eChapters

Gangana(Grewia tenax) is a deciduous tropical shrub widely distributed in arid and semi-arid region. In western Rajasthan, the natural habitat of this shrub is buried pediments, hills and pediplains (Bhandari, 1971). It does best on deep sandy loam, and can grow in very shallow, skeletal, gravelly or clay soils. It has been reported that the species grow abundantly (density = 678 individuals per ha.) in hilly waste lands of Kailana, Jodhpur. Sharma (1997) reported that its efficient root system can penetrate into minute rock crevices. It is extremely drought hardy and can withstand high temperature in hot arid climate. It tolerates frost well but plant growth is slow in arid region. Mostly fruits for sale in the local markets are collected from wild stands. It is underutilized species (Gebauer et al., 2007), the major limitations to the development as a horticultural crop is the lack of detailed information, particularly the genotype, physiology and ecology (Gebauer et al., 2007). Due to its drought hardy and dense root system, it seems promising species in arid region. It has good fodder value for small ruminants. It is naturally grown in range lands, orans, and hilly track of Aravalli. It is untapped plant species and its potential should be exploited.

Abstract

A considerable difference of gap has been observed between the generated technology and the technology available with the farmers. In order to find the possible causes or low production, a comprehensive bench mark survey of four Panchayats of Kandaghat block namely Sirinagar, Mahi, Kawarag and Bisha involving 500 farm families was done using PRA technique to ascertain the extent and gap in the generated technology and the technology adopted by the farmers. All the important components of the technology were assessed and the gap in adoption as well as the approximate cost of the gaps was estimated. In tomato and capsicum, it was observed that the farmers prepared their fields well, transplanted at the right time, performed the required intercultural operations and harvested the fruits at proper time. They however, did not treat the seed and the seed bed, applied sub-optimal/excess doses of fertilizes and adopted excessive plant protection measures against pests and diseases. In case of Cauliflower, the farmers used the recommended variety, prepared their fields well, transplanted at optimum time, adopted all cultural operations from time to time but they did not pay attention for protecting the crop against pest and diseases.They also applied ample quantity of fertilizers but did not follow proper spacing. If the farmers adopt the recommended practices, they are likely to gain around Rs 62,688/ha in tomato, Rs.55,563/ha in capsicum and Rs.54,188/ha in cauliflower.

Purpose-Planting of foliage and flowering trees, shrubs, climbers, annuals, perennials and lawn in a piece of land by adopting certain principles is termed as garden design. The objective of a garden layout by adopting a design to provide recreation, enjoyment and education to the society. Natural flora, religion, topography of land and climatic had played a major role in the development of garden designs. Basically there are two garden designs. In one the plantation of shrubs, trees, climbers etc. and lawns is done by adopting a geometrical design and maintaining bilateral balance whereas, in the other one the plantation is done by taking in account the topography and terrin of land, containing open lawns and cluster of trees. The former is called formal are artificial garden while the later is called as informal or landscape garden.

Garden Walls : A garden lover will never like to block the view of his garden by putting a wall along its periphery. A garden as it is enjoyed from inside should also be visible from outside.

• Low brick or concrete or stone wall of say 60-90 cm height and to put over it some grills.
• Alternatively walls from 1.8-5.0 m may also be erected depending upon the size of garden.
• One may grow creepers such as Ficus repens over the wall.

Flower Beds: The most essential criterion of a flower beds is display the flowers in the best way possible. It may be born in mind that flowers look best when massed in a bed. The flower beds are of special importance under condition of the plains of India since they can be kept planted throughout the year unlike those in England or other parts of Europe where nothing can be grown in the open between November-March. Annuals and herbaceous, perennial flowers, flowering plants are grown in flower beds to provide massing effect of different colours borders is continuous beds of more length than width containing plant of one kind only.

Garden pea, Pisum sativum var. hortense under the family Fabaceae (Leguminosae) having chromosome No. 2n = 2x = 14 is an all-time favourite vegetable in the world. As a cool season crop, it is extensively grown in early spring season in temperate zone and winter season in the tropics and subtropics. The immature/green peas are used as fresh vegetable as well as frozen or canned. Green peas are quite nutritious and contain high amount of protein and a fair amount of vitamin C, zinc, fibre and antioxidants. Diet containing green pea may improve the functionality of the gut.
Origin, domestication and adaptation in India
Discovery of the carbonized pea seed remains indicated that the smooth-seeded field pea was cultivated in the Near East and Europe as early as 7000 B. C. The earliest archaeological finds of peas come from Neolithic Syria, Turkey and Jordan. In Egypt, evidence of peas dates from ca. 4800–4400 BC. The wild pea was restricted to the Mediterranean basin and the Near East. Central Asia (Kazakhstan, Uzbekistan, Tazikistan, Turkmenistan, Kyrgyzstan, Afghanistan), Abyssinia (Ethiopia) and the Mediterranean basin are the primary centres of origin of pea with the near-east (Syria, Lebanon, Israel, Jordon) as the secondary centre of origin. In another view, Pisum is
considered to have been originated in Ethiopia and from where it spread during prehistoric times to Mediterranean region, Central Europe, the Near East and subsequently to rest of the world. The wild progenitor of Pisum sativum is unknown.

A number of tools, implements and machineries are used in cultivation of horticultural crops to make every operation easy and efficient. There are a number of operations involved in cultivation of horticultural crops, like making of nursery, propagation of plant material, field ploughing, breaking of clods, levelling, making bunds, sowing and planting, plant protection, training, pruning, harvesting, lawn mowing etc. All these operations are physically taxing and cannot be carried out efficiently without proper tools, implements and machineries. Following are some important tools -

1. Bill hook: To cut and remove big sized unwanted branches of trees.

2. Buckets and plastic pots: used in the orchard for spraying, transport water, carry harvested produce etc.

3. Budding and grafting knife: The budding and grafting operations in propagation of many horticultural plants are carried out using budding and grafting knife.

4. Country plough: Used in field preparation for ploughing the soil, incorporation of organic manures into the soil at the time of last ploughing, summer ploughing in conserving of soil moisture.

5. Crow bar: Used to loosen the soil, digging and deepening the pits and channels.

6. Dibbler: Used to make holes and sow the seeds in the nursery as well as in the main field.

7. Digging fork: It is of a great use in harvesting the tuber crops without damaging the produce.

7.1 INTRODUCTION

Gardening is a practice of growing different kinds of horticultural crops in a particular land area as a part of horticulture either for consumption or sale, export, beautification etc. Basing on the crops grown, gardens are named accordingly, e.g., for raising vegetables, it is vegetable gardens; for fruit crops, it is orchard; for plantation crops, it is estate plantation; for ornamental plants, it is gardening and landscape etc. The history of gardening is not new. In ancient time kings, emperors, rulers, sages were establishing different types of gardens for different purposes.

Chromatography was first employed by Ramsay (1905) to separate mixtures of gases and vapours. The first scientist to recognize chromatography as an efficient method of separation was the Russian botanist Tswett (1906), who demonstrated that, when a plant extract was carried by petroleum ether through a column consisting of a glass tube packed with calcium carbonate powder, a number of dyes were separated, as shown in Figure 1. He named this analysis method “Chromatographie” after “chroma” and “graphos”, which are Greek words meaning “color” and “to draw,” respectively.

Quantitative traits are governed by many genes or polygenes genes with small individual effects. They are often described by their gene action rather than by the number of genes by which they are governed. There are four types of gene action: additive, dominance, epistasis, and overdominance. Because gene effects do not always fall into clear-cut categories, and it should be pointed out that gene action is conceptually the same for major genes as well as minor genes, the essential difference being that the action of a minor gene is small and significantly influenced by the environment. A general way of distinguishing between these types of gene action based on interaction among alleles is as follows:

ABSTRACT

The coastal ecosystem happens to be one of the most productive ecosystems. This ecosystem has been under different kinds of threats such as climate change and consequent rise in sea level, increase in population and depletion of natural resources. All this has given rise to an increase in the level of abiotic stresses such as salinity, alkalinity, and drought affecting the agricultural productivity in the coastal region. Salinization is posing an increasing problem in coastal and agricultural areas reducing plant productivity and yield. Salinity is one of the major abiotic stresses decreasing the plant productivity.

Salinity is a significant factor limiting agricultural productivity and affecting about 9x 10⁸ hectares worldwide. Poor quality of water for irrigation and current unsustainable irrigation practices has significantly resulted in salinization and other forms of soil damage. About one third of all irrigated land is affected by salt due to secondary salinization. It is estimated that 50% of all arable land will be salinized by the year 2050. The problem of secondary salinization is also becoming more serious as it represents loss of highly productive lands. Added to this is the problem of coastal salinity where intrusion of seawater into arable land due to erosion of coastal habitat has rendered it unsuitable for cultivation. Salt-affected soils (~11 million ha in South and Southeast Asia) are found along coastlines or in inland areas where evaporation is greater than precipitation.

4.1. Multiple Choice Questions

1. GoI has indicated ??? crop will be introduced without evaluating biosafety and socioeconomic desirability.
   1. GM
   2. Organic
   3. Rabi
   4. Kharif
2. ??? is AGRI UDAAN.
   1. Food and agribusiness initiative
   2. Food and agribusiness accelerator
   3. Food and agribusiness incubator
   4. Both b and c
   5. All the above
3. Union Minister for Agriculture and Farmer’s Welfare launched --------------------------------------?? quality mark logo at New Delhi.
   1. National Dairy Development Board
   2. National Dairy Development Authority
   3. National Dairy Development Authority
   4. National Dairy Development Programme
4. --------------------------------------?? state is leading in the production of litchi.
   1. Bihar

Definition of farmer (National Policy for Farmers, 2001): A person actively engaged in the economic and/or livelihood activity of growing crops and producing other primary agricultural commodities and will include all agriculture operational holders, cultivators, agriculture labourers, share croppers, tenants, poultry and livestock rearers, fishers, beekeepers, gardeners, pastoralists, non-corporate planters and planting labours, as well as persons engaged in various farming related occupations such as sericulture, vermiculture, and agroforestry. It also includes tribal families/ persons engaged in shifting cultivation and in the collection, use and sale of minor and non-timber forest produce.

2.1. What is Greenhouse Technology?

Greenhouse technology involves primarily the structural design that can take care of climate control mechanisms to create proper micro-crop-climate and secondarily it involves the technology needed for optimum growth and production of crop grown under this structure. Combination of these two aspects may be expressed as ‘greenhouse technology’.

So the ‘greenhouse technology’ may be defined as “The technology required to built a structure, covered fully, partly or porously for manipulating the inside climatic conditions, under which crops/plants can be grown with special measures”.

Physiological plant disorder is caused by non-pathological conditions such as poor light, weather damage, waterlogging or lack of nutrients affect the operation of the system caused. Physiological condition selected from diseases caused by plant pathogens such as viruses or fungi to distinguish. Although the physiological disorder symptoms may occur such as disease, they can often be prevented by changes in environmental conditions. However, once the nutritional deficiencies of plants showing symptoms, is likely to return that season yield will be reduced.

Nature has made such a beautiful system that a fruit does not spoil unless its outer covering is removed and till it is there on the plant. For example banana will not spoil for long time if we do not remove its peel. Similar is the case with apple, guava, mango and many other fruits and vegetables. But as soon as the outer covering is removed the damage begins and the commodity is spoilt very soon.

Preservation is extending shelf life of fresh or processed food by using various methods and prevention or reduction of spoilage. Better the preservation, lesser the spoilage, more the spoilage poorer and inefficient is the preservation.

Therefore, in order to prevent or reduce the spoilage, we have to first identify and understand the causes of spoilage. There are chiefly 3 agencies that cause spoilage in fruits and vegetables i.e. (i) microorganisms, (ii) enzymes & chemical changes and (iii) man, animals, rodents, insects, etc. For effective preservation we have to check the growth and activity of these spoilage causing agencies. So, in order to prevent spoilage and preserve a perishable commodity for long time the following principles and methods are to be followed.

3.1. Introduction

Food preservation can be defined as the science which deals with the process of prevention of decay or spoilage of food thus allowing it to be stored in a safe condition for future use. Scientifically, preservation may be defined as a science which deals with the process for prevention of decay. All foods gradually undergo deterioration or spoilage from the time they are harvested or manufactured. Some commodities spoil rapidly, while others can keep for longer but limited periods. Spoilage in the food products may be caused due to some physical, chemical and microbial changes during storage. The preservation of these products can be resulted by controlling following physical, chemical and microbial changes.

Generation system of seed multiplication is nothing but the production of a particular class of seed from specific class of seed up to certified seed stage. The choice of a proper seed multiplication model is the key to further success of a seed programme. This basically depends upon,

• The rate of genetic deterioration
• Seed multiplication ratio
• Total seed demand (Seed replacement rate)

ABSTRACT

Of the total production of the crop yield, only 63 per cent is available for human consumption. The remaining is lost in more or less equal proportions to weeds, pests and diseases. Prior to genetic engineering, the exchange of DNA material was possible only between individual organisms of the same species. In the field of agriculture for instance, farmers have continuously modified naturally occurring species through seed selection and controlled breeding. With the advent of the recombinant DNA technology, it has however been possible to identify specific genes associated with desirable traits in one organism and transfer those genes within and beyond the boundaries of species into other organisms.

1. Genes for herbicide resistance

Modern agriculture has developed a range of effective herbicides to tackle the effects of weeds on crop yield. Some of the most useful of these are broad-spectrum herbicides because they are active against a wide range of weeds. However, these can only be used at times when the crop is not itself vulnerable to herbicide action. The development of herbicide-resistant crops therefore offers the opportunity to spray crops at the most effective time to kill weed species without damaging the crop plants. By definition, herbicides are much more toxic to plants than to animals. Therefore, it is not surprising that they generally affect ‘plant-specific’ biological processes. The herbicidal activity of many herbicides has been found to result from the specific inhibition of a single enzyme/protein. The following are four distinct strategies for engineering herbicide resistance: i. Overexpression of the target protein, ii. Mutation of the target protein, iii. Detoxification of the herbicide, using a single gene from a foreign source and iv. Enhanced plant detoxification.

Random Mating

Random mating occurs when each female gamete has an equal chance of being fertilized by any male gamete of the same plant or with any other plant of the population and, furthermore, there is an equal chance for seed production. It is not possible to achieve true random mating in plant breeding because selection is involved. Consequently, it is more realistic to describe the system of mating as random mating with selection. Whereas true random mating does not change gene frequencies, existing variability in the population or genetic correlation between close relatives, random mating with selection changes gene frequencies and the mean of the population, with little or no effect on homozygosity, population variance, or genetic correlation between close relatives in a large population.

Horticulture deals with the art, science, business and technology of cultivation and management of horticultural plants. The word Horticulture is derived from two Latin words viz. ‘Hortus’ (means garden) and ‘Culture’ (means growing). Horticulture is an aesthetic science that deals with cultivation of fruit, vegetable, spice, plantation, medicinal, aromatic and flower crops. There is a vast therapeutic use of horticulture wherein gardening and aroma therapy are used to deal with new age maladies like depression and various addictions.

In ancient times, huge gardening spaces to grow large number of fruits, vegetables and flowers were available and these areas were demarcated with the help of high walls. This enclosed area was referred to as garden. This led to the term garden culture. The land area is decreasing due to industrialization and population growth, at the same time, there is a drastic increase in demand for horticultural produce. To meet the increased demand for horticultural produce and to cope up with the space constraints, multitier cropping systems, vertical gardening and other intensive cultivation practices are being resorted to. Hence, horticulture may also be described as the “Practice of growing and manipulating plants in a relatively intensive manner”.

Presently, fruits, vegetables, flowers and ornamentals are grown not only within the home premises, but also in large quantities on a commercial scale. In other words, many horticultural crops throughout the world are grown primarily as business enterprises. Thus, horticulture has two aspects in general i.e., the amateur and the professional. In addition, with the establishment of horticultural experiment stations as an integral part of colleges and universities, comparatively a large amount of scientific information on the behaviour and cultivation of horticultural plants and products is freely available. This information or literature, constitutes the science of horticulture, and the application of this scientific information constitutes the “Technology of Horticulture.” Thus, present day horticulture may be defined as the science and technology of production, processing and merchandising of fruits, vegetables, flowers and ornamentals where each crop has its own science and technology. Consequently, horticulture may appear differently to different people. To a teacher, professor, research scientist, extension official and landscape architect, it is an applied science and a profession, while to a commercial producer, wholesaler, a retailer of horticultural products, or to the manufacturers or seller of horticultural products, it is a business. It is also a fascinating hobby for connoisscur.

Abstract

Genetic analysis of yield and yield components in tomato (Lycopersicon esculentum Mill.) was worked out by using half diallel mating design. The good general combiners observed were Solan Vajr, FT-5 and UHF-265 for plant height; UHF-107 and UHF-260 for days to first picking; Solan Vajr for number of fruits per cluster; FT-5, EC-191536 and UHF-120 for average fruit weight; Solan Vajr, UHF-265 and FT-5 for harvest duration and FT-5 and Solan Vajr for marketable yield per plant. The best three specific combiners for marketable yield per plant were EC-191536 x Solan Vajr, BL-342-1 x FT-5 and UHF-107 x EC-191536. Hayman’s approach revealed non-allelic interaction in the expression of number of fruits per cluster, number of fruits per plant and marketable yield per plant. Preponderance of non-additive gene action was observed with dominance towards tallness, delayed first picking, more fruits per cluster, longer harvest duration and higher marketable yield, while involvement of complimentary epistasis was indicated in the inheritance of average fruit weight and number of fruits per plant.

ABSTRACT

Though the genetic control of sex determination is being explored in several animal systems, no much information is available on the genetic basis for sex specificities in dioecious or sexually polymorphic plant species. Date palm is a unique member of the family Palmaceae which exhibits dioecy. Here we report the sex-specific variation in the genomic DNA of male and female date palms as revealed from an extensive study conducted with palms representing different date palm growing regions of the Kingdom of Saudi Arabia. The genomic DNA content in females was less than 60 per cent compared to those of the male genotypes. Polymerase chain reactions carried out to amplify different segments of the alcohol dehydrogenase (AdhA) gene from the date palm genomic DNA yielded two DNA fragments each in the female genotypes where as the same primers amplified a single fragment in male plants. Genomic Southern analysis of Eco R1 restriction digests showed RFLP between the male and female genotypes with the male plants showing a single hybridization signal of approximately 14 kb size and the females showing six additional bands of varying molecular weights. The results of our investigations reveal the potential of molecular biology in differentiating the sex in date palm at DNA level. Further research is needed to develop DNA markers that will help to unequivocally identify the sex of dioecious plants at the seedling stage.

Plant breeding is the purposeful manipulation of characters in plants to create new genotype with a set of desired characters. Hence, it may basically be referred to as designed manipulation of the heritable variation for the character concerned. Living organisms possess the remarkable capacity to convert the non-living materials into living staff, which results in movement, growth, metabolism and reproduction, and thus continuity of living organisms from one generation to the next is accomplished. The continuity of life through transmission of characters is the subject of the study of heredity, while the resemblances and differences between individuals of the same or different generations is the concern of the study of variation. These two universal processes of continuity and of change, which are referred to as “Heredity” and “Variation” are primary consequences of all organisms. Organized study of these two biological processes is the science of Genetics.
Plant breeding, which may be termed as evolution of plant type directed by the will of mankind, is basically the process of selection of character(s) from heritable variation. Desirable heritable variations can also be induced through some genetic consequences like, hybridization, segregation, mutation, changing the number of chromosomes, etc. So frame of plant breeding lay on three basics:

11.1 Introduction

In chapter 10, we have discussed the different types of variation, namely, genetic, environmental and genotype × environment interaction variations. We have also learnt how to estimate the phenotypic variance and its components including genotypic (also called genetic), environmental and g × e interaction variances from trial data. Now in this chapter, we shall discuss on the genetic components of polygenic (quantitative) variation and its implications on breeding strategies.

11.2 Genetic Components of Polygenic Variation

In this chapter whenever we call genetic variation, we mean polygenic (quantitative) variation, and we know that variation is usually measured in term of variance. However, variation, variability and variance are almost used synonymously. The genetic variance has been classified into different components by various workers. Fisher (1918) divided genetic variance into three components: additive, dominance and epistatic (interaction) variances. Wright (1935) classified genetic variance into two components: additive variance and non-additive variance (dominance and epistatic variances). Mather (1949) classified genetic variance into two components: heritable fixable variance (additive variance and additive × additive epistatic variance) and heritable non-fixable variance (dominance variance, and additive × dominance and dominance × dominance epistatic variances). Later, Hayman and Mather further divided the epistatic variance into three categories: additive × additive, additive × dominance and dominance × dominance.

ABSTRACT

India is the largest producer of banana, contributing to 17.3 per cent of the global production. In Kerala, it is the leading fruit crop, being cultivated in an area of 99,412 ha with an annual production of 7,31,650 tonnes. Biodiversity in the cultivars of banana, which consist of triploids, is complex especially in Nendran. Nendran belonging to Musa AAB plantain subgroup is the leading banana cultivar of the Kerala. in Kerala, several landraces are available, cultivated in different parts, known in different local names. Twelve Nendran ecotypes of banana belonging to AAB genomic group were collected from Banana Research Station, Kannara, Banana Nursery Farm, Palode and Instructional Farm, College of Agriculture, Vellayani to ana lyse genetic divergence using RAPD marker and morphological traits. Out of the forty one decamer primers screened for RAPD analysis, 34 could produce amplification. Twenty five primers showed high level of polymorphism. Finally, six of the most promising primers viz., OPA-01, OPA-03, OPA-13, OPB-04, OPB-10 and OPB-12 were used for RAPD analysis. Statistical analysis for the morphological traits and RAPD marker were conducted using the software programme NTSYS pc version 2.02e. The matrix average taxonomical distances (similarity coefficient) among the ecotypes ranged from 0.59 to 1.00 in RAPD profiles and morphological profiles (dissimilarity coefficient) ranged from 2.82 to 11.21. In the dendrogram (RAPD profiles), Koonoor Ethan showed the maximum genetic divergence. Quintal banana and Zanzibar came under a single clusters at a distance of 0.79 and clustered together at a distance of 0.82. Both the ecotypes showed next higher genetic divergence among the Nendran ecotypes. In the case of morphological traits, the same trend could be observed. Koonoor Ethan showed the maximum genetic divergence at a distance of 11.21 and Quintal banana showed next higher genetic divergence at a distance of 9.11. Koonoor Ethan, Quintal banana and Zanzibar were distinct ecotypes among the Nendran ecotypes of Kerala

ABSTRACT

The investigation aimed at to examine the diversity among nineteen wild and cultivated germplasms of the genus Vigna namely, V. trichuriensis, V. hainiana, V. radiata, V. aconitifolia, V. minima, V. sinensis, V. radiata var. sublobata, V. radiata var.setulosa, V. umbellata, and allopolyploid of BR3x T9 at DNA level follwing Random Amplified Polymorphic DNA (RAPD) technique. Ten random decamer primers were used in amplification reactions, five of that were reproducible and clear. The five primers constituted 55 bands of, which 9 are polymorphic. The similarity index based on 0 and 1 matrix of banding was calculated and dendrogram following UPGMA was constructed. The germplasms formed altogether 4 clusters on the basis of 0.375 linkage distance. The first and second cluster consisted of single genotype of V. hainiana. and V. minima respectively. The third cluster comprised wild and cultivated types of V. sinensis. The 4th cluster on the otherhand, consisted of genotypes belonging to V. radiata, V. radiata var. sublobata, V. mungo, V. radiata var. setulosa, V. trichuriensis and allopolyploid of BR3 and T9. The wild forms of different species were found to exist in the same cluster as their cultivated form. The three mungbean genotypes namely B105 (V. radiata), B1 (V. radiata) and BR3 (V. radiata )are crossable within themselves and they belonged to the cluster -IV.The intercluster cross between different clusters would like to generate new genotypes with wide variability. Based on limited range of accessions tasted in the present investigation, the approach holds promise for the classification of Vigna germplasm, identification of Vigna and marker assisted breeding in Vigna.

Introduction

Genetic resources are the building blocks for new varieties. The Indian gene centre is floristically extremely rich. Most of the tropical and sub-tropical fruits believed to have originated from Hindustan and Indo Malaya-Region. Hindustani gene centre possess a rich diversity of 152 crop plants distributed in different agro-ecological regions of India (Arora, 1985). The Indian sub-continent is one of the centers of origin and diversity of vegetables crops. Around 80 species of major and minor vegetables occur in wild forms (Choudhury, 1967, Seshadri 1987). Among the 118 genera belonging to the Cucurbitaceae family Cucurbita, Cucumis, Citrullus and Lagenaria genera are of great importance. There is tremendous genetic diversity within the family, genera and even within species level. The adaptation range varies from tropical and subtropical regions to extreme arid desert and in temperate regions from Tarai belts to higher altitudes. Extreme germplasm collections are maintained at different centers of the world which represents valuable resources for breeding even in wild form, primitive cultivars, landraces/ folk varieties/ farmer’s selection in a much localized pockets. Now we have very good strains for highly nutritive value, multiple disease resistant and extended shelf lives from our local material through intensive breeding.

Indigenous plant germplasm are adapted component of plant biodiversity. Such adapted components are more valuable resources either as a cultivar or as a parental line in hybridization programme. It might be also a putative material for biotechnological treatment for tolerance to biotic, abiotic factors or nutritional and quality components. Indigenous germplasm can be basically of two types, one which has been domesticated and subjected to human intervention, the other one may be called wild plants or wild relatives and still in the process of evolution without the human intervention. Biochemically the cucurbits are characterized by bitter principles, called cucurbitacins. Great variety of cucurbits contains bitter principle in portion of the plant at some stage of development. Cucurbitacins are tetracyclic triterpenes having extensive oxidation level. Bitter principals found in roots differ from those in fruits. Seedlings specially radicals contains cucurbitacins which are considered primary. The pollen also carries bitter principles and hence when bitter pollen fertilized non-bitter ovule the resulting fruit will be bitter known as metaxenia effect. Cucurbits are consumed in various forms i.e. salad (cucumber, gherkins, longmelon), sweet (ash gourd, pointed gourd), pickles (gherkins), deserts (melons) and culinary purpose. Some of them (e.g. bitter gourd) are well known for their unique medicinal properties. In recent years, abortifacient proteins with ribosome-inhibiting properties have been isolated from several cucurbit species, which include momorcharin (from Momordica charantia), luffaculin (from Luffa operculata), trichosanthin (from Trichosanthes kirilowif) and beta-trichosanthin (from Trichosanthes cucumeroides). Among these, Trichosanthin is of particular interest because its ribosome-inhibiting properties have been found to be effective in inhibiting the replication of human immunodeficiency virus (HIV), indicating its potential as a therapeutic agent for AIDS. In cucurbits three conditions are found (i) fruit and vegetative parts bitter (ii) fruit not bitter but vegetative parts bitter (iii) bitterness absent in both vegetative parts and fruits. Hence some kind of co-evolutionary relationship between cucurbits found and they are very helpful during evaluation of germplasm.

Vegetables are of short duration, have higher productivity and give more return per unit area, besides giving nutritious food to human being and can be fitted in different farming systems. They also play a major role in balancing human diet, thereby helping in alleviating hunger, poverty and malnutrition. Because of the public awareness for the significance of vegetable consumption, the demand of vegetables in the global market has increased immensely. Thus, vegetable farming is becoming profitable venture globally, opening avenues of self employment and revenue generation (Anon., 2009). At global level, India holds second position, next only to China in vegetables production with a share of about 14%. The present annual vegetables production of country is about 175 million tons from an area about 10.3 million ha with a productivity of 17.1 t/ha. India grows largest number of vegetables in the world, as having a spectrum of wide range of agro-climatic situations, ranging from dry temperate to humid tropics between the altitudes from sea level to snow line.

The Indian hot arid region is one of the most important arid ecosystems of the world in terms of biodiversity it possesses. This arid region spreads over 31.7 mha, occupies major part of north western India including Rajasthan, Gujarat, Punjab and Haryana, which together contribute 73% of arid region. High temperature, wind velocity, low humidity, low and erratic rainfall and high potential evapotranspiration are important characteristics of this region which narrowed down the choice for vegetables, besides permit their low productivity.

ABSTRACT

Of the several PCR techniques developed during the last two decades, random amplified polymorphic DNA (RAPD) offers a simple and economical means of genotype characterization. The information obtained through RAPD characterization is extensively used for the identification of genotypes, screening of duplicates, assessing genetic diversity and monitoring the genetic stability of conserved germplasm. The present study is a report on the DNA fingerprinting of P. nigrum and P. longum cultivars. Fourteen land races and three advanced cultivars of P. nigrum and eleven land races and one advanced cultivar of P.longum were used in the present study. Forty decamer primers from Operon Tech were screened using two representative genomic DNA samples of black pepper. Of these, 10 primers that yielded clear and dominant band patterns were selected for the final analysis of the 29 accessions. These generated 119 amplification products. The total number of markers per primer varied with respect to both P. nigrum and P. longum. Cultivar specific single bands were obtained for a few land races and accessions of both the Piper species.

Cocoa (Theobroma cacao L.) represented as ‘Food of Gods’ is considered as an important beverage crop next to Tea and Coffee. The economic produce of cocoa is the bean, when it is fermented and dried, become the source for chocolate. Cocoa is native to Amazon basin of South America and is domesticated and distributed to different regions by the natives Mayas, Aztecs and Pipil- Nicaraos (Wood and Lass, 1955; Young, 1994) who consumed it as an energy drink called ‘xocoatl’ by roasting and grinding cocoa beans. When Spanish conquered Mexico in 16th century they took cocoa to Europe which is christened as ‘chocolate’ the worlds’ favourite food. From then on cocoa spread to many other countries (Wood, 1991). According to World Cocoa Foundation, currently 40–50 million people depend on cocoa for their livelihood and the production is 3.97 mt in which Africa contributes 71%, Latin America 14% and Asia and Oceania 14% (Jean Marc Anga, 2013). Ivory Coast is the major producer followed by Ghana, Cameroon, Nigeria and Brazil. In Asian continent, Indonesia and Malaysia are the leading producers (www.wcf.org.).

The Para rubber tree (Hevea brasiliensis) is the most important commercial source of natural rubber, a strategic raw material. Rubber is an indispensable commodity used in the manufacture of over 50,000 products worldwide. This crop has therefore emerged as a key plantation species in various countries. The global area under rubber  cultivation is about 9.6 million hectares producing 9.2 million tones annually (IRSG, 2014). Among the major natural rubber producing countries, India occupies 4th position in terms of production with 0.91 million tones and more significantly the first position in average productivity of 1823 kg/ha/year. The major rubber producing countries are Thailand, Indonesia, India, Malaysia, Vietnam and Sri Lanka. Rubber is also commercially cultivated in Philippines, Nigeria, Cameroon, Cote de Ivoire, Liberia, Brazil, Cambodia, Nigeria, Cameroon, Guatemala, Myanmar, Mexico, China, Ghana, Democratic Republic of Congo, Gabon, and Papua New Guinea.Increase in production and improving productivity of NR continues to be the subject of considerable research efforts, particularly in the context of the widening gap between demand and supply of natural rubber. Over one million small farmers  in India owning less than 0.5 ha. of land depend on rubber cultivation for a livelihood.

Genetic purity is the vital determinant in continuing the genetic integrity in seed from generation to generation. This is the basis of variety purity maintenance. The genetic purity depends upon the purity of the seeds planted. The genetic purity of the seeds planted must exceed or equal to the final product purity standards required as the purity generally decreases with subsequent generations of propagation. The improved varieties loose their identity and healthiness unless properly maintained. Maintenance selection can prevent the seed quality deterioration.

Meaning and Importance

Genetic purity denotes the percentage of seeds (by weight) belonging to the variety/hybrid under certification. It is one of the primary criteria of seed quality. The efforts of plant breeders become fruitful only when sufficient quantities of good quality seeds of improved varieties/hybrids reach farmers / growers. This is necessary to take all round care at every step of seed multiplication before the seed is delivered for marketing. Hence, genetic purity testing is of critical importance not only to farmers but also to plant breeders, seed producers as well as quality control enforcing agencies. Increasing emphasis on hybrid cultivars due to their better performance and quality produce, more money and expertise have been put in further research of hybrid development. In this context, protection of parental lines is assuming critical importance and for that purpose, several breeding institutes do adopt various strategies for identification, characterization and protection of their parental lines as to avoid pilferage and misuse of their proprietary lines by other organizations. Use of random amplified polymorphic DNA (RAPD) and other molecular markers for evaluating seed purity of F₁ hybrids and their parental lines are closely related, thus, helps in assessing contamination of F₁ seeds even with the seeds of sib (inbred seed and seed from self-pollination of parental lines). For genetic purity testing of hybrids seeds, it is imperative that parental lines of hybrid be adequately characterized on the basis of maximum number of distinguishable descriptors (morphological, biochemical or molecular markers).

Introduction

Carrot (Daucus carota L., 2n=2x=18) is a cool-season root vegetable grown all over the world in temperate as well as sub-tropical climates. In India, it is cultivated over an area of 24,000 hectares with an annual production of 3,50,000 metric tones with a productivity much lower (14.58 t/ha) than the world average (22.17 t/ha) as per FAO, 2004. Carrots are used for human consumption as well as for animal feed. Carrot can thus be used for augmenting fresh fodder supply to milch animals during the lean winter in Kashmir (Hussan and Ahmed, 1999). Carrot has a significant place as an ingredient in soups and sauces and in dietary composition and also as a salad. A sweet preparation called Gajar Halwa is very famous dish in North India. Besides canning, it is also used in preparation of pickles. It is also exported in the form of fresh roots to the countries like Kuwait and Sharjah. Carrot is a rich source of á and â- carotene. The total carotenoid content in the edible portion of carrot roots ranges from 6.00 to 54.80 mg/100g. The yellow and orange coloured roots contain relatively more carotenoid. Carrot roots contain protein, fat, carbohydrate, minerals (especially Ca, Mg, Na, K, Cu, S etc.) besides vitamin A, B₁, B₂, nicotinic acid and vitamin C. In carrot roots, sucrose is the most abundant with endogenous sugar contents 10 times than those of glucose and fructose.

Asia minor, Afghanistan, North West India, Iran and Turkey are the centers of origin of carrot. As per Encyclopedia Britannica, carrots have originated from Afghanistan, Punjab and Kashmir with secondary centers in Ethiopia and North America. The European carotene carrot (syn. Western carotene carrot, temperate carrot) has been derived from the Asiatic anthocyanin containing forms of carrot (syn. Eastern anthocyanin carrot, tropical carrot). Afghanistan is the centre of diversity of the purple coloured carrot (anthocyanin carrot) and as such this country is suggested as the primary centre for origin. Integration between the Asiatic and European carrots has given the present day forms which are fleshy, smoother, less forked and better coloured.

Punjab and Kashmir are also considered as primary centre of origin with secondary centers in Ethopia and North America. It is still found in its wild form in Himachal Pradesh and Kashmir valley where wild animals especially brown bear feed on its roots. People still eat the wild carrots in some parts of Kashmir (Yawalkar, 1980). In north India highly coloured types of carrots are found which are not available in Europe. The colour of carrot ranges from absolute colourless to light lemon, light orange, orange and deep orange, light purple, deep purple and almost black. It is also an indication of this region being a primary centre of origin of carrot.

Introduction

Turnip is an important root crop which is very popular particularly in northern India. It is a cool season crop mainly grown as a fall or winter crop in the hills and winter crop in the plains. Turnip (Brassica rapa L. syn. Brassica compestris var. rapa) belong to family Brassicaceae. It has a chromosome number of 2n=2x=20. Two main centers of origin have been indicated. The Mediterranean area is considered to be the primary centre of origin of European type/temperate types. While Eastern Afghanistan with adjoining areas of Pakistan is considered to be another primary centre with Asia Minor, Transcaucasus and Iran as secondary centre. The parents of cultivated turnip are found in the wild form in Russia, Siberia and Scandnavia. It was cultivated by the ancients and ranked next to grapes and cereals in Italy. It was introduced in England probably in 1590 and United States in 1606 (Yawalkar, 1980). Turnips are now cultivated throughout the world.

Turnips are botanically biennial herbs, but are cultivated as annual root crops for both animal and human consumption. The turnip root contains 41.6% moisture, 6.2 g carbohydrates, 0.5 g protein, 0.2 g fat, 0.04 mg thiamin, 0.04 mg riboflavin, 43 mg ascorbic acid, 30 mg Ca, 40 mg P and 0.4 mg Fe per 100 g of edible portion. The turnip green contains 15,669 IU vitamin A per 100 g (Aykroyd, 1963). Turnip is grown for its enlarged root as well as for its foliage. Extra seedlings from thinning are often used as greens. The fresh roots are consumed in salads or cooked as vegetable or used in pickles. The young leaves contain high amount of ascorbic acid and iron, rank second in vitamin A content and are cooked as greens.

The fleshy thickened underground portion of turnip is actually the hypocotyl. The colour and shape of this underground portion vary with the cultivars and the roots are flat globular to top-shaped and long. The colour of under ground portion may be white or yellow, while that of above ground portion may be red, purple, white, yellow or green. A distinct tap root and secondary roots arise from the lower part of the swollen hypocotyl. Thickening begins in the central part of the hypocotyle, followed by the upper and lower parts. Normally, the roots attain edible maturity in 40-80 days depending on cultivar and climatic conditions.

Abstract

The potato research in India was started systematically after the establishment of Central Potato Research Institute (CPRI) in 1949. Forty-one potato varieties having attributes of early, medium and late maturity vis-à-vis resistance to various biotic and abiotic stresses have already been developed indigenously for varied agro-ecoregions in the hills and sub-tropical plains. After the establishment of CPRI, collection of potato germplasm was made mandatory. Presently there are over 2,700 accessions including 133 wild species (related to potato) in the germplasm collection of CPRI. Despite the large collection of potato germplasm at the institute the genetic base of all 41 Indian potato varieties released so far can be traced to only about 50 parents and most of these represent tetraploid potato cultivars while only a few of the exotic diploid wild species have been used in improvement of potato varieties in India. Under utilization of wild species could be mainly due to the pre- and post zygotic crossability barriers inherent in many species of genus solanum. Nevertheless, about seven wild species have been used in potato breeding for introgression of resistance genes for various biotic and abiotic stresses in the improved Indian potato varieties.

Introduction

‘Cole crops’ is a general term used to describe several vegetables in the Brassicaceae family. It is an important and highly diversified group of vegetable crops grown worldwide that belongs to Brassica oleracea (Monteiro and Lunn, 1998) and includes particularly six Brassica crops (cabbage, cauliflower, Brussels sprouts, broccoli, kale and knol kohl). All of these crops can trace their history to a common ancestry of wild cabbage originating in the Mediterranean and Asia Minor regions. Cole crops are one of the oldest cultivated plant groups in the world. They are cultivated in Europe since very ancient time from where they have spread to other parts of the world (Nieuwhof, 1969). All the cole crops (except few cauliflower, broccoli and cabbage types) require chilling temperatures for about two months to transform from vegetative phase into reproductive phase. However, the period of chilling requirement differs according to the kind of crop and varieties. Cole crops are also commonly called as European or biennial vegetables due to their cool temperatures requirements and two season requirement to complete their life cycle.

Major Resources of Cole Crop Germplasm

Germplasm is any form of the hereditary material from an organism. Genetic resources encompass all the various forms of germplasm that are available for collection, storage and use. The genetic diversity of crops, represented by traditional local cultivars and wild relatives has been disappearing rapidly during recent decades. Initial concern was noted by H.V. Harlan in the 1930s (Harlan and Martini, 1936) but by the 1960s, modern plant breeding and land-use changes accelerated loss and stimulated the realization that genetic resources in regions of diversity were being lost at an alarming rate. To conserve the genetic variation within the cole group, a comprehensive base collection of the cultivated forms of Brassica oleracea has been established at the vegetable gene bank of Horticulture Research International (HRI), Wellesbourne, (U.K.). Gene banks have also been established at Instiuut de veredeling van Tuinbouwgewssen, Wageningen, the Netherlands and the Instituto del Germoplasm, Bari, Italy (Van der Meer et al., 1984) for conservation of genetic resources. The International Board for Plant Genetic Resources (IBPGR) has recognized HRI as an international centre for conservation of Brassica oleracea (Innes, 1975). Large number of collections of cole crops is also available with the United States Department of Agriculture, Plant Introduction Service. In India, National Bureau of Plant Genetic Resources (NBPGR), New Delhi has been assigned the duty of conserving the germplasm of all crops, including vegetables. Germplasm of all the cole crops is being maintained at the Indian Agricultural Research Institute, New Delhi (tropical types) and its regional station at Katrain (temperate types). Other major institutes maintaining germplasm of cole crops include Punjab Agriculture University, Ludhiana, G. B. Pant University of Agriculture & Technology, Pantnagar, Indian Institute of Vegetable Research, Varanasi, Dr. Y.S. Parmar University of Horticulture and Forestry, Solan and SKUAS&T, Srinagar.

Introduction

Cowpea, {Vigna unguiculata (L.) Walp.} is an important food legume in the semi-arid tropics covering Asia, Africa, Southern Europe and Central and South America (Henriet et al., 1997; Mortimer et al., 1997; Van Ek et al., 1997). It is a drought tolerant and warm weather crop. Therefore, well adapted to the drier regions of the tropics where other food legumes do not perform as well. It fixes atmospheric nitrogen and grows well even in the poor soils with more than 85% sand and with less than 0.2% organic matter and low levels of phosphorus (Kolawale et al., 2000 and Sanginga et al., 2000). Also, it is shade tolerant and therefore, compatible as an intercrop with maize, millet, sorghum, sugarcane and cotton as well as with several plantation crops (Singh and Emechebe, 1998). Coupled with these attributes, its quick growth and rapid ground cover checks soils erosion and in situ decay of its roots and nitrogen rich residues improves soil fertility and structure which together have made cowpea an important component of cropping system in the dry savannas of the sub-Saharan Africa (Carsky et al., 2001 and Mortimer et al., 1997).

Cowpea is cultivated in about 14 million ha world wide with about 5 million tons annual production. However, a substantial part of the cowpea production comes only from few countries. Nigeria is the largest producer and consumer of cowpea with about 5 million ha area and about 3 million tons production annually. Niger Republic is the next largest producer with 3 million ha and over 1 million ton production. Northeast Brazil grows about 1.5 million ha of cowpea with about 500.000 tons production. In the southern USA about 40,000 ha of cowpea is grown with an estimated 45,000 tons annual production of dry cowpea seed and a large amount of frozen green cowpeas. Even though exact statistics are not available, India is the largest cowpea producer in Asia and together with Sri Lanka, Pakistan, Nepal, Bangladesh, Thailand, Indonesia and other far eastern countries, there may be over 1.5 million hectares under cowpea in Asia.

Introduction

Radish (Raphanus sativus L., 2n=2x=18) is a root cum leafy vegetable suitable for sub tropical and temperate climate. Radish probably originated in Europe and Asia. It has been under extensive cultivation in Egypt since long. It was introduced to England and France in the beginning of 16^th century. In 1806, it was introduced to America. Radish does not exist in wild stack. It is believed to have originated from R. raphanistrum which is widely distributed as weed in Europe. Radish is primarily a winter crop but with the development and release of new varieties, it can be grown all the year round. The new varieties can withstand heat and does not bolt in spring. Radish is a favourite crop because of its quick growth and availability in 4-7 weeks.

Its fleshy roots are modified roots, developed from both the primary root and hypocotyl. The leaves and roots are consumed both as salad and cooked. The radish root is a good appetizer; its different preparations are useful in curing liver and gall bladder problems. Roots are also used in treating urinary complaints and piles. The juice of fresh leaves is useful as diuretic and laxative. Pungency in radish is due to volatile isothiocyanates while pink colour is due to pigment anthocyanin.

Radish is a good source of vitamin C containing 15-40 mg per 100g of edible portion. Roots also contain proteins, fat, minerals, fibre and carbohydrates, besides trace elements like aluminium, barium, lithium, manganese, silicon, titanium, fluorine and iodine. Pink skinned radish is generally richer in vitamin C than the white skinned type. Radish contains glucose as the major sugar and also contains fructose and sucrose in smaller quantities. Pectin and pentosans are also reported to be present. The leaves are good source of extraction of protein on a commercial scale and seeds are potential source for non-drying fatty oil suitable for soap making, illuminating and for the edible purposes.

Introduction

Peas (Pisum sativum L., 2n = 2x =14) are consumed as fresh vegetables or dry seeds throughout the world. In India, peas are grown as winter vegetable in plains and as summer vegetable in the hills. As field pea, it occupies about 0.45 m ha area in India, accounting for only about 2% of the total pulse area. About 90% of its area and production is limited to Uttar Pradesh alone. The area under vegetable peas is on increase. The acreage of vegetable pea in India is 2.72 lakhs ha with a productivity of 9.9 tons/ha. Pea is a rich source of protein (7.2% in green pea & 20 % in dry pea) and minerals (0.8%).

The geographical region comprising of Central Asia, the Near East, Abyssinia and the Mediterranean is considered as centre of origin based on genetic diversity. According to Blixt (1970), the Mediterranean is the primary center of diversity with secondary centers in Ethiopia and the Near East.

Garden pea, seeds have been observed in archeological excavations of Mohan Jodaro and Harappa, there are distinct hot weather tolerant and round-seeded varieties which carry high resistance to fusarium wilt and powdery mildew (Erysiphe polygoni). These varieties have a different use as a pulse crop for meeting protein requirements of common people. These are considered as intermediate stages of domestication of the present day vegetable (garden) pea, which is sweet and wrinkled-seeded. In fact, the quick spread of Arkel variety, an introduction from England in seventies, has displaced some of the native round-seeded varieties like Asauji, Hara Bonia, Hoshiarpuri, Kaparkheda, Kalanagni, Lucknow Bonia etc. there is need to conserve these valuable germplasm, before they are swept away by genetic erosion.

Introduction

Potato is a wonder crop that can be grown under diverse range of agro-climatic conditions. Short duration; high yield per unit area and time and wide flexibility in planting and harvesting time are important virtues of potato that enable its inclusion in intensive cropping systems.

Potato is not an Indian crop but is a native of high Andean region of South America. It was introduced in India perhaps in 16^th or early 17^th century by either the Portuguese traders or the British missionaries. The present day cultivated potatoes (tetraploid, 2n=4x=48) in most of the world represent Solanum tuberosum spp. tuberosum and S. tuberosum spp. andigena, although it’s numerous diploid (2n=2x=24) relatives are still under cultivation in and around its primary and secondary centers of origin in South America (Pandey and Sarkar, 2005). The great Irish famine in the 19^th century, caused by late blight disease, nearly wiped out all the earliest potato introductions in the Europe and dramatically changed the potato cultivation and production scenario in rest of the world.

Unlike in European Countries 80% of the potato is grown in India under short day conditions as a short duration crop i.e. 70-90 days. The tubers are exposed to high temperatures during planting (September-October) and harvesting (February-May). The crop is irrigated and suffers mid day water stress. The potato varieties introduced from Europe were unsuitable for growing under the above conditions. Systematic potato research in India spanned over the last half-a-century of the 20^th century in the past millennium. The Central Potato Research Institute (CPRI), which was established in 1949, has bean mainly responsible for tremendous growth of potato production in the country. The indigenous technological advances made it possible to extend potato cultivation in almost all part of the country. Now in India, compared to the production, area and yield of potato in 1949-50, the increase over the same period was 1513%, 559% and 270% respectively (Naik and Thakur, 2007). According to the FAO, potato production worldwide stands at 329 million tones and covers more then 19 million ha.

The Cucurbitaceae family is characterized by long training viny stems. There is variation for flower size and colour among the species but all of them have similar general morphology. The species are open pollinated and self compatible. Most of them are either monoecious (eg. Cucurbita spp.) Or andromonoecious (e.g. common in melon). Other species show gynomonoecy, androgynomonoecy, androecy, gynoecy, hermaphrodite or dioecy. Chow-chow is the only member of the Cucurbitaceae that is viviparous, contains single seed and propagated by planting whole fruit. The Indian gene centre has rich diversity in genetic resources of ridgegourd (Luffa acutangula), bottlegourd (Lagenaria siceraria), bittergourd (Momordica charantia), ashgourd (Benincasa hispida), snakegourd (Trichosanthes anguina), pointed gourd- parval (Trichosanthes dioica), pumpkin (Cucurbita spp.) and roundgourd (Praecitrullus vulgaris). Cucurbits are of tremendous economic importance and are cultivated throughout the world from tropical to sub-temperate zones. China, Turkey, India and Iran are important cucurbit growing countries. In India, this diversity is concentrated in Indo-Gangatic plains, north eastern region, north western Himalayas, the Western and Eastern Ghats and sporadically in the tribal dominant belts of central India.  More diversity occurs in Cucurbita spp. in the north east as also for ashgourd, bottlegourd while for Luffa, it is more concentrated in the eastern peninsular tract.

INTRODUCTION

Potato belongs to a genetically diverse genus Solanum having nearly 235 tuber bearing species. These speciesform a polyploid series ranging from diploids (2n=2x=24)tohexaploids (2n=2x=72), with12 asthebasic chromosome number. There is also arichdiversity within the cultivatedspecies of potato and they were initially grouped under six different species. Later studies, however, recognized those species as land race populations of S. tuberosum, with the eight groups: Ajanhuiri, Andigenum, Chaucha, Chilotanum, Curtilobum, Juzepczukii,Phurejaand Stenotomum(Spooner & Salas, 2006). Thisrich genetic diversity of the species is available in the Andean mountain where potato originated. In India,however, it was quite natural that genetic variability within the locally available material will be meager since, it was introduced here only about 400 years ago. On the contrary, more than 500 differentvarieties existed in India by 1940. This paradoxical situation was primarily due to assigning different local names toasingle variety in different parts ofthe country. The available local varieties in India consisted of both early introductions belonging to either pure Solanum tuberosum ssp. andigenum or their hybrids with S. tuberosumssp.tuberosumas well as later European introductions belonging to S. tuberosum ssp. tuberosum.

Tripura is situated between 22º 56’to 240 32’ N latitude and 91010’ to 92021’E longitude with tropic of cancer passing through it. The total geographical area of state is about 10,491 km2 of which 57.98 % area is under forest cover.  Agriculture is an important sector in the state, which contributes 26 % of the State GDP of which the major contribution is from horticultural crops like fruits (pineapple, litchi and oranges), vegetables (potato TPS), plantation crops (cashew nut, coconut, rubber and tea) and spices (ginger, turmeric and black pepper). More than 75 % of the population either directly or indirectly depends on agriculture. The small and marginal farmers constitute about 90 % of total farming community and the average size of land holding is 0.97 ha (1990-91) in comparison to 1.25 ha (1976-77), which is the lowest among the seven other North Eastern states.

Introduction

The North-eastern region comprises of eight states viz. Assam, Arunachal Pradesh, Meghalaya, Manipur, Mizoram, Nagaland, Tripura and Sikkim lying between 21.5^o N - 29.5^o N latitudes and 85.5 ^o E - 97.3 ^o E longitudes. It has a total geographical area of 262180 Km² which is nearly 8 % of the total geographical area of the country. In the whole of NE region, about 35 % area is plain and the remaining 65 % area is under hills. Whereas in Assam plains account for 84.44 % of its total geographical area and the remaining 15.56 % area is under hills. Net sown area is highest in Assam (34.12 %) followed by Tripura (23.48 %), however, Arunachal Pradesh has lowest net sown area in the region. Cropping intensity is highest in Tripura (173 %) followed by Manipur (152.1 %), Mizoram (136.36 %) and Assam (123.59 %). About 0.5 million hectare area is under shifting cultivation in the NE region. Out of 4.4 million hectare net sown area, roughly 1.4 million hectare lies in hilly sub region and at least 1.3 million hectare suffer from serious soil erosion problem.

The diverse agro climatic conditions, varied soil type and abundance of rainfall offers immense scope for cultivation of different types of horticultural crops, including fruits, vegetables, flowers, plantation crops, tuber and rhizomatous crops and crops of medicinal and aromatic importance. The region has rich diversity of different vegetable crops and both indigenous tropical vegetables and temperate vegetables are grown to a considerable extent. The major vegetables grown in the region are brinjal, cabbage, cauliflower, okra, onion, pea, potato, tomato, knol-khol, radish, carrot, French bean and different cucurbitaceous crops. Tuber and rhizomatous crops like tapioca (cassava), sweet potato, Dioscorea, colocasia, ginger and turmeric grow abundantly in the region.

1. INTRODUCTION

Plants produce an array of natural products, the secondary metabolites, which play a variety of roles such as pollinator attractants e.g. pigments and scents and defense molecules against attacks by animals and microorganisms. These substances are very much important as a source of pharmaceuticals, fragrances, agrochemicals and food additives. Great efforts have been made by the chemical industry to mimic and synthesise these compounds. However little success has been achieved and plants still remain the major source of these vital compounds (Wink, 1990). In the late 1970s plant cell culture was thought to be an alternative or additional way of producing these compounds (Alfermann and Peterson, 1995). The low yields obtained with cultured cells and inferior to the amounts present in intact plants, provided a major drawback to their commercial exploitation. The plant derived pharmaceuticals represent a large market value; about 25% of today’s pharmaceuticals contain at least one active ingredient of plant origin. So only a minute fraction of the enormous biosynthetic potential of plant cells is being exploited. The most popular analgesic drug aspirin and the most valuable anti-cancer drugs paclitaxel and vinblastine are derived solely from plant sources (Pezzuto, 1996).

Over the last 10-15 years, the successful genetic transformation of plants has been reported in about 200 species including agricultural crops, trees, ornamentals, fruits and vegetables. Such genetic modification has improved specific crop traits, such as resistance to pathogens, to herbicides and to various environmental factors including drought and floods (Bajaj and Ishimaru, 1999). Following on from this success genetic transformation of medicinal plants has been attempted, primarily to enhance the production of various pharmaceuticals, flavours and pigments. During the early 90’s it was suggested that metabolic engineering of biosynthetic networks might be achieved by application of recombinant DNA methods.

Male-sterility
Normal development of the male reproductive organ (stamen) and male gametophyte (pollen grain) is essential for successful completion of sexual reproduction in angiosperms. Abnormalities at any stage of stamen and pollen development can result in male sterility. Male sterility in plants implies the inability to produce or to release functional pollen. Male sterility is caused due to failure in the formation or development of functional stamens, microspores or gametes and /or release of pollens from the anther. Male-sterility can result from mutations in nuclear genes alone or mitochondrial genes or mitochondrial genes coupled with nuclear genes. The resulting conditions are known as genic male sterility (GMS), cytoplasmic male sterility (CMS) and cytoplasmic-genic male sterility (CGMS), respectively.
Classification of male-sterility
1. Genetic male-sterility
This male-sterility is caused due to mutations in nuclear genes alone or mitochondrial genes or mitochondrial genes coupled with nuclear genes which results abnormalities at any stage of stamen and pollen development.

The potential yield levels in major crops have reached almost to a plateau. The current world population of 7 billion is likely to reach 9 billion by 2050 putting huge pressure to produce more from the available arable lands as acreage of major crops is predicted not to increase any further. The deficit of food requirements will have to be met partly by bridging the gap between farm yield (the average yield of the crop in a particular region/country/world) and the potential yield (the yield obtained usually in the breeders’ plots grown across the region of interest with the best yielding new varieties and without biotic stresses as diseases and pests, and abiotic stresses such as drought, flooding, salinity, heat and cold and partly by increasing potential yield per se.