eChapters

Marigold (Tagetes spp.) is an important annual flower crop; native to Central and South America especially Mexico and belongs to family Asteraceae (Compositae). It is commonly known as “Gainda” in India and also called as “Friendship Flower” in United States of America. Loose flowers of marigold are in great demand throughout the year. It is commercially grown in tropical and subtropical regions of India owing to its ease in cultivation, hardy nature, wider adaptability and year round availability of single, semi-double and double flowers of vibrant colours. Marigold is grown over an area of about 66.09 thousand hectares with production of 603.18 thousand MT loose flowers in India. Major states involved in loose flower production of marigold are Karnataka, Madhya Pradesh, Gujarat, Andhra Pradesh, West Bengal, Maharashtra, Haryana and Chhattisgarh. In India, Assam is the only state, which produces marigold for both cut as well as loose flower purpose on an area of about 0.61 thousand hectare (Anonymous, 2016a).

Marigold is a cross-pollinated flower crop and it is pollinated by insects (Kaneko et al., 1990). It bears terminal and solitary inflorescence, known as head or capitulum, which possesses long and hollow peduncle with swollen apex and campanulate involucres (Setshogo, 2005). Capitulum consists of peripheral ray florets and central disc florets. Ray florets are pistillate, ligulate, sessile, epigynous and zygomorphic, whereas, disc florets are bisexual, tubular, sessile, epigynous and actinomorphic (Subrahmanyam, 1996 & Setshogo, 2005).

African marigold (Tagetes erecta L.) is a diploid species (2n = 2x = 24), while, French marigold (Tagetes patula L.) is a tetraploid species (2n = 4x = 48) with basic chromosome no. of x = 12 as revealed by breeding work of various researchers (Towner, 1961, Chen and Lin, 1981, Chen and Lin, 1982, Serrato-Cruz et al. 2000, Zhang et al., 2011). Tagetes erecta and Tagetes tenuifolia are diploid species, whereas, Tagetes patula, Tagetes minuta, Tagetes biflora and Tagetes remotiflora species are tetraploid in nature (De, 2017). On the basis of floral morphology; three different types of male sterile systems i.e. apetaloid, petaloid and gynomonoecious types was observed in African marigold (Prakash et al., 2016). Out of these, apetalous male sterility (femina type) is more reliable and preferred over petalous male sterility because later is more prone to break down (Goldsmith, 1968 & Janakiram, 2004). Apetaloid male sterility was controlled by single recessive gene (Prakash et al., 2016). A monogenic recessive male sterile apetalous mutant was detected from T. erecta population by Khoshoo (1979). Cyto-genetic male sterility is also found in marigold (De, 2017). Petaloid and gynomonoecious male sterile systems were controlled by cytoplasmic inheritance (Prakash et al., 2016). In marigold, cytoplasmic genetic male sterile lines were also developed for commercial production of F_l sterile hybrids (Pratibha et al., 2000).

INTRODUCTION

Marigold is an important flower crop and constitute as one of the five most commonly cultivated and used flower in urban and rural India. They are extensively used for making garlands, beautification and other purposes i.e. pigment and oil extraction and thera eutic uses A art from these uses marigold is a widely grown plant in gardens and pots. It is highly suitable as a bedding plant, in a herbaceous border and is also ideal for newly planted shrubberies to provide colour and fill the space. French marigold is most ideal for rockery, edging, hanging baskets and window boxes. Flowers remain fresh for 4-5 days at room temperature and are used for religious offerings and social functions. Recently marigolds are grown commercially for extraction of carotene pigments mainly xanthophylls. The carotenoid extracted from petals are added to poultry feed for intensification of yellow colour of egg yolk. Lutein which is the major constituent of xanthophylls is used for colouring food stuffs. Purified extract of marigold petals containing lutein dipalmitate is marketed as an ophthalmologic agent under the name adaptinol. Dietary carotenoids can be used to treat cancer and photosensitivity diseases.

Marigold leaves contain a distinct odoriferous oil. Wild marigold (Tagetes minuta) oil has valuable and precious essential oil which is used in high grade perfumes and cosmetics. Ketones present in the oil are base material for synthesizing aroma chemicals. Marigold essential oil has bronchodilatory, tranquilizing, anit-inflammatory as well as insect repellent activities. The floral extract of marigold is used for treating eye diseases and ulcers.

Marigold is one of the easiest annual flowers to cultivate, having wide adaptability. Flowers are attractive, have good keeping quality with a wide spectrum of colour, shape and size. They produce marketable flowers in a short time and are used widely for religious and social functions as well as for garden display. 

Importance and Uses

 Marigolds are sold as loose flowers, as cut flowers and widely used for various decorations and garland making. They are also excellent landscape plants widely used for bedding purpose, in herbaceous borders and can also be grown in pots. French marigolds, being dwarf, are suitable for hanging baskets, rockeries, edging and window boxes. In fact, marigolds rank next only to jasmine in popularity in South India 

Introduction

Marigold is an important flower crop in India. They are extensively used for making garlands, beautification and other purposes i.e. oil extraction and therapeutic uses. Apart from these uses marigold is a widely grown plant in gardens and for pots. Marigolds are also grown commercially for extraction of carotene pigments mainly xanthophylls. The carotenoid extracted from petals are added to poultry feed for intensification of yellow colour of egg yolk. Lutein which is the major constituent of xanthophylls is used for colouring food stuffs.

Marigold plantation has been found beneficial to reduce the population of nematodes. Root-knot (Meloidogyne spp.) can be effectively managed in the field without pesticides.

Genetics

Marigold belongs to family Asteraceae. There are about 33 species of the genus Tagetes. Important species are T. erecta, T. patula, T. tenuifolia, T. lucida, T. lacera, T. lemmonii, T. minuta, T. pusilla and T. corymbosa. The chromosome number in diploid species i.e. T. erecta, T. tenuifolia, T. elongata, T. lemmonii, T. jaliscensis and T. lucida is 2n = 24, however, tetrapoid species i.e. T. patula, T. minuta, T. remotifolia, T. mendocina and T. biflora is 2n = 48.

25.1 Introduction

The method of selection in which a gene/QTL (Quantitative Trait Locus) is selected on the basis of the genotype of the molecular marker (also called DNA marker) linked to this gene/QTL is known as marker-assisted selection (also called marker-aided selection). The idea of marker-assisted selection (MAS) was first advocated by Tanksley (1983). MAS can be used in combination with the conventional breeding methods or novel breeding schemes could be devised to take full advantage of the marker data. MAS has been widely used for introgression of the desired genes and QTLs using backcross programmes.

25.2 Marker-Assisted Backcrossing (MABC)

The backcross programme based on molecular marker is usually called marker-assisted backcrossing (MABC). MABC has three activities: (a) foreground selection, (b) background selection and (c) recombinant selection.

25.2.1 Foreground Selection

The use of molecular marker to select the gene/QTL being introgressed is known as foreground selection. The objective of foreground selection is to select the target gene, i.e., the gene being introgressed, without phenotypic evaluation for the trait governed by the target gene. Foreground selection for a gene/QTL will be highly desirable in a variety of situation, some of which are listed below:

The world trade in flavour and fragrances in 1987 was US $ 7,000 million and at present, it is estimated at more than $ 10,000 million annually. In 1975, perfume was used by one woman in ten, but today it is used by eight out of ten women; even reticent Japanese women are adopting the habit (Anonymous, 1995 c). The average annual industry growth rate in perfumes of India is valued at about US $ 20 million with an annual growth rate of 12% (Murty, 1993),while the UK market is Rs. 2000 crores and the US market supersedes it by Rs. 4000 crores (Walia, 1997). However, the domestic luxury perfume market is estimated to grow at a rate of 20-25 % (Biswas, 2012). Besides domestic market, India earns a lot of foreign exchange from the export of total essential oils and perfumes and is fast growing as it is showed from the trends in export earnings of Rs. 11.1 corers in 1982-83 rose to 4-fold in 1986-87 of Rs. 41.1 crores (CHEMEXCIL, 1988). According to a market survey report, Ahmed (1999) reported that the daily turn over of the attar market in India is more than 50 crores.

Middle East countries continue to be the big buyers of our traditional perfumes. Kewda flavour which is used in pan masala and tobacco is a familiar one in this part of the world. Kewda essence, being one of the few flavouring oils, has a good scope for export to other developed countries where the food flavouring industry is well developed. India is the leading producer of kewda perfumes in the world and the market for kewda perfumes is fast expanding specifically in the Arab countries. India exported the kewda water of Rs. 266.2 lakhs in 1986-87 which rose to Rs. 276.4 lakhs in 1987-88 (CHEMEXCIL, 1990). Anonymous (2007) reported that about 140 distilleries (bhattis), both local and outsider, earn about Rs.1.3 crore by way of extraction charges and annually they extract 332 kgs of kewda oil (Rs.8.3 crore), 7823 kgs of kewda attar (Rs.15.65 crores) and 150 MTs of kewda water (Rs.4.47 crore), the total coming to around Rs.28 crore. For extracting attar , the extractors use about Rs. 8 crore worth of sandal wood oil procured mainly from other states, while Rs.18 crore goes to the plantation owners as flower cost and to the flower collectors.

The final chapter examines the commercial, institutional and policy dimensions of the Indian cut flower industry. It discusses domestic and international markets, export opportunities, grading, packaging, cold-chain requirements and India's competitive position. Institutional support from ICAR, APEDA, National Horticulture Board, MIDH, financial institutions and Centres of Excellence is explained. The chapter also covers Agri Export Zones, Export Oriented Units and crop insurance mechanisms relevant to commercial floriculture. Current challenges include freight costs, cold-chain limitations, quality standards and international competition, while opportunities arise from protected cultivation, precision farming, automation, AI, IoT, exports and premium flower markets.

Marketing is a critical component of loose flower production because flowers are highly perishable and subject to substantial seasonal price fluctuations. This chapter examines important local and national markets, export opportunities, transportation systems and marketing channels. It explains direct marketing, commission-agent systems, wholesaler-retailer networks and emerging contract arrangements. The role of APMC markets in price discovery, grading, auctioning and market access is discussed along with online trading, e-commerce and digital payment systems. The chapter also considers institutional support, export promotion, value addition and crop insurance. Improved packaging, cold-chain infrastructure, processing and market information systems are highlighted as important strategies for reducing losses and improving farmer profitability.

3.1 Introduction

Greenhouses are buildings with a controlled environment that facilitate plant culture and development. They offer protection from adverse external weather conditions, high temperatures, strong winds, and pests, while providing an ideal environment for plant growth. The construction of a greenhouse involves the use of various materials to ensure its structural stability, longevity, light transmission, and insulation. The different components of the greenhouse, such as the frame, flooring, and covering, are constructed using different materials such as wood, aluminum, steel, concrete, soil, gravel, and more.

The horticultural produce includes fruits, vegetables, flowers, plantation crops and spices. However, fruits and vegetables are the most consumed and important commodity among them. Morphologically and physiologically, the fruits and vegetables are highly variable and may come from a root, stem, leaf, immature or fully mature and ripe fruits. They have variable shelf life and require different suitable conditions during marketing. All fresh horticultural crops are high in water content and are subjected to desiccation (wilting, shrivelling) and to mechanical injury. Various authorities have estimated that 20-30% of fresh horticultural produce is lost after harvest and these losses can assume considerable economic and social importance.

Maturity

It is the state of reaching a stage of full or advanced development of tissue of fruits and vegetables, after which it will ripen normally. During the process of maturation, the fruit receives a regular supply of food material from the plant and at maturity, the abscission or corky layer formed at the stem end stops this inflow. Afterwards, the fruit depend on its own reserves, and carbohydrates are dehydrated and sugars start accumulating until the sugar acid ratio formation. In addition to this, typical flavour and characteristic colour also develop. It has been determined that the stage of maturity at the time of picking influence the storage life and quality of fruit, when picked immature like mango develop white patches or air pockets during ripening, thus lacks in in normal brix acid ratio or sugar acid ratio, taste and flavour. On the other hand, if the fruits are harvested over mature or full ripe, then they are easily susceptible to microbial and physiological spoilage and their storage life is considerably reduced. Such fruits continue to show numerous problems during handling, storage and transportation. Therefore, it is necessary or essential to pick up the fruits or vegetables at correct stage of maturity to facilitate proper ripening, distant transportation and to obtain maximum storage life.

Maturity can be defined as the attainment of a particular size or stage after which ripening takes place. It is also called physiological maturity. However,horticultural maturity is defined as the stage of development, when a plant or plant part possesses the prerequisites for utilization by consumers for a particular purpose. Mango, tomato, cucumbers, lettuce, peppers, etc. are harvested at various stages depending on the objective of disposal (horticultural maturity) prior to reaching physiological maturity, or completion of growth phase.

Maturity indices are the most important for deciding the stage of harvesting and to reduce post-harvest losses. The post harvest life of fruits are mainly controlled by maturity. Maturity signs are also called maturity standards or maturity indices. Maturity signs help in judging maturity of fruits and vegetables. There are many methods to determine maturity. The most common is the size and shape of fruit, change in colour, softening of tissues (fig, sapota), ease of detachment from the stalk (sapota, annona), shriveling of fruit stalk (watermelon), drying of nearest tendril (watermelon), days from blooming to picking maturity, sound by tapping jack and watermelon, when ripe produce hollow and dull sound on tapping but produce metallic sound if unripe etc.

Introduction

Measurement of pH of a solution and preparation of different types/strength of buffers are common practices in a laboratory, particularly in the Biochemistry and Molecular Biology laboratories. Therefore, in this chapter you will be acquainted with the procedures of measuring pH of a solution as well as preparation of some of the commonly used buffers in a laboratory.

Potential or Power of Hydrogen Ion (pH)

Measurement of pH of a solution is measuring the molar concentration of hydrogen ion [H+] in the solution, which is an indication of the acidity or basicity of the solution. The symbol pH stands for “power of hydrogen” and numerical value for pH is just the negative logarithm of the molar concentration of hydrogen ions [H+]. The ionic product of water (Kw ) is the basis for the pH scale. The total hydrogen ion concentration from all the sources and it can be experimentally measured.

The pH scale designates the concentration of H+ (and thus of OH−) in an aqueous solution, which ranges between 1.0 M H+ and 1.0 M OH−. The term pH is defined by the expression

Thus, the ionic product of water makes it possible to calculate the concentration of H+, with given concentration of OH−, and vice versa. The value of 7 for pH of a neutral solution is not an arbitrarily chosen figure; it is derived from the absolute value of the ionic product of water. A solution having pH greater than 7 is basic, and the concentration of OH− is greater than that of H+. A solution having a pH less than 7 is acidic.

Horticultural medicinal plants

Throughout recorded history, people have held medicinal plants in high regard due to the many health benefits they provide. Natural cures abound among these botanical marvels, and they may alleviate a wide range of health problems. The wide variety of bioactive substances found in them has been used to create pharmaceutical medications and alternative treatments, suggesting that they may have curative properties. Medicinal plants, such as aloe vera and turmeric, offer a wide range of uses, including pain relief, the treatment of chronic diseases, and general health improvement. A newfound respect for traditional herbal medicine’s knowledge and the need of preserving these priceless resources has emerged in recent years, as contemporary medicine investigates the plants’ unrealized potential.

Gladiolus saundersii

1. Introduction

Plants are reliable sources for the treatment of diseases in different parts of the world (Eisenberb et al., 1993; Cowan, 1999; Hostettmann et al., 2000) and they have been unique sources of medicines and constituted the most common use of biodiversity (Hamilton, 2004; Hiremath and Taranath, 2010). Their use contributes significantly to primary healthcare delivery (Holetz et al., 2002) as they are regarded as invaluable sources of pharmaceutical products (Olalde, 2005).

Traditional medicine, with medicinal plants as their most important component, are sold in market places or prescribed by traditional healers in their homes (Von Maydell, 1996). As a result of this strong dependence on plants as medicines, many ethnopharmacological studies have been conducted to determine their safety, efficiency and discovery of new active principles from them. Only, 1,100 plants have so far been thoroughly examined for their medicinal practices in the world (Dobson, 1995).

Herbal medicine have been in use since time immemorial and are still the mainstay mainly in the developing countries because of their better cultural acceptability, better compatibility with the human body and lesser side effects (Kamraj, 2000).

Clasping stemmed Solena or diversely leaved Melothria or creeping cucumber (Solena amplexicaulis Lam. Syn. Bryonia amplexicaulis (Lam), Melothria heterophylla (Lour), Melothria angulata Chakrav) is an indigenous cucurbit vegetable occuring in nature nearby cultivated areas on hedges or in open fields In Greek Solen means’ a tube,pipe’ refering to the nature of its flowers. The vernacular names are Bon-kundari, kudari, makal, mahakal (bengali), gometti (marati), kanduri, kuduri (bundelkhand), bankakra (champa), gometi (gujarati, anatmul, mahakal, taarali, kaduri (hindi),makirla (chattirgarh), kaage mari balli (kanarese) etc. This is a perennial vine, dioecious in nature. Tender fruits are used as salad, curry and  fried vegetable. It has significant medicinal value also.  In tribal regions of Orissa, fruits of Melothria are considered as delicacy. Visualizing the delicate nature of its fruits, it has great potential as a salad crop in  future.

1. Introduction

Plants offer a rich source of active compounds that have been exploited as scents, flavourings, pigments, pesticides, and medicinal compounds for thousands of years. Plants are thought to utilise these metabolites as a primary strategy for adapting to and surviving in a variety of ecological niches and environmental conditions, as well as to combat biotic intrusions in their environment (Weng, 2014). The increased interest in phytomedicine and medicinal supplements, as well as the increased regulatory obligations for their safety and reputable contents of active compounds, has prompted the development of methodologies for the quality control of multi - component concretes found in plant-derived nutraceuticals. Metabolite diversity in plants is thought to have evolved over time to help plants survive in harsh environments, and it is continually changing. 

The term DNA sequencing refers to methods for determining the order of the nucleotide bases, adenine, guanine, thymine and cytosine, in a molecule of DNA. In molecular terms ,the definitive understanding of a DNA molecule comes from determining its nucleotide sequence.The function of a gene can be deduced from its nucleotide sequence,for example by comparing the sequences of genes with known functions.

The first DNA sequences were obtained by academic researchers, using laborious methods based on 2 – dimensional chromatography in the early 1970s.  Following the development of dye-based sequencing methods with automated analysis, DNA sequencing has become easier and orders of magnitude faster.  Knowledge of DNA sequences of genes and other parts of the genome of organisms have become indispensable for basic research studying biological processes, as well as in applied field like diagnostic or forensic research.  The advent of DNA sequencing has significantly accelerated biological research and discovery.

19.1 Introduction

In self-pollinated crops, the methods of selection aim at improving individual plants. On the other hand, in cross-pollinated crops they aim at improving a population of plants. A population is a large group of interbreeding individuals. Hence, selection is called population improvement in cross-pollinated crops. Selection in self-pollinated crops results in isolation of pure breeding lines which is the end product. But in cross-pollinated crops, it results in an improved population which is used as the commercial cultivar. Improved inbred lines (also called inbreds) for producing hybrids can be obtained from such populations. Again, like many rounds of selection being practised in different inbreeding generations in self-pollinated crops we are also practising many rounds of selection in cross-pollinated crops. But, unlike self-pollinated crops selection in cross-pollinated crops is followed by intermating to develop a new population before starting another round of selection. One cycle of selection consists of selection of individual/family and intermating of the selected units. Such cycle is repeated till we get the improved population. This method of practising the cycles of selection and recombination in a population is called recurrent selection or population improvement. Frey (1983) prefers the use of recurrent selection for closed populations where no new germplasm is added to the population during selection. Population improvement was used for a group of breeding techniques where all aspects are similar to recurrent selection but with the provision of adding new sources of germplasm whenever feasible. It is only a matter of coincidence that past history of application of recurrent selection has been limited to closed populations, but its basic aim has always been the accumulation of favourable genes, without any restriction on the migration of new genes during the course of selection. Apart from a slight nuance, population improvement and recurrent selection are two titles of the same principle and procedure of manipulating the genetic potential of populations. Recurrent selection can also be applied in self-pollinated crops.

17.1 Introduction

Self-pollinated vegetable, spice and ornamental crops may be heterogeneous. It is exemplified by landrace cultivars. They may have originated from single plant selections but have been grown over a long period of time. Landrace cultivars are a mixture of genotypes, perhaps because of breeders’ lack of appreciation of selection techniques to produce a pure line, spontaneous mutations, chance hybridization, or a combination of factors. Natural selection in landraces has resulted in a cultivar that is well adapted to the local environment. Depending on amount of human selection, differences among genotypes in a landrace cultivar may be small and inconspicuous. On the other hand, a lack of human intervention may mean that differences among plants in a landrace cultivar will be conspicuous. After years of self-pollination, individual plants are homozygous. Selection of such individuals would result in a true-to-type reproduction of their phenotype within the limitations imposed by the environment.