eChapters

Introduction

In Indian agriculture, horticulture sector has made considerable progress after independence and as a result, horticulture has emerged as one of the major drivers of growth in the agricultural and allied sector. The horticulture sector includes large number of crops viz., fruits, vegetables, ornamental crops, spices, tuber crops, plantation crops, medicinal and aromatic crops, mushroom and their post harvest management. On the production and productivity front, the horticulture sector outperformed conventional food crops. Between 200405 and 201415, horticultural output achieved an annual growth of about 7 per cent as compared to around 3 per cent growth in food grain production. This increase in production has come from an increase in acreage and even larger increase in productivity. Over the last decade, the area under horticulture grew by about 3% per annum and annual production increased by 5.4%. Thereby, India has maintained its second rank in the global production of fruits and vegetables, next only to China. India’s fruit productivity is better than that of China, though China is the largest fruit producing country.

The country is currently producing 295.2 million tonnes of horticulture produce from an area of 24.9 million hectares, which has surpassed the estimated food grain production of 275.68 million tonnes (201617). Though the production of food grains and horticultural produce are not meaningfully comparable due to fundamental differences in resource requirements, their farming practices, characteristics of produce and most importantly, their nutritional and medicinal properties as well as energy value. The special attention was given to the this sector, especially after the introduction of the Horticulture Mission for North East and Himalayan States (HMNEH) and the National Horticulture Mission (NHM) during 11^th Plan period, owing to bumper fruit production. Given the increasing pressure on land, growth strategies have been focusing on raising productivity through high density plantations, protected cultivation, micro irrigation, quality planting material, rejuvenation of senile orchards and an emphasis on post harvest management and marketing of produce for better price realization.

Jamun is an evergreen tree commonly known as Java plum. It has its origin from Southeast Asia, India, Myanmar and East Indies. It belongs to the family Myrtaceae (which has flowers consisting of characteristic numerous stamens) and species Syzygium cuminii (L.) Skeels. Closely related to an important spice Syzygium aromaticum “Clove”. It is cultivated in tropics as an evergreen tree with dense foliage and can provide lot of shade. It is a very popular avenue tree. A unique fast growing tree, known to be tolerant to high rainfall and also to water deficit conditions, it is present in both moist and dry situations, occurring in the tropical wet evergreen forests, tropical semi-evergreen forests, tropical moist deciduous forests, littoral and swamp, tropical dry deciduous, tropical dry evergreen, subtropical broadleaved hills, and subtropical pine forests. The tree favours moist, damp or marshy situations, where it tends to form gregarious crops. It tolerates prolonged flooding, and once established it can tolerate drought.

Indian jujube (Ber) belongs to the genus Zizyphus and family Rhamnaceae having more than 600 species. The family includes trees with spine, shrubs and climbers. The original home of Ber is Myanmar and India. Many workers have tried to classify it on the basis of leaf, flowers and fruits characteristics. Some tried to divide into two groups i.e. having smooth leaves on both surfaces and having leaves downy beneath. Ber as a tree has been described it as small, much branched or a large shrub with dense spreading habit, bark dark gray, branches elongated, leaves with glabrous shining upper surface densely covered beneath with whitish hairy growth.

Ber has attracted sustained breeding attention owing to its wide adaptability, good quality and nutritive value. However, problems like poor shelf life, incidence of powdery mildew disease, fruit fly and fruit borer have hindered the extension of the area under this crop. In Chinese jujube, the problem of fruit cracking and ‘witches broom’ disease are the major hindrances in its cultivation. There are two major cultivated species viz., Ziziphus mauritiana and Ziziphus jujuba, which are widely distributed covering vast regions in Asia. The wild population found is heterozygous and extremely variable. As a result, many local selections were made, some of which have become widely recognized as cultivars. The success of any breeding programme depends on the extent of genetic variability in the source population. The assessment of variability is therefore a basic requirement of breeding programme. Since most of the plant characters of economic importance are governed by the group of genes and are highly influenced by environmental variation, it is difficult to judge whether the observed variability is heritable or due to environment. This necessitates optimizing of phenotypic variation into its heritable and non heritable components, so that the selection of parents

The Annonaceae or custard apple family comprises about 120 genera and more than 2000 species (Leboeuf et al., 1982). The genus Annona is the most economically important one, containing 120 species. The major commercial species throughout the world are: the cherimoya (Annona cherimola), sweetsop (Annona squamosa) and atemoya (a hybrid of Annona cherimola and Annona squamosa). The custard apple species name ‘squamosa’ refers to the knobby appearance of the fruit. Custard apple is a small tropical tree originating in the New World tropics, probably Central America. This species is the most widely grown in the tropical regions of the America, Africa, Asia and the Pacific. Sweetsop is synonym also named sugar apple and has many other regional names, such as Custard apple (India), anon (Spanish), ata (Portuguese), noi-na (Thailand), stis (The Philippines) and fan-li-chi (Taiwan). Sweetsop is the mostly grown Annona species. The fruit is frequently found in village markets but has not shown much potential for large commercial cultivation due to the small fruit size, frequent cracking at maturity and poor shelf life. The perishable nature and supply shortages make marketing localized or air shipment essential.

Jackfruit (Artocarpus heterophyllus Lam) is a multi-purpose tree species that provides food, timber, fuel, fodder and medicinal and industrial products. It is one of the species that has been brought into wider cultivation through a farmer-driven domestication process because its products meet the household needs of families with limited land, which require wood and animal feed to ensure family food security. Despite such vast potential and usefulness, jackfruit remains an underutilized fruit species and deserves to be given the necessary thrust for research and development. There is little progress on the genetic improvement of the species, including study on its reproductive biology, even though it demonstrated substantial use and importance. Therefore, a brief background on the reproductive biology of jackfruit is covered here before dealing with its genetic improvement.

Sapota [Manilkara zapota (L.) P. Royen, (Manilkara achras (Mill.) Fosber] is a member of the family sapotaceae. It is a fairly slow growing and long-lived tree. It is valued for its delicious fruit in India, while in Guatemala, south East Mexico, British Honduras, chickle is commercially produced which is the main ingredient in preparation of chewing gum. Chickle is extracted from trunk and unripe fruits of the tree as white latex exudate. Although synthetic gums are primarily used, countries like Mexico, Venezula and Guatemala still grow sapota for chickle.

It is native to South Mexico as well as North East Guatemala. Manilkara species is found in forests throughout tropical America, which was introduced long ago followed by West Indies, Bahamas, Bermuda and Southern part of Florida mainland. Early in colonial times, it was carried to Phillippines, and later distributed to Malaysia and other countries in the tropics (Purseglove, 1974). It is not known when it was first introduced to India. Commercial cultivation was first taken up in Maharashtra during 1898 (Cheema et al., 1954). Future of sapota appears to be promising, since attention in this crop is enthusiastic from growers and consumers in many countries. Sapota is grown on commercial basis in India, Philippines, Sri Lanka, Malaysia, Mexico and Venezuela.

India is one of the largest producers of sapota in the world. Major states growing this fruit crop are Maharashtra, Gujarat, Andhra Pradesh, Karnataka, Tamil Nadu, West Bengal, Kerala, Uttar Pradesh, Punjab, Assam and Haryana. India’s production of sapota continues to grow up and there is an active research program in India with specific goals towards improving storage, transport and marketing strategies.

Guava (Psidium guajava L) is an important fruit crop of India. It has gained considerable prominence on account of its high nutritive value, availability at moderate prices, pleasant aroma and good flavour. It is one of the commonest fruits liked by the rich and the poor and is popularly known as the ‘apple of tropics’. It is one of the hardiest fruit trees adaptable to a variety of soil and climatic conditions. It comes up well even under neglected conditions and in fact it is even considered sometime as a weed in Fiji and Hawaii. Guava fruit is relished when mature or ripe or when freshly plucked from the tree. It is also used for many commercial products like jelly, fruit butter, juice, etc.The guava is said to have originated from tropical America (Hayes, 1953). De Candolle (1904) stated that it originated in Mexico, while Purseglove (1968) opined that it originated in Brazil. It is widely distributed all over the equatorial regions of tropical and sub-tropical climate. It was introduced to India during the 17th Century. In Spanish, the tree is known as guayabo, or guayavo, the fruit guayaba or guyava. The French call it goyave or goyavier; the Dutch, guyaba, goeajaaba; the Surinamese, guave or goejaba; and the Portuguese, goiaba or goaibeira. Hawaiians call it guava or kuawa. In Guam it is abas. In Malaya, it is generally known either as guava or jambu batu, but has also numerous dialectal names as it does in India, tropical Africa and the Philippines where the name, bayabas, is often applied. Various tribal names–pichi, posh, enandi, etc., are employed among the Indians of Mexico and Central and South America.

Papaya is one of the fruit crops grown both commercially as well as a backyard crop. Papaya was mainly a backyard crop till recently. It emerged as a main commercial crop during the last decade, because of the high nutritive value. It is a rich source of Vitamin A (2020 I.U), Vitamin B1 (40 mg), Vitamin C (46mg), protein (0.5%) and mineral matters (0.4%). Ripe papaya is a favourite breakfast and dessert fruit available yearround. It is used for making fruit salads, refreshing drinks, jams, jelly, marmalade, candies and crystallized fruits. Green fruits are pickled or cooked as vegetable. Carpine, an alkaloid present in papaya, can be used as a heart depressant, amoebicide and diuretic. It is also grown for the extraction of papain, a proteolytic enzyme present in the latex, collected mainly from the green fruit. In 1875, T. P. Lucas, a British physician discovered the medicinal value of papaya and started a hospital in Brisbane, to treat patients solely with papaya. The people in Papua New Guinea use papaya for the skin and to treat rashes or sunburn or, with repeated applications, to remove the brown spots of aging. They also say that if you put papaya into the compost pile, they grow especially large! Natives in the Pacific Islands use all parts of the papaya tree for medicinal purposes — leaves, skin, seeds, bark, roots, flowers and of course, the fruit. South American women massage their breasts with thin slices of green papaya to stimulate the milk glands. Eating the fruit provides energy and nutrients for both herself and the baby. Papaya bark is used as a toothache remedy and the flowers in teas, to treat bronchial infections. For centuries, teas from the roots were used to expel parasites and to alleviate bleeding, kidney colic, and jaundice.

Pomegranate is emerging as one of the important fruit crops owing to its hardiness and ability to withstand adverse soil and climatic conditions. India contributes 40-45 percent of total 10 lakh tons production in the world. Currently the export of pomegranate is around 10,000 tons, which is just 5 percent of the total export. With the increase in population, the domestic demand of fruits has also increased substantially. As on date, out of total area of 1, 25,000 ha. under pomegranate, major area under the crop is found in Maharashtra. The state has 85,000 ha. (68 % area) under the crop, of which only 51,000 ha is under production, followed by Karnataka 12,727 ha. Gujarat 3,787 ha, up to 2003 –2004 (Anon, 2005). Earlier orchards were raised mainly with variety Ganesh, which was the leading variety. However, the variety is fast being replaced with the new cultivars like Bhagawa and Arakta, which have attractive skin and aril colour and are suitable for export.

The pomegranate is an ancient and favorite table fruit of tropical countries. It is commercially grown for its sweet-acidic fruits, which provide a cool refreshing juice, and is valued for its medicinal properties. The fruit rind, juice, leaf and roots are used in the preparation of various ayurvedic medicines. Its popularity is also due to ornamental nature of the plant especially due to bearing bright red flowers throughout the year. The fruit juice is refreshing and contains both glucose and fructose. The juice and seed contain large quantities of tannin and agolic acid, which is essential in curing several diseases. The fruit can be successfully grown even under purely rain fed conditions. In the recent years pomegranate cultivation has become an economically viable proposition.

Banana is one of the most important major fruit crops grown in India and is as old as Indian civilization. It seems that it is one of the earliest fruit crops grown by mankind at the dawn of civilization. In India, bananas are so predominant and popular among people that it is liked both by poor and rich alike. It is the cheapest among all other fruits in the country. Considering the year round availability of fruits, unlike the seasonal availability of other tree fruits, it has become an inevitable necessity in any house hold in India, for all cultural occasions.

The bananas were grown in Southern Asia even before the prehistoric periods and the world’s largest diversity in banana population is found in this area. Hence, it is generally agreed that all the edible bananas and plantains are indigenous to the warm, moist regions of tropical Asia comprising the regions of India, Myanmar, Thailand and Indo China. Historical evidences show that the Arabs have introduced the banana from India to Palestine and Egypt perhaps in seventh century A.D. (Hayes, 1953). It soon became popular in those areas and later spread to East coast of Africa at a very early date and subsequently spread throughout the African continent. Bananas were reported to have introduced to Central America in 1516 A.D., where it spread rapidly and attained commercial significance. The spread of bananas to West Indian Islands was through Christian missionaries and wherever it reached it assumed economic importance due to its greater adaptability and commercial value.

Introduction

Citrus is one of the most important fruit crops in the world. Citrus fruits are grown in the tropical and subtropical regions of the world. Some of the important countries where these fruits are grown include USA, Brazil, Spain, Israel, South Africa, Australia, China, India, Mexico and Morocco. Citriculture as a garden industry dates back to less than one hundred years. Indian citrus industry is the third fruit industry after mango and banana. The important groups of crops in citrus are sweet oranges, mandarins, limes, lemons, grapefruits and pummelo (Singh, 2001). Total world citrus production is about 115525.2 thousand tonnes, whereas in India, the production of citrus fruits is 8267.2 thousand tonnes (Anonymous 2012). The most important commercial Citrus species grown in India are the mandarin (Citrus reticulata Blanco), followed by sweet orange (Citrus sinensis Osbeck) and acid lime (Citrus aurantifolia Swingle). The main cultivars in the mandarin group are the Nagpur mandarin, Coorg mandarin, Khasi mandarin, Hill mandarin and the Kinnow mandarin. Maharashtra, Karnataka, Andhra Pradesh and Punjab are the major citrus producing states, while in Haryana, Uttar Pradesh, Madhya Pradesh, West Bengal, Tamil Nadu, Gujarat and Bihar, the fruit is grown to a limited extent. In Rajasthan new plantation of citrus are coming up very well and the main cultivars are Nagpur and Kinnow mandarins.

Mango, like some of the other perennial crops viz. Citrus has varied reproductive mechanisms i.e. both sexual and asexual. Understanding of the physiology of flowering in mango has remained largely inconclusive and tangible explanation for the irregular pattern of flowering during the recent years is not forthcoming. Mango is a highly heterozygous crop and this high heterozygosity in the cultivars which are used in hybridization and the inherent difficulties in obtaining large hybrid population have made accurate genetic analysis in mango very difficult (Iyer and Schnell, 2009). Despite the drawbacks ailing mango breeding like high heterozygosity, occurrence of only a single seed per fruit, breeding can be successful because of a number of positive attributes of the species like the wide range of available genetic variation and the ease with which a selected hybrid can be vegetatively propagated (Iyer and Schnell, 2009). However, in spite of the large variability, sufficient headway has not been made in the improvement. Naik et al., (1958), opined that it is the large variability in India, too many cultivars and heavy regional preferences which have hindered the production of new commercial varieties on a large scale. The various botanical features of mango along with features of cytology and breeding are discussed below:

Rootstocks play a very important role in propagation of plants, It may modify form or stature and adopt a variety to a soil in an incompatible climatic condition and also build up the resistance to biotic and abiotic stresses and meanwhile increase the production and productivity.

Vagaries of climate and mismanagement of soil have resulted in abiotic stresses, which in turn have lowered yield and quality production of fruits. In the course of its phylogenetic development, several fruit crops have developed various physiological and morphological mechanisms enabling plants to survive under adverse conditions. In case of fruit crops, one of the most important methods is to use rootstocks to overcome such stress conditions. However, over the years in fruit crops, the rootstocks that are present do not cater to the present day needs of pest and disease tolerance. Hence, there is an urgent need to widen the genetic base of rootstocks in different fruit crops by breeding and selecting rootstocks with desirable characteristics. It is acknowledged that the timing and intensity of the response of rootstocks to soil and atmospheric conditions are synergistically beneficial in evolving new cultivars.

Number of attempts has been made in rootstock improvement programmes all over the world. One of the methods that are being followed in perennial crops like mango is the development of large progeny population through half sib families. In this case, the female parent is common and open pollinated progeny population of varieties, in which improvement is sought, is used. Rootstocks were first used in European vineyards in the late 1800’s to combat devastating Phylloxera outbreak. Rootstock can be used to improve vigor, production and help to sustain the health and survival of fruit crops

Quantitative genetics is often considered to be the bedrock of crop breeding research. Understanding and analyzing complex nature of genetic data based on its quantitative traits is of much importance in any perennial crop improvement research. Genetics and statistics are the two sides of a same coin to unravel complex problems in the study of inheritance and heredity of quantitative traits. Application of statistical methods in genetics probably dates back to 1880’s when Galton (1886), in his historic study about inheritance of mid-parent’s heights on their children, adopted the theory of regression. In the early 1990’s, Fisher (1918), in his study on correlation in Mendelian inheritance, utilized the analysis of variance (ANOVA) technique. The distribution of quantitative traits in a population follows the normal distribution (also known as Gaussian distribution or bell curve), the central concept of statistical theory. Number of research experiments after these two historic studies essentially concentrated on analyzing vast genetic data of several quantitative traits and attributing the source of variability in traits to genetic variation. Furthermore, as emphasized by Narain, (2010) the classical genetic basis of continuous variation based on the infinitesimal model of Fisher and mostly using statistical methods has since undergone major modifications. Largely due to rapid advances in computational tools for data analysis, complex techniques, which better explain the reality in the vast data generated by the researchers, are being employed. Accordingly, an attempt is made not necessarily be exhaustive, to discuss about traditional data analysis techniques leading to modern aspects with special reference to perennial fruit crops.

Introduction

Fresh and processed products derived from fruit crops provide vital contributions to human nutrition, health, and well-being, and collectively their production constitutes the economic backbone of many rural communities worldwide. Rapid development and distribution of new cultivars with improved characteristics which meet the industry, market (both domestic and export), and consumer preferences is the need of the day. Conventional methods of perennial fruit crop improvement have almost exclusively relied on traditional breeding techniques. These techniques are expensive, time consuming and space requiring, especially for tree species due to the need of a large population of seedlings from which only a few promising ones are selected. The juvenile period of tree crops may last three to five years before onset of fruits so that 20 years or more are common before the successful introduction of a gene of interest (Baird et al., 1996). Therefore in this context, molecular tools recently made available for breeders have become tools of choice because they permit to reduce cost by fastening the selection process of woody fruit plants. Further, traits of importance like fruit quality, resistance to diseases, high yield etc. are polygenic in nature for which classical breeding is generally not suitable for detection and selection of traits. A quantitative trait locus (QTL) analysis with help of markers and linkage maps may be more appropriate for detection of such traits of interest. Also, molecular markers are being used for maintenance of core collections, for the assessment of genetic diversity between genotypes and fingerprinting.

Introduction

Pollination is an essential ecosystem service for the maintenance and conservation of biodiversity on the earth. Many food crops, barring cereals, are entomophilous in nature and rely on insects for pollination. The pollinators in turn are benefited by obtaining floral resources such as nectar, pollen or both. This mutualism has evolved over centuries and been helping both natural terrestrial ecosystems as well as man-made agro-ecosystems. Pollinators such as bees, birds and bats contribute to 35 per cent of the world’s crop production, increasing outputs of 87 of the leading food crops worldwide (FAO, 2009). The total economic value of crop pollination worldwide has been estimated at €156 billion annually (Gallai et al., 2009). The area covered by pollinator-dependent crops has increased by more than 300 per cent during the past 50 years (Aizen and Harder 2009). Pollinators are found in diverse groups of the animal kingdom, including birds, bats, reptiles, insects, etc. Among them, insects particularly honey bees, dominate in providing pollination services to several plants. There are about 19,000 described species of bees in the world (Linsley, 1958) and, with the exception of one species, Apis mellifera L., the domestic honey bee, all of them are grouped under the general term ‘wild bees’. India is endowed with the greatest biodiversity as far as honey bee species are concerned and is home to five species viz., A. cerana, A. florea, A. dorsata, A. andreniformis and A. laboriosa besides hosting A. melllifera, an introduced one. In addition, several other pollinators including stingless bees, carpenter bees, bumble bees, megachilids, halictids, sphecids, andrenids, syrphids, etc. occur in several agro-ecosystems (Thakur, 2012). Studies on crop pollination by insects are becoming increasingly critical because of a perceived global decline in pollinator stocks, with great economical and conservation consequences (Ghazoul, 2005a, 2005b; Steff an-Dewenter et al., 2005). In the recent years, there has been a concern about declines in both wild and domesticated pollinators, especially honey bees (Reddy et al., 2012a). A large proportion of horticultural crops is potentially vulnerable to declines in honey bee and other pollinator insects (Table 1). One of the essential requirements to adequately evaluate the importance of animal pollination for food production and the impact of pollinator losses is to determine the pollination needs of different cultivated plants. However, detailed studies of crop pollination requirements are incomplete in many crops (Klein et al., 2007).

Mutations are sudden and heritable changes in the genetic material. They can result in deletion, inversion and translocation of certain portions in the chromosomes, which can result in the changed expression of a trait due to the interaction of alleles within or without the locus, sometimes the effects revert back or can be heritable.

Most of the fruit crops are highly heterozygous. However, heterozygosity is one of the advantages when it comes to mutation. In highly heterozygous crops wherein there is a need for improvement in a single trait, mutations have been of great use. One of main limitations is use of vegetative material, which due to the unlikelyhood of uniform penetration and distribution of mutagenic agent can result in chimera. Although hybridization and selection have made a fair dent in the improvement of fruit crops, mutation is one of the methods that can be relied upon to develop pre-breeding lines and to bring about change in the quantitavie traits. Another very important fact is that there are crops like grapes wherein a lot of spontaneous mutants have become established varieties viz., Sonaka and Saritha to quote a few. Some of the existing varieites wherein one or two traits need to be improved, mutation would greatly help in this in comparatively short time. In some of the crops like sapota, wherein the conventional breeding would take long time, mutation can be resorted to both for inducing variability in the germplasm as well as for trait improvement. It is also to be noted here that mutation breeding can be a good supplement for conventional breeding, more so with the emergence of tissue culture propagation, which often throws up spontaneous mutants. Mutation as a methodology can also be tried in some fruit crop spp where there is no disease resistance source within. It can also be adopted in cases where there is a need to break linkages.

Apomixis was defined by Winkler as replacement of the normal sexual reproduction by asexual reproduction, without fertilization. This definition notably does not mention meiosis. Thus “normal asexual reproduction” of plants, such as propagation from cuttings or leaves, has never been considered apomixis, but replacement of the seed by a plantlet, or replacement of the flower by bulbils are types of apomixis. Apomixis deviates from sexual reproduction in several aspects: modification or complete omission of meiosis, formation of unreduced megaspores, parthenogenetic development of embryo, and autonomous, or pseudogamous, endosperm development (Ramulu et al., 1998). Apomixis produces embryos or seed progeny that are exact genetic replicas of the mother plant. The main advantage of apomixis over sexual reproduction is the possibility to select individual plants with superior characteristics and to propagate them clonally through seeds. Apomictically produced offsprings are genetically identical to the parent plant. In flowering plants, the term “apomixis” is commonly used in a restricted sense to mean agamospermy, i.e. asexual reproduction through seeds.

Fruit crops, majority of them are generally perennial in nature and owing to the outcrossing during their evolutionary stages, they are highly heterozygous. Genetic improvement is extremely difficult due to the complex genetic nature. The germplasm collection, conservation and evaluation take long time and area. Although the concept of core collection is very much valid, there is always a question mark when it comes to highly heterozygous crops as to whether the sample is good enough to represent the population. Due to the propagation by seeds, the large variability present needs to be evaluated for various characteristics. The genetical studies carried out in many of these crops are not conclusive and the progeny performance cannot be predicted. The biometrical methods to estimate the parameters viz., combining ability, heritability using the methodologies such as diallel have proven to be futile excercises to a very great extent. Parental selection, which is so vital for a successful breeding programme is very difficult as mainly selection has to be based upon the phenotype. Breeding for particular traits like biotic or abiotic stress has been difficult as resistance is not found within the spp and interspecific / intergeneric hybridization is difficult because of incompatibility barriers for eg the ‘PRSV’ breeding programme in papaya. In highly heterozygous crop like mango, there exists strong genotype x environmental interaction, which alters the performance of improved varieties.

The concept of origin of cultivated plants was first developed by A de Candolle and the geographic centres of variability were developed by Vavilov. He identified Asia as a major centre with “Indian centre” of North East region as primary or secondary centre of origin for many crop plants. Plant genetic resources are of great importance as they form the basic raw materials to meet the current and future needs of crop improvement programmes. A wider genetic base, thus, assumes priority in plant breeding research aimed at developing new varieties for increased crop production (Paroda, 1991). This diversity comprises of native landraces, local selections, elite cultivars and wild relatives of crop plants. The collection and conservation of this diversity in a systematic manner is the primary responsibility of all plant genetic resources institutes/centres. The mention of use and cultivation of fruits can be seen in epics like ‘Ramayana’. Plant genetic resources are thus our heritage, which need conservation for posterity. During the long period of domestication, utilization and cultivation, a wide array of fruit crop variability got generated by natural means and through both conscious and unconscious selection. Huge wealth of variability also got generated/adapted and diversified by crop introductions in the exotic environment or through migration of human population.