eChapters

27.1 Introduction

Crop improvement depends on genetic variation present in nature or created by hybridization followed by segregation and recombination. Again, gene transfers are possible only from the lines and species that are sexually compatible with the concerned species. Interspecific gene transfers pose many problems, including the loss of F₁ hybrids during embryo development due to abortion of the endosperm in the developing hybrid seeds. Embryo rescue technique was developed to rescue such interspecific hybrid embryos, and it has been widely used for this purpose. It is to be mentioned that embryo rescue can be used only in such cases where sexual hybridization is successful in producing zygotes that begin to develop into embryos.

Besides, the technique of somatic hybridization by protoplast fusion was developed to enable gene transfer from the species that do not produce zygotes on hybridization. This method has been extensively used and some useful lines have been derived. But this method is limited to utilization of genes present in plant species. Again, the results of somatic hybridization are unpredictable since many somatic hybrids fail to regenerate complete plants and the transfer of specific genes or groups of genes depends entirely on chance.

The recombinant DNA technology (also called genetic engineering) has permitted the transfer of genes from any organism into any organism. Besides, chemically synthesized genes can be transferred and integrated into genomes of various organisms to enable the expression of these genes. A gene transferred into an organism by genetic engineering is called a transgene. 

26.1 Introduction

We have already discussed the basics of tissue culture techniques in Chapter 2. Plant tissue culture techniques in combination with recombinant-DNA technology are essential requirements for development of transgenic plants (will be discussed in next chapter). However, tissue culture techniques like anther, pollen, ovule and meristem culture can themselves be used for improvement of different traits or as an aid to conventional breeding methods. In recent years, isolated microspore culture has been preferred as a breeding tool and an experiment system for various genetic manipulations. Besides, using protoplast fusion and hybrid embryo rescue, distant hybridization has been successfully achieved in many crops. Protoplast fusion technique can be used for the transfer of cytoplasmic male sterility from one species to another in very short duration. Somaclonal variation generated during tissue culture can also be utilized for recovery of variants showing disease resistance or other desirable characters.

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:

24.1 Introduction

When crosses are made between two different species of a genus or between two different genera, they are known as distant hybridization (also called wide hybridization). It includes both interspecific and intergeneric hybridization. Thomas Fairchild (1717) was the first man to do distant hybridization. He produced a hybrid between two species of Dianthus, viz., D. caryophyllus and D. barbatus (Carnation and Sweet William). Intergeneric hybrid produced by Karpechenko, a Russian scientist, in 1928 is Raphanobarssica. It is the amphidiploid of cross between radish (Raphanus sativus) and cabbage (Brassica oleracea var. capitata). Unfortunately, it had roots like cabbage and leaves like radish. Triticale was produced by Rimpau in 1890 itself. It is an amphidiploid obtained from a cross between wheat and rye (Triticum and Secale). Another example is Saccharum nobilisation involving Saccharum officinarum, S. barberi, S. sinensis, S. spontaneum. Wide hybridization has been used in the genetic improvement of some crops. It is an effective means of transferring desirable genes into cultivated plants from related species and genera.

23.1 Introduction

An organism or individual having more than two basic sets of chromosomes is called polyploid and the condition is known as polyploidy. Polyploidy is an important tool to increase genetic diversity by altering the chromosome number (2x) and consequently the number of genes within a single cell. Polyploidy has been one of the important mechanisms in the evolution of many cultivated crop plants.

23.2 Types of Polyploidy

23.2.1 Autopolyploidy

The condition that arises due to multiplication of the same chromosomes of a single species is known as autopolyploidy (also called ‘simple polyploidy’ or ‘single species polyploidy’). Autopolyploids have generally larger leaves, stem and other vegetative parts and flower, fruit and seeds than their normal diploids.

22.1 Introduction

Mutations are sudden heritable changes in the genotype of an organism. De Vries (1900) for the first time used the term mutation (mutare in Latin means ‘to change’) for the appearance of new types in evening primrose (Oenothera) plant. In 1901 he put forth the idea of producing mutations artificially for use in crop improvement. Alberto Pirovano (1922) was first to use X-rays and ultraviolet rays for inducing mutations in plants, but his work remained unknown. So, Muller (1927) became the first known to induce mutation in Drosophila fly using X-rays. Though Stadler (1928) had started working simultaneously on barley and maize and induced mutations, he was late in reporting mutation due to longer life cycle of these plants compared to Drosophila. Mutation may be gene mutation (the result of change in the nuclear gene or plasma gene) or chromosomal mutation (change in chromosome number, structure or chromosomal aberrations of various types).

21.1 Introduction

There are a number of field, vegetable, fruit and ornamental crops that are cultivated using asexual or vegetative parts such as stems, roots, modified flower etc. This is a heterogeneous group of plants and can be further categorized into four groups for ease in understanding the breeding methods applied to them. They are:

Group 1: Flowerless or Sterile

This group either does not bear flowers or if bears, they are sterile and do not set seed, e.g., ginger, mango ginger, turmeric, garlic, betel, many yams, etc.

Group 2: Apomicts

Apomixis has been reported in over 300 genera. But stable apomixis has been reported only in a few cultivated plants like meadow grass, citrus, mango, raspberry, etc.

Group 3: Flowers but Seed-Set Rare

In this group flowering takes place under specific situations but seed-set is limited, e.g., potato, sweet potato, sugarcane, etc.

20.1 Introduction

A hybrid cultivar (also called hybrid) is the F₁ progeny of a planned cross between inbreds, cultivars, clones or populations. Depending upon the breeding approach, the hybrid cultivar may involve two or more parents. A critical requirement of hybrid production is that the parents are divergent. This divergence is the cause of superior performance of hybrids. The outstanding performance of crops is due to the exploitation of the phenomenon of heterosis (hybrid vigour) which is high when parents are divergent. Much of what we know about heterosis breeding (also called hybrid breeding) came from the work on maize hybrid cultivar development. However, commercial hybrids are now available in many crops including self-pollinated crops.

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.

18.1 Introduction

The genetic variability present in populations of self-pollinated vegetable, spice and ornamental crops is rapidly exhausted by pureline selection. For further improvement, genetic variability must be created. This is generally achieved by hybridization. After the cross has been made, F₁ is grown and seeds set on it are harvested. This makes the seed source for raising F₂ population, and so on. The segregating populations from crosses are handled according to a suitable method. The three basic methods available for this purpose are: (1) pedigree method, (2) bulk method, and (3) backcross method. There are also certain modifications of these methods.

18.2 Pedigree Method

Pedigree method is developed from the pureline system and widely used method of plant breeding for self-pollinated crops. A main difference between pedigree selection and mass selection or pureline selection is that hybridization is used to create variability for the base population in case of the former, whereas in mass and pureline selections variability is naturally present in the base populations. The pedigree method was first described by H.H. Lowe (1927). This method predominated the crop improvement programme throughout the world until 1980s. Pedigree method is common in horticultural crops, especially where readily identifiable qualitative traits are involved. Vegetable crops in which pedigree system is used include tomato, cucumber, pepper, pea, lettuce, snap and field beans, all self-pollinated crops. In general, selection is done on F₂ plants. Yield is important in many horticultural plants, but quality is equally or even more important. Quality may be associated with identifiable traits, making the pedigree system ideal for self-pollinated vegetable 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.

16.1 Introduction

Plant introduction is the process of introducing plants from their growing locality to a new locality. Introduction of plants from a foreign country is called foreign introduction or exotic collection. Introduction from one state to another within a country is called indigenous collection or indigenous introduction. With introduction, the process of acclimatization is associated. Acclimatization is the adaptation or adjustment of an individual plant or population of plants under the changed climate for a number of generations. Plant introduction is an oldest method of plant breeding. It is used in self-pollinated, cross-pollinated and asexually propagated crops. The material of seed-propagated crops is introduced in the form of seed and that of vegetatively propagated crops in the form of cuttings or propagules. The introduced material may be a new crop, a wild relative or a new cultivar of a crop already grown in the area. There are five important sources of plant collection, namely, (1) centres of diversity, (2) gene banks, (3) gene sanctuaries, (4) seed companies, and (5) farmers’ fields.

15.1 Introduction

Plant breeding aims at developing genetically improved crop cultivars with economic benefits for small-scale and commercial farmers. Population growth, dwindling agricultural land and global climate change present increasing risk to crop production. Consequently, plant breeding aims to constantly develop crop cultivars with improved yield and quality and tolerant to drought, diseases and pests. Use of genetically improved crop cultivars and better management practices are among the best strategies to increase food production and meet a projected doubling of food demand in the next 40 years. Both the public and private plant breeding sectors face several constraints, including a shortage of professional plant breeders and breeding technicians, limited budget, inadequate facilities and lack of access to information. Successful plant breeding requires adequate infrastructural investment, in addition to the actual breeding activities. The benefits of plant breeding research and development can only be realized on a long-term basis because of the inherent nature of the crops and the eminent breeding procedures involved. Plant breeding involves two main activities, i.e., pre-breeding/ germplasm enhancement and cultivar development per se. These interdependent activities are the controlling factors that determine the pace at which cultivars are released timeously and consistently to farmers. The two phases, in turn, depend upon various factors, e.g., breeding goals, genetics and agronomy of the crop, breeder’s long-term objectives, availability of testing facilities and national cultivar-registration requirements. Despite these factors, there are certain clear steps and breeding procedures found in any conventional breeding programme. These include choice of parents, making crosses among chosen parents, and selection from recombined parents followed by extensive field testing of the candidate cultivars. Maintenance, multiplication and distribution of the seed are the ultimate stages of a breeding programme. Systematically outlined conventional breeding procedures, timeframes and estimated breeding generations are essential to objectively consider the ultimate timescales required to release new and improved cultivars of all crops. The information may assist plant breeding- students, educators, researchers, project advisors, administrators and funding agencies. Dear students, in this chapter we outline the timeframes of conventional breeding procedures of clonally (also called vegetatively) propagated, self-fertilizing (also called self-pollinated) and cross-fertilizing (also called cross-pollinated) crops.

14.1 Introduction

The mating or crossing of genetically dissimilar individuals is called hybridization. Hybridization results in recombination that in turn widens the spectrum of variation among individuals. So, the reason for genetic diversity in progenies of crosses is the formation of new combinations of genes. This newly created variability is then channelized into development of better cultivars.

The importance of pure line selection as a method of breeding started decreasing when plant breeders felt that the genetic variability existing in the land races of self-pollinated crops had been almost completely exploited and there was little chance for further improvement in these crops by using pure line breeding. Therefore, no option was left for plant breeders except to cross diverse individuals and combine together desirable characters in a single genotype from two or more parents. The planned hybridization which could avoid self-pollination and chance cross-pollination, soon became the main feature of almost all plant breeding programmes.

13.1 Introduction

F₁ plants produced by crossing two parents with contrasting characters are called hybrids. Hybrids generally exhibit increased vigour and fitness over the parents. This phenomenon is called hybrid vigour or heterosis. Thus, heterosis is the phenomenon in which the hybrid of two genetically dissimilar parents shows increased vigour at least over the mid-parental value. Heterosis is just the reverse of inbreeding depression, which results after selfing the plants of the cross-pollinated crops. Kolreuter (1761-66) was the first to report hybrid vigour in the hybrids of tobacco, Datura, etc. Most of the early plant hybridizers including Mendel (1865) had noticed this phenomenon. Shull (1914) coined the term heterosis from two Greek words, hetero (different) and osis (condition), to replace his own earlier word ‘stimulus of heterozygosis’. In current usage, heterosis and hybrid vigour are used as synonyms and interchangeable.

13.2 Types of Heterosis

Depending on the nature, origin, adaptability, reproducibility and non-reproducibility, heterosis can be categorized into two: (1) euheterosis (true heterosis) and (2) pseudo-heterosis (false heterosis, i.e., luxuriance).

12.1 Introduction

Allowing certain plants from the population to reproduce, while barring others, comprises selection. This permission for reproduction may be granted by nature or by the plant breeder. In the other words, both nature and breeder exert selection pressure. Natural selection operates through differences of fertility among the adult individuals of parent generation as well as through differences of viability among the individuals of offspring generation. Artificial selection, i.e., the selection from action of the plant breeder in the choice of parents, produces its change of gene frequency by separating the adult individuals of parent generation into two groups, viz., the selected and the discarded, that differ in gene frequency. So, selection simply implies the retaining of desirable types or culling of unwanted or undesirable types.

11.1 Introduction

In chapter 10, we have discussed the different types of variation, namely, genetic, environmental and genotype × environment interaction variations. We have also learnt how to estimate the phenotypic variance and its components including genotypic (also called genetic), environmental and g × e interaction variances from trial data. Now in this chapter, we shall discuss on the genetic components of polygenic (quantitative) variation and its implications on breeding strategies.

11.2 Genetic Components of Polygenic Variation

In this chapter whenever we call genetic variation, we mean polygenic (quantitative) variation, and we know that variation is usually measured in term of variance. However, variation, variability and variance are almost used synonymously. The genetic variance has been classified into different components by various workers. Fisher (1918) divided genetic variance into three components: additive, dominance and epistatic (interaction) variances. Wright (1935) classified genetic variance into two components: additive variance and non-additive variance (dominance and epistatic variances). Mather (1949) classified genetic variance into two components: heritable fixable variance (additive variance and additive × additive epistatic variance) and heritable non-fixable variance (dominance variance, and additive × dominance and dominance × dominance epistatic variances). Later, Hayman and Mather further divided the epistatic variance into three categories: additive × additive, additive × dominance and dominance × dominance.

10.1 Introduction

Plant breeders come across two categories of characters (traits) for improvement, namely, qualitative characters and quantitative characters. Red vs white flower, round vs wrinkled seed, determinate plant growth vs indeterminate plant growth etc. are examples of qualitative trait differences. There is no overlapping of characters and no confusion during classification. Such trait differences are usually governed by one or two gene pairs, each with large effect that can be measured even in the presence of segregation at other loci and even in the presence of effects of environmental factors. These characters are very less influenced by the environmental factors.

On the other hand, most of the traits of economic importance like yield of fruits of vegetable and fruit crops, yield of vegetative parts in fodder crops, yield of lint in cotton, yield of grains in cereals, pulses, oilseeds etc., plant height, days to maturity etc. are examples of quantitative characters. Variation observed for such traits is continuous. Again, there is overlapping of trait differences. So, one cannot assign individuals to a specific class unambiguously. Such characters are influenced by environmental factors, such that phenotypes are not same when grown over locations and/or seasons.

When different plants/lines of a species exhibit trait differences, it is called variation. Variation is essential for any improvement in a crop. It may be present in the population to be improved or else it may be created by different means such as hybridization, mutation, polyploidy, domestication, plant introduction, somaclonal variation, genetic engineering etc. Now, we shall discuss the types and estimation of variation.

9.1 Introduction

The sum total of genes in a plant species is called as plant genetic resources (also called germplasm, gene pool, or genetic stock). In other words, plant genetic resources refer to a whole library of different alleles of a plant (crop) species. Germplasm is the lifeblood of plant breeding without which breeding is impossible to conduct. It is the genetic material that can be used to perpetuate a species or population. It not only has reproductive value, but through genetic manipulation (plant breeding), germplasm can be improved for better performance of the crop. Germplasm provides the materials (parents) used to initiate breeding programme. Sometimes, what a plant breeder does is to evaluate plant genetic resources and make a selection out of existing biological variation. Promising genotypes that are adapted to the production region are then released for cultivation by the farmers. Other times, a plant breeder generates new variability by using different methods such as hybridization, mutagenesis and more recently gene transfer. This base population is then subjected to appropriate selection methods, leading to the identification and further evaluation of promising genotypes for release as cultivars. When a plant breeder needs to improve crop plants, he has to find a source of germplasm that would supply the genes needed to undertake the plant breeding programme. To facilitate the use of genetic resources (germplasm), germplasm (gene) banks are given the responsibility of collecting, evaluating, cataloguing, storing and managing large numbers of germplasm. This strategy allows a plant breeder ready and quick access to genetic resources when he needs it. The fact that Sir Otto Frankel coined the term ‘genetic resources’ only in 1968 shows that the plant breeders, though aware of the gradual loss of germplasm, failed to recognize the urgency of protecting the genetic resources of crop plants prior to a point of no return.

8.1 Introduction

In pre-historic times, people lived as hunters and gatherers. Then, gradually they began to produce the crops they ate on piece of land, and farming was born. Wild plants have certain traits that keep them protected and productive without human intervention. However, most of them are not desired for food or other use by humans. By spontaneous mutagenesis and hybridization, occasionally variant plants were found that lacked some of the undesired traits, such as bitter taste, thorns, or had particularly attractive features, such as larger fruits and more regular tuber shape. Consequently, as time passes such variation was picked up by humans by selection of such variants, keeping and advancing them. Thus, plant domestication is the process of bringing wild species under human management. In other words, plant domestication is the process by which genetic changes (shifts) in wild plants are brought about through a selection process imposed by humans. It is a method of plant breeding in the sense that, when successful, it provides domestic types that are superior to ones previously available.

Pre-historic man domesticated virtually all of our present-day crops. But, domestication of wild species continues even today and is likely to continue for a long time in the future. For example, in many countries there is an increasing emphasis on bringing forest trees producing timber, etc. under human management. A similar trend is seen for medicinal plants and plants producing specific compounds of interest, e.g., hydrocarbons, oils, etc. Kala jeera (Bunium persicum), a perennial spice, was domesticated during 1990s in Himachal Pradesh; it is being cultivated as an orchard crop. One important aspect of domestication at present is the use of particular genes from wild relatives in the improvement of cultivated species. When a plant breeder transfers one or a few desirable genes from a wild relative to a cultivated type, he is, in a sense, domesticating the wild species in part.

7.1 Introduction

Breeding plans are based on controlled mating (i.e., mating between selected strains) and selfing of selected strains or a combination of both. Continued selfing is practised to isolate purelines and inbreds. On the other hand, crossing (hybridization) is necessary to produce hybrids and synthetics. In crossing, self-pollination is prevented in the female parent. Male sterility and self-incompatibility easily exclude self-pollination, and so they are used in hybrid seed production.

7.2 Male Sterility

Koelreuter (1763) for the first time reported male sterility in flowering plants. Male sterility is a reproductive deficiency of some plants in which male organs in bisexual flowers become defunct. It relates particularly to nonviable pollen grains that are formed through a chain of vital processes during microsporogenesis. These processes are so delicately balanced under genetic control of many loci that mutation of any one locus may lead to the formation of non-functional microspores, and hence male sterility. In male sterility, pollen grains are non-functional (inactive); but the female gametes (egg cells) are normally functional.

6.1 Introduction

The process by which living beings give rise to the progeny of similar kind is called reproduction. Reproduction allows both multiplication and maintenance of a genotype/line/cultivar/species. So, the process of reproduction is also called propagation, and the plant part used for this purpose is called propagule. The way progeny originate is known as mode of reproduction (also called breeding system or reproductive system). The mode of reproduction of a crop determines its genetic composition which, in turn, is the deciding factor to develop suitable breeding methods. Knowledge of mode of reproduction is also essential for its artificial manipulation to breed improved types. The methods to be adopted for multiplication and maintenance of improved cultivars are also governed by the mode of reproduction. Especially in undertaking breeding investigations with new plants the nature of reproduction must be known before efficient breeding plans can be developed. The mode of reproduction has been well established for most of our important crop species.

6.2 Mode of Reproduction

Mode reproduction in crop plants may be sexual or asexual. In sexual reproduction (also called amphimixis), specialized reproductive cells called gametes are formed by the process of gametogenesis. Fusion of the male and female gametes leads to the development of an embryo and eventually the seed. In asexual reproduction, fusion of the male and female gametes does not occur, and new plants arise from unfertilized gametes (but not from zygote), or from specialized vegetative organs such as rhizome, tuber, bulb, corm, runner, sucker, stolon, bulbil etc., or by various artificial means of propagation such as rooting of stem and root cuttings, layering, grafting, gootee, etc., or tissue culturing.

5.1 Introduction

The development of quantitative trait loci (QTL) mapping methods to identify genes or QTLs controlling quantitative traits was a landmark achievement in plant genetics research in the late 1980s. Since then literally thousands of research papers have reported the identification of genes or QTLs for important traits across a diverse range of plant species. This wealth of genetic information was built on the foundation of decades of research in crop molecular genetics and genomics.

The selection and enrichment of QTLs within breeding material was the inevitable next step from QTL discovery to application, and there have been numerous reports of successful tracking of genes and QTLs within breeding programmes. DNA (or molecular) markers have enabled selection of major genes or QTLs for critical or important traits in a process called marker-assisted selection (MAS), which has revolutionized plant breeding. DNA markers are used as tools by breeders to improve the accuracy or efficiency of selection as well cost and time efficiency. Apart from MAS, DNA markers have numerous applications including DNA fingerprinting, genetic diversity analysis and parental characterization.

Recent developments in genotyping platforms and systems to implement molecular breeding schemes offer new tools for modern plant breeders. Single nucleotide polymorphism (SNP) markers are biallelic, co-dominant markers which are abundant in the genome. Insertion-deletion (Indel) markers are also prevalent and can be screened using high-throughput genotyping platforms. These platforms are cost-efficient, can handle large sample sizes and provide fast data turn-around time. The availability of genome sequences and genomic resources continues to provide a wealth of SNP and Indel markers which will undoubtedly be the marker type of choice for decades to come.

The availability of high-throughput SNP platforms in conjunction with advances in computational methods has also led to the molecular dissection of traits using genome-wide association studies (GWASs) across diversity panels and the development of genomics-based molecular breeding strategies. Association mapping (AM) has now emerged as a standard method for gene and QTL discovery for major crops.

4.1 Introduction

Many important traits such as yield, quality and some forms of disease resistance are controlled by many genes and are known as quantitative traits or characters (also called ‘metric’,‘polygenic,’ ‘multifactorial’ or ‘complex’ traits). The regions within genomes that contain genes associated with a particular quantitative trait are known as quantitative trait loci (QTLs). The identification of QTLs based only on conventional phenotypic evaluation is not possible. A major breakthrough in the characterization of quantitative traits that created opportunities to select for QTLs was initiated by the development of DNA (also called molecular) markers in the 1980s.

One of the main uses of DNA markers in agri-horticultural research has been in the construction of linkage maps for diverse crop species. Linkage maps have been utilised for identifying chromosomal regions that contain genes controlling simple traits (controlled by a single gene) and quantitative traits using QTL analysis. The process of constructing linkage maps and conducting QTL analysis–to identify genomic regions associated with traits–is known as QTL mapping (also called ‘genetic,’ ‘gene’ or ‘genome’ mapping). DNA markers that are tightly linked to agronomically important genes (called gene ‘tagging’) may be used as molecular tools for marker-assisted selection (MAS) in plant breeding. MAS involves using the presence/absence of a marker as a substitute for or to assist in phenotypic selection, in a way which may make it more efficient, effective, reliable and cost-effective compared to the more conventional plant breeding methods. The use of DNA markers in plant (and animal) breeding has opened a new realm in agriculture and horticulture called ‘molecular breeding’.

3.1 Introduction

Genetics deals with genes and cytogenetics with chromosomes that harbour genes. On the other hand, plant breeding strives to upgrade the genotypes of crop plants. So, the plant breeding methods should be based on genetic principles. Dear students, you should have clear understanding of genetics in broad sense so that you can appreciate the applicability of breeding methods. As I have already pointed out that you have been taught the course ‘Principles of Genetics and Cytogenetics’ in the first semester, only a brief discussion is followed for your review and better understanding.

3.2 Character

When we call ‘character’ or ‘trait’ in genetics, we mean any morphological, anatomical, biochemical or behavioural feature of an organism. For instance, flower colour, blooming period, leaf size, size of guard cells in stomata, vitamin C content, disease resistance etc. A single gene or a number of genes may govern the development of a character and, often it is influenced by the environment. Characters may be qualitative or quantitative.

2.1 Introduction

Dear students, you shall be taught plant biotechnology during the third semester in the course ‘Elementary Plant Biotechnology’. But, for understanding of non-conventional breeding methods/techniques you should acquire some knowledge of basic plant biotechnology. Hence, in this chapter plant biotechnology is introduced to you in brief.

2.2 Definition

The term ‘biotechnology’ stems from fusion of ‘biology’ and ‘technology’. It was coined by Karl Ereky, a Hungarian agricultural engineer, in the beginning of 20th century. According to him, all processes used to yield finished products from raw materials with the help of living organism come under biotechnology. It may be defined in number of ways. However, in simple terms, biotechnology may be defined as ‘the controlled use of biological agents, such as microorganisms, or cellular components, for beneficial use’ (U.S. National Science Foundation).

1.1 Introduction

The word ‘horticulture’ was first used in 1600’s, and is derived from two Latin words, ‘hortus’(garden) and ‘cultûra’(cultivation), and it means ‘the culture (cultivation) of garden plants’. Relf (1992) defined “horticulture as an applied science and art of growing fruits, vegetables, herbs and spices, nuts, tubers, aromatic and medicinal plants, plantation crops, mushrooms and ornamental plants which include shrubs, flowering plants and turfs stimulating minds, spirits and emotions of individuals, enriching health and wellness of communities, and linking human beings to nature and its landscaped exteriors for wellness and wellbeing”. Fruits and vegetables are nourishing and protective foods. It has been recognized that fruits are a rich source of antioxidants which protect us from dreadful diseases. Vegetables and fruits contain vitamin E, K, and  carotene in addition to minerals like zinc, copper and manganese. To meet the ever-increasing demand of the country for fruits, vegetables, tubers, spices, flowers, ornamentals etc., we must strive hard to deliver better cultivars in as many aspects as possible to the society so that human beings will be in sound health physically as well as mentally. To achieve this goal plant breeding in general, and horticultural plant breeding in particular will come to our help.

This is a great Hahnemannian anti- psoric. Its action is centrifugal - from within outward - having an elective affinity for the skin, where it produces heat and burning, with itching; made worse by heat of bed. Inertia and relaxation of fibre; hence feebleness of tone chracterizes its symptoms. Ebullitions of heat, dislike of water, dry and hard hair and skin, red orifices, sinking feeling at stomach about 11.00am, cat-nap sleep; always indicate sulphur homoeopathically. Standing is the worst position for sulphur patients it is always uncomfortable. Dirty, filthy people, prone to skin affections. Aversion to being washed. When carefully selected remedies fail to act, especially in acute diseases, it frequently arouses the reactionary powers of the organism. Complaints that relapse. General offensive character of discharge and exhalations. Very red lips and face, flushing easily. Often use in beginning the treatment of chronic cases and in finishing acute ones.

Imperfect assimilation and consequent defective nutrition, it goes further and produces neurasthenic states in consequence, and increased susceptibility to nervous stimuli and exaggerated reflexes. Diseases of bones, caries and necrosis. In TB it must be used with care, for here it may cause the absorption of scar tissue, liberate the disease, walled in, to new activities. It is a deep acting remedy and slow in action. It is meant for scrofulous children with large head, open fontanels and sutures, distended abdomen, slow in walking. Ill effects of vaccination. It is related to all fistulous openings. Ripens abscesses since it promotes suppuration.

Silica patient is cold, chilly, hugs the fire, wants plenty warm clothing, and hates drafts, hands and feet cold, worse in winter. Lack of vital heat. Prostration of mind and body. Great sensitiveness to taking cold. Intolerance of alcoholic stimulants/Ailments attended with pus formation.

In inflammation with pus formation, which has become chronic, silicea is of great help. It is equally useful in grandular or bony ulceration. Think of silicea in whitlow, unhealthy skin, smelly feet, mammary abscess, mammary cancer, TB of the skin, the bone or of the abdomen,

Acts especially on the portal system, with venous congestion. Stasis and thereby ptosis of viscera and weariness and misery. Weakness, yellow complexion, bearing-down sensation, especially in women, upon whose organism it has most pronounced effect. Pains extend down to back, chills easily. Tendency to abortion. Hot flashes at menopause with weakness and perspiration. Upward tendency of its symptoms. Easy fainting/ Ball" sensation in inner parts. Sepia acts best on brunettes. All pains are from below up. One of the most important uterine remedies. Tubercular patients with chronic hepatic troubles and uterine reflexes. Feels cold even in warm room.

The most important indications of Sepia are in the problems of women relating to the uterus. It has been called the best uterine remedy available. The patient feels that all her internal organs would come out of the pelvic region. She has to sit with legs crossed to relieve this feeling. Sepia is a chronic remedy. It can take care of long standing problems.

It produces contraction of the unstriped muscular fibers, hence a constringent feeling throughout the whole body. This produces an anemic condition, coldness, numbness, mortification and gangrene. A useful remedy for old persons with shriveled skin- thin, scrawny old women. All the Secale conditions are better from cold; the whole body is pervaded by great heat. Haemorrhages continued oozing, thin, fetid, watery black blood. Debility, anxiety, emaciation, though appetite and thirst may be excessive. Facial and abdominal muscles twitch. Secale lowers the flow of pancreatic juice by raising the blood pressure.

Menstrual colic, with coldness and intolerance of heat. Passive haemorrhages in feeble, cachetic women. Burning pains in uterus, brownish, offensive leucorrhoea. Menses irregular, copious, dark, continuous oozing of watery blood until next period. Threatened abortion about the third month. During labor no expulsive action, though everything is relaxed. After-pains. Suppression of milk; breasts do not fill properly. Dark, offensive lochia. Puerperal fever, putrid discharges, tympanitis, coldness, suppressed urine.

The word RHUS means red because its flowers and leaves are red in colour. TOXICODENDRON means poison tree.

The effects on the skin, rheumatic pains, mucous membrane affections, and a typhoid type of fever, make this remedy frequently indicated. It mainly affects fibrous tissues, joints, tendons, sheaths producing pain and stiffness. Ailments from strains, over lifting, getting wet while perspiring. Rheumatism in the cold season.

Rhus Tox is the first remedy one should think of in any muscular pain where the cutting pain and soreness are temporarily relieved by movement. This is in direct contrast to Bryonia where movement aggravates pain.

The word PULSATILLA is derived from PULSATUS meaning to beat or to strike as it pulsates from the blowing winds.

The weathercock among remedies. The disposition and mental state are the chief guiding symptoms to the selection of Pulsatilla. It is pre-eminently a female remedy, especially for mild, gentle, yielding disposition. Sad crying readily; weeps when talking; changeable, contradictory. The patient seeks the open air; always feels better there, even though he is chilly. Mucous membranes are all affected. Discharges thick, bland, and yellowish green. Often indicated after abuse of Iron tonics, and after badly- managed measeals. Symptoms ever changing. Thirstless, peevish and chilly. When first serious impairment of health is referred to age of puberty. Great sensitiveness.

Pulsatilla cures chronic colds, fatty dyspepsia, and painful and scanty menstruation. One of the leading indications for the use of Pulsatilla is a thick, bland, yellowish or green discharge from mucous membranes in the body. Such discharges are to be found in nasal catarrh, in expectoration from the ears, the eyes, the lungs, ulcers, leucorrhoea and in gonorrhoea. In most such cases Pulsatilla leads to a cure. In the vagina, however, this discharge is excoriating and not bland.

Phosphorus irritates, inflames and degenerates mucous membranes, irritates, and inflames serous membranes, inflames spinal cord and nerves, causing paralysis, destroys bone, especially the lower jaw and tibia; disorganizes the blood, causing fatty degeneration of blood vessels and every tissue and organs of the body and thus gives rise to haemorrhages.

Produces a picture of destructive metabolism. Causes yellow atrophy of the liver and sub-acute hepatitis. Tall, slender persons, narrow chested, with thin, transparent skin, weakened by loss of animal fluids, with great nervous debility, emaciation seems to be under the special influence of Phosphorus. Great susceptibility to external impressions, to light, sound, odors, touch, thunderstorms. Polycythaemia, fatty degeneration, cirrhosis, and caries are pathological states calling for this remedy, inflammations of the respiratory tract. Paralytic symptoms. Ill effects of iodine and excessive use of salt, worse lying on left side.

The first indication for Phosphorus is given by an intense sensation of burning in various parts of the body like the mouth, the lungs, the stomach, the small intestines, the anus, up the spine, the palm of the hand, and even the face. The patient craves for cold food, but this food is vomited as soon as it reaches the stomach. There is an insatiable hunger, an empty gone feeling in the stomach, in the whole abdomen.

The common acid " debility" is very marked in this remedy, producing a nervous exhaustion. Mental debility first, later physical. A congenital soil for the action of Phos. Acid is found in young people who grow rapidly, and who are overtaxed, mentally or physically. It is useful when the body is exposed to acute diseases, excesses grief, loss of vital fluids. Useful in relieving pain of cancer.

An excellent use of phosphoric Acidum is made in curing mental and physical debility and in acute and chronic diseases where the patient is tired in mind and body. The mental debility is a result of nervous exhaustion in persons who have been working overtime at a young age. Physical debility comes as a result of acute disease, sexual excesses, grief, and loss of vital fluids from the body. Haemorrhages in typhoid, therefore require Phosphoric Acidum.

The word NUX VOMICA is derived from Latin word NUX meaning nut and VOMERE meaning vomiting because of the peculiar property of the nut.

Is the greatest of polychrests, because the bulk of its symptoms correspond in similarity with those of the commonest and most frequent of diseases. It is frequently the first remedy, indicated after much dosing, establishing a sort of equilibrium of forces and counteracting chronic effects.

Nux is pre-eminently the remedy for many of the conditions incident to modern life. The typical Nux patient is thin, spare, quick, active, nervous and irritable. He does a good deal of mental work; has mental strains and leads a sedentary life, found in prolonged office work, over study and close application to business with cares and anxieties. This indoor life and mental strain seeks stimulants, coffee, wine, possibly in excess; or again, he hopes to quiet his excitement, by indulging in the sedative effects of tobacco, if not really a victim, to the seductive drugs, like opium etc. Nux is preeminently a male remedy. These conditions produce an irritable, nervous system, hypersensitive and over impressionable, which Nux will do much to soothe and calm. Especially adapted to digestive disturbances, portal congestion and hypochondriacal states depending thereon. Nux patients are easily chilled, avoid open air. Nux always seems to be out of tune, inharmonious spasmodic action.

The main action of this drug is on the outlets of the body where the mucous membrane and the skin meet; these pain as from splinters. Marked improvement of symptoms while riding in a carriage. Acts best on the dark complexioned and past middle life. Syphilis after abuse of mercury. Pains appear and disappear rapidly. All discharges very offensive especially urine, faeces, and perspiration. Persons who have chronic diseases and take cold easily and disposed to diarrhoea. Excessive physical irritability.

The human body has many outlets where the mucous membranes and the skin meet. Any pain on account of problems in these regions is severe. It is a sticking pain. It is a pain as if somebody is piercing the surface with splinters. Nitric Acid is the remedy for problems of this type.

The skin and the mucous membrane join at the corners of the mouth, in the nose and at the anus. On the lips the corners crack, get ulcerated and swollen. In the mouth there are blisters with a lot of pus and swelling. The gums are swollen, ulcerated and spongy. Fissures occur in the canthi. Nitric Acid is the first remedy in such cases.

The prolong taking of excessive salt causes profound nutritive changes to take place in the system, and there arises not only the symptoms of salt retention as evidenced by dropsies and oedemas, but also an alteration in the blood causing a condition of anaemia and leucocytosis. There seems also to be retention in the tissues. It is a great remedy for certain forms of intermittent fever, anaemia, chlorosis, many disturbances of the alimentary tract and skin. Great debility; most weakness felt in the morning in bed. Dry mucous membranes. Constrictive sensation throughout the body. Great weariness and weakness. Oversensitive to all sorts of influences. Hyperthyroidism. Goiter, Addison's disease. Diabetes.

According to Dr. E.B. Nash, Nat Mur is one of the best homoeopathic remedies for anemia. This anaemia can be caused by loss of fluids, by menstrual irregularities, by grief or mental diseases. The patient is pale, emaciated and in spite of eating very well he is anaemic. He suffers from a throbbing headache, soreness while climbing steps, exhaustion or physical exertion, constipation to some degree and overall depression. Some women have scanty flow of blood during menses.

Every organ and tissue of the body is more or less affected by this powerful drug; it transforms healthy cells into inflamed and necrotic cells; decomposes the blood producing a profound anaemia. This is converted into useful life saving and life preserving service if employed homoeopathically, guided by its clear-cut symptoms. The lymphatic system is especially affected with all the membranes and glands, and internal organs, bones, etc. lesions produced by Mercury are very similar to those of syphilis. Very often indicated in the secondary stage of syphilis where there is a febrile chloroanaemia, rheumatoid pains around joints, etc. all mercury symptoms are worse at night, from warmth of bed, from damp, cold, rainy weather, worse during perspiration. It is also known as human 'thermometre'. Sensitive to heat and cold. Breath, excretions and body smell foul. Tendency to pus formation, which is thin, greenish, putrid, streaked with thin blood.

The word LYCOPODIUM is derived from LUCOS meaning wolf and PES meaning the foot, as the shoots has an appearance of the wolfs foot. CLAVATUM derived from Latin word CLAVATUS meaning club-like.

This drug is inert until the spores are crushed. Its wonderful medicinal properties are only disclosed by trituration and succussion. In nearly all cases where Lycopodium is the remedy, some evidence of urinary or digestive disturbance will be found. Lycopodium is adapted more especially to ailments gradually developing functional powers, where the function of the liver is seriously disturbed. Atony. Malnutrition. Mild temperaments of lymphatic constitution, with catarrhal tendencies; older persons, where the skin shows yellowish spots, earthy complexion, uric acid diathesis, etc.; also precocious, weak children. Symptoms characteristically run from right to left, act especially on right side of body, and are worse from 4 to 8 PM.

Lycopodium is most useful in troubles relating to digestion. These troubles arise from the consumption of food, which ferments in the digestive system. That is why Lycopodium relieves a bloated and full abdomen wherein the wind is pressing downwards.

Like all snake poisons, Lachesis decomposes the blood rendering it more fluid; hence a haemorrhagic tendency is marked. Purpura, septic states, diphtheria, and other low forms of disease when the system is thoroughly poisoned and the prostration is marked. Delirium tremens with mucfrtrembling and confusion. Very important medicine during menopause and for patients of a melancholic disposition. Diphtheria carriers. Sensation of tension in various parts.

Lachesis treats the worst of throat problems, hot flushes in women during menopause, and diptheric paralysis. It is indicated in high blood pressure with constriction and in heart disease when the face is purple and bloated. Also religious insanity.

As a red inflammation leads us to use Belladonna, so Lachesis is to be thought of when the colour is purple. The face is purple; the eyes are engorged. An inflamed spot is purple and so are the inflamed glands. Ulceration bleeds, blood coagulates and the surface looks purple. There is extreme sensitivity to touch. The throat is purple and not red because the blood under the skin has coagulated. There is nothing like Lachesis if these indications are present.

Kali Bi is one of the finest remedies for the treatment of sinusitis, in diphtheric croup and in chronic, old cases. The mucous membrane of the nose responds to the administration of Kali Bi in acute as well as chronic cases. The discharge is tough, stringy, green and goes inwards into the throat.

The mucus is very difficult to take out. The patient can be heard from a distance trying to take it out but without success. One dose of Kali Bi. loosens this mucus.

There is pain in the sinuses. There is neuralgia in the orbits above the eyes. The sense of smell has been lost. The nose is stuffed. At times, there is violent sneezing. The patient suffers from chronic inflammation of the frontal sinuses. Only Kali Bi. gives relief and cure to such a patient.

Catarrhal laryngitis cough has a brassy sound. True membranous croup, extending to larynx and nares. Cough with pain in sternum, extending to shoulders. Pain at bifurcation of trachea on coughing from midsternum to back.

The name Ipecacuanha is from the Portuguese meaning, 'Road-side-sick-making plant⁷, and mention of it as a remedy for the bloody flux or dysentery goes back as far as the late sixteenth century.

The principle feature of Ipecacuahna is its persistent nausea and vomiting, which form the chief guiding symptom. Indicated after indigestible food, raisins, cakes, etc. especially indicated in fat children and adults, who are feeble and catch cold in relaxing atmosphere, warm moist weather.

One cannot think of treating persistent nausea without Ipecac. This is a nausea in which there is no relief by vomiting. The patient is as sick after as before. The second major problem for which Ipecac is a great cure is a chest complaint, bronchitis in infants, bronchitis with coarse rattling. Ipecac is also a remedy for infections of the upper respiratory tract wherein a peculiar wheezing sound is produced on breathing out. Old incurable cases of asthma are relieved by Ipecac. Ipecac is useful in uterine haemorrhages.

Suits especially scrofulous and lymphatic constitutions that are inclined to have eruptions and glandular swellings. Unhealthy skin. Blondes with sluggish character and weak muscles. Great sensitiveness to all impressions. Sweating patient pulling blanket around him. Chilliness, hypersensitiveness, splinter-like pains, craving for sour and strong things are very characteristic. The tendency to suppuration is more marked, and ahs been a strong guiding symptom in practice. The side of the body on which he lies at night becomes gradually insufferably painful; he must turn.

Hepar Sulph is the medicine for abscess, for the tendency to suppuration. Every little injury suppurates. Accompanying this suppuration is shooting pain. Suppuration or pus formation can be on any part of the body. If throbbing and shooting pain accompany it, it requires a does of Hepar Sulph in a high potency of 200 and above. Hepar Sulph can abort pus formation if given at the earliest stage of suppuration. Later it will hasten the pointing and discharge and help in healing the ulcer.

Like all the carbons, this remedy is an antipsoric of great power, but especially active in patients who are rather stout, of fair complexion, with tendency to skin affections and constipations, fat, chilly, and costive, with delayed menstrual history, take cold easily.

Children impudent, teasing, laugh at reprimands. Anaemia with redness of face. Tendency to obesity.

By and large, Graphites is a skin remedy. Eruptions oozing out at thick honey - like fluid require Graphites. Such eruptions may be on any part of the body. These would be especially found on or beyond the ears, on the head, the face and the genitals or on the eyelids.

Graphites is indicated in eczema of the legs where there is a thick oozing of sticky fluid. Eczema of the eyelids, where the eruptions are moist and the margins of the eyelids are fissured, also requires Graphites.

The word GELSEMIUM is derived from Latin word GELSIMINO meaning jasmine and SEMPERVIRENS meaning ever green.

Gelsemium is one of the most effective remedies in the treatment of influenza where there is body pain, pain in the head at the base of the brain, that is, in the occiput, and where there are accompanying throat problems.

Mentally, the Gelsemium patient desires to be left alone in peace. He is torpid, sleepy and dreads movement. He is dull. He cannot think clearly or concentrate.

As indicated above, Gelsemium is one of the remedies used in the treatment of influenza where there is body pain, a feeling of chill going upwards in the spine and congestion on the occiput. The eyes burn and itch with great discomfort. The patient sneezes and experiences coolness at the root of the nose. There may be acute running nose with dull headache and fever. At times the nose is blocked. The face is hot, flushed, dark red and looks like that of fool. The skin is very hot. The temperature goes up. There is itching and tickling in the soft palate, in the throat and in the nasopharynx. The throat feels rough; it burns. At times there is the feeling of a lump in the throat, which cannot be swallowed. There is pain in the temples, in the throat, radiating towards the ear. The entire system of the ears, nose and throat appears to be affected.

CINCHON, a place where the Countess Ann, a wife of the 4^th Count of CINCHON lived. She was cured by tertian fever in 1638 by the use of cinchona bark. Its virtues were made known to Europe in 1640. The botanists identified it in 1717. This drug shows the pathway for the establishment of homoeopathy.

The key word in the prescribing of China is 'debility' or weakness caused by excessive loss of blood or other fluids from the body, through nursing or salivation or excessive and bloody leucorrhoea, menstruation or long-continuing diarrhoea or through profuse pus formation or after an attack of influenza. There may be haemorrhages from the wounds, the lungs, the bowels or from the nose, a sudden depletion leading to fainting, loss of sight, ringing in the ears or to an over all weakness of the body. China acts as a marvelous remedy in such cases. The dose should be frequently repeated in 200 potency.

The word CHAMOMILA is derived from CHAMAEMELUM and MATRICARIA from MATRIX means apple on the ground, because the plant grows to the ground and has an odour like that of apples. It has been used since long as a domestic remedy by the name chamomile.

The chief guiding symptoms belong to the mental and emotion group, which lead to this remedy in many forms of disease. Especially of frequent employment in diseases of children, where peevishness, restlessness, and colic give the needful indications. A disposition that is mild, calm and gentle; sluggish and constipated bowels contra-indicate Chamomilla.

Chamomilla is sensitive, irritable, thirsty, hot, and numb. Oversensitiveness from abuse of coffee and narcotics. Pains unendurable, associated with numbness night-sweats.

The child patient wants to be carried in the arms. His mood is very irritable and snappy. He does not know what he wants. He needs a dose of Chamomilla. Even in elders, the patient is cross, ugly, spiteful and snappish. He cannot bear others. He cannot bear pain. He wants things but on getting them throws them away. He is uncivil.

Manifests its action mainly in chronic rheumatic, arthritic and paralytic affections, indicated by the tearing, drawing pains in the muscular and fibrous tissues, with deformities about the joints; progressive loss of muscular strength, tendinous contractures. Broken down senile. In catarrhal affections of the air passages, seems to choose preferably dark - complexioned and rigid fibered persons. Restlessness at night, with tearing pains in joints and bones, and faint - like sinking of strength. This weakness progresses until we have gradually appearing paralysis. Local paralysis, vocal cords, muscles of deglutition, of tongue, eyelids, face, bladder and extremities. Children are slow to walk. The skin of Causticum person is of a dirty white sallow, with warts, especially on the face. Emaciations due to disease, worry etc. Burning, rawness and soreness are characteristic.

Causticum is indicated in the treatment of chronic rheumatism and paralysis accompanying it. Here, Causticum ranks with Rhus Tox and Sulphur.

The typical Carbo patient is sluggish, fat and lazy and has a tendency to have chronic complaints. Blood seems to stagnate in thq capillaries, causing blueness, coldness and ecchymosis. Body becomes blue icy-cold. Bacteria find a rich soil in the nearly lifeless blood stream and sepsis and typhoidal state ensues. Weakness due to excessive diarrhoea, menstruation or other debilitating diseases. The patient may be almost lifeless, but the head is not, coldness, breathe cool, pulse imperceptible, oppressed and quickened respiration and must have air, must be fanned hard, must have all the windows open. The patient faints easily, are worn out must have fresh air. Haemorrhages from any mucous surface. Indicated for persons who have never fully recovered from the effects of some previous illness. General venous stasis, bluish skin, limbs cold.