eChapters

X    :    Times; power; multiplied by.

Xenobiotic    :    Compound foreign to biological systems. Often refers to humanmade compounds that are resistant or recalcitrant to biodegradation and decomposition.

WORLD HISTORY

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

INTRODUCTION

Various procedures which are used for genetic improvement of crop plants are known as breeding methods. The breeding approaches that are more commonly used for genetic improvement of crop plants are called conventional breeding methods. Following conventional breeding methods were followed in improvement of crops.
    (A)    Plant introduction
    (B)    Pureline selection
    (C)    Mass selection
    (D)    Progeny selection
    (E)    Synthetic and composite breeding
    (F)    Pedigree method
    (G)    Bulk method
    (H)    Backcross method
    (I)    Heterosis breeding
    (J)    Clonal selection

MUTATION BREEDING

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

MOLECULAR BREEDING

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

Genetic markers

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

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

INTRODUCTION

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

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

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

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

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

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

Gerbera (Gerbera jamesonii), a tender, stemless, perennial flowering plant, belongs to family Asteraceae. Gerbera was named in honour of the German botanist and naturalist “Traugott Gerber” who was a friend of Carolus Linnaeus. Gerbera is very popular and widely used as cut flower or as a decorative garden plant. It was discovered in 1878 near Barberton, eastern Transvaal (South Africa), therefore, referred as the Barberton daisy or Transvaal daisy. It is ideal for beds, borders and pots and is the fifth most important cut flower in the world.

Gladiolus (Gladiolus spp.) belongs to family Iridaceae and subfamily Ixioideae. Gladiolus is a Latin word, the diminutive of “gladius” meaning sword, sometimes called as sword lily. The plant is herbaceous perennial and semi-hardy. It is commonly grown from rounded, symmetrical corm, which is enveloped in several layers of brownish, fibrous tunics. The cultivated gladiolus is a complex assemblage of cultivars originating from complex ancestry of natural selection or hybridization involving several species. Modern garden gladiolus is a complex of at least twelve species (Raghava, 2000). It is an important commercial cut flower in both domestic and international markets.

Heliconia belongs to family Heliconiaceae is popular as ornamental plants and cut flowers because of their brilliant colours and exotic appearance. The genus name “Heliconia” is derived from “Helicon”, a mountain in southern Greece regarded by the ancient Greeks as the home of the Muses, thus suggesting the relationship between these plants and the bananas, genus Musa (Berry and Kress, 1991). Unique features of the Heliconiaceae are (1) medium to large erect herbs rising from underground rhizomes; (2) each erect shoot is composed of a stem and leaves, whereas the stem is made up of an axis covered by overlapping sheathing leaf bases, technically called a pseudostem; (3) inverted flowers and (4) the presence of a single staminode. Heliconia has long been popular horticulturally because of their showy inflorescences. It was so attractive that early explorers of the tropics returned to Europe with several species that became prized green house specimens. Heliconia, grown in nearly all of the tropical regions of the world, including Africa and Asia. In India, heliconia is grown in North-East region and Kerala.

Kangaroo Paws (Anigozanthos spp.) belongs to family Haemodoraceae. It is commonly known as Sword-like or Iris-like. The word Anigozanthos was coined by French botanist Jacques de La Billardiere. This is derived from Greek words “anoigo” meaning to “expand or unequal” and “anthos” meaning “flower or irregular corolla”. It can be used as cut flower, pot plant, landscape plants or dry flower (Gui et al., 2005). The kangaroo paws is gaining popularity among gardeners, horticulturists, nursery man also in world market due to its beautiful, unique, colourful pattern of flowers and also being perennial in nature.

Lilium is a popular genus of ornamental bulbous plants, belonging to family Liliaceae. Lilium is originated from a Greek word “li” meaning whiteness. It is an herbaceous perennial plant having scaly bulb. Despite the range of forms and their popularity as garden plants, there are two main groups of commercial importance as cut flowers i.e. Asiatic and Oriental Hybrids. They are the result of interspecific hybridization. However, intraspecific and interspecific hybridization face the hurdles like interspecific incompatibility, embryo abortion, degeneration of ovule, poor seed set and pollen sterility. There are several breeding methods and techniques which have been used to overcome these hurdles.

Lisianthus is among top ten cut flower crop of the world. In short duration of 20-30 years it become top ranking flower crop of world due to its beautiful flowers which bears beauty of different top ranking old commercial flower crops with variation in flower colours, shape, size with long vase life. It looks like tulips as they began to open and as poppies when fully opened, gaps between the petals appears like daisy, ruffled petals resemble carnations and the most important one is the flower buds and opened double type lisianthus resemble rose buds and open flower respectively and there is no doubt that this is a primary reason for consumer acceptance. Double flowered lisianthus are more demanded in U.S. as cut flower about 80% of lisianthus market whereas, single flowered are more dominant in Japanese and European markets. In Japan over 129 million cut stems were sold in 2001 placing it on number one position in Europe, over 122 million cut stems were sold in 2001 and placing it in top ten ranking and in the United States over 14 million cut stems were sold in 2002, it is not only popular as a cut flower but also as a bedding plant and a pot plant in market (Grueber et al., 1985, Halevy and Kofranek, 1984, Roh and Lawson, 1987, Tjia and Sheehan, 1984, Tija and Sheehan 1986, Skrzypczak et al., 1993 and Harbaugh, 2007), a plant bears 20-30 flowers per plant (Skrzypczak et al., 1993).

Tulip cut flower is first among the bulbous ornamentals due to its attractive colours and exquisite flowers. Tulip is a member of Liliaceae family, commonly grown from bulbs. The name tulip is derived from the Persian word “toliban” meaning “turban”, which is an appropriate term to describe the flower shape of certain tulips. The mother bulb dies and is replaced by several daughter bulbs, each of which is an annual unit of growth borne in the axils of the mother bulb scale. Tulips are basically grown for three purposes i.e. bulb production, forcing as cut flower and potted plant and for landscaping (Singh, 2006). The world tulip flower industry is dominated by the Netherlands. Another important tulip producing country is France.

Zantedeschia commonly known as Calla lily, Richardia or Pig lily belongs to family Araceae. It is the only genus in the tribe Zantedeschiae which is the sub family philodendroideae. The name Zantedeschia was given as a tribute to Italian botanist “Giovanni Zantedeschi” (1773-1846) by the German botanist Kurt Sprengel (1766-1833). It is considered by many people in the Republic of Ireland to be a symbol of Irish Republicanism. The Romans valued them so much that they often decorated the edges of the bloom with filaments of gold. These spectacular flowers are beginning to rival the rose in popularity for bridal bouquets. In India there has been initiation in the production of tubers of Calla and few tissue culture labs have started production for New Zealand and Dutch Companies. It is used as potted plants, callas are very attractive. It is used for decoration throughout the spring and early summer months focal point for a spectacular arrangement or bouquet.

China aster (Callistephus chinensis L. Nees) belongs to family Asteraceae. It is a half hardy and branching annual. Its generic name Callistephus is derived from two Greek words “kalistos” meaning beautiful and “stephos” meaning a crown alluding the large colourful flower heads. Plant is erect having hispid-hairy branches (Bailey, 1963). It is propagated through seed. It is cultivated as cut flower both in the field and under protected condition in temperate countries (Post, 1956 and Warren Auman, 1980). Whereas, in India it is widely grown in Karnataka, Tamil Nadu, West Bengal and Maharastra for cut as well as loose flower production (Janakiram et al., 2001).

Chrysanthemum (Dendranthema spp.) belongs to family Compositae (Asteraceae). It was named by Carolus Linnaeus from the Greek prefix “chrys” means golden and “anthemon” means flower. Chrysanthemum morifolium is the modern florists chrysanthemum, which evolved as a result of endless variation and hybridization from C. sinensis, C. indicum and C. ornatum (Bailey, 1963). This group is also distinguished as C. hortorum. The name of C. morifolium Ramat has been changed to Dendranthema grandiflora Tzvelev (Anderson, 1987, Heywood and Humphries, 1977). Chrysanthemums are mainly herbaceous perennial and bear flowers in capitula. Chrysanthemum perennates in nature by means of stolons and is readily propagated through basal stem cuttings. It ranks second next to roses in importance among the cut flower crops in the world.

Modern rose (Rosa × hybrida) belongs to family Rosaceae. Rose is derived from Greek word “Rhedon” means fragrance. From the ancient time its beauty and attractiveness drag the attention of breeders to create new colours and types. Present cut roses are complex hybrids developed through interspecific hybridization, polyploidy with male and female sterility and these heterozygous genotypes are propagated vegetatively. Rose occupies the first rank among the cut flowers in international market and in India it occupied first position in cut flower export trade.

Tuberose (Polianthes tuberosa L.) belonging to family Amaryllidaceae is half hardy, perennial, bulbous plant. Bulbs are made of scales and leaf bases and stem remains concealed within scales. The generic name Polianthes is derived from Greek word “polios” meaning shining or white and “anthos” meaning flower, in allusion to the blooms of the common tuberose and species tuberosa, the plant being tuberous in nature. Tuberose is commercially cultivated in tropical and sub tropical areas for cut and loose flower trade and also for the extraction of it’s highly valued natural flower oil.

Cyclamen (Cyclamen persicum Mill.), belonging to family Primulaceae, is cultivated throughout the Temperate Zone. Many people have enjoyed the charming plants as potted and/or garden plants. The cyclamen is one of the most famous and important commercial ornamental plants in many countries. It is commonly grown for its flowers, both outdoors and indoors in pots. It is used on a terrace, in flower boxes, in hanging baskets or in beddings. Several species, particularly Cyclamen hederifolium, are hardy and can be grown outdoors in mild climates such as Northwest Europe and the Pacific Northwest of North America. The cyclamen commonly sold by florists is C. persicum, which is frost-tender. Selected cyclamen cultivars can have white, bright pink, red or purple flowers. The use as cut flower is not important part of cyclamen production (Grey-Wilson, 2002), but not rare in Europe, especially in Germany. Some cultivars for cut flower production were bred in Europe, but cut flower cyclamen production is not popular in USA and Japan. Its popularity as pot plant led to many studies on the group, including cytology (Bennett and Grimshaw, 1991), hybridization (Gielly et al., 2001 and Grey-Wilson, 2002) and phenology (Debussche et al., 2004).

Freesia is ornamental flowering plant belongs to family Iridaceae subfamily Ixioideae. Freesia is named after a physician and botanist from Germany named “Friedrich H.T. Freese” (1795–1876). Dr. Christian P. Ecklon, a collector of plants from South Africa, named the flower after his friend and student. Modern freesias are known as Freesia × hybrida and cultivated for cut flowers. Freesia is grown for two purposes i.e. cut flower and pot plant.
 
It is excellent cut flowers because of its appealing shapes and found suitable for various types of arrangements and bouquets. Wide range of colour increases its beauty. Hence, its flower demand increased dramatically in recent year in global market. Forced freesias are grown as pot plant. Colours in freesias consist of pink, red, orange, yellow, blue, lavender, cream and white. Some flowers are multicoloured and possess several variations of colour within the same bud. Because of their delectable fragrance, Freesias have been drafted as a vital ingredient in many fragrance oils. Freesia fragrance oils are utilized for many oil burners and vaporizers. It is used as an essential fragrance in potpourris. Freesia essence oil is high grade essence oil. This is because it is undiluted, alcohol free, and long lasting. The oil is used for aromatherapy to scent candles, soaps, massage oils, bath oils and perfumes.

Gypsophila is herbacaeous annual or perennial flowering plant belongs to family Caryophyllaceae. It contains several ornamental species of which Gypsophila paniculata L. is the only species used as a cut flower (Zvi et al., 2008) and it is applied as filler in flower arrangements (Jones, 1995 and Rehman, 2002). Gypsophila derived from “gypson” meaning chalk and “phylos” meaning lover, an etymology which alludes to its preference for calcareous soils (Vettory et al., 2013). Mainly found in temperate or warm-temperate regions in the Northern Hemisphere, best developed in the Mediterranean region and Near East (Ataslar et al., 2009 and Cronquist, 1981). It is a perennial plant often grown commercially as an annual crop. Root is rich source of triterpine saponins (Henry, 1993, Hostettmann, 1995 and Gevrenova et al., 2010) which are used for commercially in medicines, detergents, adjuvents and cosmetics (Hostettmann, 1995, Tschesche and Wulff, 1973 and Gevrenova et al., 2010).

Stock or Gillyflower (Matthiola spp.) belongs to family Brassicaceae. It is a hardy annual, biennial and perennial plant, flowering in terminal clusters. Matthiola incana is ornamentally important and grown for various purposes i.e. cut flower, fragrance, pot culture, etc. This species develops a woody base in areas where it grows as a biennial or short-lived perennial, hence the name of stock. Generic name “Matthiola” was given in the honour of “Dr. Pietro Andrea Gregoria Matthiole” (1501-1577), personal physician of Emperor Maximilian of Austria. “Incana” means “hairy or gray-white” in reference to plant leaves. It exists as both single and double forms and is valued for fragrant flowers that can be used as fresh or dried cut flower. They are excellent pot plants for the greenhouse in winter and spring and provide good cut flowers. Flowers are well arranged on a long column and colours are variable from white to rose, crimson, purple, yellow, mauve, pink, etc. The highly fragrant flowers are used as a garnish, especially with sweet deserts. Many old names were given to Matthiola incana including stocks, sea stocks, wallflowers and wall or gillyflowers.

Crossandra belongs to family Acanthaceae. It is also known as Kanakambaram in Tamil or Kanakambara in Kannada and Fire cracker in English because of cracking sound during opening of seed pod. Crossandra is derived from Greek word “krossoi” meaning fringe and “aner” meaning male i.e. fringed anthers. Crossandra is an evergreen shrub and one of the important loose flower used for adornment. The flowers are commonly grown for flower adornment in the form of garlands, venis and gajras. Though it is not fragrant, flowers are very popular because of its attractive bright colour, light weight and good keeping quality. These are used for making garland, either alone or in combination with jasmine flowers. Using crossandra flowers in combination with jasmine is becoming increasingly popular in India, particularly in southern parts, because the jasmine flowers provide colour contrast and the desired fragrance. Crossandra varieties show a remarkable range of colours, varying from orange, pink, red, yellow and double coloured blue-type with white throat.

Jasmine (Jasminum spp.) belongs to the family Oleaceae, order Oleales are climbing, trailing or erect shrubby plants and there are both deciduous and evergreen species. The generic name Jasminum is derived from Arabic word “Jassamine”, “Jasmin” and “Jasminum” (Bailey, 1963). Flowers are white, yellow or rarely reddish. Flowers are used for making garlands and Veni. Jamine oil extracted from the flower is highly valued in perfumery industry. France, The Netherlands, Italy, Belgium, Algeria, Turkey, Morocco and Tunisia are major jasmine oil producing countries (Singh, 2006).

Marigold (Tagetes spp.) an annual flowering plant belongs to family Asteraceae, alternately known as Compositae. The word “marigold” means “Mary’s Gold” and refers to the “Virgin Mary”. However, word “Tagetes” named after the Etruscan God “Tages” who supposedly emerged from the earth as it was being ploughed and was imbued with the power of divination. Cultivated species include Tagetes erecta commonly referred as African marigold and Tagetes patula as French marigold. Marigold commonly propagated by seed and cutting is a leading loose flower of India. Selection of variety is favoured by a higher proportion of double inflorescences.

Cattleya belongs to the family Orchidaceae. It is highly important in floriculture and has been cultivated since the 19^th century. The name “Cattleya” was given in the honour of “Sir William Cattley”. Cattleyas have earned the reputation as the “Queen of Orchids” and are known to the public as the ultimate in floral corsages. While no longer the reigning queen of the orchid floral industry it is difficult not to be impressed by a well-flowered Cattleya. No longer limited to white and various shades of lavender and purple, high quality flowers occur in all colours except true blue and black and in a wide range of plant sizes. They are widely known for their large, showy flowers and were used extensively in hybridization for the cut-flower trade until the 1980s when pot plants became more popular.

Cymbidium is a genus in the orchid family Orchidaceae. It was first described by Olof Swartz in 1799. The name is derived from the Greek word “kumbos”, meaning “hole”, “cavity”. It refers to the form of the base of the lip. The flowers are long-lasting, both on the plant and when cut large attractive and available in a wide range of colours. Smaller plants are now coming into vogue as decorative pot plants. These have smaller flowers but they are as desirable as the standard varieties and often more acceptable in modern homes. The popularity of miniature cymbidium is now spreading from Asia to the worldwide orchid community. These ancient flowers have been treasured in numerous societies for nearly two thousand years. Many orchid lovers are most charmed by its fragrance and form rather than its petite size.

Dendrobium is a huge genus of orchids. It was established by Olof Swartz in 1799. The name is from the Greek word “Dendron” means “tree” and “bios” means “life”; it means “one who lives on trees”, or essentially, “epiphyte”. The truly spectacular genus Dendrobium contains the largest diversity of horticulturally interesting specimens. More than 1,000 natural species make dendrobium the second-largest orchid genus. Dendrobiums are among the most commonly encountered orchids in the retail trade. Flowers are very long-lasting both on the plant and once cut, looking fresh for up to three weeks or more. Faded flowers on the bottom of the stem can be removed to encourage upper buds to open. Dendrobiums are sturdy orchids that can add a focal point to any room.

Paphiopedilum is a genus of the orchid subfamily Cypripedioideae  and family Orchidaceae. It is derived from Paphos and ancient Greek word “pedilon” means “slipper”. Paphiopedilums are often called “slipper orchids” because of their unique pouch. The pouch traps insects seeking nectar and to leave again they have to climb up past the staminode, behind which they collect or deposit pollinia. Paphiopedilum has a highly ornamental value being the treasure of Orchidaceae. They are easily grown as houseplants and their care is very similar to African Violets.

Vanda is a genus in the orchid belongs to family Orchidaceae. The name Vanda is derived from the Sanskrit name for the species Vanda tessellate. The name Vandas will be used here to cover all vandaceous orchids including Vanda, Ascocentum, Aerides, Renanthera, Rhynchostylis, etc. and hybrids between them. Although there are some vandaceous orchids that originate in mountainous areas most are low-level plants that love warm temperatures. This has contributed much to the work of hybridists producing flowers for the cut flower market. It is one of the five most horticulturally important orchid genera because it has some of the most magnificent flowers to be found in the entire orchid family. It is highly prized in horticulture for its showy, fragrant, long lasting and intensely colourful flowers.

Year                    Milestones
1951    :    First amino acid was sequenced by F. Sanger and H. Tuppy.

1953    :    J.D. Watson and F.H.C. Crick proposed that DNA is a double helix.

1958    :    Discovery of DNA polymerase by Kornberg’s group and DNA replication studies began.

1959    :    Isolation of RNA polymerase.

Wild relatives of cultivated plants constitute a part of crop genepool, which possess genes that have great potential for their utilization in crop improvement programmes. Wild genepools especially those occurring in biotically disturbed habitats are under threat of genetic erosion and require immediate collection to make use of their wider adaptability, tolerance/resistance to disease, insect-pests, yield, quality attributes and other biotic and abiotic traits. The wild relatives of crop plants occur in all the major phytogeographical regions of India as component of different vegetation types and exhibit variable life forms and habitat specificity. High priority demand is towards collection of those that are at the risk of erosion due to habitat disturbance by manmade/natural causes and over-exploitation of species for commercial use.

INTRODUCTION

Heterosis has contributed significantly towards increased crop production and it has become the basis of multibillion dollar agro-businesses in the world (Phillips, 1999). Hybridization is the important way that can create genetic variability and make new options. The F1 population is obtained from the crossing of two homozygous but genetically dissimilar gametes or individuals (purelines in self pollinated crops or inbred lines in cross pollinated crops) that shows increased or decreased vigour over the better or mid parent value. Heterosis is maximum in F1, generation which diminishes gradually in later generations. Hence, production of F₁, hybrid seeds of different flower crops is considered as the extreme focused area in floriculture industry.

Since floricultural and ornamental crops are grown for aesthetic purpose and are non-edible there is likely to be less concern in bio safety issues compared to other food crops. Hence there is considerable potential for developing transgenics in ornamental crops. Advances in transgenic technology provide new opportunities for manipulation of the genome. These will have significant impact on expanding and diversifying the gene pool of crop plants, introducing specific genes and shortening the time required for the production of new varieties or hybrids. Molecular breeding is beneficial to increase the production and quality by creating plants with enhanced resistance to diseases, insects or viruses and increased tolerance to environmental stresses like salinity, temperature or drought. Through this technique genes for shelf life, flower colour and architecture may be directly transferred to develop new varieties that are tailor made to customer preferences. Bioluminescent orchids and blue roses are the significant outcomes of the genetic transformation studies in ornamentals (Swarnapiria, 2009).

INTRODUCTION

The seed (or zygotic seed) is the vehicle that connects one generation to another in much of the plant kingdom. By means of seed, plants are able to transmit their genetic constitution in generations and therefore seeds are the most appropriate means of propagation, storage and dispersal. A synthetic seed or ‘synseed’ is “an encapsulated single somatic embryo”, i.e., a clonal product that can be handled and used as real seed for transport, storage and sowing and that, therefore, would eventually grow either in vitro or ex vitro, into a plantlet through a process of “conversion”. Now a day, artificial seed technology is one of the most important tools to breeders and scientists of plant tissue culture.

INTRODUCTION

Seed is one of the most vital and important inputs for increasing agricultural production. Commercial flower seed production is an international business involving highly specialized growers. Compared with the production of seeds of cereals, pulses oilseed even vegetable seeds, it is done on a relatively small scale. However, a large number of species are being produced under very different cultural conditions. It seems to have great scope for expansion in developing countries like India, especially under northern India climatic zones having favourable growing conditions, skilled and cheap labour.

Plants belonging to the Rhododendron subgenera Pentanthera (deciduous) and Tsutsusi and Azaleastrum (evergreen) are called azaleas. Azalea belongs to family Ericaceae. Azaleas are one of the favourite ornamental plants used by home owners and professional landscapers. They are used as foundation, accent, individual specimen plants, and as mass plantings. Azaleas are good companion plants, working well in designs with many trees, shrubs and ground covers, offering a variety of landscape options. Azaleas can be found in all ranges of colours, from delicately pink-tinged white to strong, bright red, and there are species that has the startling colour of flame. Its bold colour scheme has caused people to carry it far and wide, for use wherever a sudden note in strong hue is appropriate among the milder expressions of the rest of the flowers. The evergreen azalea, Rhododendron simsii  Planch., is one of the most important pot plants in Western Europe and the USA. The breeding history of this vegetatively propagated plant is a relatively short one, and breeding has been focused on flower characters because the public is continually asking for new flower colours and flower types.

Bougainvilleas (Bougainvillea spp.) are tropical and sub tropical plants belonging to Nyctaginaceae family. They are thorny, evergreen and some are fragrant. Bougainvillea is named for “Louis A. de Bougainville”, a French navigator (1729-1811) who discovered the plant in Brazil in 1768. Bougainvillea plant spreading horizontally or hanging downwards as it is climbing upwards, it makes itself at home in almost any situation. It can be grown as a hedge, groomed as a ground cover, pruned as an espalier, trained as a tree or contained in a pot in a variety of shapes. Bougainvillea is ideal for bonsai. Red, violet, orange, yellow or white bracts appear at the ends of new growth.

The  Camellia  is  one  of  our  most  beautiful  and most  appreciated ornamental  plants belonging to the family Theaceae. The genus Camellia was named by Linnaeus after the Jesuit botanist “Georg Joseph Kamel”. Camellias represent gratitude, love and perfection and are a perfect way to tell someone they possess those qualities. The camellia is the state flower of Alabama. Industrial use of Camellia is in the oil industry. Seeds of several species belonging to the sections Oleifera, Paracamellia, Camellia and Furfuracea are used for extracting edible oil, which is used extensively for cooking in China (Ming, 2000, Gao et al., 2005 and Zhang et al., 2007). In China, more than 3 million hectares are used for camellia oil production and nearly 645000 tons of seeds are harvested each year, which yield nearly 164000 tons of edible oil (Ming, 2000 and Gao et al., 2005).

Lagerstroemia indica belongs to family Lythraceae commoly known as Crape myrtle. It it grown well in India for various landscape purposes. It is called Sawani or Shravani (Hindi), Dhayti (Marathi), Chinagoranta (Telugu), Pavalakkurinji (Tamil). Lagerstroemia a long period of striking rainy season flower colour, attractive fall foliage and good drought-tolerance all combine to make a favourite shrub or small tree for either formal or informal landscapes. It is a deciduous, multi stemmed; rounded crown; dense branching and is highly recommended for planting in urban and suburban areas.

Hibiscus a well known member of the family Malvaceae, grows as an evergreen shrub plant. The plant is extensively cultivated as an ornamental plant that bears large flowers on the bushy hedges. These enormous flowers are usually dark red in colour and are not usually fragrant. The huge size and the reddish colour and hues attract humming birds (Kumar and Singh, 2012). The generic name is derived from the Greek word “hibiskos” which was the name Pedanius Dioscorides gave to Althaea officinalis. Hibiscus rosa-sinensis was named by Carolus Linnaeus. The Latin term “rosa-sinensis” literally means “rose of China”, though it is not closely related to the true roses. Member species are often noted for their showy flowers and are commonly known simply as hibiscus, or less widely known as rose mallow. The hibiscus is used as an offering to goddess Kali and Lord Ganesha in Hindu worship. Hibiscus is an important flowering and garden plant. It has various medicinal values (Chopra et al., 1996 and Sayed et al., 2012).

The genus Hydrangea is the best-known member of family Hydrangeaceae tribe Hydrangeae from the Asterid order Cornales. With more than two centuries of horticultural trade, Hydrangea cultivars are among the most popular ornamental shrubs worldwide (McClintock, 1957 and Kardos et al., 2009). Hydrangea (Hortensia) is a very popular ornamental plant for gardens. Hydrangeas occur most often on partly shaded but open slopes, rock edges, cliffs, roadside banks, edges of woods, or in moist open woods. Usually, restricted to the more moist, protected slopes. Recently it is commercialized for the production of cut flowers (Sacco et al., 2012). In India is widely grown in hilly areas.

Ixora is an ornamental plant which is a medium-sized, tropical flowering, evergreen shrub that is used in landscapes. The genus Ixora belongs to the family Rubiaceae. The plants have glossy green leaves which are arranged oppositely along each stem. All Ixoras produce clusters of star-shaped flowers on stem tips or terminal growth. They are grown for their beautiful flowers which bloom in summer in clusters of different shades of red, pink or yellow (De Block, 1998 and Husain and Paul, 1988). The colour of the wild flowers is red or reddish-orange but ornamental varieties may have white, yellow, salmon or pink flowers. It is commonly known as West Indian Jasmine. The other common names of this plant are Jungle Geranium, Flame of the Woods, Jungle Flame, Burning Love, Red Ixora, Ixora, Amor Ardiente, Cruz de Malta, Dola de Coral, Equisosea and Rajana (Griffiths,1994 and Liogier,1997), Rangan, Kheme, Ponna, Chann Tanea, Techi, Pan, Santan, Jarum-Jarum and many more. Members of Ixora prefer acidic soil and are suitable for bonsai (Frommer, 2001). I. coccinea is used extensively for landscaping and is also grown as a potted ornamental (Lakshmanan et al., 1997). Ixora coccinea and Ixora parviflora are generally used as the ornamental plants in gardens and parks.

Nerium (Nerium oleander L.) belongs to family Apocynaceae is a Mediterranean evergreen shrub characteristic of watercourses, gravely places and damp slopes (Portis et al., 2004 and Herrera, 1991). The first Oleanders came to subtropical Galveston in 1841. Joseph Osterman, a prominent merchant, brought them from Jamaica. After distributing these oleanders, these new plants were growing throughout the city. Later as early as 1908, an editorial in the Galveston Tribune observed that the oleander was emblematic of Galveston. In 1910, The Galveston Daily News also reported that Galveston was known throughout the world as “The Oleander City” and in 1916, an article named it one of the most beautiful cities in the South. It is widely grown as an ornamental in warm temperate and subtropical regions, due to its abundant and long-lasting flowering and moderate hardiness. It is used for screens, hedging along highways, planting along beaches and in urban areas as, by removing suckers and leaving just a few stems, it can also be formed into very attractive small trees (Portis et al., 2004). Nerium oleander is among the most toxic of all ornamental plants. More than fifty toxins have been isolated, including cardiac glycosides, general cell toxins and the strychnine-like compound rosagenin. The ancient city of Volubilis in Morocco took its name from the old Latin name for the flower.

Rhododendron belongs to family Ericaceae. The word “Rhododendron” is derived from the ancient Greek word “rhódon” which means rose and “déndron” which means tree. This genus is characterized by shrubs and small to (rarely) large trees. The smallest species grow up to 10–100 cm tall and the largest Rhododendron giganteum is reported to grow over 30 m tall. They are noted for their clusters of large flowers. The alpine species have small flowers and small leaves and tropical species grow as epiphytes. The colour of the rhododendron flower is available in nearly every colour of the rainbow including various shades of blue, yellow, pink white, red, orange and purple. Rhododendron flower from January through August, depending on the location and the climate.