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The family Enterobacteriaceae belongs to the order Enterobacterial. The family comprises 25 genera such as Escherichia, Salmonella, Klebsiella, Yersinia, Proteus, Providencia, Shigella, Enterobacter, Morganella, Edwardsiella, Budvicia, Cedecea, Citrobacter, Ewingella, Hafnia, Kluyvera, Leclercia, Leminorella, Moellerella, Pantoea, Rahnella, Tatumella, Trabulsiella, Serratia and Yokenella, out of which the first 10 genera are consistent pathogenic in humans, animals and birds.

Escherichia coli

Escherichia coli were first isolated by Theodor Escherich in 1885 from the faeces of infants. It was named in honour of the German pediatrician and its major natural habitat (colon). Previously it was also known as Bacillus coli or Bacterium coli (B. coli).

Lucke (1862) first described that the bluish green discolouration of surgical dressing is associated with the presence of small vibrio like organisms. Gessard (1882) first isolated the bacteria as Pseudomonas.

Identification of the etiologic agent of glanders was performed in 1882 by isolating a bacterium from the infected liver and spleen of horse. Since its discovery, the pathogen has been classified as Loefflerella mallei, Pfeifferella mallei, Malleomyces mallei, Actinobacillus mallei, Corynebacterium mallei, Mycobacterium mallei, Pseudomonas mallei, and currently as Burkholdria mallei. The genus Burkholderia was created to accommodate former rRNA group II (Pseudomallei group) Pseudomonas bacteria. It was based on the 16S rRNA sequences, DNA-DNA homology values, cellular lipid and fatty acid composition.

Louis Pasteur (1881) first isolated the bacterium from fowl cholera outbreak and attenuated the bacteria to develop a vaccine for the chicken. Trevisan (1887) coined the generic name ‘Pasteurella’ in honour of Louis Pasteur. Lignieres (1900) proposed the name of the species according to the animals acted as the major hosts such as Pasteurella aviseptica for fowls, P. suiseptica for pigs, P. boviseptica for bovines, P. oviseptica for ovines and P. leptiseptica for rabbits. Rosenbuch and Merchant (1939) proposed the name of single species Pasteurella multocida which is in use till date.

Mannheimia is an exclusive animal pathogen and is associated with ‘shipping fever’ or bovine respiratory disease (BRD) in cattle. Kitt (1885) first described the bacterium as Bacterium bipolare multocidum isolated from shipping fever in cattle. The nomenclature was further changed into Bacillus boviseptica and finally into Pasteurella haemolytica. Based on fermentation capability of arabinose and trehalose, P. haemolytica was subdivided into two biotypes (A and T) and several capsular serotypes. The biotype A (with 12 capsular serotypes) was classified under a new genus Mannheimia due to disparities in 16S rDNA sequence, cultural and pathological characteristics.

Lignieres and Spitz first isolated Actinobacillus from the cattle with actinomycosis like condition in Argentina in 1902. The findings were also confirmed by Nocard in 1902. Later the isolated bacterium from the cattle was named as Actinobacillus lignieresii in memory of Lignieres.

Pfeiffer (1892) first isolated Haemophilus influenzae as a cause of human influenza and it is also known as ‘Pfeiffer’s bacillus’. Other workers isolated and described different species of the genus Haemophilus from animals and birds. In 1903, Friedberger, a research assistant of Pfeiffer, isolated similar kind of bacteria from prepuce of dogs which was described later as Haemophilus canis. In 1925, Mitchell isolated Haemophilus ovis from the respiratory tract of sheep. Lewis and Shope (1931) isolated and illustrated Haemophilus suis from the infected pigs. Glasser found the association between fibrinous serositis, polyarthritis in pigs (Glasser’s disease) and a small gram-negative rod as early as 1910, later became known as Haemophilus parasuis. The bacteria was first isolated by Hjarre and Wramby in 1943. De Blieck (1931) isolated a hemophilic bacterium from the birds suffering with ‘infectious coryza’ and named the bacteria as Bacillus haemoglobinophilus coryzae gallinarum. Later it became known as Haemophilus paragallinarum (Avibacterium paragallinarum).

Clinical conditions similar to brucellosis have been described since the time of Hippocrates (450 BC). J. A. Marston (1861) first described brucellosis as gastric remittent fever in Malta, the Southern European island country. Sir David Bruce (1886) first isolated small coccobacilli from an infected soldier’s spleen and purified the culture in 1887, and named Micrococcus melitensis. Later the genus was renamed as Brucella in his honour. Similarly, Bang and Stribolg (1897) first isolated Brucella abortus from abortion material of a cow. Traum in 1914 isolated Bacillus abortus suis, currently known as Brucella suis. In 1953, Brucella ovis was firs isolated in New Zealand by Budlle and Boyes from the aborted material of sheep. Carmichael and Bruner (1968) first isolated B. canis from the aborted placenta of a dog.

In India first report of ‘contagious abortion’ associated with Brucella was found in annual report (1918) of imperial veterinary research institute (presently Indian veterinary research institute), Mukteswar, Uttarakhand and later in 1942 by Polding.

Since the periods of Hippocrates and Lord Buddha cholera like symptoms was described in human. The first outbreak of cholera was described in India in 1817. Filippo Pacini (1854), an Italian anatomist, observed a gram-negative bacterium associated with human cholera. Robert Koch (1884) first isolated and confirmed the association of ‘comma-shaped bacteria’, later designated as Vibrio cholerae with the disease in Calcutta (India). In 1959, Sambhu Nath De, Professor of Pathology at Nilratan Sircar Medical College in Calcutta discovered the exotoxin produced by V. cholerae and a simple method (rabbit ligated ileal loop assay) to study the in vitro effect of exotoxins. The Ganges delta of India and Bangladesh is considered as the worst affected place with cholera although the infection is widespread throughout the world. The spread of cholera in different continents occurred through six ‘waves’ (‘pandemics’) since 1817. The current seventh pandemic (7P) was originated in Indonesia (Sulawesi) in 1961 and spread throughout Asia, Africa and Latin America. In 1963, the seventh pandemic reached South Asia and circulated for more than 50 years with intermittent transmission to other continents. The recent major 7^th pandemic outbreak was detected in Haiti causing more than 9400 deaths in 2010 which was originated through patients from endemic countries.

In 1886, Escherich observed Campylobacter like organisms in stool samples of children with diarrhoea. In 1913, McFaydean and Stockman first confirmed the bacteria as Campylobacter in foetal tissues of aborted sheep. Confirmatory tests were also carried out by Smith in 1918 when similar bacteria were isolated from aborted bovine foetuses. The bacteria were then known as Vibrio foetus. In 1963, due to certain differentiating characteristics, the organisms were separated from Vibrionaceae family and the new genus Campylobacter (means ‘curved rod’) under Campylobacteraceae family was proposed.

Guillame de Baillou (1673), a physician, described an outbreak of recurrent severe cough that could induce vomition and suffocation in human in Paris. The infection was described as ‘Quintan^tussis which was later confirmed as ‘whooping cough’. The causative agent Bordetella pertussis was discovered by Jules Bordet and Octave Gengou in 1906 in Paris. The Gram-negative bacilli were isolated from sputum of Jules Bordet’s son. Bordetella bronchiseptica was first isolated by Ferry (1911) and M’Gowan (1911) who considered the bacteria as the cause of distemper in dogs. Later B. bronchiseptica was known as primary cause of ‘kennel cough’ infection along with the Canine Adenovirus and Canine Parainfluenza virus. Moreno- Lopez named the bacteria B. bronchiseptica.

The genus Moraxella was named after Morax who first isolated the bacteria from human conjunctivitis in 1896.

Properties

1. Bacteroides, Dichelobacter and Fusobacterium are major gram negative anaerobes isolated from human and animals. Other gram negative anaerobes are listed below (Table-1).

2. The bacteria are tolerant to oxygen in comparison to strict anaerobes. The bacteria do not die after oxygen exposure.

3. The bacteria naturally inhabit the intestine and mucosal surfaces of human and animals. Majority of them are opportunistic pathogens. Often they cause mixed bacterial infection along with aerobes. The aerobes remove oxygen and create an anaerobic condition favourable for their growth. The aerobes may also supply other growth requirements. For e.g. Porphyromonas asaccharolytica requires vitamin K for its growth, supplied by another aerobic bacterium, not the host.

Antony Van Leeuwenhoek (1681) first observed the spirochetes under the microscope and described them. In 1833, Ehrenberg used the name Spirochaeta for free living spiral shaped organisms. Obermeir (1873) first described a spirochete of pathogenic significance isolated from human patients with relapsing fever. Inada (1916) first isolated Leptospira icterohaemorrhagiae from human patients of Weil’s disease. In 1980, Nogochi proposed the name as Leptospira.

In India, Taylor and Goyale (1931) first reported Leptospira from human patients suffering with jaundice in Andaman Islands. Ayyar (1932) first reported Leptospira from dogs in Chennai city.

The word ‘Mycoplasma’ is originated from the Greek word mykes (fungus) and plasma (formed). It was first used by Albert Bernhard Frank (1889), a German biologist. He thought it was a fungus. An older name for Mycoplasma was pleuropneumonia-like organisms (PPLO), referring to organisms similar to the causative agent of contagious bovine pleuropneumonia (CBPP).It was later found that the fungus-like growth pattern of Mycoplasma mycoides is unique to the species. It was first isolated in 1898 by Edmond Nocard and E. Roux from bovine lungs. Mycoplasma pneumoniae was considered as a virus previously. Eaton and his co-workers cultured the causative agent of human primary atypical pneumonia (PAP) or ‘walking pneumonia’. It was known as ‘Eaton’s agent’. In the early 1960s, Leonard Hayflick, in Philadelphia, was first to isolate and cultivate the causative agent of primary atypical pneumonia and identified the agent as a Mycoplasma pneumoniae.

Properties of genus

1 Morphology: Mycoplasma have no cell wall and therefore are resistant to the antibiotics used to inhibit the cell wall synthesis like penicillin, cephalosporin and vancomycin. The bacteria are the smallest prokaryote (0.3-0.8µm). They are pleomorphic due to absence of the rigid cell wall. The different shapes include ring, globules, filaments and elementary bodies. Due to their plasticity in shape and size, they can be passed through the membrane filter with pore size of 0.45µm. The cell membrane is constituted of trilaminar structure enriched with phosphoprotein, lipoprotein, glycolipid, phospholipid and sterol. So Mycoplasma require sterol for their growth.

History of rickettsial infections went back to 16^th century and it has long been associated with famine and war. Epidemic typhus had major impact to decide over the outcome of several wars. The epidemic alone killed or caused great sufferings to over 1,00,000 people during World Wars. However, the causative agent was not determined until the early part of the 20^th century. Rocky Mountain spotted fever (RMSF) was the first detected rickettsial infection in 1896 in Idaho Valley, USA. It was originally known as ‘black measles’ due to its clinical appearance in the form of characteristic spotted rash throughout the body. Howard Taylor Ricketts, an American pathologist for the first time described the causative agent of Rocky Mountain spotted fever and was able to isolate it in the laboratory animals during 1902-1909. He was a dedicated scientist and on several occasions injected himself with the pathogen for experiment. The causative pathogen of Rocky Mountain spotted fever, Rickettsia rickettsii was named after him. Later, the family Rickettsiaceae as well as the order Rickettsiales was named after him. Ernest William Goodpasture, an American pathologist and physician, invented the methods of isolation and culturing the rickettsial pathogens in chicken embryos and fertilized chicken eggs.

The word ‘chlamydia’ comes from the Greek word ‘chlamys’ means ‘cloak draped around the shoulder’. It describes how the intracytoplasmic inclusions produced by the bacterium appear under the microscope(‘draped’ around the host cell nucleus). Chlamydia was first discovered by a Czech zoologist and parasitologist, Stanislaus von Prowazek in 1907 in Berlin. Originally because of its structure it was thought to be a virus. In 1963 it was recognized as a bacterium rather than a virus.

Properties of genus

1. Morphology: Chlamydia are Gram-negative, non-motile, pleomorphic and obligate intracellular bacteria. The Gram-negative cell wall consists of cytoplasmic and outer membrane. However, they lack peptidoglycan layer. Moreover, they also encode major outer membrane protein (MOMP), the key antigenic determinant used for serological differentiation of chlamydiae.

They are poorly stained by Gram’s stain. Chlamydiae are readily stained by Castaneda (blue in appearance), Giemnez and Macchiavello (red in appearance) methods. However, Giemsa staining is preferable to stain the inclusions (chlamydial micro colony) in the cell culture. Inclusion bodies of the Chlamydiae are basophilic in nature. The staining of the inclusion bodies may differ depending on the species. In C. trachomatis, the inclusion bodies contain glycogen matrix and can be easily stained with iodine solution.

I. Definition of wasteland

Wasteland include degraded forest, overgrazed pastures, drought- struck pastures, eroded valley, hill slopes, water logged marshy lands, barren lands etc.

Different authors have defined wastelands as:

Land which is lying unproductive or which is not being utilized to its potential.

Land which is incapable of producing material or services of value (American Society of Soil science).

Land which has been abandoned and for which there is no further use (Mine spoils).

Land which produces less than 20% of economic potential. e) Land where no greenery can be sustained.

Land which is neither under forest cover or agricultural cover or assigned for specific purposes such as National park or National hydro power projects.

The Technical Task Group Report of the National Wasteland Board defines the wasteland due to different constraints.

Crusting soils

What is soil crusting?

Soil crusting refers to formation of a compact thin layer having high bulk density and high penetration resistance at the soil surface when dries after dispersion of fine particles and clogging of pores due to beating action of rain drop and slaking of irrigation water.

In arid and semiarid regions, crust formation occurs due to the destruction of soil aggregates. Crust formation occurs in all types of soils except sand. It is characterized by high bulk density, low non capillary pores, low hydraulic conductivity and aeration and high penetration resistance.

Calcareous soils

In arid regions, calcareous soils are developed from limestone or marl parent materials. The content of calcium and magnesium carbonate may be as high as 60 to 70 per cent of the total soil mass. In calcareous soil lime content may vary from a small amount in some places in the profile to appreciable amounts throughout the profile.

Calcium carbonate coatings occur in sand, silt and clay size fractions of calcareous soils. In sub soil, large amounts of lime forms hardpan under high water tables.

In general, pH of the soil increases to alkaline pH with increasing the proportion of water to soil ratio. This may happen in part from a reduction of CO₂ pressure. The dilution of salts in soil solution also permits greater hydrolysis of calcium clay. The dilution of calcium carbonate with production of hydroxyl ions may lead to higher pH as:

Iron Toxic Soils

Lowland rice is being cultivated on approximately 128 million hectares of either irrigated or rainfed land out of which 100 million hectares suffer due to nutrient deficiency or toxicities. Among the toxicities, iron toxicity is well recognized as a nutritional disorder in low land rice production. Iron toxicity is a syndrome of disorder associated with high concentration of Fe²⁺ in soil solution. A wide range of soil types show iron toxicity problem including acid sulphate soils, acid clay soils, peat soil and valley bottom soil. During monsoon rains in the wet season, soluble iron (Fe²⁺) migrate to the surface and its iron content increases to subtoxic or toxic levels.

In rolling topography and with heavy monsoon downpour there is considerable lateral flow of iron containing water from the adjacent uplands to mid – and low lands. This increases the iron content to toxic levels. Poorly drained sandy soils in valleys receiving interflow water from adjacent uplands with laterite horizon (Plinthudults) showed iron toxicity in Srilanka and Kerala and Odisha in India. These soil groups come under the taxonomic orders Alfisols, Ultisols and Oxisols occurring in association with Entisols and Inceptisols. The iron concentration (Fe²⁺) in soil solution that affect low land rice yield ranges from 10 to > 2000 mg L^-1 Iron toxicity induced yield reduction which is associated with poor nutrients . status (deficiency of P, K and Zn) and H₂S toxicities.

Soil erosion refers to detachment and transport of soil and soil particles from one place to other by the action of water, wind or gravity. Soil erosion consists of (i) detachment of soil particles from surface (ii) their transport from one place to other and (iii) deposition in another place.

Soil erosion are of two types: Natural erosion and accelerated erosion. The natural or geological erosion is steady, nondestructive and slow process of nature. On the contrary the accelerated erosion caused due to human activities like cutting of forest, intensive cropping, construction of roads and building is very rapid and destructive. Surface one inch of soil which is formed in thousand years can be lost within one year due to accelerated erosion.

In India, out of total 175 million hectares of degraded land, soil erosion due to water and wind accounts for 150 million hectare. Soil erosion due to shifting cultivation, salinity, alkalinity, water logging and shifting of water courses account for 25 million hectare.

Average soil loss from various land surfaces in India has been estimated to be 5334 million tonnes per year out of which 29 percent is permanently lost to sea, 10 percent is deposited in reservoirs and 61 percent is transported from one place to other. The plant nutrients lost through 5334 million tonnes of eroded soils was estimated to be 8.4 million tonnes which includes 2.5 million tonnes of N, 3.3 million tonnes of P and 2.6 million tonnes of K.

Siltation of reservoirs through water erosion is a major concern in India. This accelerated silting has considerably reduced the estimated life span of major reservoirs. The rate of siltation depends on the catchment area, soil erodability, topography and rainfall pattern. Larger the catchment area, smaller is the siltation load in the reservoirs because, the coarse fraction of eroded particles may be settle down in the stream valley before the water enters into the reservoir.

Acid soils occupy about 30 percent of the land area of the world out of which 67% acid soils support forests and wood lands and 18 percent are covered by grassland vegetation. Only 4.2 per cent (179 million hectare) of the acid soils across the globe is used for arable crops.

Soil acidity is a major constraint in crop production. The removal of basic cations especially Ca and Mg by leaching and their replacement by acidic cations, H, Al and Fe on exchange complex leads to soil acidity. Soil developed from granite parent material are more acidic than those developed from basalt, shale or lime stone. In acid soils, low pH leading to toxic concentration of H⁺, Al³⁺, Mn²⁺ influences nutrient availability, organic matter decomposition and microbial activity.

Efficient soil amelioration and nutrient management practices are necessary for crops susceptible to soil acidity.

Saline and alkali soils occur commonly under arid climate due either to the presence of an excess of soluble sodium salts or to the predominance of sodium among the exchangeable bases.

Saline and alkali soils have been classified as follows

1. Saline soils

Saline soils were originally called “White alkali” soils. Russians term them as “Solonchak” soils.

The soils are classified as saline if the electrical conductivity of saturated soil paste is more than 4 dS /m at 25⁰C, exchangeable sodium is less than 15 percent and pH is less than 8.5.

2. Alkali soils

The soils have been classified as alkali if the electrical conductivity of saturated soil paste is less than 4 dS/m, exchangeable sodium is more than 15 percent and pH is 8.5 to 10.0.

Water used for irrigation contain some salts, but quantities and kinds vary greatly depending on the source of water. Since sodic status of soils can be greatly influenced by salts in irrigation waters, successful irrigation practices require the evaluation system to judge irrigation water quality and methods employed. The actual damage done by salt to plants or soils depends on the concentration in soil solution rather than the quality of irrigation water applied. Thus, the use of some water source for irrigation might lead to severe salt problem in soils where drainage is restricted.

Criteria for evaluation of irrigation water

Various criteria considered in evaluating the quality of irrigation water are:

1. Salinity hazard

The most satisfactory method for rating the salt content of irrigation water involves measuring electrical conductivity. Various conductivity limits have been proposed to indicate the degree of salinity problems that might be anticipated with use of irrigation water on crops. There are four classes of salinity hazard such as C₁, C₂, C₃, and C₄.

In India rice is cultivated under two land situations. In uplands, rice is grown under rainfed conditions and the yield is normally low. In medium or low land conditions rice is grown under wet condition where plenty of rain water or irrigation water is available. Here an intensive tillage is practiced in wet to create a soft puddle condition and then paddy is transplanted. Land submergence is thus an essential condition for successful rice cultivation.

Rice soils are not necessarily soils with water at or near the surface. Many soils have a fairly deep water table, but their surface is kept under submergence maintaining depth of 3-5 cm water. This condition is maintained either by puddling when wet or by having a compacted layer in the sub surface.

A rice soil is characterized by reducing conditions, when it is cropped with rice during wet season and oxidizing conditions during dry season, when the land remained fallow or planted with dry season crops if, irrigation water is available.

Pollution

Pollution is an undesirable change in physical, chemical or biological characteristics of air, water or land caused by excessive accumulation of pollutants (substances causing pollution).

Kind of pollution

Pollution can be classified in many ways:

Soil health

Soil health is defined as the continued capacity of soil to function as a vital living system, by recognizing that it contains biological elements that are keys to ecosystem function within land use-boundaries. These functions are able to sustain biological activity of soil, maintain the quality of air and water as well as promote plant, animal and human health.

The characteristics of a healthy soil depends on the physical, chemical and biological properties of soils which directly or indirectly influence crop production.

Soil quality and soil health are terms that are discussed in agricultural community. Both these terms encompass a complex, dynamic concept, different to define and hard to measure. The term soil quality and soil health are often used interchangeably in the scientific literature, with scientists in general preferring soil quality and producers preferring soil health. Soil health may be considered as the state of soil at a particular time equivalent to the dynamic properties in short term. In contrast, soil quality may be considered for a particular purpose over a longer time scale, equivalent to static soil quality. In a broader way soil quality may refer to both permanent and static soil properties. (Fig. 11.1).

A static soil property relates to natural characteristic of soil (texture) which are derived from pedogenic processes. These properties cannot be easily amended. The dynamic properties are readily related to management practices. The dynamic component is of most important for the growers because it allows the soil to come to its full potential.

Sustainable management of soil resources is essential for food, nutritional and economic security of the country. The continued degradation of soil resources is considered an important factor in lowering the total and partial factor productivity of agriculture in the country. The process like soil erosion, nutrient loss, water logging, desertification, acidification, compaction, crusting, salinization and soil contamination affect food and environmental security in most parts of the country. The future agricultural growth at higher rate cannot be sustained with a deteriorating soil resource base. We need to monitor the quality of soil resources and devise appropriate management strategies for sustainable crop production without deteriorating the environment.

In India, several agencies like National Commission on Agriculture (NCA), Ministry of Agriculture (Soil and Water conservation Division), Society for Promotion of Waste lands Development (SPWD), NBSS&LUP, Nagpur have been constantly inventorizing and characterizing soil resource for drawing up land use and development plans at National and State levels. However, there is a great variance in estimates due to differences in approaches and criteria for assessment. For an example,the total degraded land as estimated by NCA is 148.09 Mha as against, 175.0 Mha by Ministry of Agriculture (Soil and water conservation Division), 129.58 Mha by SPWD and 187.7 Mha by NBSS&LUP, Nagpur.

In soil profile development, we focused on vertical variability in soils - the differences among soil horizons. In this chapter we focused on horizontal variability- how soils differ from place to place across the landscape. Spatial variations in soil properties occurs across distances having geographic meaning for land management-from a few meters to many kilometers. We need to monitor regularly the status of our soil resources employing modern technologies to refine our understanding about them and renew our commitment to their preservation. The applications of Remote Sensing (RS), Geographical Information Systems (GIS) and Global Positioning System (GPS) have greater opportunities to offer in this regard.

Sustainable management of soil and water resources is essential for food, nutritional and environmental security of the country. The total and partial factor productivity of agricultures in India declined over years because of continued degradation of natural resources. The process leading to land degradation are generally triggered by excessive use of land and water resources to meet the growing demand of population for food, fibre and fodder. Various anthropogenic activities leading to accelerated land degradation through salinization, flooding, water logging, erosion of water and nutrients, drought reduced agricultural productivity and nutritional security in the country. These problems can be overcome by optimum utilization of land adopting suitable management practices. For effective land management practices, the soils should be interpreted in forms of their land capability, suitability for irrigation and crop growth. This will not only help the farming community and extension specialists, but also to the administrators and policy makers for using soils for sustainable agricultural production.

Trees are an integral and indispensable constituents of our natural surroundings. The trees keep the environment clean, make the soil healthy and provide food, fibre and shelter to mankind and wild animals. Trees help in stabilizing the soil, a vital natural resource, prevention of soil and water erosion, control run off water in the catchment areas, acts as a shelter belt against wind erosion in arid zone, act as a wind breaker to protect the coastal region during storm and cyclone besides contributing substantially to economic development. The National Commission on Agriculture stress the need for afforestation of about 40 million ha of land presently lying barren because of salinity, sodicity, waterloggings, ravines, coastal sandy areas, stony and gravelly lands, high altitude and slopping lands. Several agencies in various parts of the country are engaged in afforestation of these degraded lands.

Soil conservation in hilly areas

Soil erosion is a major problem on hills because of steep slopes. It has been estimated that about 6 million ha of land requires intensive conservation measures in Himalayan and sub-Himalayan regions of Uttar Pradesh, Uttarakhand, Punjab and Himachal Pradesh. Anthropogenic activities like shifting cultivation, deforestation, over grazing accelerate soil erosion in hilly ecosystem.

During the last decade organic agriculture has emerged as a dynamic alternate farming system. This has been necessitated as a consequence of resource degradation because of to achieving high yields in various crops to meet the increasing demand of food by the burgeoning population. These have resulted in change in soil structure, imbalance in soil micro-organisms and organic matter, resistance among various weeds to weedicides, increased salinity, sodicity and have affected the water holding capacity of the soil and brought in health and environmental problems. Organic farming is a specified form of diversified agriculture that not only aims to produce nutritious food of high quality but also lead to the generation of more income and employment opportunities for rural population. In true sense, organic farming is a production system which avoids or largely excludes the use of synthetic fertilizers, growth regulators, livestock feed additives and pesticides. Moreover, it relies on agronomic management practices like crop rotation, crop residues, animal manures, legumes, green manures, off-farming organic wastes and aspect of biological pest control to maintain soil productivity.

The inability of Indian agriculture to meet the demand for food in the country during the two and half decades immediately after independence had been a matter of concern at those times. The system of our agriculture based on the traditional knowledge and practices handed down from generation to generation could not produce enough to feed the increasing population. The ignominy of our dependence for food on the western developed nations and the politics of food aid practiced by them added to our determination to be self-sufficient in food production by modernizing agriculture. The green revolution fulfilled our aspirations by changing India from a food importing to a food exporting nation. However, the achievement was at the expense of ecology and environment and to the detriment of the well-being of the people.

Plant breeding is described as an art and science of changing the genetic architecture of plants with a goal towards betterment of mankind. Apart from this generalized concept, plant breeding is accomplished through inter-disciplinary mode assorted from simple selection in a variable plant-population having some desirable traits to the application of biotechnology and more. Worldwide, cultivars of different crops are routinely manufactured by Multinational and National level Industries, Government Institutions, Universities, Crop specific Organizations, professional plant breeders and even by the individuals such as gardeners and farmers.

Plant breeding is basically operated by the principles of Genetics where selections are practiced from a variable population and the selected variation needs to be inherited. Three categorized broad goals of plant breeding are 1) high yield 2) uplift in quality and 3) resistance against biotic and abiotic stress.

Spice crops are known to add nutritive value and increase the palatability as well as quality of food. Therapeutic uses of spices are also well recognised. The spice industry in India and trade has shown stunning progress over the last 5 years with 120% increase in revenue which is very close to touch $ 3 billion. East Asia is the major market for spices, followed by America and the European Union and the world spice trade has almost touched $ 17 billion by 2020. So, increased production is of paramount importance across the world and the potential is increasing. On the other hand, quality improvement is one of the primary objectives of spice crop breeding apart from achieving high yield. Cultivar and species diversity are the principal components of diversity of spices (Sasikumar et al. 1999; Krishnamoorthy et al., 1997; Prasath and Venugopal, 2004). A good amount of variability is found in many important Indian spices like black pepper, cardamom, cinnamon, curry leaf, ginger, garcinia, tamarind and turmeric. A number of cultivars have been released followed by intra-germplasm evaluation and selection in spices. Contribution of recombination breeding is less in spice crops with regard to other field crops and a number of valuable varieties have been bred by clonal and seedling selection (Peter, 2008). Deployment of high yielding, water use efficient, climate resilient genotypes and technologies are also necessary.

A. General Morphology

2.1 The Root

It is the organ of a plant that typically lies below the surface of the soil.The root is best defined as the non-leaf, non-nodes bearing parts of the plant’s body. However, important internal structural differences between stems and roots exist. Root spices are, rather surprisingly, rare. Some popular examples of spices having roots are: Apium graveolens (Celery), Armoracia rusticana (Horse radish), Coriandrum sativum (Coriander), Ferula asafoetida (Asafetida), Glycyrrhiza glabra (Licorice), Levisticum officinale (Lovage), (Petroselinum crispum (Parsley), etc. All of the mentioned plants have aromatic roots.Roots of gingiberaceae are adventitious and storage roots arise from among the nodes of these scales.

Since historical times, Indian spices have been contributed not only to the country’s wealth and prosperity but also to the subcontinent itself as a whole. Spices precisely witnessed many wars, bloodshed, armoury alongwith the glowing accounts and adventurous voyage by Pliny, Ptolemy, Marco Polo, Vasco da Gamma and other travelers. The Southern parts of India, especially the Malabar Coast, with its abundance of the World’s best pepper, cinnamon and ginger was enormously creating impact of a plethora of spices which attracted the foreign trade and continue even today by creating a unique brand value globally. In the past, invaders travelled to India by overcoming many odds and barriers with the prime focus on capturing spice trade and dominating the trade scenario of those days throughout the world. As a result, gradually Indian spices travelled far and wide to traditional destinations by providing flavor, aroma, pungency, taste and colour to a variety of foods and beverages.

It was the end of 18^th century, from when scientific research began on the idea of origin of cultivated plants. The pioneers of this field were Darwin, Alphonse de Candolle, N.I Vavilov and many more. Charles Darwin wrote his famous book ‘On the Origin of Species by Means of Natural Selection’, or the ‘Preservation of Favoured Races in the Struggle for Life’ published on 24^th November 1859. According to him, cultivated plants may have originated from its wild form after a series of intense modifications. Afterwards, a Swiss botanist Alphonse de Candolle studied 247 cultivated plant species and documented his work in the book “Origin of cultivated plants” in 1886. Later, Vavilov first identified the Centres of origin. He could determine the origin of plants by analyzing the pattern of variation and proposed that, crop plants have been evolved from their wild species in the geographic region of the greatest genetic diversity of that particular plant. That area is known as the primary centres of origin of the particular plant. But, some crop species were found to show substantial genetic diversity even though they did not originate there. Such areas are known as secondary centres of origin for that particular species.

Cultivated plants in general including the spice crops observed today have been evolved through selections from their weedy and wild types. Apart from this, there had been another force which could bring the wild forms into cultivated forms named human intervention which is actually the process of domestication. Natural mutations and genetic recombination after selfing and crossing also played a significant role in the entire process. Whereas, natural forces take a long time to come into act, the techniques of plant breeding was devised and fine tuned throughout passing of times, essentially to accelerate the speed of evolution using these natural phenomenons. It was, therefore, mandatory for us to know the modes of reproduction and pollination to create variability in natural population and make all thise happen to what we see today in organised cultivated forms. Moreover, knowledge on reproduction of different plant species helps the breeder to choose the right breeding procedure to be used for crop improvement. Modes of reproduction help to evaluate the genetic constitution of crop plants by determining the extent of homozygosity or heterozygosity which, in turn, are unanimously applicable to any plant. To comprehend modes of reproduction in spice crops effectively, understanding about the floral biology is absolutely necessary. Plant reproduction, a process by which one species gives birth to its offsprings, may be of two types

Pollination

Pollination is the act of transfer of pollen from the male reproductive organ of a plant to the female reproductive organ of same or another plant.

Pollination is of two types

5.1 Self Pollination

It is the transfer of pollen from the anther to the stigma of the same flower from where the anthers have been generated. Thus, self pollination happens to be denominated as autogamy where auto means “same” and gamy means “union”. Obviously, self pollination is found in bisexual flowers. But self pollination also occurs when pollen is transferred from one bisexual flower to the stigma of another bisexual flower of the same plant. This kind of autogamy is known as geitonogamy. So, self pollination has to be defined keeping the parent plant on the main focus not the flower. If genetical consequences are considered, self pollination promotes the occurance of purelines or homozygotes. Self pollinating species developed themselves evolutionary fit due to homozygous balance and do not exhibit significant inbreeding depression.

6.1 Introduction

Plant breeding is the indispensible component of elevating production and productivity of spices by evolving high yielding and/or with good quality type. Thereby, the practice of identification and selection of desirable traits and introgression of those characters in a single plant is being done since the beginning of organized agricultural activities by humankind. The act of plant breeding was reshaped and got a momentum with a scientific basis after the discovery and rather rediscovery of Mendel’s laws. Worldwide, humankind could enjoy the direct benefits of methodical plant breeding during green revolution. Manipulation of genetic architecture for creating variation in the population and successive selection is the basic of all kinds of crop breeding. But the process of creation of variability and selection differs from crop to crop depending on their mode of reproduction. It is comparatively easier to get a new homogeneous population in self pollinating plants. Therefore, segregating generations are handled differently in these two categories of self and cross pollinated crops.

7.1 Plant Tissue Culture

Spices have great socio-economic impact in moden food habit of human but loss of resources day by day due to various reasons (industrialization, high population pressure) make the access of these valuable spices limited to people. Low production is general phenomena of common spices due to lack of high yielding varieties. Hence there is a need to improve the propagation method to meet the gap between demand and supply. Conventional vegatative propagation method is common approach for propagation but low multiplication rate, seasonal dependency and susceptible to abiotic stresses and diseases are major problems to achieve the optimum productivity. To overcome these drawbacks scientists have chosen the plant tissue culture technique (a modern approach of biotechnology which deals with the propagation the valuable/endangered plants under laboratory condition). Details about this technique and its role on spices are given below.

Plant Tissue Culture: Basic Components and Objectives

The technique of growing of a whole plant cell, tissue or organ under an aseptic condition in suitable synthetic medium is termed as plant tissue culture (Thorpe, 2007). De-differentiation and re-differentiation are two essential fundamental processes which help in the physio-morphological development of the plant.

8.1 Black Pepper Breeding

Black pepper (Piper nigrum L., family:Piperaceae), known as the ‘King of Spices’ and “Black gold”, is one of the important spices since time immemorial and perhaps the oldest spice regarded globally. It is a perennial climber grown for its fruits that are used as spice with plethora of medicinal properties. Black pepper is also very important in traditional medicine (Ravindran, 2000). However, it is mainly valued for its characteristic pungency and flavour, as an ingredient in food preparations and also as a condiment.

Genetic Resources

World’s largest collection of black pepper germplasm is maintained by the Indian Institute of Spices Research (IISR) at Kozhikode, Kerala, containing local cultivars, wild forms collected from the area of origin and related species. At present there are about 3466 accessions, consisting of 1266 wild relatives, 2062 cultivars, in addition to 9 exotic collections maintained in India. These collections were characterized and evaluated to estimate the genetic diversity for various yield and quality characters. Cultivar diversity is one of the principal components of diversity in black pepper. The cultivars are evolved directly from the wild P. nigrum.

1.1 Introduction

Irrespective of caste, creed, culture, sex, age or religion people like garden. A well-maintained garden serves as lungs of the city or locality as it is a prime source of plenty of oxygen and people enjoy the surrounding and feel happy by fresh air. In holy books of Hindu religion, the importance of plants as well as gardens are explained very beautifully. In the holy Bible it is mentioned that Adam and eve lived in garden. In Quran it is explained as the paradise on earth. So, scriptures of all religions explain about gardens. It shows gardens and plants are closely related to human from the origin of human belief.

2.1 Introduction

Generally, gardens are divided into different sections as per the rules and regulation followed in the placement of different elements and features in it. On the basis of this garden types are divided into 4 categories such as

3.1 Introduction

Many gardens follow strict rules. So those are known as formal gardens. Generally formal gardens include:

Italian gardens

French gardens

Persian gardens

Mughal gardens

4.1 Introduction

Many styles of gardens do not follow strict rules and so those are known as informal gardens. Some gardens evolved as informal garden in due course of time as per the choice of people but some gardens are informal in nature from origin. Informal gardens are:

English garden

Japanese garden

Hindu garden

Buddhist garden

5.1 Elements of Landscape Gardens

5.1.1 Introduction

Elements of a garden are the basic units of any visual design which form its structure and convey visual messages. Elements are based on the art principles of landscaping. Process of landscape design includes concepts and elements of landscape designing. Generally, elements of a garden are divided into 2 types

6.1 Introduction

Garden design encompasses the aesthetic beauty, artistry, knowledge of plant growth and development with basic maintenance of plants and other elements as required. Principles are the basic rules of designing a landscape. The basic principles of garden design are very simple; however, each is often referred to by more than one name. Principles of landscape garden keeps the garden lively and beautiful. The principles of gardening should be kept in mind always while designing a garden.

6.2 Axis

It is an imaginary line in landscape designs around which the garden is created striking a balance. In a formal garden the central line is the axis.

7.1 Introduction

Garden designing is an important and crucial step as whole aesthetic view of the garden depends upon it. A beautifully designed garden can attract plenty of viewers as well as fauna while a poorly designed garden can destroy the view of the garden as a whole. So, while designing a garden all the basic principles and elements of gardening should be kept in mind.

7.2 Steps in Preparation of Garden Design

Site identification

Generally, the site for garden development is provided by the client itself. So, in this case we should go for site analysis step directly. Site identification is always a choice of client/human. If landscape architect has liberty to identify a land for garden establishment, he should identify the site as per choice of the client, usage and special considerations of the client.

8.1 Introduction

One important aspect of bio-aesthetic planning is to landscape public places on a priority basis compared to private places. For this specific reason, the railway station and the railway lines should attract attention at the very outset for landscape gardening.

8.2 Definition

Bio-aesthetic planning means the proper utilization of the available flora and fauna in the beautification of the surroundings. The concept of bio-aesthetic planning is given by concept of Prof. Lancelot Hogben.

In India, the theme of bio-aesthetic planning was propagated by Dr. M. S. Randhawa. Le Corbusier and his associates, Pierre Jeanneret, E. Maxwell Fry and Jane B. Drew had planned Chandigarh city as per the principles of bioaesthetic planning.

9.1 Introduction

Xeriscaping is the fine art of creating water-efficient landscapes by using plants that are appropriate to the natural environment. Xeriscaping (zer-i-skaping) is a word originally coined by a special task force of the Denver Water Department, Associated Landscape Contractors of Colorado and Colorado State University to describe landscaping with water conservation as a major objective. The derivation of the word is from the Greek “xeros,” meaning dry, and scape meaning the pattern of the landscape – thus, xeriscaping. The term xeriscaping represents a practice or philosophy with the goal to establish and maintain an attractive and healthy landscape while reducing water usage. One of the prime practices in xeriscaping is the use of drought tolerant plants, but xeriscaping is more than that. It also includes changes in the landscape design, soil improvement, efficient irrigation, mulching, and other maintenance practices which contribute towards a water-wise landscape. But xeriscapes are not dry and dull. Well-designed xeriscapes are enchanting and beautiful. The best xeriscapes use a fraction of the water needed by traditional lawn-dominated landscapes. Some xeric plants require little or no supplemental watering once they are established. And xeriscapes require far less ongoing maintenance.

1.1. Plant Quarantine

The literary meaning of the word quarantine is” a state, period or place of isolation in which the people or animals or plants or acquacultures that have arrived from elsewhere or been exposed to infectious or contagious disease are placed.

Plant quarantine is a technique of keeping the imported or introduced plants or planting material in isolation for detecting the exotic pests, diseases and disease pathogens and weeds which may be harmful to the importing country for its crop plants, agriculture or the ecosystem. These plants/planting material are kept in isolation for a specified period which differ from plant species to plant species depending on the type of pathogen/pests for which the material has to be quarantine. This is based on the Rules and regulations promulgated by governments to regulate the introduction of plants, planting materials, plant products, soil, living organisms, etc. with a view to prevent inadvertent introduction of exotic pests, weeds and pathogens harmful to the agriculture or the environment of a country/region, and if introduced, to prevent their establishment and further spread. Plant quarantine is thus designed as a safeguard against harmful pest /pathogens exotic to a country or a region.

Plant quarantine is a most important activity in the introduction of plants and planting material as various insects, including mites and nematodes and diseases caused by fungi, bacteria, viruses, viroids, phytoplasmas,rickettsialike organisms are known to attack various crops of economic importance to not only reduce the quantity but also spoil the quality of the produce to a considerable extent and if these pests and pathogens are introduced with the planting material in its non ecosystem areas may prove fatal to the agriculture or ecosystem

2.1. Guidelines for Pest Risk Analysis

This standard describes the process of pest risk analysis for plant pests for the purpose of preparing phytosanitary regulations by National Plant Protection Organizations. Pest risk analysis (PRA) consists of three stages: initiating the process for analyzing risk, assessing pest risk, and managing pest risk.

Initiating the process involves identification of pests or pathways for which the PRA is needed. Pest risk assessment determines whether each pest identified as such, or associated with a pathway, is a quarantine pest, characterized in terms of likelihood of entry, establishment, spread and economic importance. Pest risk management involves developing, evaluating, comparing and selecting options for reducing the risk.

PRA is only meaningful in relation to a defined “PRA area” considered to be at risk. This is usually a country, but can also be an area within a country, or an area covering all or parts of several countries [e.g. the area covered by a Regional Plant Protection Organization (RPPO)].

3.1. What is the International Plant Protection Convention (IPPC)

The International Plant Protection Convention (IPPC) is a 1951 multilateral treaty deposited with the Food and Agriculture Organization of the United Nations (FAO) that aims to secure coordinated, effective action to prevent and to control the introduction and spread of pests of plants and plant products. The Convention extends beyond the protection of cultivated plants to the protection of natural flora and plant products. It also takes into consideration both direct and indirect damage by pests including weeds.

The IPPC as an intergovernmental treaty signed by over 180 countries, aiming to protecting the world’s plant resources from the spread and introduction of pests, and promoting safe trade. The Convention introduced International Standards for Phytosanitary Measures (ISPMs) as its main tool to achieve its goals, making it the sole global standard setting organization for plant health.

The IPPC is one of the “Three Sisters” recognized by the World Trade Organization’s (WTO) Sanitary and Phytosanitary Measures (SPS) Agreement, along with the Codex Alimentarius Commission for food safety standards and the World Organization for Animal Health (OIE) for animal health standards.

In Article IX of IPPC, it is stated that RPPOs shall

• Function as coordinating bodies in the areas covered by the IPPC (including information sharing)
• Cooperate with the IPPC Secretariat in achieving the objectives of the IPPC (including the development of ISPMs)
• Cooperate with other RPPOs and participate in the regular Technical Consultations for RPPOs that are convened by the IPPC Secretariat

At present, there are 10 RPPOs covering the different regions of the world. Each RPPO has its own independent statutes and conducts its own regional cooperation programme. RPPOs produce regional standards for their members. They cooperate with each other and with the IPPC Secretariat. In particular, they meet in Technical Consultations to promote the development and use of relevant ISPMs and to encourage inter-regional cooperation on phytosanitary measures for controlling quarantine pests and preventing their introduction and spread.

5.1. Australia’s Experience and Approach to Pest Risk Analysis

Australia applies the principles of pest risk analysis for the identification and management of sanitary and phytosanitary risks associated with new trade proposals and, where the need is identified, to the review of sanitary and phytosanitary risks of existing trade. One such trade activity is the intentional importation of exotic plant species not yet established in Australia.

Of approximately 250 000 plant species in the world, 30 000 have been intentionally introduced to Australia since European colonization, along with an unknown number of unintentional introductions, of which about 2 700 have naturalized (Cunningham et al., 2003). Some become problematic plants of which about 300 have become serious weeds of agriculture and natural ecosystems. Clearly, the majority of plant species have yet to be introduced to Australia and some of these would become weeds if allowed into the country.

The weed risk assessment (WRA) system is a decision support tool that is employed by Australia in applying the principles of pest risk analysis to the review of sanitary and phytosanitary risks associated with the intentional importation of exotic plant species not yet established in the country. The WRA system is used specifically to assess the weed potential of such species. It generates a score for a species based on its history as a weed in other parts of the world, climatic suitability to Australia and biological attributes. The weed risk assessment (WRA) system is one means by which the assessment component of pest risk analysis is addressed. The WRA system is a question-based scoring method that can be operated using a computer or manually using paper-based forms. A Microsoft® Excel spreadsheet version of the system, including documentation, has been made available through the International Phytosanitary Portal