eChapters

Abstract

Natural sunlight is the cheapest source available, but for horticulture it is not always attainable in sufficient quantities. Therefore, the use of artificial light has become very common in order to increase production and quality. Under artificial lighting technologies, LED lighting is one of the technology that can help in producing crops and flowers in a more effective and sustainable way around the world. The benefits of LEDs are that the spectrum and intensity can be selected and adjusted, the energy efficiency is higher than most conventional light sources and their small size, durability, long lifetime, cool emitting temperature, and the option to select specific wavelengths for a targeted plant response make LEDs more suitable for plant-based uses than many other light sources. These advantages, coupled with new developments in wavelength availability, light output, and energy conversion efficiency, can bring about a revolution in horticultural lighting. Light quality plays a major role in the appearance and productivity of ornamental and food specialty crop species. Far-red light, for example, is important for stimulating flowering of long-day plants (Deitzer et al., 1979; Downs, 1956) as well as for promoting internode elongation (Morgan and Smith, 1979). Blue light is important for phototropism (Blaauw and Blaauw-Jansen, 1970), for stomatal opening (Schwartz and Zeiger, 1984), and for inhibiting seedling growth on emergence of seedlings from a growth medium (Downs, 1956). The interactions are complex and continue to be unraveled at the molecular level (Devlin et al., 2007), but much of our understanding of these responses comes from studies with narrow-waveband lighting sources, in which LEDs provide obvious advantages. Thus, one potential role of LEDs in horticulture could be to enhance desired characteristics for specific crops. The artificial LED lightings increase the possibility of year-round production of ornamental plants, which will subsequently increase the income of growers related to ornamental industry. Light-emitting diodes pave the way for a better understanding of the interaction between light and pests, diseases, natural enemies and plants, as they make possible the use of very narrow wavelengths. LEDs as an option for reducing the use of growth retardants and obtaining better product quality in ornamental pot plants. Production of secondary metabolites increase with higher blue light ratio. Secondary metabolites production are increased and act against Reactive Oxygen Species (ROS) and pathogens, precondition the plant for environmental changes so they can cope with stress more efficiently.

Vegetative propagation enables horticulturists to multiply plants while retaining desirable genetic characteristics of selected mother plants. This chapter covers important methods including cuttings, layering, budding, grafting, division, and specialized vegetative structures. The physiological basis of rooting, wound healing, callus formation, compatibility, and environmental requirements is discussed. Grafting and budding are particularly important for combining desirable scion characteristics with suitable rootstock traits such as vigor, disease resistance, stress tolerance, and adaptation. Proper sanitation and selection of healthy propagation material are emphasized to minimize pathogen transmission. Modern techniques such as rooting hormones, mist chambers, protected propagation, and clonal multiplication further improve the efficiency and uniformity of vegetative propagation.

1. Introduction

Several herbs have been used traditionally to prevent and treat human and animal diseases. Recently, scientific evaluation of plants and preparations of plant origin medications have received more attention. Cassia occidentalis had been reported to be used as antidote of poison, blood purifier, expectorant, anti inflammatory agent and a remedy for the treatment of liver diseases (Ghani, 1920, Kabiruddin, 1951). C occidentalis was tested for antifeedant and insecticidal properties. It was studied successfully for its anti-parasitic (Tona et al., 1999), hepatoprotective activity (Jafri et al., 1999). Stimulation of the immune system is highly desirable for the treatment of immunodeficiency and infectious diseases. The  anti-inflammatory and hepato protective effects of C occidentalis may relate to an influence of plant compounds on immunocompetent cells. The present study was undertaken to find out the effect of methanolic extract of C occidentalis leaves on the humoral immune response in rabbits.

Botanically aster belongs to the family Asteraceae and scientifically known as Callistephus chinesnsis which is basically native to China aster and annual aster. It is native to China and Japan and it is cultivated worldwide as cut flower, loose flower, bedding plant, for flower decoration and for making floral ornaments. It can easily cultivate in the open fields and green houses for the production of cut-flowers. The genus Callistephus derives from two Greek words that is ‘Kalistos’ and ‘Stephos’ meaning ‘most beautiful’ and ‘a crown’, respectively. The name Aster comes from the Ancient Greek word acx^p (aster),, meaning “star”;, referring to the shape of the flower head (Janakiram, 2006).Among various flowering annuals, China aster is having an important position in Indian floriculture industry. It holds the position next to chrysanthemum and marigold among the traditional flowers. In fact, it has widely replaced an already grown annual Chrysanthemum up to greater extent in Indian floriculture industry.

This flower is most preferred for wide cultivation by virtue of its wide variation in attractive color and longer vase life. It is also very much used for beautification in landscape gardening which create mass effect. In India it is cultivated in about 1,020 ha with a production of flower 800 million tonnes. It is commercially cultivated in Karnataka, Tamil Nadu, West Bengal and Maharashtra. In Karnataka it account for 6 % of the total area and 8.8 % of the total flower production.

Asteraceae or Compositae is one of the largest families of flowering plants, represented by about 1,707 genera and over 23,600 species which are worldwide in distribution. Radford (1986) has mentioned the number of genera to be ‘One thousand to 2000’. About 140 of its genera and over 700 species have been reported from India. Some of the largely represented genera include Senecio (2,000+), Eupatorium (1,200), Vernonia (1,000), Hieracium (1,000), Centaurea (600), Aster (500), Helichrysum (500), Cousinia (400), Artemisia (400), Baccharis (400), Mikania (250), Bidens (230), Crepis (200), Inula (200), Erigron (200), Chrysanthemum (160), Cirsium (150), Ligularia (150), Helianthus (110), Lactuca (100), Hypochoeris (100) and Carduus (100).
In the Chrysanthemum genus, the modern autumn flowering perennial Chrysanthemum morifolium Ramat is most important. The name of C. morifolium Ramat has been changed to Dendranthema grandiflora Tzvelev (Anderson, 1987; Heywood and Humphries, 1977 and Kitamura, 1978). Chrysanthemum (D.x grandiflora) is an internationally recognized floriculture crop. It ranks second among commercial flowers in the international market. It is known as ‘Queen of East’ in Japan while in USA, it is considered as the ‘Queen of the fall flowers’. Flowers are in great demand in landascape, for making garland, wreath, veni and religious offerings. Pot chrysanthemums are
commonly known as ‘mums’ and large flowered cultivars are used as potted plants.

Atuna racemosa subspecies racemosa is shown to be a species with many uses throughout its range from Malaysia to Melanesia. The principle uses described are the seed oil used as anti-inflamatory massage oil and for hair dressing, the seed pulp that is used for caulking and varnishing boats, the wood for house construction, and many parts of the plant as ingredients of local medicines. The medicinal uses of this species deserve further study since it has been shown to have both anti-bacterial and anti-inflamatory action. It is also uncertain whether its distribution over the Pacific is natural or human caused.

Atuna racemosa Rafin. is a widely distributed tree species that ranges from the Malay Peninsula through Malesia, Australasia and to the Pacific islands as far as Fiji, Tonga and Samoa. As with many useful plants, its natural distribution is uncertain because it has been transported around from island to island during the various migrations of the Pacific islanders.

Protected structures such as cloches, low tunnels, greenhouses, livestock housing, aquaculture facilities and phytotrones provide varying degrees of climate control for agricultural production. While cloches and low tunnels provide only passive modification of the growing environment, all other protected structures have the possibility of active and precise growing environment control.

GREENHOUSE TECHNOLOGY

Greenhouse technology permits the management of both biotic and abiotic stresses related to plant growth to maximize the productivity and quality. Resultantly, profitability per unit area per unit time increases by two to three orders of magnitude as compared to open field cultivation. Introduction of greenhouse technology in India for commercial production is only about three decades old, whereas it is more than two centuries old in USA, UK, Holland, France, Italy, etc.

A greenhouse is a framed or inflated structure covered with a transparent or translucent material where plant environment could be, at least partially controlled and which is large enough to permit a person to enter and carry out cultural operations. A greenhouse is called a glasshouse, when covered with glass, and plastic house when plastic is the glazing material. Materials of construction and cropping activities are also used to identify greenhouses. In addition to the growing facility, a commercial greenhouse complex has a head house, an input storage and a sales area. All these components are so arranged that unwanted movements of man and material are obviated.The greenhouse complex should have adequate wind breaks on the upstream side of the wind direction to provide protection against heavy winds.

What is the use of several trees grown in the forest? A single tree by the way side is far better where under people can rest (Vrikshayurveda).

The towns and villages are made more healthy, more beautiful and more efficient by well planned streets with avenue planting. There is no doubt that, an impressive avenue gives any property the special distinction that it desires. In the past, Emperor Ashoka and Mughal rulers paid attention to roadside planting. Avenue trees primarily provide shade and act as windbreaks, weather conditioners-by purifying and humidifying the air, check radiation of heat and obstruct glare, limit noise and enhance the beauty of the street where they are planted. Roadside planting has two aspects; beauty and utility and both these aspects should be combined. This requires a thorough knowledge of plant material and imagination in planning.

What is the use of several trees grown in the forest? A single tree by the way side is far better where under people can rest (Vrikshayurveda).

The towns and villages are made more healthy, more beautiful and more efficient by well planned streets with avenue planting. There is no doubt that, an impressive avenue gives any property the special distinction that it desires. In the past, Emperor Ashoka and Mughal rulers paid attention to roadside planting. Avenue trees primarily provide shade and act as windbreaks, weather conditioners-by purifying and humidifying the air, check radiation of heat and obstruct glare, limit noise and enhance the beauty of the street where they are planted. Roadside planting has two aspects; beauty and utility and both these aspects should be combined. This requires a thorough knowledge of plant material and imagination in planning.

Flowers symbolize beauty, purity, peace and love. These are intricately associated with social beliefs and no social function is complete without the use of flowers; especially in a country like India, where it is a popular saying that flowers are associated with man from birth till death. Floriculture can be defined as a specialized branch of horticulture which deals not only with the cultivation of flowers, foliage, climbers, trees, shrubs, cacti, succulents, etc., but also with their marketing and production of value-added products from them.

Floriculture is increasingly regarded as a viable diversification from the traditional field crops due to higher returns per unit area and increasing habit of “saying it with flowers”. Flowers play a cardinal role in human behaviour and culture, bringing tranquility and peace of mind. From a symbol of love, flowers have transformed into an industry, generating both income as well as employment. India is blessed with a diversity of agroclimatic conditions prevailing in different regions of the country ensuring production of almost all the ornamental crops through out the year. Floriculture in India is a dynamic and expanding industry recording impressive annual growth rate.

The floriculture industry comprises of:

1. The florist trade traditional and contemporary cut flowers and cut foliage, both fresh and dried and value-added products like bouquets, floral baskets, flower arrangements and garlands.
2. The plant nursery for propagation and supply of plant material including tissue culture plants, seeds, bulbs, corms and other propagated material.
3. Plant rental service for supply of house plants on annual rent for a specific period.
4. Flower perfume and gulkand.

As a result of political changes in India, many entrepreneurs are changing to floricultural activities, which have become a high priority for the Indian government. Due to availability of sufficient winter and summer sunshine, high temperature, good soil fertility, good water quality, different climatic zones for different type of products and low labour and investment costs, India has great potential for floriculture. In the flower industry, significant changes are occurring in the competitive relationships worldwide. European integration, democratization in eastern Europe and the liberalization of world trade in the context of the GATT negotiations will have consequences on international trade. A number of traditional markets are displaying signs of saturation while, on the other hand, new countries are trying to get their place on the market. At the same time, we see new developing markets and in some parts of the world (USA, Japan) it is expected that per capita consumption will go up. Enormous genetic diversity, versatile human resources and varied agro-climate offers India unique scope for diversification not explored yet fully.

Euphorbiaceae is a large family that includes 310-320 genera and 7500 species (Walters and Keil, 1996). Two centers of distribution for this family are tropical America and tropical Africa. The family has an extremely variable life span and habits are found as annual and perennial herbs, vines, succulents, shrubs and tall trees. Members of the Euphorbiaceæ are found in many habitats, from deserts to rain forests. Euphorbiaceae family has genera used as unconventional foods

In Mexico, 826 species under Euphorbiaceae family are found with 50 genera including those introduced from elsewhere and cultivated. A subfamily with a larger number of genera is Acalyphoieae (16), while Euphorbioideae has more species (306), and Crotonoideae has more specific endemism (Martinez-Gordillo et al, 2002). Some of these plants are used in traditional medicine, in oil industry, as ornamental plants, and as food additive. A few examples of its uses include edible wax from Euphorbia antisyphilitica (candelilla) that coats fruits and vegetables to retard water evaporation. Jatropha dioica is a small shrub that is used in traditional medicine and Euphorbia pulcherrima (Poisenetta) an ornamental plant.

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.

ORIGIN AND DISTRIBUTION

Nevertheless, very little was known about the origin and the ancestor species used for this important ornamental crop. Rhododendron simsii, the species that is accepted to be the main ancestor, originates from hilly areas in China (Chang Jiang valley), Thailand, Laos and Burma. Apart from R. simsii, at least three other species from the Tsutsusi subgenus, from South-Asia and Japan, might have contributed: R. indicum, R. x mucronatum (Blume) G. Don and R. scabrum (Heursel, 1999).

From a floricultural viewpoint, azaleas are firstly divided into the two broad categories of deciduous and evergreen plants. The former, notoriously more rustic, have North American, Caucasian, and Asian origins, and are classified in the subgenus Pentanthera G. Don, whereas the latter derive exclusively from Asian species and are classified in the subgenus Tsutsusi (Sweet) Pojarkova (Chamberlain and Rae, 1990). Within the evergreen azaleas at least four more or less well defined groups of cultivars are distinguished according to their traditionally recognized most important ancestor: pot or Belgian azaleas (R. simsii Planch. putative hybrids), Hirado azaleas (R. scabrum G. Don putative hybrids), Kurume azaleas [putative hybrids of R. kiusianum Makino var. kiusianum and var. sataense (Nakai) D.F. Chamb. and R. kaempferi Planch.] and Satsuki azaleas [putative mutants or hybrids of R. indicum (L.) Sweet and R. eriocarpum (Hayata) Nakai]. The Hirado, Kurume and Satsuki groups are often referred to as Japanese azaleas because of their geographical origin (Scariot et al., 2007).

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.

Fusarium wilt of carnation caused by Fusarium oxysporum f.spp dianthi causes severe yield losses under protected cultivation. For the management of Fusarium wilt, 27 isolates of Bacillus strains were isolated from the rhizosphere of different crops including carnation. Among various species of Bacillus, Bacillus amyloliquefaciens (BSC7) was identified as a most virulent antagonistic bacterial isolate. Studies on antagonism under Environmentally Controlled Scanning Electron Microscopy (ESEM), depicted the presence of rod shaped bacterial cells with biofilm formation at 44847x. Detection for the presence of antibiotic biosynthetic genes reflected the presence of surfactin, iturin, bacillomycin and fengycin genes. The 24 isolates of Bacillus spp. showed positive reaction for surfactin gene. Nineteen isolates were amplified for Iturin A gene except BS5, BS9, BSC1, BSC2, BSC11, BSD1 and BSD2. Strains of B. subtilis BS1, BS2, BS5, BS6 and BS8 expressed Bacillomycin D gene. The genomic DNA of strains BS1, BS2, BS4, BS6, BS7 BS8, BS11 and BS14 showed positive for Fengycin D gene. The isolate of B. subtilis BS2 showed positive reaction for four genes namely surfactin, iturin, bacillomycin and fengycin.

In vitro screening of Bacillus, B. amyloliquefaciens (BSC7), P. aeruginosa (P1) and T. viride (TV1) showed highest inhibition against F.oxysporum f.sp.dianthi to an extent of 55.95, 55.29 and 81.61 per cent over the control respectively. The antifungal activity of antagonistic B. amyloliquefaciens BSC7 and T. viride TV1 against F.oxysporum f.sp. dianthi was confirmed under ESEM by observing disintegration, lysis and structural abnormalities of the hyphae of the pathogen at the zone of interaction.

Bael is one of the oldest and useful trees of India. The bael fruit, (Aegle marmelos Correa) is also called Bengal quince (John and Stevenson, 1979), Indian quince, golden apple, holy fruit, stone apple, bel, belwa, sriphal and maredoo in India. Among the indigenous fruits of India, Bael occupies an important place. All the parts of bael tree have their own importance. It is a medicinally and economically important fruit crop with immense potential for extending its cultivation in semi-arid degraded land. Mention of bael cultivation in Indian literature dates back to 800 B.C.  Bael fruit is available in almost all states of India but most abundantly available in Uttar Pradesh, West Bengal, Bihar and Orissa.

The Bael fruit is one of the most nutritious fruits. It contains 61.5 g water, 1.8 g protein, 0.39 g fat, 1.7 g mineral, 31.8 g carbohydrate, 55 mg carotene, 0.13 mg thiamin, 1.19 mg riboflavin, 1.1 mg niacin and 8 mg vitamin C / 100 gm of edible portion (Gopalan et al., 1971). It contains the highest riboflavin content among fruits. Marmelosin is, most probably, the therapeutically active principle of bael fruit. It is isolated as a colorless crystaline compound (Dixit and Dutt., 1932).The astringent taste of bael fruit is due to phenolic compounds. The medicinal properties of bael have been dealt with in Charaka Samhita (Aiyar, 1956). Bael fruit has curative, pesticidal and nutritive properties. The leaves of bael are used for worship of Lord Shiva. Green bael fruits are used for preparing Murabba (preserve) generally taken for stomach ailments. Bael fruits have an immense potential for processing into products like squash, jam, toffee, candy and syrups for internal and foreign market.

In the world of greenhouse cultivation, achieving optimal plant growth, maintaining robust health, and effectively managing pests is crucial for successful crop production. It requires a comprehensive approach to balance various factors, including chemical growth regulation, disease control, and pest management. Greenhouse technology plays a vital role in providing a controlled environment to fine-tune these variables. As we dive into the details of this delicate balance, it becomes clear how important it is to combine science and technology to find innovative solutions to ensure thriving crops while minimizing environmental impact.

Impatiens balsamina (Balsam, Garden Balsam or Rose Balsam or Gulmehndi) is a species of Impatiens widely cultivated as an ornamental plant in landscaping belongs to the family Balsaminaceae. It is a qualitative short-day plant, propagated by seed and is one of the popular species of North India. It is called kamantigue in the Philippines. This species of Kamantigue are used in teas. In many English speaking countries they are known as “Touch me not”, possibly due to the ripe seed pods explosively bursting when touched. Different parts of the plant are used to treat disease and skin afflictions such as the leaves, seeds, and stems. It is also edible if cooked. Juice from balsam leaves treats warts and also snakebite, while the flower can be applied to burns to cool the skin. Impatiens balsamina L. has been used as indigenous medicine in Asia for the treatment of rheumatism, fractures, and fingernail inflammation. In Korean folk medicine Impatiens (‘Bong Seon Wha Dae’) has been used to cure constipation and acute gastritis by meat. There are mainly four forms of I. balsamina namely red, purples, white and pink.

ORIGIN AND DISTRIBUTION

Impatiens balsamina is a species of Impatiens native to southern Asia in India and Burma, but has been cultivated widely. It is now naturalized in many tropical and temperate areas of the world. Jones and Smith in 1966 proposed the Himalayan region as the centre of origin. The major centres of diversity are in highlands and mountains of tropical and sub-tropical Africa, Southeast Asia and the Indian sub-continent. In the U.S., Impatiens balsamina is found primarily in a wide strip encompassing the Northeast and Southeast regions from Florida to New York with specimens being found as far west as Missouri. Impatiens denisonii is a scapigerous herb which is found only in the Western Ghats in South India and are endemic in the Nilgiri Hills. Impatiens ecornuta, the spurless touch-me-not or western touch-me-not, is an annual flowering plant native to the northwestern United States and British Columbia in Canada. Impatiens flaccida is native to the Western Ghats in India and to Sri Lanka whereas, Impatiens hawkeri (New Guinea impatiens) is native to Papua New Guinea and the Solomon Islands. It has been bred and hybridized in cultivation to produce a line of garden plants. The species has been crossed with Impatiens aurantiaca and I. platypetala to improve characteristics such as drought-resistance. Impatiens irvingii is native to tropical Africa. Impatiens namchabarwensis (Blue Diamond Impatiens) is a 40–50 cm tall perennial plant, native to the Himalaya overwintering by a thick fleshy rootstock. Impatiens psittacina, known variously as the “parrot flower” or “parrot balsam” is a species of balsam from Southeast Asia that was described by the botanist Joseph Dalton Hooker and was noted for its flower that resemble a “flying cockatoo”. It is known from Thailand, Burma and parts of India (Morgan, 2007). Impatiens sodenii is native to Kenya and Tanzania. It is widely cultivated as an ornamental plant. I. walleriana is native to East Africa and yielded ‘Elfin’ series of cultivars, which was subsequently improved as the Super Elfin series.

Impatiens balsamina (Balsam, Garden Balsam or Rose Balsam or Gulmehndi) is a species of Impatiens widely cultivated as an ornamental plant in landscaping belongs to the family Balsaminaceae. It is a qualitative short-day plant, propagated by seed and is one of the popular species of North India. It is called kamantigue in the Philippines. This species of Kamantigue are used in teas. In many English speaking countries they are known as “Touch me not”, possibly due to the ripe seed pods explosively bursting when touched. Different parts of the plant are used to treat disease and skin afflictions such as the leaves, seeds, and stems. It is also edible if cooked. Juice from balsam leaves treats warts and also snakebite, while the flower can be applied to burns to cool the skin. Impatiens balsamina L. has been used as indigenous medicine in Asia for the treatment of rheumatism, fractures, and fingernail inflammation. In Korean folk medicine Impatiens (‘Bong Seon Wha Dae’) has been used to cure constipation and acute gastritis by meat. There are mainly four forms of I. balsamina namely red, purples, white and pink.

Balsam (Impatiens balsamina) is an annual herbaceous flowering plant valued for its attractive flowers and use as a loose flower crop. It performs well under warm, humid conditions and is suitable for rainy-season cultivation. The chapter presents its origin, distribution, genetics, botanical characteristics, varieties and climatic and soil requirements. Detailed production practices include seed propagation, stem cuttings, micropropagation, land preparation, nutrient management, planting, irrigation, weed control, mulching, staking and pinching. Plant growth regulators, insect pests and diseases are also discussed. Particular attention is given to harvesting, postharvest handling and yield, making the chapter useful for commercial cultivation and practical floriculture education.

Abstract: Impatiens are popular seed and vegetatively propagated bedding plants with numerous series (Shadeglow, Firefly, Peach Ice, Circus, Hawaii, Pixie, Show Topper, Elfin, Shady Lady, Fanciful, Fantasia, Fiesta, Futura, Jewel, Minarette, etc.) and F₁ hybrid cultivars available on world market. The history of balsam development as a crop is highlighted. Continued domestication by flower breeders produced a wide range of flower colours and flower patterns. Ample genetic information and trait heritability has been established for this crop; plant breeding continues to produce new variants for commercial production. Continuous breeding and improvement of balsam focus on flower colour/ size/ pattern, double flowers, plant growth habit/ branching and disease resistance. Important traits for both production and landscape use include flower colour/ size and bloom time, larger flowers, resistance to biotic and abiotic stress and other valuable traits. Results achieved through interspecific hybridization and polyploid breeding are discussed. The chapter concludes with future prospective for research and breeding in the genus.