eChapters

Hybridization is a potent technique to create variability for selection and breaking yield barriers, evolve varieties having built in high potential. The selection of suitable parents for hybridization is one of the most important step in hybridization program. Selection of parents on the basis of phenotypic performance alone is not a sound procedure since phenotypically superior lines may yield poor recombinations in the segregating generations. It is therefore essential that parents are chosen on the basis of their genetic value. Some of the commonly utilized techniques for assessing the genetic value of a genotype are:

Introduction

The emerging functional foods market presents a considerable challenge to all manufacturers to keep abreast of the use of adequate packaging materials for their products. The interest in functional foods is intrinsically linked to the potential health benefits of their bioactive components. Preserving these bioactive components is, therefore, a crucial factor to providing the anticipated health benefits of functional foods. However, recurring failure in maintaining the quality of functional foods has been reported. Functional foods include a wide variety of products such as prebiotics and probiotics, dried foods (fibers, tea, herbs, etc.), fermented products (yogurts, kefirs, vegetables), and fresh fruits and vegetables. Their bioactive components (minerals, vitamins, fibers, peptides, proteins, w–3 polyunsaturated fats, antioxidants, enzymes, and symbiotics) range from very simple molecules to complex living organisms such as bacteria.

Chow-Chow [Sechium edule (Jacq.) Swartz] is used in many parts of Latin America, humid tropical regions of Central America and Southern Mexico. It is cultivated in South East Asia (India, Malaysia, Indonesia and Phillipines), Central and Western Africa, Central and South America (Brazil) and other tropical regions. (Dutta 1994). In India, local cultivars are commonly grown in coastal and low-hills (1000-2000m) of Maharashtra, Karnataka, and Tamilnadu. In Tamil, it is called “Seeme Kattrikkai” (Bailey, 1947). It is an important part of dietary system of tribals of  North East Regions. It is found in kitchen gardens of every tribal. It is found in almost all states and regions but maximum variability is found in Sikkim, Mizoram and Meghalaya (Yadav et al., 2005). Its variable fruits and roots, are important elements in diet of people. Chow-Chow is widespread and is an important export crop for  Latin American countries, much still need to be learned  about this crop (Rafael Lira Saade,1996). Chow-Chow is a single seeded fruit of  Cucurbitaceous family (MacGillivray, 1953). It is a perennial rooted vine that bears edible fruits (Thompson and Kelly, 1957). In subtropical and tropical regions, it produces large edible tuberous roots. It thrives under moderate temperature in  tropical or semi-tropical environment, though it can also be successfully grown under high temperature near sea level. Chow-Chow is a herbaceous perennial creeper (Choudhury, 1967) and is a robust grower in warmer months of year and during  cold weather of July and August  plant dies back temporarily. It has a viviparous type of germination (Patnaik, 1967). S.edule is called chayote, probably from  Greek ‘Sekos’ to  fatten in a fold because it was fed to hogs ( Bailey, 1963).

Nutrition plays a pivotal role for the animal research, be it health or production. Research in animal nutrition employs many basic techniques and chromatography is one of them. Chromatographic processes can be defined as separation techniques involving mass transfer between stationary and mobile phases. Various types of chromatography have one application or the other in analysis of food/feed components (Day and Williamson, 2001), quantitation of nutrients as well as the characterization of the effect of nutrients in biological samples like serum/plasma or tissues (Merken and Beecher, 2000).

A. Principle

Basically all chromatographic systems consist of the stationary phase that may be solid,gel,liquid or a solid/liquid mixture that is immobilized and the mobile phase, which may be gas or liquid and it flows over or through the stationary phase. This partition is achieved in one of the following ways:

Adsorption chromatography : It is one of the oldest types of chromatography. It utilizes a mobile liquid or a gaseous phase that is adsorbed onto the surface of a stationary solid phase. The equilibrium between the mobile and the stationary phase accounts the separation of different solutes e.g. adsorption chromatography, hydrophobic interaction chromatography.

Partition chromatography : It is based on a thin film formed on the surface of a solid support by a liquid stationary phase. Solutes equilibrate between the mobile and the stationary liquid (e.g. partition chromatography, reverse phase chromatography, gas-liquid chromatography, etc.).

Chromatography is a general technique available for the separation of closely related compounds in a sample. The term chromatography is derived from Greek where chroma means colour and graphein means to write. It is a very useful technique for both qualitative (preparative ) and quantitative (analytical) analyses. The separation is effected by the differential distribution of the components between two immiscible phases, namely, stationary and mobile phases. The various constituents of the mixture travel at different speeds, causing them to separate. The separation is based on differential partitioning (partition coefficient) between the mobile and stationary phases. The stationary phase is a porous medium through which the sample mixture percolates under the influence of a moving solvent (mobile phase).

Research related to biochemical analysis has been greatly benefited due to the development of chromatographic technique, since this technique makes it possible to resolve mixtures of closely related substances on a milligram to picogram range and to identify individual components by comparison with reference standard compounds. Chromatography ‘gives information where other analytical means have failed’ [Tswett, M. (1906) The macro-chemical and micro-chemical detection of carotene. Ber. Deut. Botan.Ges. 24 : 384- 393].

The relationship between gene and chromosome was suspected at the time of rediscovery of Mendelian^, Laws. During that period Montgomery (1901) and Walter Sutton (1902) working on grasshoppers showed that chromosomes occur in distinct pairs, often of recognizable shape and size, and that synapsis involves the union of maternal and paternal chromosomes, while Winiwarter (1901) concluded from his studies in rabbit ovaries that bivalents in the first meiotic division resulted from the chromosome pairing side by side and not end to end as believed by some other workers of that time . Theodor Bovery (1902) showed from his work on polyspermy in the fertilization of sea urchin eggs that the chromosomes of an individual were not equivalent (genetic information) to one another and hence a full chromosomal complement is essential for normal development of cell. Correns (1902) and Cannon (1902) pointed out close parallelism between Mendelian segregation and chromosome reduction during meiosis and concluded that genes are located on chromosomes but they, like de Vries, supposed that maternal and paternal chromosomes move to opposite poles during meiosis. In the same year Guyer established an understanding that random assortment between different pairs of chromosomes would give the independent assortment of genes required by Mendel. Ultimately Sutton (1903) brought together the ideas from cytology and genetics to clearly show the role of chromosomes in heredity and hence to establish the field of cytogenetics. Boveri also through his work, advanced many of the same ideas and thus the hypothesis correlating genes and chromosome transmission was established, which is known as the “Sutton-Boveri Hypothesis or chromosome theory of inheritance”.

Since the linking of the abnormal chromosome constitution of 45, XO to the peculiar phenotype of Turner’s syndrome (Ford 1959), an increased interest in the association between abnormal chromosome constitution and some clinical syndromes was perceived worldwide. The advent of “banding” techniques in the late 1960s helped to refine the detection accuracy and provided for more and better information about cytogenetic make-up of cells and contributed significantly to the localisation of certain genes (McKusik 1992). This phenotypic-karyotypic correlation was done on the basis of visual deletions, insertions, and duplications etc. of DNA segments of various lengths. However, many instances are known in which, because of a parent carrying a balanced translocation, two or more offsprings suffer from a deficiency and/or excess of chromosomal material. Some familial chromosomal arrangements are beyond detection by our current cytogenetic methods, although remarkable results have been forthcoming with high resolution banding. Similarly, paracentric inversions in a parent may not be evident except when carefully studied with high resolution banding, but can give rise to a variety of abnormalities in children.

Introduction
Chromosome engineering has emerged as a revolutionary approach, offering immense potential for genetic improvement by manipulating the structure and composition of chromosomes. Using genome engineering technologies, it is possible to introduce desirable traits into plants, such as disease resistance, increased yield, and enhanced nutritional content. To sustain the current standard of living, agriculture must yield significant increase in production (Gerland et al. 2014). Novel cutting-edge techniques developed for chromosome engineering hold great promise for addressing the challenges faced by modern agriculture, including climate change and food security. Engineering ability to precisely modify the genetic makeup of plants, chromosome engineering opens new avenues for creating novel cultivars with improved characteristics. While classical breeding has been successful in developing improved cultivars, it has its limitations. The process is time-consuming and often relies on probability to bring desired genetic changes. Since genes are organized into chromosomes, one important step to solve this issue is the development of novel genetic tools for chromosome reorganization and manipulation. When (Sears 1956) used X-ray irradiation to introduce foreign chromosome segments into the wheat chromosomes to transfer new traits, it was the beginning of plant chromosome engineering. Since then, plant chromosome engineering has evolved.
Applying methods such as chemicals and X-rays, induced mutagenesis was essential to the Green Revolution. Induction of polyploidy yielded more vigor and benefits like larger and higher-quality fruits (Osborn et al. 2003). Insect resistant and herbicide resistant transgenic crops successfully contributed to enhanced food production with less input into the farms. Genome editing enables precise modifications to increase disease resistance and stress tolerance (Ma et al. 2015). Considering practical features of chromosome engineering, this article discusses the use of induced mutagenesis, polyploidy induction, transgenesis, and genome editing, as the practical tools. The purpose of this chapter is to provide an in-depth analysis of chromosome engineering, exploring its scope, historical milestones, techniques, and its contributions to genetic diversity improvement and crop improvement. It also highlights the importance of efficient delivery techniques to overcome constraints such as off-target effects and concerns about genetically modified organisms (GMOs).

(Chroma - Colour; Some - Body)
A chromosome is a thread-like self-replicating genetic structure containing organized DNA molecule package found in the nucleus of the cell. Clear and detaile decriptions of mitotic chromosomes in plants and animals were published by Strasburger in 1875 and by the German scientist Walter Flemming in 1879- 1882.Heinrich Wilhelm Gottfried Waldeyer coined the term chromosome in 1888.
Normally Chromosomes are of two types
Autosomes - Control characters other than sex characters or carry genes for somatic characters.
Sex chromosomes (S    
Humans and most other mammals have two sex chromosomes X & Y, also called heterosome, odd chromosome, or idiosome. Females have two X chromosomes in diploid cells; males have an X and a Y chromosome. In birds the female (ZW) is hetero-gametic and male (ZZ) is homo-gametic.
Haploid: Haploid cells (N) have only one copy of each chromosome.
Diploid: Diploid cells (2N where N- chromosome number) have two homologous copies of each chromosome. The body cells of animals are diploid.In animals, gametes (sperm and eggs) are haploid.
Homologous Chromosomes
Diploid organisms have two copies of each chromosome (except the sex chromosomes). Both the copies are ordinarily identical in morphology, gene content and gene order and hence known as homologous chromosomes.Each pair of chromosomes made up of two homologs.
Homologous chromosome is inherited from separate parents; one homolog comes from the mother and the other comes from the father.

Chromosomes are giant molecules of DNA

Found in nucleus: never leave except in cell division

Carry hereditary units, genes

Two homologous copies in diplod cells

Unwind when replicating or making RNA

Wind up (condense) in cell division

Attach to spindle and separate in meiosis & mitosis

Crossing over in prophase of 1st meiotic division

Chromosomes are equally distributed in mitosis, meiosis

Gametes have half the number of chromosomes as body cells

Sister chromatids are observed to split apart longitudinally in anaphase

Portrait of a Chromosome

• Cytogenetics is the study of chromosome abnormalities and associated effects on health or other traits.
• Excess or deficient genetic material can cause syndromes or end prenatal development.
• Chromosomes consist of highly coiled DNA, RNA, histones, and nonhistone proteins.

Telomeres and Centromeres are Essential

Telomeres consist of repeat sequences and protect chromosome tips.

A centromere is a constricted site where spindle fibers attach during cell division.

Centromeres are regions of repeated DNA bound to centromere-associated proteins.

Weaning foods

Introduction

Breast milk is natural and best for the growth and development of newborn babies. Although breast milk is adequate to provide an optimum nutrient till the age of six months but after that it is not sufficient to sustain optimum growth and fulfill their nutritional requirements. Various nutrients are required to supplement milk until child is ready to eat adult meal. This additional food along with the breast milk is referred as “complementary Food”. With adequate amount of complementary feeding breast-feeding continues up to two years of age and beyond so, referred as complementary feeding period.

Appropriate and adequate amount of complementary feeding helps in preventing malnutrition stunting and promoting growth. Introduction of this complementary food is called as weaning.

Weaning is the process of introducing adult food and beverage to the infant to support their growth and development. This is very crucial period in infant’s life. This is a period for diet transition as the nutrition requirements for growth and brain development is quite high. Introduction of various taste and texture promotes biting and chewing skills (Guthrie, 1975). Most six-month age children start eating semisolid foods. Weaning homogenized infant foods play a major role in the nutrition of infants (Martinez, 2004).As infants grow, their nutritional requirements also increase. To keep up this growing demand WHO recommends that infants start eating solid, semi-solid or soft foods at the age of 6 months to ensure sufficient nutrient intake.

Botany :Annual Chrysanthemum is a winter annual that can be grown either as pot plants or in groups as bed plants for various ornamental purposes. There are two types of annual Chyrsanthemums: Chrysanthemum Segetum and C.coronarium. Major varieties of Chrysanthemum segetum L. are Morning Star, Evening Star, Eastern Star, Blanca, Eldorado, Gloria, Isabel, Romeo, and yellow Stone while popular cultivars of C. coronarium L. include Nivea, Oreon, Albo, Golden Crown, Luteum, Tom Thumb Golden Gem, Tom Thumb-Primrose Gem and Tetra Comet. In addition to this, there is another type of annual Chrysanthemum, i.e. C. carinatum. Popular varieties of C. carinatum S. are Merry, Atrococcineum, Burridgeanum, Eclipse, Flammenspiel, John Bright and Northern Star.

Propagation

Annual Chrysanthemums can be propagated by seeds. Their sowing time depends upon climate. It varies in different parts of India. In the Northern plains, winter season annual Chrysanthemums are sown during September–October. The seeds are sown in nursery beds, earthen pots, seed pans or wooden seed trays. The seed compost should consist of one part each of garden soil, coarse sand, farmyard manure and leaf-mould. For preparing the nursery beds, the soil should be dug up thoroughly and sufficient farmyard manure, should be mixed in soil. Raised nursery beds of convenient size (normally 60cm wide and 15cm high) should be prepared. If soil is heavy, some quantity of sand may be added. It is better if the soil of nursery bed or earthen pots is sterilized with 2% formalin. For this, soil is drenched with formalin solution and is covered with polythene sheet for 45hr. Afterwards, the polythene is removed and soil is dried before sowing the seeds.

1. Introduction

Chrysanthemum is commonly known as ‘Guldaoudi’, “Queen of the East”, “Glory of East” or “Autumn Queen”. It is one of the most beautiful and widely cultivated flowers that can be grown for its aesthetic value as well as for its commercial potential. The word chrysanthemum is derived from two Greek words, viz. “Chrysos” means gold and “Anthemon” means ‘flower’ i.e. golden flower. Chrysanthemum is the only crop that offers a great genetic diversity of flower colour, shape, forms, size, easy to propagate, growing habit, longer flowering duration and excellent vase life. Based on the shape of flower heads and floret arrangement of petals it can be used as pot plants for indoors and outdoors decoration as well as exhibition purpose; as cut flowers for flower arrangements, bouquets making and vase decoration; loose flower for making garlands, worshipping purpose and for bedding and garden decoration. Tall cultivars are suitable for background planting in borders and the dwarf and compact can be planted in front rows. 

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.

ORIGIN AND DISTRIBUTION

Chrysanthemum is originated in northern hemisphere (Europe and Asia). However, some workers reported that China is the native place of chrysanthemum (Carter, 1980). Most of the species in the lineage of present day cultivars are from China.

Chrysanthemum was first cultivated in China as a flowering herb and is described in writing as early as 15^th century B.C. As herb, it was believed to have the power of life. In 18^th century, they appeared in Japan as the crest and official seal of the Emperor. Japan also has a national chrysanthemum day, which is called the Festival of Happiness. In the western world, they are introduced in England, Japan, France and U.S. have developed a wide range of colours, shapes and sizes of flowers. Since the chrysanthemum was first introduced in the U.S. during colonial times, its popularity has grown such that mums now reign as undisputed ‘Queen of the Fall Flowers’. The Netherlands is the foremost importer of chrysanthemum cut flowers and is the centers for re-export to other parts of the world. In India, chrysanthemum is successfully grown under protected as well as open conditions in different states.