quite often used interchangeably. However, the term squash is more commonly used for C. pepo which is consumed as an immature fruit. The term pumpkin is normally applied to the edible fruit of any species of Cucurbita utilized when ripe as a table vegetable or in pies.
 
Origin:  The genus Cucurbita is native to America.  The center of diversity is the tropics near the Mexico- Gauatamla border. The archaeology evidences indicate that these were widely cultivated in South Western United States, Mexico, and northern South America in Pre-Colombian times i.e. prior to 1492 A.D.

C. pepo : Summer squash : Some varieties belong to winter squash, pumpkin and marrows. It has bushy habit, peduncle hard, sharply angular, grooved, leaves broad, triangular in outline, usually with deep lobes little or no expansion of peduncle at fruit attachment. In North America it is commonly found.

C. mixta : Squash, cymlins, cushaws: It is used as summer and winter squash, leaves shallowly lobed, hard corky peduncle. This is also commonly found in North America.

Southern pea / black eyed pea are the other names associate with cowpea. It is grown for vegetable and also as pulse crop and varieties are specific for use.

Classification of Cowpea
1.    Vigna unguiculata (L.) Walp. Cv. Sesquipedalis: yard long bean or asparagus bean: Possess long pods and used as vegetable. 
2.    Vigna unguiculata (L.) Walp. Cv. Cylindrica: dual purpose, i.e. vegetable and pulse 
3.    Vigna unguiculata (L.) Walp cv. Radiata: Pulse type.
 
More emphasis is given for pulse types for crop improvement. Less attention is given to vegetable types. Pole and bush types are available in vegetable type. Cowpea improvement is from vine to bushy habit with low fiber content and low glucosides and increased protein content.
Origin and Distribution: Cowpea is in cultivation from ancient times in the tropics of old world. Country of origin is uncertain. In India, it has been known from the vedic times. Vavilov (1939) considered India as the primary centre of origin. But it is now generally agreed that Africa is centre of origin since wild forms are found in Africa and in Asia wild forms are absent (Smartt, 1990). Faris (1965) concluded that, cowpea arose from domestication of wild form Vigna unguiculata ssp dekindtiana in West Africa. But domestication is actually happened in Ethiopia and dissemination was West wards Africa, East ward across the Indian Ocean. It has spread from Africa to Asia and Europe through Egypt. Introduced to West Indies in 16th century by Spaniards and was taken to USA around 1700. Now cowpea is widely distributed throughout the tropics and subtropics.

Carrot (Daucus carota L.) is a cool season root vegetable and temperature is the important factor affecting root shape and colour, besides soil type and moisture content of soil. It provides an excellent source of vitamin A and fiber in the diet. The genus Daucus, which include carrot, has many wild forms that grow mostly in the Mediterranean region and South West Asia. Representatives are found in Africa, Australia, & North America. For Daucus carrot L. it is generally agreed that Afghanistan is the primary center of genetic diversity and therefore the primary source for dissemination. Asia Minor, Afghanistan, North West India, Iran and Turkey are the centers of origin of carrot. Banga (1957& 1963) has provided evidence that the purple (anthocyanin) carrot together with a yellow variant spread from Afghanistan to Mediterranean area as early as 10th and 11th century. It is known in Western Europe in 14th and 15th century, China in 14th century and Japan in 17th century. The European carrot (Carotene carrot) derived from the Asiatic (anthocyonin containing) form of carrot (tropical carrot).  Afghanistan is the centre of diversity of the purple coloured carrot (anthocyanin). Integration of Asiatic and European carrots has given the present day forms. The yellow coloured (carotene rich) forms were also thought as mutants of anthocyanin carrots. The yellow mutants were traced in Asia Minor in 10 and 11th centuries, Spain in 12th century, North Western Europe in 14th century and England by 15th century.  The crop was introduced to China during 14th century and to Japan during 17th century. D. carota and D. sativus are only cultivated species of the genera with Chromosome No. 2n = 18. All forms have same chromosome number. 

Bone marrow contains variety of tissues including hematopoietic lineage cells and mesenchymal stem cells (MSCs). The hematopoietic cells are the major source of the blood cells in the adult body which are regulated within the microenvironment of the stromal cells of the bone marrow. MSCs are multipotent cells and can be differentiate into various cell lineage depend upon their environment and culture condition in which they are kept. Rat bone marrow derived stem cells (rBM-MSCs) have long term self renewing and capabilities of pluripotency including osteoblast, adipocytes, chondrocytes, tenocytes, muscle cells and neurogenic cells, which make them ideal source of stem cells for regeneration of injured tissue.

Bone marrow derived mesenchymal stem cells have been isolated from different species. Each species is having different culturing and growing capacity. For example human bone marrow derived stem cells are easy to harvest and maintain in culture condition whereas rat MSCs it is more difficult compared to other species. Technical difficulties in isolation limited the number of animal experiment and its required animal transplantation model for pre clinical studies. Density gradient centrifugation, plastic adherence and immunomagnetic selection like various methods are available for isolation of MSCs from bone marrow. No appropriate methods are available for selection of suitable cells. Each method has their own pros and cons. Therefore, in this chapter, combined density gradient centrifugation and plastic adherence as easy and reliable method for isolation, culture and characterization of rat bone marrow derived mesenchymal stem cell is described.

Despite the benefits that minimally invasive surgery and osteosynthesis have brought to fracture management and bone healing, there are still many circumstances where bone healing remains challenging. Large bone defects are serious complications that are most commonly caused by extensive trauma, tumour, infection, or congenital musculoskeletal disorders. In nonunion cases repairing of bone defects with composite biomaterials as defect filler can promote bone regeneration. Currently, the gold standard for bone regeneration is use of autogenous bone graft. In order to avoid morbidity at the donor site or if large amount of autogenous bone is needed, bone substitution materials can be used.

Bone substitution materials can be combined with cells such as mesenchymal stem cells (MSCs) to increase bone formation. Bone-marrow derived mesenchymal stem cells (BMSCs) represent an attractive cell population for tissue regeneration. Bone marrow stem cells are pluripotent cells that have been used to facilitate bone repair because of their capability of differentiating into osteoblasts. Several studies on the regeneration of bone have shown that cultured BMSCs, seeded on different bioabsorbable implants are able to induce bone formation in vivo and lead to improved healing of critical-size defects.

Downy mildew is refered to a condition of plant disease where the fungal growth and infection appears on the dorsal side of the leaf surface while the corresponding ventral side of the leaf shows faint yellowish color. It is also refered to the fungus which causes this disease.The word mildew in Latin language means mil + dew i.e honey like dews.The fungal growth on plant surface resembles to the milky dews in the beginging which turn to golden brownish honey like dews in later stage. Subsequently the affected areas turn grayish brown and dry. Besides the infection of leaves, the fungus also infects the fruits. The downy mildew infection on fruits causes the deformities on the affected fruits. The infection of the downy mildew pathogen on some of the cereals like pearlmillet causes the symptoms like green ear disease .

Downy mildew pathogens can cause major damage in the nursery, in greenhouse, in field crops and in landscape in the form of leaf spots, blights, and distortions with mildew growth. Downy mildews are primarily foliage blights with mildew growth of the fungus on affected portion. The fungus attack and spread rapidly in young, tender green leaf, twig, and fruit tissues. The fungal development are severe when a film of water is present on the plant tissues and the relative humidity in the air is high during cool or warm, but not hot, periods. Downy mildews can cause severe losses in short periods of time. Downy mildews often cause rapid and severe losses of young crop plants still in the seedbed or in the field. They often destroy from 40 to 90% of the young plants or young shoots in the field, causing heavy or total losses of crop yields. The severity of loss depends on the prolonged presence of wet, cool weather during which the downy mildews fungus sporulate profusely, cause numerous new infections, and spread into and rapidly kill young succulent tissues.

10.1. Downy mildew of Plantago psyllium

Downy mildew is the major and serious disease of Plantago particularly P. ovata. It causes enormous quantitative and qualitative loss and often becomes a limiting factor in the successful cultivation of the crop (Desai and Desai, 1969). Usually the disease appears at the time of spike initiation.

Pathogen: Peronospora alta and P. plantaginis

Geographical distribution
Plantago ovata under commercial cultivation has been reported to suffer from downy mildew disease. Downy mildew occurs on ripe seeds of Spanish, French and European plantago. The downy mildew is a native of Mediterranean region especially Southern Europe, North Africa and West Pakistan.
The plantago commercially cultivated in Gujarat and to a limited extent in Haryana and Rajasthan provinces in India is observed to be infected with downy mildew.

Food, Water and Air are three essential elements for existence and sustenance of life. Primarily food is manufactured by the plants by trapping the energy of Sun in presence of carbondioxide and water. Foods can be broadly classified into energy foods and protective foods. While energy is required for all bodily functions, protective foods confer a degree of resistance against diseases, corrects some disorder and prevents occurrence of certain conditions that occur due to deficiency of certain elements and phytochemicals. The balanced diets are said to be those which have an appropriate amount of carbohydrates, proteins and fats. All these three components play certain essential role in the process of metabolism. Deficiency or insufficiency of these major food components may lead to energy deficient disease conditions and are considered responsible for malnutrition world wide. Energy deficiency can threaten the existence of life. Food grains, tubers and roots are major sources of carbohydrates, and proteins. Sufficient intake of carbohydrates, proteins and fats alone does not ensure health. Health and wellbeing are the two important aspects of life, which makes it worth living. For being healthy, besides energy, body requires minerals and vitamins which are present mainly in fruits and vegetables. The role phytochemicals play in cleansing the body and fight against diseases, was understood quite recently. Therefore, for a healthy life we need to consume a balanced diet comprising of appropriate amounts of carbohydrates, proteins, fats, fruits, vegetables and nuts. While the former three can be consumed based on the energy requirement of an individual, one should consume at least 180 and 300 grams of fruits and vegetables respectively everyday.

The split-split plot design is an extension of the split-plot design to accommodate a third factor .It is uniquely suited for a three –factor experiment where three different levels of precision are desired for the various effects. Each level of precision is assigned to the effects associated with each of the three factors. This design is characterized by two important features :

1. There are three plot sizes corresponding to the three factors, namely, the largest plot (main plot) for the main-plot factor, the intermediate plot (sub-plot) for the subplot factor, and the smallest plot (sub-sub plot ) for the sub-subplot factor.
2. There are three levels of precision, with the main-plot factor receiving the lowest degree of precision and the sub-subplot factor receiving the highest degree of precision.

The method of analysis is entirely analogous to that for the case of 2 factors. The analysis consists of 3 parts, between whole plots, between split plots within whole plots,between split-split plots within split plots, each part being put on the basis of a split-split plot in order that the parts may be combined into one complete analysis.

Introduction

As a chief feature of RCBD, formation of blocks is a necessity to achieve homogeneity of plots within each block so that an irrevelant source of variation existing to the error component could be removed for purposes of treatment comparisons. But quite frequently, in agricultural experiments, the fertility gradient varies in all directions so that the plots within a block in RCBD could still be heterogeneous. In order to control or remove this additional source of variation, one can think of extending the concept of blocking yet in another direction , orthogonal to the first direction, leading to a new design called Latin Square Design(LSD). In otherwords, if the blocking concept is one-dimensional in RCBD, it is two-dimensional in LSD. As a guiding principle for formation of two-dimensional blocks, it may be stated that each row-block and each column–block should remove as much variability as is possible from total variability so that error component becomes smaller. The chief restrictive features of LSD are:

In many experimental situations, it becomes necessary to repeat an experiment over time ( for a number of seasons or years ) and / or over space ( a number of places). This repetition ( or replication ) of the experiment broadens the scope of the experiment in the sense that our recommendations will be applicable for a number of seasons /or a number of places . A single experiment performed in one place for only one season will provide recommendations for that place and for that season . It may not be applicable to other places or for other seasons . In the case of agricultural experiments , for example , there may be present treatment x place interaction and/ or treatment x season interaction . So the results of a series of experiments , performed over different places for different seasons with the same set of treatments,will have wider applicability .

We shall consider the simplest case of repetition of experiments of identical structure over a number of places ( it is the same for a number of seasons ). Let us consider randomized block experiments with t treatments in r blocks and conducted in p places. The analysis of the experiment in a place is based on the linear model . Before attempting a combined analysis for the p experiments ,it is necessary to perform the analysis for the p places separately and interpret the results separately .It may be of interest to find out whether differences among the treatments are the same in the different places so that a ‘ best ‘ treatment may be recommended for all the places, or whether different treatments are to be recommended for different places . The model for this combined analysis may be written as

This is an extension of the analysis of variance to cover the case where observations are taken on more than one variable from each experimental unit. Interest, however, centres on one of these (y, called the dependent variable) and the question is whether the variation of the dependent variable over the classes is due to class effects or due to its dependence on the other variables, (x’s, called the independent or concomitant variables ), which also vary from class to class. The analysis of covariance controls the experimental error by taking ito consideration the dependence of y on x.