eChapters

INTRODUCTION

Scientists have known that certain animals can regenerate missing parts of their bodies. But we can not replace a missing leg or a finger; our bodies are constantly regenerating blood, skin and other tissues. The identity of the powerful cells that allow us to regenerate some tissues was first revealed when experiments with bone marrow in the 1950’s established the existence of stem cells in our bodies and led to the development of bone marrow transplantation, a therapy now widely used in medicine. Stem cell therapies are one of the most promising areas of medicine, and many such therapies are now in development by industrial and academic groups. The first successful allogenic stem cell graft in humans using donor bone marrow was undertaken in the USA in 1968 and bone marrow transplantation continues to provide the best example of the clinical use of adult stem cells. Currently, cell therapies are regulated under the US Food and Drug Administration’s (FDA’s) Good Tissue Practices Final Rule, which uses a tiered system based on the level of risk associated with the cell product. Scientists were able to extract embryonic stem cells from mice in the 1980s, but it wasn’t until 1998 that a team of scientists from the University of Wisconsin–Madison became the first group to isolate human embryonic stem cells and keep them.

Every aspect of the living organism is the sum total result of the metabolism carried out within its cells and in other organisms. Metabolism is the sum total of the chemical reactions occurring in the cell or organism. Metabolism is of two kinds:

1. Anabolism- It is also known as constructive metabolism as it involves synthesis of complex substances from the simpler ones, which are required for growth, maintenance and storage in the organism. Example: Formation of starch from glucose.
2. Catabolism- It is also known as destructive metabolism as it involves breaking of the complex substances into simpler ones, leading to release of the energy required for performing various activities of living beings. Example: Respiration.

Metabolite is the end product or the intermediate product of a biological pathway. Metabolite can be classified into two types mainly:

ABSTRACT

During the efficient genetic transformation of plants with the gene of interest, some selectable marker genes are also used in order to identify the transgenic plant cells or tissues. Antibiotic and herbicide selective agents and their resistance gene are commonly used to introduce economically valuable genes into crop plants. According to the biosafety authority and consumer view points, the presence of selectable marker genes in released transgenic crops may be transferred to weeds or pathogenic microorganism in the gastrointestinal tract or soil, and will make them resistant to treatment with herbicides or antibiotics, respectively. Sexual crossing also raises the problem of transgene expression because redundancy of transgenes in the genome may trigger homology-dependent gene silencing. The future potential of transgenic technologies for crop improvement depends greatly on our abilities to engineer stable expression of multiple transgenic traits in a predictable fashion and to prevent the transfer of undesirable transgenic material to non-transgenic crops and related species. Therefore the development of efficient marker free transgenic plants system is very essential. That is why many technologies and various approaches designed to timely elimination of transgenes when their function is no longer needed. Due to the limited number of available selectable marker genes, in future the stacking of transgenes will be increasingly desirable. The production of marker-free transgenic plants is now a critical requisite for their commercial deployment and also for engineering multiple and complex trait. Here we describe the current technologies to eliminate the selectable marker genes (SMG) in order to develop marker-free transgenic plants and also discuss the regulation and biosafety concern of genetically modified (GM) crops.

INTRODUCTION

Plants are rich source of nutrients for most of the organisms including microbes' arthropods and vertebrates. There are various biotic viz. insects, weeds and pathogens and abiotic factors viz. temperature, humidity, salinity etc. that causes harm to plants. For yield loss due to pest EIL (Economic injury levels) calculation is important (Stern et al, 1959). EIL calculation will define economic damage (yield losses equal to management costs) in calculable terms. Since plants are sessile they cannot move to avoid the menace of these factors, but they have developed a unique way of structural, chemical, and protein-based defences which are specifically designed to detect and inhibit invading organisms before they are able to cause extensive damage. In response to the incitations by the pathogens some genes are activated which in turn codes for defence proteins (Grennan, 2006). Understanding how plants defend themselves from pathogens and herbivores is essential in order to protect our livelihood and nutritional security. In addition to proteins, plant anatomy and some of the ecological relationship also plays an important role in plant defense mechanism. Induction of plant resistance against fungi and bacteria was reported in 1900.

ABSTRACT

Genomics is a relatively new scientific discipline, having DNA sequencing as its core technology. As technology has improved the cost and scale of genome characterization over sequencing’s 40-year history, the scope of investigation has commensurately broadened. Demand has never been greater for revolutionary technologies that deliver fast, inexpensive and accurate genome information. This challenge has catalyzed the development of next-generation sequencing (NGS) technology. Over the past few years, massively parallel DNA sequencing platforms have become widely available, reducing the cost of DNA sequencing by over two orders of magnitude, and democratizing the field by putting the sequencing capacity of a major genome center in the hands of individual investigators. These new technologies are rapidly evolving, and near-term challenges include the development of strong protocols for generating sequencing libraries, building effective new approaches to data-analysis, and often a rethinking of experimental design. Next-generation DNA sequencing has the potential to dramatically accelerate biological and biomedical research, by enabling the comprehensive analysis of genomes, transcriptomes and interactomes to become inexpensive, routine and widespread, rather than requiring significant production-scale efforts. This article explains the methods, advantages and disadvantages of methods and softwares of Next Generation Sequencing with its impact and applications on genomics and other related field of biology.

INTRODUCTION

DNA sequencing is a process of deciphering the complete order of nucleotide in the DNA molecule with precision. Over the past few years, there has been a shifting from the automated Sanger’s method of sequencing to next generation technologies. There was a milestone in the year 2003 for the researchers when fine sequence of human genome project was declared complete. The project was completed in 13 years with nearly $3 billion expenditure and more than 20,000 researchers and technicians took part in it all over the Globe. DNA sequence determination is performed using dideoxy chain termination technology (Ronaghi, 2001). The dideoxy sequencing method was developed by Frederick Sanger and his colleagues (Sanger et al., 1977) and is called as First-generation sequencing technology. Since early 2000s, there became drastic improvements in the sequencing technologies from Sanger’s method used for Human genome project to Next Generation Sequencing (NGS) technologies used these days. The change in technologies not only reduced the expenditure to the minimal but also involved minimum use of human resource and time. High –throughput sequencing technologies are increasingly being used to address varied range of biological objectives. It provides a promising approach to increase the scale, robustness and efficiency of the results of whole genome within few hours and minimum expense. Key players in the field of NGS are 454 GX Flex Roche, Solexa Illumina, SOLiD ABI (Applied Biosystems), ViSiGen biotechnologies, Helicose Biosciences and Polonater systems.

INTRODUCTION

Massively Parallel DNA sequencing also known as next-generation sequencing, revolutionize the genomics and transcriptomics research as their effects are increasingly widespread. A new generation of non-Sanger-based sequencing technologies has delivered on its promise of sequencing DNA at unprecedented speed, thereby enabling impressive scientific achievements and novel biological applications. Before the next generation sequencing, the Sanger’s enzymatic di-deoxy chain termination was used for nucleotide sequencing from last 30 years with various original improvements. Sanger enzymatic di-deoxy chain termination technique first described in 1977 and the Maxam and Gilbert chemical degradation method described in the same year, which was used in sequence cases which could not easily be resolved with the Sanger technique. The two laboratories where the first automated DNA sequencers were produced, simultaneously, were those of Leroy Hood at Caltech, commercialized by Applied Biosystems, and Wilhelm Ansorge at the European Molecular Biology Laboratory EMBL and commercialized by Pharmacia-Amersham, later General Electric (GE) Healthcare. The Sanger method was used in the first automated fluorescent project for sequencing of a genome region, in which sequence determination of the complete gene locus for the HPRT gene was performed using the EMBL technique; in that project the important concept of paired-end sequencing was also introduced for the first time.

1. INTRODUCTION

The key global challenges facing the mankind in the 21st century are food, water, energy security, environment, combating cancer, and infectious diseases. Solving these challenges requires concerted efforts using modern scientific and technological advances in multiple disciplines. One such technology that has revolutionized life science research is “next-generation sequencing”. The NGS technology has brought an enormous technological shift in DNA sequencing through dramatic high-throughput and a precipitously dropping cost of raw sequence data. NGS technologies changed the dynamics and pace of genomic research in humans, animals, plants and microbes largely due to their rapid, inexpensive and highly accurate sequencing capabilities. The capillary electrophoresis based sequencing technology pioneered by Sanger and Coulson.

1. INTRODUCTION

Increasingly, in recent years, we hear of new technologies for the production of clean energy or, as they say now in common usage, from renewable energy sources, there are many sources of renewable energy, but certainly the ones that deserve special attention are those derived from algae. Today, thanks to innovative systems called photobioreactors, you have a way to start producing, though unfortunately still a small part, the amount of clean energy from algae and various biological processes that develop. The photobioreactor is one of the most innovative systems of the 21st century, and is paving the way for a new concept of energy utilization , although the fossil fuel (oil of course) continues to lead the way, even if you are aware of the drastic and continuous decrease the world’s resources. Although still under investigation, but there are many aspects that allow, thanks to special engineering studies , already now create systems suitable for the production of energy directly from algae , while biofuels obtained from the latter, there are several studies and tests , which aim to further lower production costs, in order to bring them at par or even below the threshold of current fossil fuels. In addition, these photo bioreactors, allow to produce, under controlled conditions, products and raw materials from the algae for food and non-food market, often providing a viable substitute, nutritious and natural, to all those raw materials that are harmful to human health and animals, especially in the food and health sectors.

Large number of edible fruits exists in tropics and subtropics of world. Many of such fruit species are identified, domesticated and are being utilized for various purposes, though their full potential has not been exploited. There is yet another group of plants producing edible fruits with great potential in different parts of world, which are not at all being grown and utilized by people other than in a very localized manner. Such under and un-utilized fruits are made the subject for detailed study. They are evaluated for their nutritive value, potential uses for other purposes, for possibilities of commercial cultivation in suitable areas and chances for marketing. Since all of them may not be acceptable for fresh consumption as table fruit, product diversification should be thoroughly evaluated to gain popularity for such plants. Practices and techniques employed for utilizing these fruits by local people where these plant species are seen at present can be scientifically and systematically refined for commercial exploitation.

Broad spectrum of agro climatic conditions and diversity in people’s preference for taste offer great chances to identify right fruit to a particular region for commercial cultivation in India. In this context, significance of under and un-utilized fruits for exploiting potentials become more clear. Identification of such plant species in different regions, extend and method of present utilization, nutritive value and pomological significance of the products, specific climatic and cultural requirements for successful growth and development should be documented as first step for exploitation of lesser known fruit species. Some of the under and un-exploited fruit species prevalent in tropical and subtropical conditions are discussed. In addition to this, attempt is made to incorporate an exhaustive list of plant species, which have potential for utilization as fruits and are rarely exploited at present. These are confined to only limited localities where people use produces for various purposes and are in most cases little known to other parts of world.

AONLA

Emblica officinalis Gaertn

F: Euphorbiaceae

Aonla is one of the most important minor fruits of Indian origin, which is predicted to be the ‘fruit of the 21^st century’ even though it existed from time immemorial. It is also called as ‘Indian gooseberry’, ‘amla’, ‘nelli’, ‘amlaki’, ‘amali’, ‘ambala’ and ‘amalakamu’ in different parts of India. This species is indigenous to tropical SouthEastern Asia precisely the Central and Southern India. The crop is seen in Sri Lanka, Malaysia and China. In India, aonla is being cultivated on a commercial scale in northern parts comprising Uttar Pradesh, Maharashtra and Gujarat.

AVOCADO

Persea americana Mill.

F: Lauraceae

Avocado, also known as butter fruit gained importance over years as one of the most nutritive fruits. Demand for this fruit increased over the past few years and now it has become an important fruit in international trade.

Original home of Avocado is Mexico in Central America and grows wild all over South America. The Spanish explorers took this fruit to Spain during 1601. It was introduced to Jamaica in about 1650. Avocado was first reported in Mauritius in 1780, Florida in 1833, California in 1856 and Zanzibar in 1892, but its cultivation started extensively in these areas during 1900 (Purseglove, 1974). It was introduced to South and West Coasts of India about 100 years ago from Ceylon. Avocado is now growing in most of tropical and sub tropical countries.

Avocado is grown commercially in USA, Israel, South Africa and Australia. USA, Israel, and South Africa are main exporters. In India, it is mainly grown in South where it is centred on hill slopes of Tamil Nadu, Kerala, Coorg and in selected regions of Karnataka and Maharashtra.

BANANA

Musa paradisiaca L

F. Musaceae

Banana, an antique food crop of the world is known as the ‘Apple of the Paradise’ and botanically named as Musa paradisiaca. Plants of the Musaceae family as a whole are strictly old world plants which are believed to be originated in the hot, tropical regions of S. E. Asia (Simmonds, 1962). Malaysia is considered as the primary centre of origin of M. acuminata (AA and AAA cultivars) and from there, it spread to India and Burma where M. balbisiana is the native. In the IndoBurman peripheral area, natural hybridization of acuminata and balbisiana types occurred and thus India is regarded as a major centre of origin for more the 300 types (AB, AAB and ABB cultivars) out of the 600 types of Musa germplasm. Mention of plantain in Ramayana (2000 BC), Arthsastra (250 BC) and in Chilappathikaram (500 AD) suggests the antiquity and long period of domestication of banana fruit in India. Present day type/cultivars were originated through natural hybridization, mutation and polyploidy breeding and perpetuated through vegetative propagation.

It was introduced to East Africa even before Christ and to the Mediterranean region about 650 AD. It reached the New World in 1516 AD and its cultivation is distributed throughout the warmer countries situated in the region between 30⁰ N and 30⁰ S of the equator. Now banana is grown widely in 130 countries like Brazil, China, India, Ecuador, Columbia, Venezuela, Florida, Panama, Cuba, Uganda, Tanzania, Zaire, Ivory Coast, Kenya, Honduras, Nigeria, Fiji, India, Philippines, Thailand, Indonesia, Sri Lanka, Australia etc. and total (world) area is 88.5 lakh ha with a production of 97.2 million tonnes. Fifty per cent of the global production is from India, Ecuador, Brazil and China.

Fruit crops can be classified into many groups or categories based on certain criteria, which may vary according to climatic and soil requirements, growth habits and of late with consumer rating. Horticultural and botanical classifications are two important types of classification followed in fruit plants. Classification often helps to identify the names and to group the plants. It also gives an account about relatedness among them which further suggest the breeding possibility and grafting compatibility. Different types of classifications followed are discussed here:

CLASSIFICATION BASED ON CLIMATIC REQUIREMENT

Fruit plants are classified based on their climatic adaptability and it is also known as ecological classification. In horticultural point of view, this classification has got much significance. Fruit growers can select crops suited to a particular region by following the demarcations given here. Fruit plants are categorized into the following groups in this classification.

Temperate fruits

Fruit crops need exact climatic requirements for their growth and development, flowering and fruiting. These plants are grown only in places where winter is distinctly cold, they are deciduous and become dormant during this season. Plants should be exposed to specific chilling temperature for certain period for flower induction. These plants are suitable to higher elevations and they can withstand frost. eg. Apple, plum, peach, pear, almond, walnut.

Orchard is a long-term investment and careful planning and resource analysis prior to establishment is essential. Lack of attention and care in the initial stages of orchard development results in irreversible damages. Essential resources for successful orcharding can be broadly grouped into two categories as biophysical and socioeconomical. Biophysical resources include land, soil, agrochemicals, planting materials, irrigation and manpower, while socioeconomic factors are finance, security, market, technical knowledge, transport, storage and social amenities.

Selection of crops and varieties should be done carefully, the most important factor being market demand. Popular fruit crops, which have demand in local markets, can definitely be a good choice. Previous experience and expertise of growers of selected locality can be made use before finalizing plans.

SITE SELECTION

Factors like climate, soil, availability of water, trained labour and inputs like fertilizers and plant protection chemicals should be considered. Accessibility to market, railway station, transport, nearness to road, storage facilities and processing units which facilitate expeditious disposal of perishable fruits, help in getting good returns from orchards. Successful fruit growing in a particular locality depends to a great extent on the natural factors especially climate and soil.

‘FRUIT’, “a food, drink and medicine, neatly packed by nature in attractive, handy and easy-to-open containers”, is a sensible definition indicating significance of fruits in human life. In botanical terms, fruit is a ripened ovary and in horticultural science it is the plant product, which is edible on ripening. From the nomadic age to present day civilized life, man has used fruits as food. Human civilization is irrevocably linked with the culture of fruit plants and trees. References of larges number of fruits in the very ancient literature of different languages throw light to this fact.

Fruits exhibit vast diversity in various forms, shapes and aspects. According to climatic requirements, they are temperate, tropical and subtropical crops. Major tropical and subtropical fruits include mango, banana, citrus, grapes, litchi, pineapple, papaya, sapota, guava, mangosteen, avocado, jack, ber, passion fruit etc. Fruits can be grown in very rich and favourable climatic conditions, but some fruits are adapted to adverse conditions of dessert (date palm), moisture-stress arid zones (aonla, ber, custard apple) and saline regions. Fruit plants vary in morphological traits such as plant size and shape. They may be herbaceous as banana and pineapple, shrubs as cherries and phalsa, small trees as ber and limes, big trees as mango and jack and vines as passion fruit and grapes. Fruits are of different sizes and shapes also. The range is from very small berries of phalsa to very big fruits of durian and jack. Taste wise variation is also very clear in fruits. We have very sweet fruits (litchi, sapota, dates and banana) acidic/sour ones (aonla, tamarind, bilimbi) and fruits with specific sugar/acid blend (varieties of mango, grapes, oranges).

Growing fruits can be fun, delightful experience and a challenging hobby. There are several good reasons to grow fruits. Fruits add beautiful colour and variety to your garden. Large amounts of fruit can be grown in a relatively small area.Store-bought fruits are often picked, shipped, and sold before they are fully ripened and generally stock selections that look prettiest but are not necessarily the best tasting. In addition, fresh garden fruits are a good source of vitamins; minerals, carbohydrates, fibre (Table 1) and will provide your family with flavorful, delicious and nutritious food. As an added bonus, the fruits you grow will taste much better than the fruits you find in the grocery store. Establishment of an orchard are a long term investment and require critical planning, selection of proper location and site, planting system and planting distance, varieties and the nursery plants to ensure maximum production.

Even if you have limited space, you can still enjoy growing fresh fruits in your garden by growing fruit plants in containers. You can grow any fruit tree in a container for a few years and then transplant it. You can also choose a dwarf variety, which is well suited to living in a container. If you carefully choose the kind and varieties of a fruit before you plant, you can harvest dessert-quality fruit from early summer through the fall. Many fruit plants are aesthetically pleasing and are good for “edible landscaping.” Some fruits, such as apple, citrus, blueberries and figs, make outstanding ornamental plants. Some people find a natural setting with plants placed throughout the landscape most aesthetically pleasing. But this makes maintenance more challenging.

Rapid urbanization and industrialization has led to continuous deterioration of air quality, which is a major environmental problems in many urban areas in both developed and developing countries. Air pollution is characterized by high concentration of suspended particulate matter, oxides of sulphur and nitrogen resulting primarily from increased use of vehicles. Air pollution effects are not limited to the short term nor to the plant damaged or killed. Rather, air pollution has long term effects that affect plants including fruit trees. Horticultural crops are injured when exposed to higher of abnormal levels of various air pollutants. The injury symptoms range from visible marks on foliage, reduced growth and yield to premature death of the plant. The development and severity of injury depends not only on the concentration of the particular pollutant, but also on a number of other supporting factors. These include the duration of exposure to the pollutant, the plant species and development stage as well as conducive environmental factors.

Various types of winter damage can occur to fruit trees. Temperature-related injuries include sunscald, tip dieback, bud death and heartwood damage. Even after planting frost tolerant varieties and rootstocks, it is important to manage frost occurring in regions where it is suspected to happen, it is necessary to prevent injury. When temperatures dip below the freezing point, water molecules move out of plant cells through the cell membrane due to ice formation in the intercellular spaces. Other cell constituents like sugars become more concentrated within the cell and with gradual reduction in water leads to dehydration and necrosis. At relatively short and moderate freezing temperatures little damage occurs to plants, but when temperatures fluctuate drastically or descend below -4^oC, ice crystals form and intracellular freezing occurs leading to cell death. Tip dieback, bud death, and heartwood damage usually occur in situations where temperatures drop dramatically before the plant has hardened off adequately.

The decline of productivity and health of the tress may be due to faulty management i.e. unsuitable site and climate, cultivation of intercrops, inadequate nutrition, improper planting, undesirable planting materials, incidence of insect pest and disease and other biotic and a biotic stresses. The decline of trees are characterized by sparse appearance, yellowing and different type foliage symptoms, undergrowth and sickly appearance, dried-up top growth with small and less number of fruits. The branches of trees start to die from the top to downwards, ultimately resulted poor quality fruits. Such type of decline may be seen in whole orchards, on in a single tree or patches. Senile orchards with poor productivity are now a common problem in temperate, tropical and subtropical fruits. Since most of the fruit trees has long juvenile period, hence going for replanting, rejuvenation may be better option to convert sick tree into productive ones.

Diseases are often the most important constraint to the production of different fruit crops. They directly or indirectly reduce yields by debilitating the plant, and depleting the fruit quality. They range from aesthetic problems that lower the marketability of the harvested product to lethal problems that devastate the overall production. Virtually all fruit crops are affected by one or more serious diseases. Diseases determine how and where a crop is produced, what postharvest treatments are utilized, in what markets the crops are sold, and whether production is sustainable and profitable. Hence, as a fruit crop student one should know have the knowledge of different diseases occurring on major fruit crops, their symptoms and management strategies;

Management system adopted for fruit trees are quite different, especially with regard to nutrient than that adopted for field crops. The shift in management system could be commenced 3-4 years after planting depending on the tree size. Nutrients are required for flowering and fruiting while at the same time trees are allowed to grow and maintain sufficient vigour for producing high yields in following years. To maintain productivity of trees in long run and maintain the sustainability of tree production capacity, application of nutrient should be based on actual requirement and availability of nutrient in the soil. Application of plant nutrients economically at correct time with right amounts in a way that nutrients could be taken up by plants efficiently with minimum losses. The purpose of assessment of nutrient requirement of fruit trees is to keep mineral nutrient levels in the tree with in the desired range to have the growth and development effects and fruiting of trees as desired.

The most important thing in nutrient management for bearing trees is to analyze the importance of timing of nutrient application in relation to tree phenology or growth cycle.

Determination of Specific Gravity

The palatability of the citrus fruit is associated with its internal quality. Measuring specific gravity provide clues to internal quality of the fruit. The ratio of the weight of the fruit to its submerged weight indicates specific gravity. Specific gravity also indicates relationship between fruit weight and volume.

Steps: To determining specific gravity

Record the weight of fruit in air on top loading balance.

Losses resulting from pre harvest and harvest drop of fruits have long been a serious problem to the fruit growers. As the fruits of some species and varieties approach the picking maturity, they tend to loosen from the stalk and considerable quantities may drop prior to and during the picking operation. Such fruits are badly damaged and if salvaged have a very low value compared with those picked from the tree. In certain fruit crops, the problem of fruit drop is very serious. Whereas in some, the fruit drop starts right from the time of fruit set and is severe at a number of stages of fruit development. In some fruit crop serious drop occurs before harvest.

Maturity indices and their adoption at harvesting and in post harvest management of fruits provide a information against quality loss, microbial decay and deterioration of external appeal. Fruit harvesting at proper stage of maturity has direct effect on quality and market value of produce. Stage of harvesting also influence the after harvest enzymatic activities of the horticultural produce, which determines the levels of different pigments, sugars, acids and vitamins in fruits, flowers and vegetables. Maturity can be described as the attainment of a particular size, stage after which ripening takes place. However, horticultural maturity is defined as the stage of development when a plant or plant part possess the prerequisites for utilization by consumers for a particular purpose. Cucumbers, lettuce and peppers are harvested at various stages (Horticultural maturity) prior to reaching physiological maturity, or completion of growth phase.

There are many methods to determine produce maturity. The most common is the size of the individual commodity.Some other commonly used crude methods are colour change, Softening of the tissues (fig,sapota) ease of detachment from the stalk (Sapota, annona), shrivelling of fruit stalk (water melon), time elapsed from the date of flowering to picking maturity, sound by tapping jack and water melon when ripe produce hollow and dull sound on tapping but produce metallic sound if unripe etc. Another physical characteristic is the firmness and it is determined with a pressure tester. Firmness is often correlated with chemical changes that occur during ripening. Chemical characteristics include TSS, acidity, sugar, vitamins and pigments. There are certain test which accurately gives the maturity measurements such as use of colour charts (judge colour), penetrometers (firmness), brix: acid ratio etc. Other recent methods viz. thermal conductivity X-rays and NIR have also come in practice to judge the maturity of fruits and vegetables. Some commonly use maturity indices are given below in some of the important fruits.

Alternate bearing (AB) or biennial bearing (BB) is a major challenge to growers and traders of fruit crops. It is typically initiated by an abnormally heavy crop in trees (on year), followed by a light or no subsequent crop (off year).When on and off year sequence does not follow a systematic pattern it is called periodicity of cropping or irregular bearing. Alternate bearing is assigned due to genetic factor while irregular bearing may be due to lack of good orchard management practices. Alternation becomes entrained and difficult to change unless severe climatic events intervene, or drastic management interventions are made. A heavy “on” crop results in reduced vegetative shoot and root flushing, and less carbohydrate (energy reserves) build-up. Phenomenon of alternation is more prominent in the perennial fruit crops particularly in Anacardiacae (mango and pistachio), Carylaceae (Hazelnut), Oleaceae (olives), Rosaceae (apple, pear, plums, apricot etc), Rutaceae (orange, Tangor, Satsuma etc) and also tamarind, jamun etc. fruit crops. Within a tree species some cultivars are regular while others are alternate bearer e.g. in mango Amrapali is regular while Langra is strongly alternate bearer.

Water is an important input in crop production. It acts as solvent, reactant and used for transpiration and maintaining cell turgidity. Hence, knowledge of soil moisture is essential for making irrigation scheduling. For determining soil moisture status, the commonly used methods and instruments are discussed along with their advantages and disadvantages. The soil moisture can be measured by determining either the soil water content or the soil water potential. The measurement of soil water content is an estimation of the mass or volume of water in the soil, while the soil water potential is an expression of the soil water energy status. The relation between content and potential is not universal and depends on the characteristics of the local soil, such as soil density and soil texture. We can measure soil moisture content both by direct and indirect methods. In direct method, we remove the water from the soil sample by evaporation and the amount removed is determined. This method is popularly known as gravimetric method. We measure property of soil that is affected by soil water content under the indirect methods. Indirect methods employ tensiometric, nuclear (neutron and gamma radiations), electromagnetic (radar and time domain reflectometers), hygrometric (electrical resistance, capacitance, Infrared absorption) techniques besides remote sensing for making soil water models. In the following paragraphs both the methods of soil water measurement has been discussed.

Training and pruning are an important activity in fruit crops to have better frame work and optimum fruiting area. Training refers to giving a desired shape to the plants by tying or staking or supporting over a structure and or selective pruning for a good strong frame work. Pruning refers to cutting of certain portion of plants for maintenance of fruitfulness and quality besides vigour of the trees or vines. Pruning affects the functions of the plants and assists in better fruiting and in getting more quality fruits. It is one of the most crucial operations and require some scientific knowledge regarding bearing behavior of the plants.

There are several planting plans or systems which can be adopted for planting an orchard. The main principle for the layout of orchard is:

1. It should accommodate maximum number of plant per unit area.
2. Provide adequate space for the development of the tree.
3. Ensure convenience in orchard operations.

The various lay out systems used are the following

Plant Growth Regulator (PGR) are diverse group of organic compound other than nutrients, produced artificially or by plants which in low concentrations promote, inhibit or modify the physiological process in plant. Among the PGRs produced by plants are auxins (indole-3-acetic acid and its derivatives), gibberellins, cytokinins, abscisic acid and ethylene.

Application of certain plant growth regulators promotes the process of seed germination, and development of roots in cuttings and layers. Various growth regulators have been used with striking success. Of these auxins such as indole3-acetic acid (IAA), indolebutyric acid (IBA) and naphthalene acetic acid (NAA) have the greatest effect on root formation in cuttings and layers. These chemicals speed up the healing of the wound, induce more roots and their development. They are now used universally in the propagation of many fruit plants. The growth regulators are effective in minute concentration and are usually applied in dilute solutions and dust formulations or rarely in grease bases such as lanolin. Plant growth regulators are generally calculated in the form of parts per million (ppm) or microgram per gram (mg/g).

The packing methods practiced by nurserymen for transport of nursery plants to distant places in India are neither uniform nor efficient. In different parts of the country, various practices are followed which are claimed to have been evolved by long experience of the local nurserymen. They vary according to nature of the plant, the season and the cheapest packing material available at the time of packing.

In many parts of the country, citrus nurserymen uproot plants, tie them in large bundles (with or without soil), keeping the plant tops exposed to air and roots tightly packed or tied in the gunny cloth. The pomegranate and guava plants prepared by air layering are packed as such if they are not already potted in small pots.

Many nurserymen pack the rooted or newly lifted plants in a ball of sticky clay. The ball of earth is then covered with grass and tied as firmly as possible, thus securing the roots against drying. A number of plants, thus prepared, are filled closely in light locally knit bamboo baskets. The baskets are covered thinly with coconut leaves as protection against injury during railway shipment. Mango grafts in pots are packed in light baskets with some cushion of grass to reduce the impact while loading and unloading the parcels on their long journey by rail and road.

Some nursery men use large baskets, woven out of coconut leaves with limp walls or sides. Plants such as coconut, chikoo, guava, mango are packed tightly in these baskets and shipped by truck or rail. This packing is done irrespective of plant containers such as pot or a ball of earth, with or without grass covering. The plants packed in all such fashions are usually damaged and some of them do not survive, unless care is taken during or after transplanting them in the permanent places. For better success, it should be seen that the roots of grown up plants do not get irreparable injury while removing from the bed or the pot. During transport, loss of water by transpiration should be kept at minimum, while the plants are awaiting dispatch or delivery at the railway platform, precaution should be taken against pilferage or damage by animals.

What is Nursery?

Nursery is a place, where seedlings, samplings, trees and other plant material are grown and maintained until they are planted in permanent place. Setting up of a horticultural nursery is a long term venture and needs proper planning for good return.

Establishment of Nursery

To be a viable venture, the nursery should be established in such an area where cultivation of fruit crops is on sizeable area and there is need for a nursery, having demand for saplings. In such area/region, following considerations need to be observed for selecting an appropriate location.

Rootstocks play an important role in the propagation of plants. It may modify form or stature, adapt a variety of a soil, fit in an incompatible climate, impart or resist disease to the scion, increase production, hasten maturity of crop, change the colour of the fruit, effect the flavour of the fruit, shorten life of the tree, increase the size of the fruit, develop vigour, effect salt tolerance and influence storage capacity.

The propagation of plants has been one of the fundamental occupations of mankind since civilization begins. Most of the selected plant would have lost or could have attained undesirable forms if they were not propagated under strict environment conditions. Growth, in all nature, result from the division of cells to form more similar cells. Thus bacteria reproduce by simple division, in higher plants and animals, a new individual is genetically formed only when cell division fallows the fusion of two cells. This is known as sexual reproduction. There are thus two methods of producing new plants, sexual and asexual or vegetative reproduction.

I. Sexual Propagation

Raising of plants by means of seeds is called sexual propagation. There are many plants raised for our garden from seeds. The plants produced through seeds are called seedlings. In sexual method, the sex organs of flower are involved in process like pollination and fertilization, resulting the formation of seeds. eg rootstocks plants of many fruit crops are grown through seed propagation.

1. Mango

Varieties released from I.A.R.I., New Delhi

Malliaka: (Neelum x Dashehari)

This variety was released in 1971. Tree moderate, semi-vigorous to vigorous, moderate spreading, bearing moderately and regular. Fruit large, ovate-oblong; beak slight, sinus absent, peel thick, apricot yellow; flesh firm, fibreless. Fruit quality superb with excellent sugar acid blend., TSS (24-20° Brix), good keeping quality (15 days). It is suitable for table and canning purposes. Maturity during 3^rd – 4^th week of July.

After doing all hard work during fruit production the last operation is harvesting on field. Though it is last operation, it should be done very carefully to get the quality harvest. Harvesting of fruits mainly depends upon the nature of fruit. Here nature refers to the classes of fruits divided on the basis of their respiratory pattern and ethylene production. On the basis of the respiratory pattern the fruits can be divided in to two categories, first one is climacteric and the second one is non climacteric.

1. Climacteric fruits: The meaning of word „climacteric is a critical period or event. Here, climacteric refers to the event of respiratory rise before the ripening phase. Those fruits which show such patterns are known as climacteric fruits (Taiz and Zeiger, 2002) Examples: Mango, guava, apple, banana, sapota, papaya, peach, pear, plum, fig, Annona.
2. Non climacteric fruits: Non climacteric fruits do not exhibit the respiration and ethylene production rise (Taiz and Zeiger, 2002). Examples: Citrus, grapes, pineapple, pomegranate, litchi, ber, jamun, cashew, cherry, strawberry.

Fruit drop is a premature shedding of fruitsbefore harvesting for commercial purpose. There are so many reasons for fruit drop like internal (Hormonal balance, morphological and genetical) and external (biotic and abiotic) factors. Fruit drop is very much serious in some fruits like apple, peach, currant, mango, citrus etc. Fruit drop may occur at various stages of fruit growth,starting right from fruit setting till its harvesting. It may be natural, environmental or pest related.Losses due to fruit drop at various stages have long been a serious threat to the fruit growers. After determining the actual cause of fruit drop, adoption of a suitable control measure can bring relief to the growers. Among different drops, pre-harvest drop is of great economic importance which can cause serious crop loss to farmer.

Fruit is a structure which arises from an ovary or fusion of several ovaries after fertilization and may or may not carry associated floral parts. Fruit formation is an evolutionary mechanism designed to support and dispersal of seed by various agencies.With few exceptions e.g. banana, it is necessary for the flowers to be fertilized to set fruit. Fruit set succeeds the process which involves fusion of male and female gametes inside the ovary and is called fertilization. Fruit setting has long been remained a major problem as is evident from the old Greek literature and wall paintings where male panicles of date palm were being rubbed against the female flowers to get good fruit set.Lack of pollination with compatible source leads to the flowers drop except the flowers which set parthenocarpically. Further if fertilization is affected even then the flower drop and this decision depends upon the internal hormonal levels of the plant and prevailing climatic conditions.On the basis of pollination requirement fruit plants can be autogamous, allogamous or geitonogamous. In case of fruit plants like grape, peach where pollen produced by the same flower affect the fertilization are called autogamous and fruits like apple, kiwi, pistachio necessarily require pollen produced on some other plant or cultivar which are compatible can affect fertilization are called allogamous. Another condition exists where pollen grains from the same plant affect fertilization in flower at different part of the plant e.g. Walnut, pecan nut and is called geitonogamy. Similarly on the basis of compatibility between pollen and stigma, plants can be self unfruitfull, partially self fruitfull and self fruitfull.Self fruitfulness indicates that fruit species or cultivars produce abundant viable pollen grains whose shedding coincides with the receptivity of stigma, pollination is effective and there are no pre and post fertilization barriers. However, partial self fruitfulness and self un-fruitfulness exhibits number of causes. In case of fully self fruitfull types, a solid block of a single cultivar can be raised without making any provision for cross pollination, however it has been reported that provision of cross pollination in autoganmous crops increases the fruit-set. In case of self unfruitful and partially self unfruitful types, provision of cross pollination is necessary to get the fruits. Proper selection of the cultivars is therefore important from the point of fruit yield for which besides overlapping of blossoming season over long periods, the time of maturity, productiveness, market values etc. are of importance. Pollenizer must be a heavy pollen producer to ensure better chances of cross fertilization. Although pollenizers are desirable, their number must be restricted so that these do not become uneconomical because the pollenizer trees occupy space, consume nutrition and take away attention of the fruit grower without any return in yield, which would have otherwise been diverted to the trees capable of bearing fruits. Numerous environmental, edaphic, plant characters affect the fruit set and are discussed as under:

Introduction

Fruits play a vital role in improving human health which are called as protective foods rich in vitamins, minerals, fats, oils, proteins and improves in economy of producers, exporters and industrialists. Fruit crops can be classified into two broad categories i.e. ever green and deciduous trees.

1. Evergreen fruit trees grow under tropical and subtropical climate and they are not dependent on chilling requirement for floral bud differentiation and flowering. Ex: Mango, Citrus, Guava, Sapota, Papaya etc.,
2. Deciduous fruit trees require dormancy during winter season and chilling units for floral initiation and have specialized modifications to protect sensitive growing tissue from unfavourable conditions. Ex: Apple, Pear, Peach, Plum, Apricot, Cherry, Grapevine, Walnut, Almonds etc.,

Water is one of the most important and critical input for agricultural production system. The demand for food grains is increasing day by day due to increasing population. The irrigated agriculture provides the crop water productivity of about 2.5 tonnes per hectare and the overall irrigation efficiency is only about 30%, which is below the world average level. In the above scenario it is necessary to have the irrigation system in which both the crop water productivity and irrigation efficiency increases considerably. Micro irrigation has become the most viable and efficient technology in such a situation. It provides several advantages in the context of crop agronomy, water and energy conservation. Micro irrigation has the potential to achieve the crop water productivity to a desired level of 4 tonnes per hectare and simultaneously maintain the irrigation efficiency above 80%. The total coverage of micro irrigation in the tenth plan is only about 2 million hectare. The task force on micro irrigation (2004) has indicated a potential of 69 million hectare for our country. So there is a tremendous potential available and the coverage of micro irrigation has to be increased to cover more crop and more new areas.

In the words of Leonardo the vinci, “water is the driver of life”. It is said to be the liquid of life or elixir of life. Water availability is essential to consider as commercial orchards must have reliability of supply and cannot produce optimum yields without irrigation. Water management is one of the largest and most important inputs into an orchard. The single environmental component which determines the type of fruit plants to be selected for a specific ecological situation is the moisture status of the region. Different fruit plants preferring diverse moisture status have wide peculiarity in their anatomical and morphological structures as well as various modifications in their water absorbing organs. They are also seen to have varied capabilities to acquire and utilize water efficiently. In the plant system, the rate of dry matter production has a definite relation with the rate of transpirational loss of water and this transpiration ration is calculated on the basis of unit of water required to produce unit of drymatter. However, while calculating the water requirement of fruit plants, a number of factors, in addition to water use efficiency, are taken in to consideration. Naturally water requirement of a particular fruit plants varies with the agro-ecological condition of different places. Moreover the same cannot be equal in an established orchard and a newly planted one. In established orchard, the trees are grown in community where improved water use efficiency lower down the water requirement of the trees.

Growth is the fundamental property of all living organisms. It is an irreversible permanent increase in size, volume or mass of a cell or organ or whole organism accompanied by an increase in dry weight. Where, development is sum total of growth and differentiation. It is governed by both environmental and internal factors. The development of a plant is highly complex phenomena (Table 1).

In nature, plantspecies flowers produce fruits and seeds and the primary objective is to reproduce them. Plant species those are unable to produce viable seeds, reproduce themselves by other means. With a common of these processes they vary in various aspects of flowering and fruiting. The variations may be due to their different growing habits, requirement of different environments, differences in their basic nature etc. Here we are going to discuss different types of bearing habits do exists in fruit crops.

Growth Habit

Growth is quantitative irreversible increase in the existing size of say plant or a shoot or simply a leaf etc. Fruit crops can be classified on the basis of their growth habits in two major classes. One is evergreen and second is deciduous. Evergreens include those plants which bear their leaves throughout the year. Examples are mango, litchi, guava and orange. Whereas, deciduous trees shed their leaves during a part of year (when weather is adverse i.e. during winter). Mostly temperate fruits belong to this category. The presence or absence of leaves makes very big difference in their physiology, their bearing season and pattern etc. These two categories also make a basic group to study them separately with respect to many aspects viz. source and sink relationships, pruning etc.

The damage due to frost in fruit crops has been a problem for farmers since starting from their cultivation. Damage caused by frost is a worldwide problem because if all aspects of crop production are well managed, one night of freezing temperatures can lead to complete crop loss. According to Bagdonaset al. (1978) frost periods in temperate regions are shorter in duration and occur more frequently whereas in subtropical climates it is occurs with slow moving cold air masses. In tropical regions, there is usually no or very less freezing damage except at higher elevations. In subtropical fruits crops, damages occurs mainly during the winter, whereas in deciduous fruit and nut trees, it occur mainly in spring, but sometimes it occurs in autumn as well. The region prone to frost should adjust the date of planting of crop, microclimate, variety and other preventive measure. According to Attaway (1997) in South Carolina, northern Florida and Georgia, orange fruit were commonly grown before 1835, but losses due to frost damage, farmers did not prefer to grow oranges in that regions. The history of frost damage is more sporadic in nature leading to some major losses from time to time. In December 1990 and 1998

Californiacitrus industry suffered two major damaging events of frost which ranged from little damage in some regions to severe damage in the other region. The economic losses to fruit crops were high in the frost occurring in 1990 compare to frost in 1998.

Apple (Malus x domestica Borkh) is the most widely grown temperate fruit of the world considered as king of temperate fruit. It is one of the most delicious fruit rich in carbohydrates, minerals like calcium, phosphorus, iron, potassium, vitamin B6 and low in calories. Apples are extremely rich in important antioxidants, flavanoids, and dietary fiber. Apple is recommended to reduce the incidence of dental caries, and the phytonutrients and antioxidants may help reduce the risk of developing cancer, hypertension, diabetes and heart disease. Apple is chiefly used as table fruit. The various processed product like juices, jelly, preserve, canned slices, wine, concentrated juice, cider and powder are prepared from apple fruit.

Bael is one of the oldest and nutritional fruits of India (John and Stevenson, 1979). The tree is very hardy and thrives in almost all types of soil and climate. The ripe fruits of bael are rich in protein, fat, minerals, riboflavin, carotene, thiamine, niacin and vitamin C. The ripe fruit is lucrative while unripe fruit is prescribed for diarrhoea and dysentery (Mitra 1999, Roy, 1996, Singh and Ali, 1992, Singh, 2000). The marmelos in is most probably the therapeutically active principle of bael fruits.

18.1.1 Centre of diversity

The Bael tree has its origin from Eastern Ghats and central India. Its indigenous to Indian subcontinent and mainly found in tropical and subtropical regions. Even though it is native to India, it is found throughout Southeast Asia (Neeraj et al., 2017). The tree is also found as a wild tree, in lower ranges of Himalayas up to an elevation of 500 meters. Bael is also found growing along foothills of Himalayas, Uttaranchal, Jharkhand, Madhya Pradesh and the Deccan Plateau and along the east coast (Sharma et al., 2007).

Pineapple is one of the most important commercial fruits of the world. It is good source of vitamin A, B and fairly rich in vitamin C, minerals like calcium phosphorus and iron. Fresh fruit of pineapple is used as dissert fruit in the form of slices. Fruit is also used for juice, squash, jam, mixed jam and in canned form, fruit cone is used for preparing candy. Some cultivars of pineapple are used for extraction of fibre. The important states of pineapple growing are Assam, West Bengal, Tripura, Kerala, Andhra Pradesh, Bihar, Karnataka and Madhya Pradesh (Bal, 1997).

Cashewnut is an important delicious and dollar earning cash crop of India. This crop was remained neglected due to its poor yield potential and prolonged harvesting season. Cashew was introduced mostly for soil conservation purposes. In the beginning of the 20^th century cashew kernels gained importance in the international trade as edible nut and the crop began to be considered as having commercial value. Cashew is commercially grown for its kernels although cashewnut shell liquid (CNSL) and apples are also valuable by - products. It is considered to be the most important edible nut in the world trade (Ascenso, 1986). India is the largest producer and exporter of cashewnut in the world. Cashew kernel is the rich source of protein, carbohydrate, unsaturated fats and minerals like calcium, phosphorus and iron. Cashew proteins are complete with all essential amino acids. Fats of cashewnut are considered as complete, attractive, easily digestible and non fattening, it can be used by both olds and infants. The cashew apple juice is rich in vitamin C and it has some medicinal properties.

Coconut is a monocotyledonous woody plant belonging to the family Arecaceae or Palmae. It is presumed that the generic name Cocos and popular name coconut are derieved from Spanish word ‘Coco’ meaning “Monkey face” a probable reference to the three scars on the base of the shell resembling two eyes and a nose of monkey face. Coconut is valued most for its nut, the other components are coconut water, kernel, shell and husk. Coconut water is one of the most refreshing drinks which is also known for its medicinal value. It increases blood circulation in kidneys, causes profuse diuresis and eliminates mineral poisoning. It is a good substitute for saline glucose under gastroenteritis conditions. The coconut has been regarded as Kalpavriksha (tree of heaven) because all the parts of the palm is useful to mankind in one way or the other.

The dried kernels commonly called as copra is richest source of vegetable fat i.e. 60 to 67% oil. Coconut is major source of edible oil and it is propagated through seeds. India is largest producer of coir and its product. The coconut plant has about 4-6 years of juvenile phase with 60 years of productive life.

Litchi is a delicious fruit and generally consumed as a table fruit. It is one of the most popular fruits of India which is commonly taken as fresh or in dried forms. Litchi is also recognized as “Queen of the fruits”. Dried litchi commonly known as ‘Litchi nut’ is very popular among the Chinese living all over the world. This subtropical fruit cannot tolerate frost in winter and dry heat in summer. An interesting feature of the litchi plant is the symbiotic growth of Mycorrhiza fungi on roots of the tree. These fungi form nodules on the roots of litchi. The trees and the fungus live together to benefit each other. Litchi makes an excellent canned fruit and highly flavoured squash is prepared from inferior fruits. Besides, fruit, other parts of the plant like leaves, bark and roots are also used for various purposes. In China leaves are used for making poultices, bark and roots for making decoctions for throat gargle.