eChapters

INTRODUCTION

The genus Pratylenchus was established in 1936. It has a cosmopolitan distribution prevalent in temperate, sub-tropical and tropical regions. The species of Pratylenchus are popularly known as lesion nematode or meadow nematode. They are migratory endoparasites. Various pulse crops are damaged by them. P. thornei attacks chickpea,  P.zeae on mungbean (Walia and Seshadri, 1986); P. mulchandani on urdbean (Nanad Kumar et al., 1969) and Pratylenchus sp.on lentil (Mishra and Gaur, 1980) and cowpea (Aung and Prot, 1990).
Besides pulses species of Pratylenchus attack a number of other crops also. The infested plants exhibit various types of symptoms and results in heavy yield losses. Investigations have been made on various aspects of host-nematode relationship, distribution, host range, yield losses, biology, life cycle, disease cycle, interaction with other microorganism and management through cultural, physical, chemical, biological methods and host resistance.

INTRODUCTION

Soil-borne pathogens cause heavy losses to most agricultural crops. Repeated planting of a crop in the same piece of land results in a high inoculum build-up, which forces the farmers either to change the crop or the land. Thus, the search for new, effective, inexpensive and non-hazardous methods for the control of soil-borne diseases is a continuous one. Over the years, efforts have been made to manage the soil-borne pathogens by employing fumigants, chemical pesticides, biological control agents, different type of soil amendments and also by causing modifications in different cultural practices. But, pathogen control is often hampered by the fact that both the inoculum of the pathogens and the lethal agents applied to the soil are affected by the soil’s physical, chemical and biological environment. Keeping in view the bottlenecks with different methods of management of soil-borne pathogens; harnessing of solar energy i.e. soil solarization is an effective method to control soil-borne pathogens.

INTRODUCTION

Many economically important diseases are caused by Phytophthora spp. There are as many as 60 described Phytophthora species, most of which are primary invaders of plant tissues with limited saprophytic ability. Some important diseases with respect to symptoms, etiology and management have been described in this chapter as given below.

INTRODUCTION

Plants are susceptible to different types of pathogens, which are responsible for production of varied symptoms and causing losses. In the absence of the crops pathogens perpetuates in different manners and survival in the soil is one of the most important amongst these. Because of the constant presence of the pathogen in the soil, these become more destructive. These may reduce the plant growth, results in rotting of different plant parts, reduce yield or may cause the death of the plant. The destructiveness of soil borne pathogen increases because of the ability to survive in the soil as dormant structures for several years. Efficient control of soil borne diseases is thus difficult but can be achieved by employing various disease management practices in an integrated manner (Verma and Varma, 1992; Gupta, 1996, Gupta and Sharma, 1999).

1. Introduction

Fruits and vegetables represent highly perishable items of agriculture, mainly because of their high water content in fresh form. Their production, yield and management under agriculture is dealt essentially under horticulture. They abound in species and varieties in different geographic regions of the world, influenced by the agro-climatic conditions. Some are endemic and confined to certain geographic regions only. Accordingly, they may be tropical, sub-tropical or temperate, depending on their requirements of temperature for growth and yield.

1. Introduction

Vegetables and fruits are the next in demand for human consumption after rice and wheat, in all parts of the globe. Fresh fruits & vegetables and their value added products are increasing in popularity day by day almost in all the countries, because of their richness in dietary fibre, minerals & vitamin contents and for their medicinal properties. Maintaining agricultural produce quality and its evaluation are thus naturally important. Decisions concerning maturity and ripeness of fruits and vegetables are based mostly on visual inspections, which are subjective in nature. The quality of fruits and vegetables is mostly decided on the basis of size, shape, colour, gloss, flavour, firmness, texture, taste and freedom from external as well as internal defects. Internal quality factors such as maturity, sugar content, acidity, oil content and internal defects, however, are difficult to evaluate non-destructively. Methods are needed to better predict the internal quality of fruits and vegetables without their destruction. Recently, there has been an increasing interest in non-destructive methods of quality evaluation, and a considerable amount of effort is being made in this direction. But the real problem is how these methods are to be exploited practically on commercial scales and what are the constraints faced in implementing them.

1. Introduction

Food is processed for its preservation, hygienization or value addition. To date, the food preservation technologies such as canning, dehydration, freezing, pasteurization and controlled atmosphere and modified atmosphere packaging have been the main processes employed to preserve foods, with the use of antimicrobials and microwaves also being employed more recently. In future, however, technologies such as exposure to ionizing radiation, high pressure processing, ohmic heating and pulsed electric field processing, could potentially be the new alternatives to the above food preservation technologies.

Irradiation of food involves the exposing of food, either in prepacked form or as such to controlled doses of ionizing radiation being generated either by electrically driven machines such as electron beam accelerators, x-rays or gamma rays produced by radioactive isotopes such as CS-137,CO-60, to achieve certain desirable objectives. The process of exposing a range of food stuffs to specific doses of ionizing radiation is being used to extend the shelf life of food stuffs, to improve their overall safety and quality by eliminating pathogenic bacteria, by reducing number of food spoilage organisms, to reduce the bacterial load on herbs and spices and thereby making them safe to incorporate into food stuffs, to inhibit sprouting in stored tuber and bulb crops such as potatoes, onions and garlic, to disinfest grains, grain products and tropical fruits to prevent damage to the commodity and to meet the quarantine regulations(Arun Sharma, 2004, Farkas, 2006).

1. Introduction

Pectin is a polysaccharide present in the middle lamella of plant cell walls. The firmness and structure of the plant tissue are attributed to the presence of pectin in the middle lamella. The insoluble form of pectin is called protopectin and the soluble form is called soluble pectin (Kertez, 1951). Protopectin is abundant in green fruits and contributes to hardness of cell, where as soluble pectin is responsible for viscous nature of juice and pulp. Conversion of protopectin to soluble pectin results in loosening of the bonds between the cells and softening of the fruit tissues. Protopectin is reported to be hydrolyzed to pectin by enzyme action during ripening. Protopectin on restricted hydrolysis yields pectin or pectinic acid. Braconnot (1825) discovered pectin as the gelatinous principle of fruits.

1. Introduction

At present there is an increasing demand for colourants from natural sources. Since there is a possibility of banning of synthetic colours in view of their carcinogenic properties and already a reduction in number of permitted synthetic colours from 13 to 8 numbers in our legislation (PFA, 2005), the demand for natural colours is evident. In Japan and European countries because of the green movement, the demand for synthetic colours has been reduced. Synthetic colours in global market account for 400 million dollars. Despite processing limitations and higher costs, the global market for natural colours is estimated to be more than 939 million dollars (Espszezola, 1998). Color is recognized as a major factor affecting food acceptance. The consumer expects a specific food to possess a well defined colour and rejects any appreciable deviation from the normal. The change in colour during the preparation of food is a useful guide to quality control and is used by many food processors as the criterion for selecting raw materials. The characteristic colour of raw food is due to the natural pigments present in the plant and animal material. These can be enhanced in processed food products through the addition of food colourants. Addition of colour can make up for the colour losses during processing. Some of the major groups of colours are anthocyanins, carotenoids, betalains, chlorophylls, flavones and chalcones. Some of the plant sources of pigments are kokum, roscelle, chilli, marigold, beetroot, grapes and safflower. Sources of natural colours can be plants, animals or microbes. Fruits and vegetables form one of the main plant sources of pigments. Some of the plant materials rich in colours viz., alfalfa, marigold, safflower, strawberry, aronia fruits, grapes, red cherries have been exploited for pigment extraction and the results have shown positive effects. Some of the interesting features of the work carried out by researchers in this area are presented in the following sections.

1. Introduction

In this era of genomics, proteomics and metabolomics the challenge in nutritional science is to clarify human nutrient requirements and design nutritional strategies to promote health and functional longevity. Our ancient Indian belief that ‘we are what we ate’ and our future health as individuals may well depend upon what we eat today. Plant-based dietary antioxidants are believed to have an important role in the maintenance of human health because our endogenous antioxidants provide insufficient protection against the constant and unavoidable challenge of reactive oxygen species (ROS). We have various endogenous defense chemicals but they are inadequate to prevent oxidative damage that makes human system prone to various degenerative diseases. Hence, it is necessary for increased intake of dietary nutraceuticals that may help maintain the balance between oxidants and antioxidants, slow age-related changes, and prevent onset of degenerative diseases.

1. Introduction

Pulpy and juicy fruits like orange, guava, banana, grape, mango, papaya, pears, apples and jackfruit can be converted into fruit products like squashes, juices, cordials and ready-to-serve (RTS) fruit beverages. These RTS fruit beverages are both refreshing and thirst quenching and have become very popular. Liquid fruits are the clarified juices prepared from these pulpy and juicy fruits. There is a demand for liquid fruits in the international market for various applications. The liquid fruits can be used as a natural alternative to synthetic beverages. They can be suitably concentrated or diluted, blended with other juices and also can be carbonated as fruit based soft drinks. Removals of pulpy material from the juices make them easier to preserve by pasteurization and are amenable to carbonation. Pulpy fruits can be successfully processed into liquid fruits (clarified juices) by using pectic enzymes. The emphasis of the fruit juice processing industry has, so far, been mainly on conventional clarification processes like enzymatic and chemical treatments followed by filtration using filter aids; and concentration by vacuum evaporation.

1. Introduction

Intermediate moisture foods are semi moist foods that have some of their water bound by glycerol, sorbitol, salt or certain organic acids, thus preventing the growth of many microorganisms (Stewart et al. 2001). It is now well recognized that fruits and vegetables are dehydrated to an intermediate moisture level (20-50%) (Stewart et al. 2001; Purvi et al. 2003). As the intermediate moisture products are characterized by a semi moist consistency so these foods have enough moisture content to permit easy chewing but low enough water content to prevent spoilage production of intermediate moisture foods is based on an increased scientific understanding of the chemical reactions involved in traditional food preservation methods (Purvi et al. 2003).
There will be better retention of original flavor and texture compared to fully dried products, with concomitant reduction in bulk, weight and cost of packaging, transportation and storage. Such intermediate moisture foods are more appropriate for developing countries in view of their minimal processing requirements, stability under ambient conditions, safety, convenience, ease of nutrient content adjustment, energy savings and low capital investment. They are also eminently more suited than dehydrated or canned foods for military rations (FAO, 2005).

1. Introduction

There is intense commercial interest in dehydrated fruit and vegetable products especially mango powder, banana powder, orange powder, papaya cereal flakes to powder, tomato juice powder and other vegetable powders, which are in great demand for soups, biscuit type cookies supplemented with fruit powders (Ana Maria et al. 2009; Sunita and Chauhan 2008), pizza mixes and sauces. Natural fruit and vegetable powders are gaining lot of popularity in recent years as they are very easy to handle after production, require minimum storage space and they are attractive. Tamarind powder is developed from tamarind fruit (Tamarindus indica) (Manjunath et al. 1991) and recently cashew apple and guava residues from fruit juice industry were successfully converted into fruit powders and used at different levels of wheat flour substitution for cookies formulation (Ana Maria et al.2009) and fruit puree like papaya can be mixed with cereal flour to prepare slurry and after gelatinization, the slurry can be useful for preparing drum dried flakes and powder (Sunita and Chauhan 2008). Tropical fruits are exotic in flavor but their juices and purees are seldom available in dehydrated powder (James, 1971). Citrus juice concentrates were produced during world war II in powdered form by using spray, drum, vacuum-puff, and freeze drying (USDA, 1962). The preservation of fruits and vegetables by dehydration offers a unique method, which may be considered as an alternative low cost preservation technique. A shift from fresh to more and more processed foods with significant value addition is bound to occur sooner or later considering the socio-economic changes taking place in the country and the rapid integration of Indian economy with global system. Most popular brands are found in the “ready to consume” food sector.

1. Introduction

Bamboo has historically been an integral part of human culture. Bamboo is a mystical plant representing symbol of strength, flexibility, tenacity, endurance and compromise. Throughout Asia, bamboo has for centuries been integral to religions, ceremonies, art, music and daily life. Bamboo provides numerous environmental benefits such as playing a critical role in the balance of oxygen/carbon dioxide in the atmosphere. Bamboo is the fastest growing canopy for the regreening of degraded areas and generates more oxygen than equivalent ultraviolet rays. It is an atmospheric and soil purifier. Its soil conservation properties create an effective watershed, stitching the soil together along fragile river banks, deforested areas, and in places prone to earthquakes and land slides. Its fast growing and high yield nature makes it a highly valued renewable resource. Its low cost and abundance call for its utilization to a full extent. 

1. Introduction

 Mushrooms have been part of man’s diet for centuries (Rajarathnam and Shashirekha, 2003). Mushrooms grow on wide range of agro-residues, biodegrade and biotransform them into edible fruiting bodies (Rajarathnam and Zakia Bano, 1988a; 1988b; 1990; Zakia Bano and Rajarathnam, 1988; Zakia Bano et al., 1993; Rajarathnam et al., 1998). Their post-harvest life is very ephemeral at room temperature (Rajarathnam et al., 1983) due to delicate flavor (Rajarathnam et al., 1990) and high moisture content, with a range of chemical constituents (Zakia Bano and Rajarathnam, 1986; 1982; 1988; Rajarathnam and Zakia Bano, 1990; Rajarathnam et al., 1983; 1992). Since, they contain large quantities of water and therefore suffer considerable weight loss during transportation and storage, causes serious economic losses, due to reductions in weight and quality (Gray, 1970). When the supply of water, organic substances and minerals are cut off at harvest, the fresh mushroom enters a deterioration or perishable phase. Cap opening and stem elongation are the usual symptoms of senescence constituting visible evidence of deterioration. At room temperature, the shelf-life of mushrooms cannot be for more than 24 h (Rajarathnam et al., 1983). During this period, there are considerable changes in color, texture and taste. In addition, water is continuously being lost as a result of transpiration and respiration. Additional loss occurs from surface cracks and bruises that develop during growth and handling (Salunkhe et al, 1991). Fresh mushrooms are white or light buff, with no dark marks on either the cap or stem. The veil is closed and the gills are not visible. The upper surface of the caps should be strongly convex and stems should be plump rather than elongated. Mushrooms are grown on compost, usually in mushroom houses where the temperature and humidity can be controlled. Eventually after harvest, the mushrooms can never be able to withstand any increase in temperature and decrease in relative humidity. Mushrooms are commercially preferred at the immature stage characterized by closed caps, invisible lamellae, round stipe and light color. Agaricus development is classified into various stages (Table 1). Thus, the concept of physiology of fresh mushrooms being very complicated, bears a great impact on the delicate problem of extending the storage life. The various means and methods studied and adopted by various researchers to aim at extended storage life of fresh produce, underlined by its physical, chemical and biochemical properties and also development of value added products are critically evaluated.

1. Introduction

Fruits and vegetables in fresh form in general contain very high water content, with the fast rate of metabolic activity, including respiration rate, which may vary with the fruit type. Accordingly, the storage life at room temperature is considerably less, to expect acceptable quality. A range of transformational changes occur in various features of the fruits and vegetables, such as color, flavor, texture, structure, sweetness, sourness, pungency, astringency and so on. Phenolic browning of mushrooms, intensive softening of papaya, coloration and softening of ripe banana, softening of pear and jackfruit , flavor transformations of mango, banana and jackfruit after ripening, their color and texture transformations, are classic examples of post-harvest changes in fresh commodities, over a course of storage period at room temperature. These physical and sensorial perceptions of fresh commodities over a length of storage period are based on the range and multitude of operations of physical, chemical and bio-chemical reactions occurring in various constituents of the fresh fruit or vegetable such as moisture, pigments, vitamins, pectin, cellulose, hemicelluloses, phenolics, lignin, sugars, flavor compounds, amino acids, fatty acids and so on. In order to increase the storage stability, the fresh fruits and vegetables are processed and converted into various products such as juice, RTS beverages, jam, jelly, marmalade, fruit spread, dehydrated, spray dried powder, frozen stored, fruit cereal flakes, canned, candied, fruit bar and so on. Based on the nature of processing, the original form, shape, size, texture and structure are transformed, however with due maintenance in storage acceptability. A number of external factors are applied to achieve this product range such as heat, air velocity, pressure, radiation, chilling, freezing, vacuum impregnation etc. The ultimate quality of the final product is essentially an interaction between and amongst the various chemical constituents so characteristic of each fruit or vegetable under study, and a sum total of positive and negative reactions related to sensorial acceptability of the product. This quality is again a function of the storage period and the conditions of storage. Consumers in modern days are more health conscious to choose between consumption of fresh or processed fruits and vegetables. For trade over distance and time and particularly for geographic regions not producing a particular fruit or vegetable, it is of utmost importance to process the fresh produce. Enzymatic transformations in color, texture and flavor deserve utmost attention to ensure acceptable quality of the processed product, in particular over the course of storage period or until consumed after transportation and marketing. Microbiological quality of the product in final form is a most vital factor of consumers' health and this is dependent on water activity, sugars and protein / amino acid contents. In this regard, additives and preservatives come into picture. Strict regulations are imposed on their use, type and concentration over a storage period, for healthy consumption. Accordingly, this chapter would deal with several examples of processing conditions influencing the quality of the product, that emanates. Processing involving chemical, bio-chemical, engineering, bio-technological and microbiological methods to achieve a product are vivid, varied and different to different species / variety of fruits or vegetables to target different products.

1. Introduction

Processed foods have become a way of life in the modern world. Manipulation of chemical and physical properties facilitated by modern food technology and followed by addition of food additives has created a plethora of innovative food products that offer consumers greater convenience, variety, safety, satiety and quality.
Food additives have been in use for centuries for preservation, for providing improved appearance or desired texture and flavour. Preservation of foods started with salting and smoking. The Egyptians used colours and flavours, Romans used saltpeter and in India, turmeric is being used. Similarly additives such as baking powder as a raising agent, thickeners for sauces and gravies and colours- synthetic as well as from natural sources are being used.
Today more than 2500 food additives have been in use mainly due to the spurt in the research activities in food science and technology that are aimed at providing different characteristic functions to foods. Out of these, about 1300 are the flavouring additives.

From the earliest time, man had to conserve and preserve his food, so that surplus at harvest following a successful crop can be stored for use throughout the year. Prime agricultural products in general and more so with fruits and vegetables which are being processed world wide or preserved to a more stable form so that they can withstand transport, handling and storage over a long period. As civilization developed, man learnt to preserve fruit and vegetable products with salt, spices and by drying , smoking or cooling which could extend their shelf life. Later by experience, he learnt that by protecting it from environmental factors such as air, moisture and light, the shelf life of these processed products could be further increased. He tried to keep them dry and covered to protect from insects and rodents. As with solid foods, primitive man experimented with beverages also. It is likely that the first beverage known to him after water was fruit juice. This undoubtedly led to the discovery of wines made from the fermented fruit juices. Later on, preservation methods and development of packaging materials underwent drastic changes.

1. Introduction

Fruits and vegetables have been an integral part of man’s diet from immemorial times. Fruits are the portions of plants that bear seeds, while vegetables are the edible components of a plant, including the leaves, stalks, roots, tubers, bulbs, flowers and seeds. These can be eaten raw or cooked. Fruits and vegetables can be preserved for short-term intervals under refrigeration, with or without receiving a minimal treatment like slicing, chopping, shredding or peeling. Fresh produce may also be irradiated or packaged in controlled or modified atmosphere in films for short-term storage. Long-term preservation includes canning, juicing, drying and addition of preservatives. Food contamination with hazardous biological agents remains a worldwide challenge in food safety and nutrition (Kenny 2002; Schlundt 2002; Tauxe et al 1997). Microorganisms form part of the epiphytic flora of fruits and vegetables and many will be present at the time of consumption. Production practices, growth conditions and the location of the edible part during growth (soil, soil surface, aerial part) will in combination with intrinsic, extrinsic, harvesting and processing factors affect their microbial status at the time of consumption. Man-made sources may be directly from farm laborers and from the equipment used for harvesting or storage. The types of microorganisms on fruits and vegetables would also vary with the orchards, vineyards or growing fields. The resident microflora normally subsists on the slight traces of carbohydrates, proteins and inorganic salts that dissolve in the water exuding from or condensing on the epidermis of the host. The numbers of bacteria present will vary depending on seasonal and climatic variation and may range from 104 to 108 per gram. The inner tissues of fruits and vegetables are usually regarded as sterile (Lund 1992). However bacteria can be present in low numbers in the insides of the fruits and vegetables as a result of the uptake of water through certain irrigation or washing procedures.

1. Introduction

The chemical composition of a food is of utmost importance from many standpoints, including nutrition, safety, and stability to microbiological, chemical or physical changes. Analysis of these food components is required to provide nutrition labelling for informing the health-conscious consumer, for quality assurance during processing and storage, and for regulatory purposes. The methodology used in analysis will depend on the particular component and the nature of product being analyzed, the purpose of the analysis, and the availability of resources. The emphasis of this chapter is on understanding the principles, procedures and calculations involved in estimating a particular component in fruits, vegetables and their products.

1. Introduction

Mushrooms represent a highly specialized group of fungi, mostly basidiomycetes, with production of fruiting bodies bearing the spores for continued propogation. The fruiting bodies vary greatly in shape, size, color, texture, structure and aroma (Rajarathnam et al., 1998). They are endowed with the unique ability to biodegrade cellulosic wastes, including lignin, and biotransform into edible fruiting bodies (Rajarathnam et al., 1992, 1998, Rajarathnam and Zakia Bano, 1990). Their chemistry is also varied comprising characteristic polysaccharides, phenolics, proteins, amino acids, peptides, lectins, fatty acids, minerals, and so on (Rajarathnam et al., 1998). The wide spectrum of compounds have endowed the mushroom species with a spectrum of biofunctional activities of medicinal importance and accordingly their role in human health are implicated through studies on chemical, cell culture and animal feeding experiments. Vast literature available on this subject is condensed for presentation here.
Fifty nine medicinal species are reported from Diaoluoshan Nature Reserve in Hainan Province, China (Li et al., 2003). A health food made from luminescent mushrooms (Mycena chlorophos) is described. The luminescent parts that emit light in the carpophore of the mushrooms are dried without thermal decomposition and pulverized (Sugimoto, 2006). Consideration is given to the health promoting properties of 3 types of Asian fungi, namely, shiitake (Lentinus edodes), reishi (Ganoderma lucidum) and maitake (Grifola frondosa). Properties considered include beneficial components (e.g polysaccharides, vitamins, amino acids) and effects on the immune system (Anon, 1997). Auricularia auricula (kikurage or tree-ear) and Tremella fuciformis (shirokikurage or white jelly-leaf) are widely used in Chinese cuisine. Chemical structures of some of the polysaccharides from A. auricula and T. fuciformis, in relation to their medicinal and nutritional effects are described (Misaki and Kakuta, 1995).

1. Introduction

 Banana is the developing world’s fourth most important food crop (after rice, wheat and maize) accounting for 70 million metric tons per annum (FAO stat, 2007 faostat.fao.org/site/567/Desktop Default.aspx?). Banana is also the second highest fruit crop in the world, representing a wide range of varieties of cooking and dessert types, providing a staple, nutritious inexpensive food for millions of people. The word “banana” is a general term embracing a number of species or hybrids in the genus Musa of the family Musaceae known simply as the banana family. Two Musa species namely Musa acuminata and Musa balbisiana, out of the 28 described were first noted in 1865 by Kurz as being the origin of most of the commercial clones (Stover and Simmonds 1987). Cultivated clones are parthenocarpic, mostly sterile with starchy fruits. Indeed, wild types are very fertile; their fruits are full of seeds with little starch, and are seldom fit for human consumption. Its abundance, varietal diversity, availability round-the-year and low cost make banana an important commodity for the religious occasions in many tropical countries. The vegetable bananas, generally grouped under ‘Plantains’ are larger, more angular than dessert type and are generally intended for cooking unripe, although ripened ones are quite like dissert bananas.

1. Introduction

As dealt in earlier chapters, fruits and vegetables represent the most essential of horticultural component for acreage of production, yield, nutritional and nutraceutical values, of definite taste, texture, flavor and colour, involving defined health and medicinal benefits. Every year and over the course of every ten years, significant quantum of research data accumulates on the various facets of fruit and vegetable technologies, and also trends in production, processing and marketing, may also tend to change. At every stage, more thinking has gone to improve the technology, product quality and cost economics to suit wider markets, both domestic and foreign. It is a continuous endeavor to record newer and newer problems emerging and to set the strategies to solve them. Several relevant references, fitting to the various aspects representing the cross section of the fruit and vegetable technologies are dealt here, to conclude the subject and spell out the future.
Consumer demand for healthy convenience meals with ‘near fresh’ properties challenges researchers and industry to develop new or improved conservation procedures for processed products. Development of a dehydration process based on electromagnetic energy (EME) may bring about a major breakthrough with respect to retention of product quality and improved rehydration characteristics (Nijhuis et. al., 1996). Economic potential and current limitations of fruit and vegetable processing in India included improvements in preliminary treatment (harvesting, washing/cooling) precooling (including refrigerated transport/storage) and processing of juices and pulps. Establishment of a National Horticulture Board has aided to provide market information and so aid growers to get remunerative prices (Anon, 1993). The use of food irradiation as a quarantine method for treatment of food and agriculture commodities was organized by the joint Food and Agriculture Organization/International Atomic Energy Agency Division of Nuclear Techniques in Food and Agriculture, held in Kuala Lumpur, Malaysia, on 27-31 Aug., 1990. (FAO,1992). This has been experimented with various commodities, particularly for export trade of fruits like mango, as stipulated by the importing country like U.S.A.

Genetic architecture of a population is the result of prolonged natural selection. The populations which exist in diverse environments might have been strongly diversified genetically. So, it is necessary to understand the extent and rates of genetic divergence existing between the diversified forms or types. Genetic diversity must be sufficient enough to justify breeding effort. Genetic diversity may be available in improved germplasm or it may exist only in genetically inferior stocks. The availability of statistical tools to quantitatively measure the genetic divergence between two or more populations and the relative contribution of individual characters to the total divergence have permitted to trace the evolutionary patterns in some crops such as rice and tobacco and in choosing the parents for hybridization in crop plants (Rao, 1958; Blackith, 1960; Morishima and Oka, 1960; Murthy et al.,1962). Among the several statistical methods developed for measuring the divergence between population, multivariate analysis (D² statistic) developed by Mahalanobis in 1936, has been found to be potent tool.

Mahalanobis D² analysis is an effective tool in quantifying the degree of divergence at genetic level and provides a quantitative measures of the association between geographic and genetic diversity based on generalized distance.

Rice (2n = 24) is an annual grass (family: Graminae) with terminal panicles bearing the grains. It originated in Asia between the fourth and fifth millennia B.C. A substantial portion of the people in south and Southeast Asia and the southern part of China are depending on rice as staple food (Chang, 1976). Rice is planted in the most diverse environmental conditions of any major food crop, from sea level to around 3000 m altitude and from 30°S to 49°N. Temperature and day lengths are therefore quite diverse in the rice growing areas. Rice is also grown under water regimes ranging from dry land to deepwater fields where water may reach 5 m depth. The wide geographical distribution of rice and its early history of cultivation have resulted in the development of a great diversity of varietal types (Vergara, 1985).

Rice has been used as food by man for over 10,000 years and has fed a great number of people for a longer period than has any other crop. “Rice is life” for almost four billion people of the world contributing over 20 per cent of the total caloric intake of human population (Chaudhary and Tran, 2001). Rice is cultivated in 113 countries and on all continents except Antarctica and it is the staple food for 17 countries in Asia and the pacific, eight countries in Africa, seven countries, in Latin America and the Caribbean and one in the near east (IRC, 2003).

Globally rice is grown in around 155 million ha occupying one tenth of arable land, with an annual production of 579 million tonnes of rough rice (Iiyas Ahmed, 2003). The average productivity of 3.89 t ha^-1 of rice provides a per capita. Consumption of 100 to 240 kg per year across the globe. Over 90 per cent of the world’s rice is produced and consumed in Asia and more than half of it from India and China exploiting maximum arable land. More than two billion people obtain their 80 per cent calorie from rice and its derived products from 90 per cent of world’s rice area (FAO, 1999). Rice based on production systems and their associated post harvest operations employ nearly a billion people in rural areas in developing countries (IRC, 2003).

In recent years, we are just experiencing marginal surplus production in cereals leading to self-sufficiency through green revolution. However, the shortage of production in edible oils has drawn the attention for the increased cultivation of oil seeds, and increased productivity per unit area to provide sustainable food and nutrition security (Swaminathan, 1989).

The importance of oil seeds cannot be over emphasized in the Indian economy. Oilseed occupied nearly 19 million hectares, next only to food grains, in 1986-1987. Yet, the domestic production in the country has lagged far behind the increasing demand for edible oils, necessitating a massive import of edible oils which lead to the drain of the valuable foreign exchange. The total import bill on edible oil has increased from 1.41 per cent in 1970-71 to 3.05 per cent in 1986-87. Even then, the annual per capita availability of edible oils registered only a nominal increased from 3.5 kg to 5.9 kg during the same period, against the nutritional norm of 14 kg (Suresh Pal, 1989). Due to the concerted efforts made through the ‘Technology Mission on Oilseeds’, oil seeds production reached a peak of 178.9 lakh tonnes during 1988-’89 in India (GOI, 1990a). This is an impressive achievement in Indian Agriculture, to reduce the bill on the import of edible oils from 4.11 per cent (1987-’88) to 2.58 per cent (1988-’89) (Gill, 1990). Further efforts in increasing oilseeds production definitely will go a long way in drastically reducing the present import bill.

Among the oilseed crop, sesame (Sesamum indicum L.), “The Queen of Oil Seeds”, is one of the important ancient and traditional crops occupying third position in terms of acreage on the oilseeds map of the country. It is commonly known as Gingelly, Til, Benniseed and Simsim. It is an important source of edible oil for the nutritional refugees of most part of the world, especially for India. The oil is rich in oleic and linoleic acid. In addition, it serves as a good source of proteins, vitamins and minerals (Nagaraj, 1990). Its high keeping quality deserves special mention.

Introduction

India is the largest producer of pulses in the world, both in quantity and variety. But, presently, India is one of the largest importer of pulses. India imported pulse grains upto a tune of approximately 4000 crore rupees during 2006-07. It accounts for about 20 per cent of the total import bill during 2006-07. This is because of the green revolution (quantum jump in cereal production) accompanied with changes in the infrastructures and incentives including input supplies and price support systems in favour of major cereals. It altered the traditional cropping pattern against pulses with decades of emphasis on research as well as production in superior cereals coupled with a near total neglect of the rainfed areas, pulses were driven out of not only the irrigated areas, but also the rainfed farming and were relegated to the marginal lands. Further more, the weak infrastructural support for input supply, credit and marketing in the rainfed areas, the traditional home of pulses, also adversely affected the prospects for pulses. A vicious circle of low input use and low output thus got built in. Lack of processing and marketing facilities in pulses also contributed its share to the woes of pulse growers. The increasing shortage of pulses, resulted in the need for more and more import which, in turn has dampened the speed of rejuvenation of pulses sub-sector of agriculture sector.

The net per capita availability of pulses has fallen from 60.7 (1950-51) to 33.4 g (1991-92). On the contrary, the daily per capita availability of cereals has registered an increase from 334.2 (1950-51) to 443 g (1991-92). It leads to increase in the pulses/cereal ratio from 0.18 to 0.08 g i.e., by 55 per cent. This is despite the increases of 24.36 per cent in area; 61.71 per cent in production and 29.93 per cent in production. It is significant to note that almost all these increases had taken place during 1950-51 to 1960-61. The area, production and yield of pulses have either stagnated or declined since then. This stagnation of pulse production and productivity should be viewed seriously not only from the point of security and quality of food for our people, especially the poor and the rural population, but also from the soaring import bill, imbalance and distribution in the cropping pattern and resource allocation among various sub-sectors of agriculture.

Introduction

The nature and magnitude of genetic variability present in the genetic stock afford the plant breeder, information to formulate a purposeful breeding programme for crop improvement. The association and the influence of yield components with yield, their heritability and genetic advance would characterise the various steps in the breeding programme in achieving the aim of the breeder. Studies on these lines in various crops have hastened the realization of crop improvement in general.

India grows a variety of pulse crop which probably no other country in the world grows. These are multiple utility, energy high crops as they provide protein for human consumption, green nutritious fodder and enrich soil fertility through biological nitrogen fixation. Vigna radiata (L.) Wilczek, commonly known as greengram or mungbean, is the most widely distributed of the six cultivated Asiatic Vigna species.

The current breeding approaches to yield improvement in greengram are based on the recognition that this crop have lost a large part of their genetic variability in the process of adaptation to stress environment. This variability must now be regenerated.

The foremost need for this purpose is the collection of germplasm from different parts of the world and the organisation of a very intensive hybridization programme, using diverse genetic stocks as parental lines. Selection of parents for hybridization based merely on geographic diversity can no more be a suitable criterion. The importance of genetic diversity has long been appreciated by crop specialists. Such an analysis will eventually help to choose desirable parents for hybridization and evolve superior genotypes.

In recent years, we are just experiencing a surplus production in cereals and oil seeds leading to self-sufficiency through green revolution and yellow revolution. However, shortage in the production of vegetables has drawn the attention for increasing the cultivation of vegetables to provide food and nutrition security.

Vegetables are being cultivated over an area of 49 million hectares with the production potential of 487 million tonnes in the world. This accounts for 2.85 per cent of total cropped area in the world. India is the second largest producer of vegetables next to China, sharing nearly 12 per cent of the total world output (Joshi and Shukla, 1997). Vegetables occupy nearly 8.02 million hectares with the production potential of 133.10 million tonnes in the year 2009 in India (Anonymous, 2009).

Bhendi (Abelmoschus esculentus (L.) Moench) is an important member of family malvaceae and commonly known as okra or ladyfinger in India. It is one of the most ancient and traditional vegetable crops grown in tropical and subtropical regions of the world (Martin and Ruberte, 1978). Bhendi is originated from tropical Africa with 2n = 8x = 72 or 130 or 144 chromosomes and is an allopolyploidy in nature (Joshi and Hardas, 1956; Suresh Babu, 1987). Martin (1982) reported that it behaves as a diploid. Under the genus Abelmoschus, there are 30 species in the old world and four in the new world (Joshi et al., 1974). Out of them, Abelmoschus esculentus, is the only species known to be cultivated. Bhendi is being raised in India in an area of 0.44 million hectares with an average production of 4.52 mt with the productivity of 10.27 t/ha (Anonymous, 2009).

The Coconut palm is a monotypic species of the family Arecaceae, under the tribe Cocoideae. It is considered as an important commercial crop in more than 18 countries in the world. The palm provides food, drink, shelter and also supplies raw materials for a large number of industries. Every part of the palm is utilized for some economic purpose or another. Hence, it is referred to as ‘Tree of Wealth” or the “Tree of Life” (Satyabalan, 1993). It is native of South East Asia. Genetic diversity has become one of the keywords of scientists who are concerned about the sustainable management of different tree crops. Genetic diversity plays an important role in tree breeding, because hybrids between populations of diverse origin, generally display a greater heterosis than between closely related parents (Zobel and Talbert, 1986). The present study was formulated to identify divergent parents for future breeding programme.

Two hundred and fifty genotypes of coconut cultivar Chawghat green dwarf, distributed in the two districts of Kerala viz., Kottayam and Pathanamthitta were evaluated for nut yield per plant during June-July, 2000. Seventy five genotypes, which had single tree nut yield of more than population mean ± 2 SE were selected as per the method outlined by Ledig (1974). These 75 genotypes were observed for 10 nut and endosperm characters in two seasons (years), during June-July 2000 and 2001.

Each tree was considered as a single genotype. Thirty nuts from a single tree were collected and divided into three replications (Chauhan and Kanwar, 2001; Thirugnanakumar, 2006a, b). Observations were recorded on 10 nut and endosperm characters viz.,1) oil content (%), cold percolation method; (Kartha and Sethi, 1957), 2) weight of unhusked nut (g), 3) weight of husked nut (g), 4) diameter (polar) of the husked nut (cm), 5) diameter (equatorial) of the husked nut (cm), 6) thickness of husk (cm), 7) husk: nut ratio, 8) thickness of meat (mm), 9) weight of kernel (g) and 10) weight of copra (g). The mean values so obtained were subjected to statistical analyses, in Randomized Block Design, as suggested by Chauhan and Kanwar (2001) and Thirugnanakumar et al.(2006a, b). The D² estimates were made following Mahalanobis (1936), as described by Rao (1952). Clusters were prepared following Tocher (Rao, 1952).

Pomegranate is one of the popular fruit crops of tropical and sub tropical in India and enjoys high reputation for its dietetic and medicinal properties. The fruit is native of Iran and is extensively cultivated in Mediterranean countries like Spain, Morocco, Egypt, Iran, Afghanistan. It is also grown to a lesser extent in Myanmar, China, Japan, India and U.S.A.

The area under pomegranate cultivation has increased several folds in the recent past after the introduction of soft seeded varieties. Out of 30,000 hectares under this crop in India, Maharashtra state alone grows over eighty per cent of area with an average production of 8000 kg ha^-1 (Mote et al.,1992). The export of pomegranate fruits was 1790.3 tonnes in 1991-92 valued at rupees 215.3 lakhs which was more than two fold over the previous year’s export earnings (Chadha, 1994). The utility of the crop is gaining importance and at present new orchards of pomegranate are being planted on large acreage. Because of its versatile adaptability, hard nature, low maintenance cost, steady and high yields, fine table and therapeutic values, better keeping quality and very good export potential, there is greater scope for extending its area and increasing the production especially in the hot and semi arid regions of India.

In pomegranate, market preference is for the attractiveness of the fruit which are exhibited through better size, colour with bold and deep coloured arils besides possessing high juice-content. However consumers prefers the softness of the arils with low acidity. While, there are number of cultivated types available with these desirable characters, there are hardly cultivar having a combination of all or atleast a majority of them. Pomegranate improvement work, therefore has to be oriented towards the production of soft seeded type with other desirable characters (Phadnis, 1974).

The mango is one of the choicest fruit crops of tropical and sub-tropical regions of the world. Its popularity and importance can easily be realized by the fact that it is referred as ‘King of fruits’ in the tropical world. India ranks first, both in area (2.51 million hectares) and production (15.02 million tonnes) of mango and it contributes to 42.1 per cent of world’s mango production. Presently, India is home to more than 1000 mango cultivars differing in taste, aroma, size, fibre content and pulp characteristics.

Though more than 1000 mango cultivars are reported, only 25-30 are of commercial importance. Most of the important cultivars are not amendable to hi-tech cultivation practices and do not meet the requirements of modern horticultural production systems like precocity in bearing, dwarfing, regularity in bearing with high yield, resistant to diseases, pests, physiological disorders and good keeping quality. Hence, breeding attempts to develop an ideal mango variety would be dwarf, regular bearer with medium size fruits (250-300g). Additionally, it should be highly tolerant to various fungal and bacterial diseases. A variety suitable for pickling is also gaining the attention of the breeders. An ideal pickling type should have high acidity, high fibre, good texture and characteristic raw mango flavour.

The first and foremost step in developing an ideotype is to explore the vast diversity and systematic characterization for utilization in the breeding programme.

Considering the importance of conserving the available gene pool, systematic exploration works are being carried out by National Institute like Indian Institutes of Horticultural Research (IIHR, Bangalore), National Bureau of Plant Genetic Resources (NBPGR, New Delhi) and others to collect and conserve the germplasm in Field Gene Banks. Recently, in addition to the traditional germplasm conservation methods, cryopreservation is also gaining importance especially in the conservation of nuclear gene (pollen parent) diversity for future breeding.

Utilizing the conserved germplasm in the breeding programme requires precise information on the genetic relationships within such germplasm. Information on the genetic distance among the germplasm accessions will also help to avoid the duplicates, widen the genetic base of the core collections and ultimately help in preserving the valuable diversity.

Jack bearing the largest edible fruit in the world, is a tropical evergreen tree belonging to the family Moraceae. Previously, it was known as Artocarpus integrifolia.It is an indigenous fruit crop, probably originated in Western Ghats of India (Santapau, 1966) and is widely cultivated in South Asia, East Indies and other warm areas of both the hemispheres. Jack tree is commonly grown in Burma, Malaysia and Brazil. It is hardly recognized as a commercial fruit crop in India even though it is widely distributed in Southern states viz,. Kerala, Tamil Nadu, Karnataka and Andra Pradesh. It is also cultivated in other states like Assam, Bihar, Orissa, Maharashtra and West Bengal. It is an invariable component of Kerala’s homesteads and also grown as a shade crop in coffee, arecanut and cardamom plantations. It is also grown as a standard crop in pepper plantations. The crop has got a rare distinction of being used as the staple food of Kerala tribals and also in some African countries like Uganda.

Gamboge tree Garcinia gummi-gutta (L.), is a member of the Clusiaceae family. It is a botanical cousin of Garcinia indica Choisy. It is a cross pollinated crop. It is called as Kodumpuli in Kerala. It is native of Tropical Asia. It thrives best in the ever green forests of Konkan, stretching from southward to the Kerala coast and Western Ghats upto 1800 m min the Nilgiris (CSIR, 1956). In Kerala, majority of the populations occur naturally in the central districts of Kerala, of different altitudes ranging from sea level to 200 m.

It is one of the potential under-exploited fruit crops. Now, it is gaining momentum for its commercial, industrial and medicinal importance. The dried rind is sold in the market at the rate of Rs. 200 per kg (Muthulakshmi et al.,1999). It is used as a food preservative, spicy source with astringent taste. It is meant for its good flavour, taste and keeping quality. The fruits are too acidic and cannot to eaten raw. The dried rind has unique use in fish curries for imparting its delicate flavour (Sarah, 1998). Dried rind can also be used for polishing gold, silver and coagulating rubber latex. Hydroxy citric acid (HCA) is a very rare natural components being extracted from the rind and is marketed in the name of ‘citrin’ and ‘citrimax’. It has high export value and fetches considerable foreign exchange. In foreign countries, it is used as a herbal medicine against cardiac diseases and for weight management through blocking fat synthesis. The derivatives of acid are potent metabolic regulators of obesity. The unique acid, lowers the blood lipids such as cholesterol and triglycerides by triggering the fatty acid oxidation in the liver through thermogenesis.

Rice (Oryza sativa L.) is the most popular crop and source of food for more than one-third of the world’s population. About 90 % of the world’s rice is grown in Asia and more than 3 billion Asians rely on rice for 30–75 % of their total calories (Braun and Bos 2004). It has been cultivated in four different ecosystems viz., irrigated, rainfed low land, upland and flood-prone (Halwart and Gupta, 2004). Since rice planting has been started around 8,000 to 9,000 years ago, the level of diversity would be more than it expected. The genetic diversity plays a major role in survival and adaptability of a species, as changes happen in environment. Organism needs to make changes in the phenotype that enables it to adapt and survive in unfavorable conditions. The inadequate knowledge on diversity of a species reduces the chance of widening the genetic base of that species. The venture of green revolution in Indian agriculture has narrowed down the genetic base of any popular crops. Therefore, collection, conservation and utilization of germplasm are very much needed in the present scenario for improving the varieties against biotic and abiotic stress.

Morphological and biochemical trait based diversity studies being largely influenced by environment as phenotype and/or enzymes are altered by the environmental and developmental changes. Therefore, adapting DNA based molecular markers for genetic diversity studies would be more reliable to overcome the environmental influence. Being molecular markers as a versatile tool, it establishes its strong holds in several fields of life science. Molecular marker based technique does not require DNA sequencing but it is generally based on nucleic acid hybridization or polymerase chain reaction (PCR). The PCR based tests has several advantages over hybridization technique as it is cheaper, speedy and sensitivity. Therefore, PCR based markers have been used extensively in genetic diversity study for assessing genetic variation within the species. The recent advent of molecular and computational tools now enables the estimation of genetic diversity and allele frequency between the genotypes easy.

A successfully developed new cultivar should have stable performance and broad adaptation over a range of environments, seasons and locations, in addition to high yield potential. Evaluating performance stability and range of adaptations is becoming increasingly important in breeding programs. Since stability and adaptability are important selection criteria in breeding programs, in depth research on stability is needed for a better estimate of crop performance and adaptability (Lin and Binns, 1988).

Having realized the importance of genotype × environment, several biometrical models have been developed to analyse the stability of genotypes. Such models have been discussed, critically reviewed comprehensively by Knight (1970), Freeman (1973), Hill (1975), Brain (1986) and Gautam et al. (1986).

However, the various methods proposed for the statistical analysis of genotype × environment are based on one of following approaches (Jain, 1982). In the first the variance interactions are estimated by equating the observed mean squares in the analysis of variance to their expectations on the random model. The second approach called phenotypic approach by Hill (1975) used the technique of partitioning the genotype _× environment component of variability into its linear and non-linear portions of assessing the stability of genotypes over a range of environments. This approach which is very widely adopted in plant breeding, came to be known as “Joint regression analysis”.

Many workers contributed for the development of this approach, notably Finlay and Wilkinson (1963), Eberhart and Russell (1966), Freeman and Perkins (1971) and Shukla (1972). The third approach called genotypic approach which also suggested by Hill (1975) is based on fitting of general models in which it specify, the contribution of genetic, environmental and genotype × environment to the generation means and variance. The contributions for he development of this approach were from Bucio (1966), Bucio and Hill (1966), Bucio et al. (1969), Perkins and Jinks (1968), Breese (1969), Hill and Perkins (1969) and Perkins (1970). Linear regression and joint regression models were more commonly used due to their simplicity and reliability in biological experiments. In general, these approaches fall conveniently into two parts.

Stability and adaptability studies have been carried out for upland or hill rice varieties also. Amirthadevarathinam (1987) observed significant genotype × environment and reported that both linear and non-linear components were equally important for assessing stability of yield and four yield components in four environments. Both TKM 6 and Poongar were high yielding with adaptability and stability in addition to being especially suitable for unfavourable environments. Kuruvaikalangium was the best performer for all characters except grains per panicle for which PM 1023 was the best.

Dineshkumar (1987) evaluated sixteen early maturing genotypes for their stability in four major agroclimatic zones of the Karnataka state. No genotype was found stable as they observed more of unpredictable variance (pooled deviation) than predictable (genotype × environment linear).

Ganesh and Soundarapandian (1987) observed that stability of number of ear bearing tillers was a major contributor for yield stability Shivaprakash (1987) reported similar results.

Studies by Sinha and Biswas (1987) on yield and yield components of twenty photo insensitive rice cultivars revealed IR-36 and IET-4094 as high yielder with unit ‘bi’ and least ‘S² d_i’ and hence they were recommended to be suitable for general cultivation for all the environments under study. Similarly IET-2881, which had high mean yield with high ‘bi’ was found suitable for high yielding environments.

Genotypes × Season interaction is of major importance to the plant breeder in developing stable high yielding varieties of crop plants. When new varieties are tested over a series of seasons, the relative ranking of the varieties for any given attribute is rarely the same at each season. This increases the difficulty of identifying superior stable genotypes. Comstock and Moll (1963) have shown statistically the effect of large genotype × environment interaction is reducing the progress from selection.

In order to minimize the genotype × season interaction, stratification of the seasons can be practiced. The implification in stratification is that suitable selections could be made for the infavourable and favourable seasons encountered within the sampling units proposed. Stratification of environments has been practicised for a long time to identify suitable selection that could be made for the narrower range of environments encountered within the sampling units proposed. However, even with this refinement of technique, the interactions of genotypes with locations in a sub-region and within environments encountered at the same location in different years, frequently remain too large (Allard and Bradshaw, 1964). Little is known about the environmental factors contributing to such interactions. Sprague (1966) suggested that even if such information are available, the possibility of materially reducing genotype × environment interaction in field experiments would remain questionable.

On line with Allard and Bradshaw’s (1964) statement, the interactions of genotypes with locations in a sub-region with different seasons at the same location in different years, may remain too large. As far as sesame is concerned, practically nothing is known about the factors contributing to such genotype × season interactions. Hence, the progress in breeding a stable variety of sesame has been slow. Since sesame in India is grown essentially as rainfed crop, fluctuations in yield levels closely follow changes in the environment and seasons. Breeding for multiseasonal variety for may small regions within a state is being considered necessary. There is widespread awareness of achieving stability of production as well as improvement in yield of sesame under low and high-in-put conditions as well as for different seasons.

In developing countries, the most important challenges is to increase food productivity for the continuously growing population from limited land area. To great extent, this challenges has been met with good amount of success in cereals but not in case of pulses. Pulses from an indispensable component of Indian agricultural too. Further, it is an excellent source of protein to the growing population who are mostly vegetarians. The high level of lysine in the protein makes them ideal supplement to cereals. Moreover, they are endowed with nitrogen fixation, and thus improve the soil fertility.

India is one of the major pulse growing countries in the world with a total area of 23.31 million hectares, with a total production of 14.50 million tones (Source: FAO, 2011). The area, under pulses has decreased particularly during the last decades as a consequence of intensive diffusion of techniques in green revolution on the high yielding varieties of cereals. This is mainly due to the low yield potential of legumes even under high input conditions.

Among the various pulses, blackgram/urd bean known scientifically as Vigna mungo (L.) Hepper, former known as Phaseolus mungo (L.) belonging to the tribe Paseolea of family Papilionaceae is of immense importance. It is the most widely grown and highly esteemed grain legume. In India it occupies 2.9 million hectares with an annual production of 1.24 million tones (Source: FAO, 2011).

In Asia this crop is widely cultivated in India, Pakistan, and Bangladesh both in kharif and rabi seasons. In India, it is mainly grown in the states of Madhya Pradesh, Maharashtra, Uttar Pradesh, Rajasthan, Karnataka and Bihar. Tamilnadu is placed eleventh and tenth in area and production respectively (FAO, 2011).

Ramya (2012) studied stability of 12 hybrids in three environments. The researcher selected the 12 hybrids based on the standard heterosis. The hybrids are: P₂ × P₅, P₁ × P₅, P₃ × P₅, P₂ × P₇, P₂ × P₃ and P₁ × P₂. Among the twelve hybrids, the cross combinations viz., P₂ × P₅, P₂ × P₇ and P₂ × P₃ showed non-significant reciprocal effects for most of the traits including fruit yield per plant. The direct hybrid P₁ × P₂ showed less than 40 per cent standard heterosis for fruit yield per plant. It also exhibited low standard heterosis for number of fruits per plant. Eight hybrids viz., P₂ × P₅, P₅ × P₁, P₃ × P₅, P₂ × P₇, P₁ × P₅, P₂ × P₃, P₂ × P₁, P₅ × P₃, based on standard heterosis (>40 per cent) and their parents viz., P₁, P₂, P₃, P₅, P₇ were selected and grown in three different locations for finding their stable performance. Several authors have suggested different types of models to identify the stable genotypes. The model most commonly preferred by breeders is Eberhart and Russell (1966) model which was used in the present investigation. Various stability parameters were worked out on the available data and the results were discussed below.

Among the ten traits studied, days to first flowering, fruit weight and fruit girth showed non-significant genotype × environment interaction. Hence, the remaining seven traits were taken for further analysis. ANOVA across environment revealed highly significant mean sum of square for genotypes, indicating the presence of wide genotypic variability among the genotypes involved in the study for all the characters studied. High significant differences were observed for environments for the traits viz., number of branches per plant, fruit length and fruit yield per plant, indicating the divergence among the growing environments and differential response of genotypes to the various environments. The main factors contributing to the divergence of the environments might be temperature differences during crop season, intensity and duration of sun shine hours. Therefore, the genotypes must be tested over an extensive range of environments for proper assessment of stability of genotypes (Salesh Kumar Jindal et al.,2008).

WORLD HISTORY

Work on ornamental crops was first initiated in Krelage Nursery founded by Ernst Heinrich Krelage for bulbs, lilium and dahlias in 1811. During 1895, Taiwan Agricultural Research Institute was established for ornamental crops. The first yellow corn Golden Bnatam was listed in Burpee’s Catalogue in 1902. In 1909 Primadonna F₁ hybrid variety of begonia was released by the Benary Seed Company in Germany and in the same year Atlee established seed farms at Floradale in California, Erfurt in Germany Anglia in UK and Kashmir valley in India for annual garden flowers. Luther Burbank did excellent breeding works on ornamental trees, flowers and fruits in 1926.

David developed the first successful hybrid in Nasturtium (1934) and Red and Gold hybrids of marigold (1937). In 1940, Burpee was successful in chromosome doubling and transformation of wild flowers and developed “Bright Scarlet” and “Super Tetra Series” in antirrhinum and “Jumbo Scarlet” in zinnia. He produced new strains of marigold, zinnia, nasturtium and snapdragon. William Houston in 1940 initiated the Ageratum breeding. Morden Research station was set up in Western Canada in 1945 for ornamental crop breeding. In 1968, Dr. Gustav A.L., Mehlquist was recognized as an international authority on breeding of ornamental plants. George J. Ball breeder of peas, asters and calendulas was a pioneer for the supply of dwarf impatiens and orange impatiens ‘Super Elfin’ in 1968. Israeli breeders during 1990 gave more attention towards the development of carnation, lily and anemone varieties. Longwood Gardens in 2008 got success in breeding of stock. The first record of chrysanthemum hybridization, germination and selection of superior seedlings occurred in 1827 by M. Bernet.

INTRODUCTION

Various procedures which are used for genetic improvement of crop plants are known as breeding methods. The breeding approaches that are more commonly used for genetic improvement of crop plants are called conventional breeding methods. Following conventional breeding methods were followed in improvement of crops.

(A)Plant introduction

(B)Pureline selection

(C)Mass selection

(D)Progeny selection

(E)Synthetic and composite breeding

(F)Pedigree method

(G)Bulk method

(H)Backcross method

(I)Heterosis breeding

(J)Clonal selection

MUTATION BREEDING

Mutation refers to sudden heritable change in phenotype of an organism or permanent change in the number, kind and sequence of nucleotides in genetic material, while individuals showing these changes are known as mutants. Mutation was first discovered by Wright in 1791 in male lamb which had short legs. Hugo de vries coined the term mutation. In crop improvement the breeders are always look for wide range of variability and stabilization of desirable traits. Mutation breeding is very useful in inducing new variability, which is an essential requirement of any plant breeding programme. The modern day cultivars are the resultants of various breeding techniques like selection, hybridization, tissue culture and mutagenesis including some biotechnological tools. Novelty in commercial traits like colour, size, shape, length, post harvest life of flowers etc. are always valued and preferred by consumers. Mutation breeding by exposing planting material with irradiation has play vital role in inducing novelty in a number of flower crops.

TYPES OF MUTATION

Based on occurrence

(1)Spontaneous mutation: Occur spontaneously in nature and not present in sufficiently high frequency and spectrum.

(2)Induced mutation: Artificially produced by the treatment of various mutagenic agents and present in sufficiently high frequency and spectrum

MOLECULAR BREEDING

Molecular breeding is the application of molecular biology tools, often in plant breeding.

Genetic markers

Genetic marker is defined as a gene whose phenotypic expression is usually easily discerned, used to identify an individual or a cell that carries it, or as a probe to mark a nucleus, chromosomes or locus (King and Stansfield, 1990). Three broad classes of genetic markers are morphological markers, biochemical markers and DNA or molecular markers.

(1) Morphological markers

Morphological markers are based on the visually assessable traits viz., morphological and agronomic traits. However, they are limited in number.

Features of morphological markers

i.They are easy to identify, there is no need of any complex analysis. Trait of interest can be identified visually.

ii.Morphological markers are inherited qualitatively or quantitatively.

iii.Frequency of availability of morphological markers is less in number i.e., morphological markers may not be available for all the traits of interest.

iv.They are influenced by environment.

v.Since they are influenced by environment, they are unstable in inheritance.

vi.They are stage specific i.e., a particular marker will be useful to identify in a particular stage of plant and not any stage of the plant.

vii.They are influenced by genotype and developmental stages of the plant.

Besides drawbacks, the morphological markers are useful to the plant breeders for the selection purpose in certain situation.

INTRODUCTION

Hybrid crops are derived from an established and well-proven breeding method used in ornamental sectors. The development of hybrid crops has been one of the major factors behind a dramatic increase in global crop yields. Hybrid is produced by crossing between two genetically dissimilar parents. Pollen from male parent called pollen parent will pollinate, fertilize and set seeds in female called seed parent to produce F₁ hybrid seeds. For production of a hybrid, crossing between two parents is important, the crossing process will results in heterosis or hybrid vigour. Heterosis is defined as the increase in size or vigour of a hybrid over its parent. This boost in performance, combining the best yield, quality and agronomic characters from each parent, is the result of hybrid breeding.

F₁ hybrid seed offers to the growers a significant benefits in terms of yield improvement, agronomic performance and consistency of end-use quality. But attempting to farm-save hybrid varieties will result in segregating populations producing highly variable offspring, which can lead to reduced yield, disease resistance and quality. As this factsheet explains, it doesn’t make economic or agronomic sense to save seed of an F₁ hybrid. In self pollinated crops it is difficult to cross but in cross pollinated crops it is easier. In nature to create genetic variability and for its wider adaptation in different environmental conditions, flowering plants has adopted many mechanisms for cross pollination. Cross pollination results in genetic heterogeneity and show wider adaptations. F₁ hybrids are in immense usage throughout the world with the rapid increasing interest in flowers, however the total number of the hybrids developed in flowers is still less. In India hybrid seed production is taken up in Bengaluru, Pune, Delhi, Punjab, Haryana, Jammu and Kashmir and Himachal Pradesh for export.

F₁ hybrids in ornamental crops were known even before Shull 1911 when he propounded the classical theory of hybrid vigour in plant breeding for the first time. In 1909 F₁ hybrid variety Prima Donna in begonia was released by Benary Seed Company in Germany. The first commercial F₁ hybrid in petunia was produced by Japan during World War II, in 1942. From 1950 onwards, F₁ hybrids were available in ornamental flowers from The Netherlands, Denmark, Germany, USA and UK besides Japan and produced in flower crops like ageratum, anemone, gerbera, primula, petunia, cyclamen, marigold, pansies, begonia, geranium, portulaca, dianthus, balsam, stock, wall flower, ornamental sunflower, gazania, hollyhock, calceolaria and zinnia. Flower breeders became familiar with the F₁ hybrid production of those crops also which were formerly propagated by vegetative parts such as pelargonium and gerbera. A few important hybrids were first released in petunia in 1940-50, geranium single in 1960, antirrhinum, marigold, pansy and zinnia in 1965, ageratum in 1966, geranium double in 1970, dianthus, impatiens, portulaca in 1976-77, gerbera in 1980 and carnation in 1981.

Intellectual Property Rights (IPR) are legal rights, which result from intellectual activity in industrial, scientific, literary and artistic fields. These rights safeguard creators and other producers of intellectual goods and services by granting them certain time-limited rights to control their use. Protected IP rights like other property can be a matter of trade, which can be owned, sold or bought. These are intangible and non exhausted consumption. The term “intellectual property” denotes the specific legal rights which authors, inventors and other IP holders may hold and exercise and not the intellectual work itself (Chadha, 2013). Intellectual property rights are essentially territorial in nature so, where registration is necessary, for patents, registered designs and trademarks, these will not exist in other countries unless registration has been sought and obtained there.

IP protection is crucial for a sustainable contribution of plant breeding and seed supply. Breeding new varieties of plants, which are developed after contributing number of years to the selective inheritance of traits which provide improved yields, higher quality and better resistance to such plant varieties requires a substantial investment in terms of skill, labour, material and economic resources. However, a new variety once released could in many cases be readily reproduced by others so as to deprive its breeder of the opportunity to benefit adequately from the investment made. Thus, an effective system of plant variety protection (PVP) is a key enabler for investment in breeding and the development of new varieties of plants or improving existing plant varieties, encourage importation of foreign varieties, promote exportation of plant varieties provide access to information of the created products and the methodology of creation for the enhancement of social welfare and generally benefit the market place. An international system of IPR protection for plant varieties expands these benefits by facilitating access to new varieties created in other states (Gautam et al., 2012).

Intellectual property is usually divided into two branches: (i) industrial property and(ii) copyright and the rights which neighbour upon copyright. The principal categories of industrial property are: patents, trademarks, geographical indications, industrial designs and trade secrets. Industrial property according to the 1883 Paris Convention for the Protection of Industrial Property is to be understood in the broadest sense and to apply not only to industry and commerce proper but also to agricultural and extractive industries and to all manufactured or natural products including wines, grain, tobacco, leaf, fruit, cattle, minerals, mineral waters, beer, flowers and flour.

Alstroemeria belongs to the family Alstromeriaceae. Alstroemeria flowers third in terms of popularity and foreign exchange earnings in Kenya after roses and statice. Alstroemeria is named after a Swedish botanist “Baron Klas von Alstroemer”. The popularity of this flower is still growing in the global perspective. It is one of the quickest growing flowers with varying colours like purple, lavender, salmon, red, pink, white, orange, yellow and bicolour. It is grown for cut flowers but is also popular as a potted plant. It is grown in the higher ranges of the Western Ghats, Himachal Pradesh, Jammu & Kashmir and Karnataka in India.

ORIGIN AND DISTRIBUTION

The alstroemeria, sometimes called the Peruvian Lily, is native to Tropical America particularly Chile. There are some 30 species of alstroemeria that occurs in grasslands and Pampas of South America, Argentina, Bolivia, Brazil, Chile, Paraguay, Peru and Venezuela. In America, it flourishes in different climates from high in the Andes mountains to the deserts of Pacific coastline. Even deep into the tropics of Brazil, the plants flourish abundantly. It was introduced to Europe in 1753 when seeds were sent to Europe by Claus Alstroemeria of Sweden during his travels in South America. It was widely cultivated in England during the early 1800’s and it was John Hedgewood, the founder of the Horticultural Society who first introduced the white variety in 1832. Since then, the Alstroemeria has been hybridized extensively. It is named after a Swedish botanist, Baron Klas von Alstroemer, who brought the first seeds of A. oelegrina from South America to Europe. Columbia is the number one in the world as far as growing area of alstroemeria is concerned. The second and third positions are taken by the Netherlands and Japan respectively. Other producing countries are United Kingdom and Italy. Alstroemeria is a new introduction into the world floriculture scene.

Most commercial cultivars of alstroemeria are patented and protected through plant breeder’s rights. Because of the fact that quite a large number of new varieties and hybrids of alstroemeria are planted in various countries in each year, royalty is paid based upon their square footage under production or number of plants leased. The new Inca Collection bred by Konst Alstroemeria B.V. is a breakthrough in the presently dwarf alstroemeria assortment. The new extended range of alstroemeria cultivar offers the opportunity to grow these top quality perennials in the garden, pots and for cut flower. These dwarf type plants reaching a height from 20-50 cm, combine with the quality and colours of the long lasting flowers. New varieties have gained popularity in California (USA), New South Wales (Australia) and Spanish south east coastline, Sicily (Italy). However, for a very long time already alstroemeria has been cherished worldwide for its exotic flowers.

In India cultivation of alstroemeria has been started around Bengaluru, Pune and Hyderabad. It has been introduced in Palampur, Solan, Srinagar and hills of Uttrakhand and Ooty, to popularize this crop among growers for domestic and export markets (Singh, 2006).

Anthurium (Anthurium andraeanum Linden) belongs to the complex family Araceae, is a slow growing perennial that requires shady, humid conditions as found in tropical forests. The name anthurium is derived from Greek word “anthos” meaning flower and “oura” tail referring to the spadix. Thus, anthurium is also known as “tail flower” (Tajuddin and Prakash 1996). Anthuriums are gaining popularity due to higher returns per unit area and their beautiful and attractive long lasting flowers. Anthurium ranks ninth in the global flower trade and commands a respectable price both for its cut flower and whole plant. Commercial production has focused on two major species viz. A. andraeanum and A. scherzerianum. A. andraeanum is grown mostly for cut flower production, the main production areas being Hawaii, The Netherlands, and some other tropical and subtropical countries. A. scherzerianum is sold as a flowering potted plant, with main production areas located in Europe. In India, the anthurium cut flower industry is still in its infancy. At present anthuriums are mostly grown in some small gardens and nurseries. The important states cultivating anthuriums are Assam, Kerala, Tamilnadu (Salem), Karnataka (Coorg) and Mizoram where the favourable climate exists (Agasimani et al., 2011).

ORIGIN AND DISTRIBUTION

Anthurium andreanum Linden Ex Andre is named after a French Horticulturist Edouard Francois Andre (1840-1911) who discovered it in 1876 and described it for the first time. The genus includes around 1000 species (Croat, 1980). Most of them are tropical herbs originating from warm areas of Central and South America (Gantait et al., 2008). The distribution of this genus extends from northern Mexico and the Greater Antilles to southern Brazil, northern Argentina, and Paraguay (Croat and Sheffer, 1983). Most anthurium species are native of tropical rain forests and are primarily epiphytic in nature. Thus, in their natural habitat, they receive ample, frequent water with good drainage. In Brazil, it is noted the occurrence of around 130 native species (Gonçalves, 2003).

In Malaysia, anthurium is mostly grown in Pahang (Cameron highlands), Selangor, Perak and Johor mainly for cut flower production. The Netherlands is the chief supplier of the anthurium in the European market. Hawaii covers 60% export share of Japan and the rest of the west coast of the USA. The Caribbean produces the anthurium for the east coast of United States and Canada. Mauritius is one of the important producer of anthurium and it exports to Japan and Italy. While some eastern countries like Taiwan, Philippines, China and Thailand mainly produce for their local market. In India, anthurium is commercially grown in Kerala, Karnataka, Tamil Nadu, West Bengal, Maharashtra and north east India. Kerala is identified as the most desirable place for growing anthurium (Singh, 2006).

Antirrhinum is a genus commonly known as snapdragon belongs to family Scrophulariaceae. Snapdragon is one of the flowering plant present with vast genetic diversity in India. The term Antirrhinum is derived from the Greek word “anti” means like and “rhin” means a nose, referring to the snout like shape of the flower. The cultivated Antirrhinum majus is grown in tropical, subtropical and temperate countries. The common name snapdragon, originates from the flowers reaction to having their throats squeezed, which causes the mouth of the flower to snap open like a dragon’s mouth. Flowers are borne on terminal long spikes of many colours except blue and with numerous shades. It is one of the excellent cut flowers which have long lasting qualities. These are also used as garden plants, bedding plants, in rockeries or herbaceous borders and as potted plants. Plants can be grown for cut flowers in an open field or under protection depending on the climate. The leaves and flowers are antiphlogistic, bitter, resolvent and stimulant (Chiej, 1984).

ORIGIN AND DISTRIBUTION

The garden snapdragon (Antirrhinum majus) has emerged as a model organism during early studies of inheritance and mutation (Darwin, 1868) because of its diploid inheritance, ease of cultivation and variation in morphology and flower colour. The genus Antirrhinum includes 15 New World species in the section Saerorhinum and 21 Old World species in the sections Antirrhinum and Orontium. A. majus (Snapdragon) is a species of Antirrhinum native to the Mediterranean region, from Morocco and Portugal north to southern France and East to Turkey and Syria. Most species are found around the Mediterranean Sea and in North America (Stubbe, 1966). The progenitor of the modern snapdragon is from the Mediterranean region and more specifically, it is native to southern France. It was believed that the snapdragon reached Britain with the Romans at an early date, where it has been naturalized on mountainous regions. Thereafter, it spread to different parts of the world from Britain.

The scientific name of the genus Antirrhinum was first defined by Carl von Linne in the year 1753. In the year 1914 Professor Erwin Baur the founder of the MaxPalnck-Institut für Züchtungsforschung in Cologne published a volume called ‘Einführung in die experimentelle Vererbungslehre’ (Introduction to Experimental Genetics) 2nd edition. This book contained several plates with reproductions of water colour paintings of snapdragons as examples. He crossed a white line with a red line resulting in a pink flower. This pink flower then was selfed and the offspring showed the typical distribution of 1 white, 2 pink and 1 red as a demonstration of Mendelian inheritance. Antirrhinum glandulous is native of California. In United States of America, winter flowering cultivars were introduced in 1926 by Frank Volz of Cheviot, Ohio. In 1959, snapdragon were included in the Agricultural Censuses of Horticulturally Special Crops and ranked seventh as a cut flower crop.

The genus Antirrhinum offers an inexhaustible resource for genetics-based studies in developmental biology, biochemistry and evolution (Stubbe, 1966). Wide diversity of Antirrhinum species, combined with classical and molecular genetics, the two traditional strengths of Antirrhinum provides an opportunity for developmental, evolutionary and ecological approaches (Schwarz-Sommer et al., 2003). Transposons responsible for flower variegation were identified in the 1980s. The Max-Planck-Institute in Cologne, Germany, allowing genes involved in flower and leaf development and in pigmentation to be isolated by transposon tagging. Population genetic studies that have been applied to Antirrhinum species show different population sizes, geographic distributions and breeding systems, from self-fertility to obligate out-crossing (Jimenez et al., 2002 and Mateu-Andres and de Paco, 2006). It was introduced to India with the advent of British. Among them, only A. majus has been domesticated as an ornamental.

Carnation (Dianthus caryophyllus L.) is a member of the family Caryophyllaceae. Dianthus word was first coined by Theophrastus from Greek word “dios” meaning divine and “anthos” meaning flower. It is a half hardy, perennial plant, propagated commercially by terminal cuttings. It is being produced as a cut flower in the world. Carnation cut flower trade contributed about 15% of the world flower market. Till now, new carnation varieties have been produced mainly through conventional breeding method. The breeding procedure typically consists of hybridization, self-pollination and selection (Holly and Baker, 1992). The breeding programme did not get enough momentum due to heterozygosity, limited gene pool and inadequate knowledge of genetic make up. However genetic engineering and molecular breeding have opened the way to achieve novel colour and good vase life of flowers.

ORIGIN AND DISTRIBUTION

It is native of Mediterranean region and its distribution is restricted to Greece, Italy, Sicily and Sardinia (Tutin et al., 1993). According to Pliny, the centre of origin of carnation is Spain. The generic name Dianthus comes from writing of the Theophrastus who lived about 300 BC; dios, divine and anthos, flower; the flower of the gods. The species name caryophyllus is coined from Greek word Caryon, nut and phyllon, leaf. Linnaeus chose the species name, caryophyllus, after the genus of clove, as the fragrance from carnation is reminiscent of clove. The common word carnation probably comes from a Greek word coronation because of its use as decorating the crowns of Greek athletes during ancient times. Carnation has been cultivated for over 2000 years and today commercial cultivation is the result of 200 years of improvement and breeding. During sixteenth century its improvement work was started in various countries. The gardens of Italy, France, Germany, Holland and England have contributed much to the development of cultivars. The natural climates for carnation occur near 30^o N or S latitudes of equator and on the western edges of the continents.