eChapters

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.

1. INTRODUCTION

During fermentation, the fruit wines have to be monitored for different parameters to know the progress of fermentation and to control the quality of the finished products. It is essential to maintain the quality of the products, for which it is necessary to keep a complete record of wine fermentation. One such form is the fermentation control record or fermentation logbook, which is kept to monitor and record fermentation progress. It includes the name of fruit, variety, original characteristics of juice/pulp, amelioration, tank number, inoculum type and quantities, sampling time, date of start of fermentation and completion. It should also have daily record of temperature of fermentation, total soluble solid or ^oBrix reading, titrable acidity and volatile acidity, racking time/date and other comments on the fermentation. Fermentation control records should be completed and all new wines be entered in the bulk wine book inventory, the annual supplemental records can be kept in a file entitled, for example ‘Vintage season 2018’.

EXPERIMENT

TECHNOLOGY FOR EXTRACTION OF KERNEL OIL FROM STONE FRUITS

Apricot, peach, plum, cherries, nectarines etc are the important stone fruits belonging to the family Rosaceae. These fruits are known to contain stones/pits i.e., apricot (6.0-11.5%), peach (7.5-11.5%), plum (4.5-7.0%) and these stones are reported to contain kernels (%) apricot (28.0-32.0%), peach (5.7-5.9%), plum (10.0-20.8%), almond (28.0-30.0%). These kernels can yield an oil yield of (42.5-45.5%), (38.5-41.5%), (39.2-40.6%) and (52.0-58.9%), respectively. Thus, these stone fruit kernels can be utilized for extraction of kernel oil by using the improved technology developed for extraction of oil. The developed technology consists of mechanical decortication of stones by the use of mechanical decorticator, kernel separation by using specific gravity separation technique, oil extraction by using table oil expeller and oil filtration through oil filter press followed by packing in PET bottles and PE pouches.

Mechanical decorticator: The mechanical decorticator is a type of roller crusher consisting of two rollers moving in inward opposite directions with the help of 3 HP motor and is provided with a hopper and feeder assembly. The clearance between two rollers is adjusted according to the respective size of stones.

Table oil expeller: Oil expeller is a 24 patti screw type oil expeller driven by 7HP motor, in which the kernels are fed into the moving hopper at pre-determined flow rate, which are pressed in between rollers (worm) and side walls of the expeller. The kernels are then, passed through the expeller 3-4 times until a thin slice of press cake is obtained.

EXPERIMENT: MINIMAL PROCESSING OF CAULIFLOWER (FREEZING PRESERVATION AND STEEPING PRESERVATION)

Materials and reagents

Material : Fresh cauliflower, glass jars, polythene pouches

Reagents: 15% sodium chloride

FRUIT TOFFEES

Fruit toffees can be prepared from different fruits like apricot, plum, apple and other fruits. Concentrate the fruit pulp to about half of its volume by cooking with sugar and other ingredients. Milk powder should be added in the form of paste. Heavy stirring is required till it hardens enough on cooling.

PRACTICAL 1: PREPARATION OF READY-TO-COOK MUSHROOM PASTA

Pasta is a product originally made from wheat and is of different shapes and sizes. It is generally rich in carbohydrate but is deficient in protein especially amino acid balance. Therefore, addition of spices and dried vegetables may solve this problem. Moreover, fortification of pasta with tomato, garlic, mushroom or spinach makes it nutritious for consumption. Since instant foods are widely becoming popular and consumed throughout the world and is also a fast growing sector of the noodle industry because of busy life schedule of people.

Beverage is a drinkable product which includes all drinks fermented or unfermented, sweetened or unsweetened. It may be fruit based or non-fruit beverage. Fruit based beverage is the fruit juice that has been considerably altered in its composition before consumption e.g. drink, squash, nectar etc. In this chapter, preparation of RTS drink and squash has been discussed.

1. PREPARATION OF READY-TO-SERVE (RTS) DRINK FROM FRUITS

Theory: RTS is a type of fruit beverage which contains at least 10% of fruit juice and 10 degree Brix as Total Soluble Solids (TSS) with 0.3% acidity. It is not diluted before serving, hence it is known as ready-to-serve beverage. It can be prepared from fresh/preserved pulp/juice of various fruits like mango, litchi, apricot, guava, lemon etc.

1. INTRODUCTION

Marketing is a general term used to describe the activities that lead to the sale of your product. It is the process of planning and executing pricing, promotion and distribution programs to satisfy customer needs. It involves collecting information, analyzing alternative market outlets, developing different product forms, pricing products to compete in the marketplace, defining the scope of the proposed market area and meeting consumers’ needs. So marketing is more than just selling a product or service. It is an essential part of any business. Without a good marketing program, even the best businesses fails.

Value-added agricultural groups typically don’t pay enough attention to marketing. Selling agricultural commodities usually only involves hauling the commodities to a market where there is usually a willing buyer. So farmers often spend their time analyzing brick and mortar issues associated with processing and manufacturing (making the product rather than marketing the product). Often the attitude is that, if we make the product, someone will come along and buy it. So value-added agricultural businesses consistently fail because they do not understand the importance of designing and implementing a good marketing program.

As a first step, ‘A Marketing Primer and Marketing Basics’ will help you with a basic understanding of marketing. Successful marketing involves designing and implementing a marketing strategy for your product. Marketing Strategies provide generic strategies for various types of products and product buyers. In a simple term, marketing activities and strategies result in making products available that satisfy customers while making profits for the companies that offer those products.

1. INTRODUCTION

Food is any substance consumed to provide nutritional support for the body. It is usually of plant or animal origin, and contains essential nutrients, such as carbohydrates, fats, proteins, vitamins, or minerals. The substance is ingested by an organism and assimilated by the organism’s cells in an effort to produce energy, maintain life, or stimulate growth. A food contains some non-nutrients, some of which may even have a detrimental influence on the consumers, while some may be inert and have no effect. Nature has endowed many plants with the capacity to synthesize a wide variety of chemical substances that are known to exert a deleterious effect when ingested by animals and are called as antimetabolites. These substances are also referred to as antinutritional factors when they are present in food/feedstuffs and influence a metabolic pathway when introduced into and/or eaten by an organism.

There is a wide distribution of biologically-active constituents throughout the plant kingdom, particularly in plants, used as animal feed stuff and as human food. The knowledge that these compounds elicit both toxic and advantageous biological responses has given rise to several investigations in recent times as to their possible physiological implications in various biological systems. It is well known that plants generally, contain antinutrients acquired from fertilizer and pesticides and several naturally-occurring chemicals. Some of these chemicals are known as ‘‘secondary metabolites’’ and they have been shown to be highly biologically active. They include saponins, tannins, flavonoids, alkaloids, trypsin (protease) inhibitors, oxalates, phytates, haemagluttinins (lectins), cyanogenic glycosides, cardiac glycosides, coumarins and gossypol and the list is inexhaustible. Some of these plant chemicals have been shown to be deleterious to health or evidently dis-advantageous to human and animal health, if consumed in appropriate amounts. Most of these secondary metabolites elicit very harmful biological responses, while others are widely applied in nutrition and as pharmacologically-active agents. The pharmacological and other beneficial effects of these antinutritional factors in plants have been reviewed here.

1. INTRODUCTION

Fruits and vegetables are increasing in popularity in the daily diet of people of both the developed and developing countries. Product quality and quality evaluation methods are extremely important. The decisions concerning harvesting, maturity, ripeness and quality are based mostly on subjective and visual inspection of the external appearance of the fruits. The quality of fruits and vegetable is mostly based on size, shape, colour, gloss, flavour, firmness, texture, taste and freedom from external and internal defect. Many techniques for evaluating the external quality parameters are now available commercially. Internal quality parameters such as sugar content, acidity, oil content and internal defects however, are difficult to evaluate. Methods are needed to predict the internal quality of fruits and vegetable better without destroying them. Recently, there have been an increasing interest in non-destructive method of quality evaluation and a considerable amount of efforts has been made in this direction. The development of science and technology, especially of information technology has made available many non-destructive methods of analysis of materials which can also be applied to fruits and vegetables. The fruit industry needs non-destructive techniques for online sorting and certifying high quality fruit.

Non-destructive method can be classified according to the principle used to detect fruit properties; mechanical, acoustic, optical and Nuclear Magnetic Resonance (MRI) Techniques.