eChapters

Abstract

The genetic improvement of crop plants is possible only through employing an appropriate breeding technique. The use of plant breeding technique depends on mode of pollination and reproduction of plant species e.g. selection and hybridization are used in sexually reproduced species, while clonal selection in asexually propagated plant species. The plant species/ varieties are usually derived through conventional techniques (vi z. introduction, selection, hybridization etc.), which are commonly used in various breeding programmes, while some modern techniques viz. transgenic breeding and marker assisted selection etc. are also available which are equally effective for improvement of all crop species. Various techniques applied for development of new varieties and hybrids are briefly described in this section.

Plant breeding is an art, science and technology of improving genetic make-up of crop plants in relation to their economic usefulness for mankind. Various techniques/methods of breeding used for genetic improvement of crop plants are: introduction, selection, hybridization, mutation, transgenic breeding etc.

Classification of Breeding Techniques: Plant breeding techniques are classified as conventional and modern breeding techniques.

Livestock is one of the fastest growing agricultural subsectors in developing countries. In India has a vast diversity of animal genetic resources. Among them, sheep is an important ‘five star’ livestock species contributing significantly to rural economy through production of mutton, wool, manure, skin and milk etc. Sheep make a valuable contribution to the livelihood of the economically weaker sections of the society. The total Livestock population is 535.78 million and total sheep population is 74.26 million in in the country showing an increase of 4.6% and 14.1%, respectively over Livestock Census-2012. And it’s ranking 3rd in the world after China and Australia. Rajasthan is the fourth largest sheep rearing state in India with 7.9 million population (Livestock Census, 2019). Malpura sheep is one amongst the heaviest sheep breed of India, widely distributed in the semi-arid region of Rajasthan, mostly Tonk, Jaipur and Sawai Madhopur districts. Malpura sheep is reared and improved for mutton production since year 1975 at CSWRI, Avikanagar. The objective since then has been to improve the growth characteristics of this sheep breed for producing more carcass yield.The sheep is known for its adaptability to the harsh environment and potential for high meat production.Coat colour of Malpura sheep is white with coarse wool. The face is light brown with short, blunt ears. Animals have square compact body and long legs. Farmers also have liking for the long tail of animals for aesthetic purpose. The farmers like Malpura sheep for its properties like good mothering ability and produce sufficient milk to sustain and accelerate the growth of their neonates (Mishra et al., 2005), higher weight gain, number of lambs weaned, wool quality, walking capacity and the ease of management.

As the ornamental fish industry expands throughout the world, genetic considerations have become more important in terms of production, sustainability and conservation. Genetic technologies are now being applied to increase food production in aquaculture through traditional and modern breeding programmes. Genetic markers can help to manage capture fisheries and distinguish farmed from wild stocks in mixed fisheries. Genetic technologies are also now finding application in post-harvest and trade to assist in product identification and traceability. Genetic improvement of fish has considerably increased the fish production from aquaculture. It includes selective breeding, hybridization, polyploidy, gene and nuclear engineering. For any genetic selection programme, induced breeding is the basic and initial step. Intensive selective breeding is practiced with various species of fish in perfecting appearance, shape and color so that new strains are produced.

Domestication

Most of the fish being widely grown in captivity are domesticated to some extent, but there are very few which have undergone genetic improvement. Just as terrestrial livestock and crops are bred to be not only productive, but productive in convenient proximity to humans, aquatic plants and animals are now undergoing these same pressures.

In comparison to agriculture crops, fruit plants and animals, aquaculture is much behind with regard to the domestication of the fish, especially ornamental fish. Never the less, a good number of ornamental fish have been domesticated which can be considered for selective breeding to improve their traits. The available technologies and tools could be used to remarkably speed up domestication and genetic improvement process.

Domestication implies much more than merely keeping wild animals in farms or homes. Domestication is a very long process, during which captive individuals become more adapted to captive environments. Domestication leads to permanent genetic modifications of a bred lin-eage, while taming or keeping wild fish in captive conditions is only conditioned behavioral modification of individuals. The entire life cycle of the domesticated fish species must be fully closed in captivity. Once full life cycle is completed in captivity, the process of domestication can proceed further.

The first truly domesticated fish species was certainly the goldfish, for which the domestication was initiated by the Chinese about 1500-2000 years ago.

Technologiocal intervention is essential for improving pulse productivity through introduction of suitable high yielding varieties (Masood Ali and Shiv Kumar 2009). This is only possible through: (i) development of high yielding varieties with multiple resistance/tolerance to major diseases like mung bean yellow mosaic virus (MYMV), powdery mildew (PM) and Cercospora in mung bean and urdbean; (ii) development of varieties having resistance and tolerance to pre-harvest sprouting in mung bean, (iii) development of efficient plant type with high biomass and harvest index, (iv) development of varieties suited for intercropping system, (v) broadening genetic base of developed varieties, (vi) development of 50-55 days varieties of mung bean having 1 tonne/ha productivity and resistance to YMV for summer cultivation, (vii) development of high yielding and early maturity varieties of peas having resistance to powdery mildew, (viii) developing rajmash genotypes resistant to bean common mosaic virus and sclerotia rot, tolerant to high/low temperature and shattering resistance are important ones for increasing production through varieties intervention (AICRP MuLLaRP, http://iipr.res.in/mullarp).

The Para rubber tree (Hevea brasiliensis) is the most important commercial source of natural rubber, a strategic raw material. Rubber is an indispensable commodity used in the manufacture of over 50,000 products worldwide. This crop has therefore emerged as a key plantation species in various countries. The global area under rubber  cultivation is about 9.6 million hectares producing 9.2 million tones annually (IRSG, 2014). Among the major natural rubber producing countries, India occupies 4th position in terms of production with 0.91 million tones and more significantly the first position in average productivity of 1823 kg/ha/year. The major rubber producing countries are Thailand, Indonesia, India, Malaysia, Vietnam and Sri Lanka. Rubber is also commercially cultivated in Philippines, Nigeria, Cameroon, Cote de Ivoire, Liberia, Brazil, Cambodia, Nigeria, Cameroon, Guatemala, Myanmar, Mexico, China, Ghana, Democratic Republic of Congo, Gabon, and Papua New Guinea.Increase in production and improving productivity of NR continues to be the subject of considerable research efforts, particularly in the context of the widening gap between demand and supply of natural rubber. Over one million small farmers  in India owning less than 0.5 ha. of land depend on rubber cultivation for a livelihood.

Livestock is an important source of income for the rural poor and marginal farmers which enables earn income and food security using common resources.It is a best option to utilize such waste resources in proper way to earn income. About 65-69% of Indian population consisting of small and marginal farmers and land less laborers reared animal as supplementary occupation by feeding their animals agriculture by products. Indian agriculture is very difficult to sustain without dairy animals. Per capita availability of milk comes out to 281gm per day, which is below than the average of 300gm recommended by Nutrition Council of ICMR. Thus, there is a further need to increase the milk production of the country in view of minimizing difference between per capita availability and requirement. Milk production in India has increased from a modest 22 million tons during 1970-1971 to about 122 million tons in 2011—2012 (Deptt. of Animal Husbandry and Dairying).

ABSTRACT

Plant tissue culture is an important and efficient technique for the production of desired plant products with different and improved variety in aseptic conditions. Plant tissue culture methods have a wide scope for the creation, conservation, and utilization of genetic variability for the genetic improvement of field, fruit, vegetable, forest crops, medicinal and aromatic plants. The main objective of this communication were to collects the information and techniques of tissue culture to genetic improvement of the medicinal plants. Tissue culture technique in combination with molecular techniques has been successively used to incorporate specific traits through gene transfer. Modified varieties of medicinal plants is mostly required, as some compounds like alkaloids, terpenoids, steroids, saponins, phenolics, flavanoids, and amino acids etc are extracted from these plants. From the ancient time up to 20th century, most of the human-being are dependent on the medicinal plant for basic healthcare needs and improving such a crop is the most important for this billionaire world. As far conventional methods of genetic improvements the tissue culture techniques takes cheap and lesser time required for traits specific improvements in the MAPs.

Phenotype is a result of gene products brought to expression in a given environment. Genes specify the structure of proteins. All known enzymes are proteins. Enzymes perform catalytic function, causing the splitting or union of various molecules. All of the chemical reactions which occur in the cell constitute the subject of intermediary metabolism. These reactions occur as stepwise conversions of one substance into another, each group being mediated by a specific enzyme. All of the steps which transform a precursor substance to its end product constitute a biosynthetic pathway. Several genes are usually required to specify the enzymes involved in even the simplest pathways. Before gene-enzyme relationship could be postulated, soon after rediscovery of Mendelian principles of inheritance, it was discovered that genes were not merely separate elements producing distinct individual effects, but they could interact with each other to produce completely novel phenotypes. The simplest example of gene interaction could be the fact that allele A could be characterized by phenotype A, and the allele B by the phenotype B and an organism having both alleles A and B at the same time might show phenotype C. The occurrence of such interactions means that the phenotype we observe is not present in the genes themselves but arises from a complicated developmental process resulting from a biosynthetic pathway as illustrated below (Stansfield, 1969)

Introduction
Aquaculture is rapidly outpacing all other sectors in agricultural development. The study of fish genetics gained traction in the 20th century, driven by advancements in the understanding of Inheritance and reproduction. During the 1960s, selective breeding programmes aimed at enhancing genetic qualities became more common (Gjedrem and Baranski, 2009). Currently, more than 60 fish and shellfish species are going through selective breeding (Gjedrem and Baranski, 2009). Despite this, many critical traits like resistance to disease, efficiency of feed conversion, fatty acid composition and quality of meat are challenging to assess in breeding prospects but significantly impact the yield and profitability of several aquaculture species. Genetic mapping refers to the process of creating a genetic map (Van Ooijen and Jansen, 2013). Making genetic linkage maps is still essential for carrying out genetic and genomic research and many aquaculture species have had such maps developed. Developments in genotyping and sequencing technologies have made it the creation of higher-density, high-resolution (HR) genetic linkage maps. However, there are now important tasks in linkage analysis due to the usage of a large number of molecular markers. High-density linkage maps are valuable tools for studying genomic biology and evolutionary genetics because they serve as the foundation for QTL (quantitative trait loci) mapping. They facilitate the quantification of recombination rates, linkage disequilibrium levels, and chromosomal rearrangements across chromosomes, between sexes, and among different populations. The development of marker-Assisted Selection (MAS) has gained significant consideration and has significantly accelerated genetic breeding efforts in numerous cultured aquatic organism (Li, 2019; Yu, 2019). Quantitative trait loci (QTL) linked to economically important variables are frequently mapped using genetic linkage maps, which are an invaluable tool for examining genomic regions. (Huang, 2020; Wan 2017; Zhou, 2021). Growth rate, flesh quality, and disease resistance are only a few of the important features that are regulated by several genes or loci. The use of genetic maps in QTL (quantitative trait loci) mapping is essential for determining the locations of genes linked to these traits. (Huang, 2020; Li, 2019; Wan, 2017; Wang, 2018). The mapping of trait-related quantitative trait loci has been greatly improved by recent developments in high-throughput next generation sequencing techniques (You, 2020). Research in this field has greatly advanced through the use of a variety of techniques, including restriction site-associated DNA sequencing (RAD-seq), genotyping-by-sequencing, specific-locus amplified fragment sequencing, and genome-wide association studies (GWAS). Of these, RAD-seq is thought to be an appropriate, robust, and economical approach that has demonstrated 172 Aquaculture Genetics: Breeding, Conservation, and Sustainable Production efficacy in detecting genotypes and single nucleotide polymorphisms (SNPs) (Andrews, 2016). Linkage mapping in aquaculture is a valuable tool that has revolutionized selective breeding. By revealing the genetic foundations of key traits, it allows for more efficient and sustainable aquaculture practices. The integration of linkage mapping with other genomic technologies is expected to enhance productivity, improve disease management, and ensure the long term sustainable growth of aquaculture industries worldwide.

Linkage and Crossing Over

Crossing over may produce recombinant phenotypes.

Bateson and Punnett discovered two traits that did not assort independently.

Morgan provided evidence for the linkage of several X-linked genes and proposed that crossing over between X chromosomes can occur.

A chi square analysis can be used to distinguish between linkage and independent assortment.

Creighton and McClintock correlated crossing over that produced new combinations of alleles with the exchange of homologous chromosomes.

Crossing over occasionally occurs during mitosis. Genetic Mapping in Plants and Animals

The frequency of recombination between two genes can be correlated with their map distance along a chromosome

Alfred Sturtevant used the frequency of crossing over in dihybrid crosses to produce the first genetic map.

Trihybrid crosses can be used to determine the order and distance between linked genes.

Interference can influence the number of double crossovers that occur in a short region.

Genetic Transfer and Mapping in Bacteria

Bacteria can transfer genetic material during conjugation

Hfr strains contain an f factor integrated into the bacterial chromosome

Conjugation experiments can be used to map genes along the E. coli chromosome

A detailed genetic map of the E. coli chromosome has been obtained from many conjugation studies

Bacteriophages can also transfer genetic material from one bacterial cell to another in the process of transduction

Cotransduction can be used to map genes that are within 2 minutes of each other

Bacteria can also transfer genetic material by transformation

Horizontal gene transfer is the transfer of genes among different species

Genetic characterization using DNA markers is a cutting edge technology that makes it possible to study animal variability at basic level. A genetic marker can be any stable and inherited variation which is measurable or detectable by a suitable method and can be used subsequently to detect the presence of a specific genotype or phenotype other than itself, which otherwise is non-measurable of very difficult to detect. Such variations exist at morphology, chromosome, biochemistry or DNA levels that can serve as genetic markers. Molecular markers are the markers that reveal variations at the DNA sequence level. The polymorphisms observed at the DNA sequence has many applications which include percentage determination, genetic distance estimation and evolution, determination of individual identity, identification of disease carrier (heterozygous) animals, determination of twin zygosity and freemartinism, gene mapping, marker assisted selection (MAS), sex determination, DNA fingerprinting and transgenic breeding. Gene mapping is a tool to identify the genes responsible for specific traits.  The genetic map is constructed from linkage relationship based on the frequency of meiotic exchange (amount of recombination) among linked traits. Genetic map helps

Genetic purity is the vital determinant in continuing the genetic integrity in seed from generation to generation. This is the basis of variety purity maintenance. The genetic purity depends upon the purity of the seeds planted. The genetic purity of the seeds planted must exceed or equal to the final product purity standards required as the purity generally decreases with subsequent generations of propagation. The improved varieties loose their identity and healthiness unless properly maintained. Maintenance selection can prevent the seed quality deterioration.

Meaning and Importance

Genetic purity denotes the percentage of seeds (by weight) belonging to the variety/hybrid under certification. It is one of the primary criteria of seed quality. The efforts of plant breeders become fruitful only when sufficient quantities of good quality seeds of improved varieties/hybrids reach farmers / growers. This is necessary to take all round care at every step of seed multiplication before the seed is delivered for marketing. Hence, genetic purity testing is of critical importance not only to farmers but also to plant breeders, seed producers as well as quality control enforcing agencies. Increasing emphasis on hybrid cultivars due to their better performance and quality produce, more money and expertise have been put in further research of hybrid development. In this context, protection of parental lines is assuming critical importance and for that purpose, several breeding institutes do adopt various strategies for identification, characterization and protection of their parental lines as to avoid pilferage and misuse of their proprietary lines by other organizations. Use of random amplified polymorphic DNA (RAPD) and other molecular markers for evaluating seed purity of F₁ hybrids and their parental lines are closely related, thus, helps in assessing contamination of F₁ seeds even with the seeds of sib (inbred seed and seed from self-pollination of parental lines). For genetic purity testing of hybrids seeds, it is imperative that parental lines of hybrid be adequately characterized on the basis of maximum number of distinguishable descriptors (morphological, biochemical or molecular markers).

Characterization of Germplasm / Hybrids, Varietal identification, mutants etc.

Accurate identification of plants is desired for patent protection of plant varieties. Accurate characterization is also necessary to trace out the parents of new varieties. Use of present day molecular markers in addition to the classical methods provides more positive identification of new cultivars. RAPD and other molecular techniques have been used in a variety of plant materials for such studies (Sneath and Sokal 1973, Saitou and Nei 1987, Demeke et al., 1992, Selvam and Rajasekaran  1993, 1994, Dubouzet, et al., 1997, 1998, Hallden, et al., 1994, Hu and Quiros 1991, Jain et al., 1994, Matsumoto and Fukui 1996, Williams et al., 1990, Wolff et al., 1995). RAPD technique has been used in the genus Bougainvillea. It is often difficult to distinguish both mutants and hybrids and sports having a common progenitor, or progenitors themselves. Therefore, the industry needs a DNA-based fingerprinting technique to distinguish mutants or cultivars reliably. Reports are available on investigation about the molecular systematics and genetic differences for better understanding of varietal relationships in bougainvillea (Chatterjee et al., 2007, Kumar et al., 2006, Kumar et al., 2014, Hammad 2009, Pavan Kumar et al., 2015). 

Poultry has been extensively used for various biological experiments and its contributions to science are impressive. Among poultry species, chickens have made fundamental contributions to our current understanding of many immunological processes and it ranks high in the biological world. It still serves as an animal model to investigate immunogenetic aspects of disease resistance and tumor regression. Among the major contribution from poultry, the first evidence for viral induced tumor came from chicken (Rous, 1911; Nobel prize, 1966), reverse transcriptase enzyme was isolated from Avian Leukosis virus (Tamin and Baltimore, 1963; Nobel Prize, 1975), oncogenes in virus are from host cells (Bishop & Harold Varmus; Nobel Prize, 1989) and major two arms of immune response i.e. the T and B cells were first discovered in chicken.

Introduction

India is a vast country comprised of different agro-ecological regions with diverse climate, natural vegetation resources, topography, possesses almost all domesticated animal species, landraces and crops with different production systems. Domestic animals provide a considerable amount of   food requirements for mankind. India ranks first in milk production with 112.5 million tonnes milk produced in 2010-11. As India is a tropical country, in summer the temperature hikes about 40-48°C in various parts of the country. Such a temperature is certainly not within the comfort range of animals and thus the animals respond to the stress imposed by temperature on them in various ways to combat the stress and to maintain the homeostasis.

Mastitis is a disease of the mammary gland caused by pathogens that find their way into the lumen of the gland through the teat canal. Our efforts have been focused on developing mastitis resistant dairy cattle for a variety of reasons. Firstly, mastitis is a significant detriment to agricultural productivity. Mastitis is on every dairy farm and affects both the production and post harvest segments of the dairy industry. It is clearly a global disease. Secondly, the incidence of mastitis has not declined appreciably since the implementation of the extensive antibiotic therapy and culling of infected animals. Thirdly, considerable effort has been expended in developing vaccines that have not been as efficacious as hoped. Given these past efforts it is far from certain that a truly effective vaccine will ever be realized. Finally, because of the low heritability of mastitis resistance selective breeding has not been a useful tool for combating mastitis. Additionally, there is a strong desire to reduce the on-farm use of those antibiotics that are also used in human medicine, and certainly not least is a desire to improve the welfare of our dairy animals.

International Board for Plant Genetic Resources (IBPGR) now known as International Plant Genetic Resources Institute (IPGRI) uses the following items in genetic resources documentation. 
    i)    Passport (accession identifiers and information recorded by collectors) 
    ii)    Characterization (consists of recording those characters which are highly heritable, can be easily seen by the eye and are expressed in all environments) 
    iii)    Preliminary evaluation (consists of recording a limited number of additional traits thought to be desirable by a consensus) of users of the particular crop
Characterization and preliminary evaluation will be the responsibility of the curators while further characterization and evaluation should be carried out by the plant breeders. The data from further evaluation should be fed to the curators who will maintain a data file.

Introduction

Carrot (Daucus carota L., 2n=2x=18) is a cool-season root vegetable grown all over the world in temperate as well as sub-tropical climates. In India, it is cultivated over an area of 24,000 hectares with an annual production of 3,50,000 metric tones with a productivity much lower (14.58 t/ha) than the world average (22.17 t/ha) as per FAO, 2004. Carrots are used for human consumption as well as for animal feed. Carrot can thus be used for augmenting fresh fodder supply to milch animals during the lean winter in Kashmir (Hussan and Ahmed, 1999). Carrot has a significant place as an ingredient in soups and sauces and in dietary composition and also as a salad. A sweet preparation called Gajar Halwa is very famous dish in North India. Besides canning, it is also used in preparation of pickles. It is also exported in the form of fresh roots to the countries like Kuwait and Sharjah. Carrot is a rich source of á and â- carotene. The total carotenoid content in the edible portion of carrot roots ranges from 6.00 to 54.80 mg/100g. The yellow and orange coloured roots contain relatively more carotenoid. Carrot roots contain protein, fat, carbohydrate, minerals (especially Ca, Mg, Na, K, Cu, S etc.) besides vitamin A, B₁, B₂, nicotinic acid and vitamin C. In carrot roots, sucrose is the most abundant with endogenous sugar contents 10 times than those of glucose and fructose.

Asia minor, Afghanistan, North West India, Iran and Turkey are the centers of origin of carrot. As per Encyclopedia Britannica, carrots have originated from Afghanistan, Punjab and Kashmir with secondary centers in Ethiopia and North America. The European carotene carrot (syn. Western carotene carrot, temperate carrot) has been derived from the Asiatic anthocyanin containing forms of carrot (syn. Eastern anthocyanin carrot, tropical carrot). Afghanistan is the centre of diversity of the purple coloured carrot (anthocyanin carrot) and as such this country is suggested as the primary centre for origin. Integration between the Asiatic and European carrots has given the present day forms which are fleshy, smoother, less forked and better coloured.

Punjab and Kashmir are also considered as primary centre of origin with secondary centers in Ethopia and North America. It is still found in its wild form in Himachal Pradesh and Kashmir valley where wild animals especially brown bear feed on its roots. People still eat the wild carrots in some parts of Kashmir (Yawalkar, 1980). In north India highly coloured types of carrots are found which are not available in Europe. The colour of carrot ranges from absolute colourless to light lemon, light orange, orange and deep orange, light purple, deep purple and almost black. It is also an indication of this region being a primary centre of origin of carrot.

Introduction

Turnip is an important root crop which is very popular particularly in northern India. It is a cool season crop mainly grown as a fall or winter crop in the hills and winter crop in the plains. Turnip (Brassica rapa L. syn. Brassica compestris var. rapa) belong to family Brassicaceae. It has a chromosome number of 2n=2x=20. Two main centers of origin have been indicated. The Mediterranean area is considered to be the primary centre of origin of European type/temperate types. While Eastern Afghanistan with adjoining areas of Pakistan is considered to be another primary centre with Asia Minor, Transcaucasus and Iran as secondary centre. The parents of cultivated turnip are found in the wild form in Russia, Siberia and Scandnavia. It was cultivated by the ancients and ranked next to grapes and cereals in Italy. It was introduced in England probably in 1590 and United States in 1606 (Yawalkar, 1980). Turnips are now cultivated throughout the world.

Turnips are botanically biennial herbs, but are cultivated as annual root crops for both animal and human consumption. The turnip root contains 41.6% moisture, 6.2 g carbohydrates, 0.5 g protein, 0.2 g fat, 0.04 mg thiamin, 0.04 mg riboflavin, 43 mg ascorbic acid, 30 mg Ca, 40 mg P and 0.4 mg Fe per 100 g of edible portion. The turnip green contains 15,669 IU vitamin A per 100 g (Aykroyd, 1963). Turnip is grown for its enlarged root as well as for its foliage. Extra seedlings from thinning are often used as greens. The fresh roots are consumed in salads or cooked as vegetable or used in pickles. The young leaves contain high amount of ascorbic acid and iron, rank second in vitamin A content and are cooked as greens.

The fleshy thickened underground portion of turnip is actually the hypocotyl. The colour and shape of this underground portion vary with the cultivars and the roots are flat globular to top-shaped and long. The colour of under ground portion may be white or yellow, while that of above ground portion may be red, purple, white, yellow or green. A distinct tap root and secondary roots arise from the lower part of the swollen hypocotyl. Thickening begins in the central part of the hypocotyle, followed by the upper and lower parts. Normally, the roots attain edible maturity in 40-80 days depending on cultivar and climatic conditions.

Abstract

The potato research in India was started systematically after the establishment of Central Potato Research Institute (CPRI) in 1949. Forty-one potato varieties having attributes of early, medium and late maturity vis-à-vis resistance to various biotic and abiotic stresses have already been developed indigenously for varied agro-ecoregions in the hills and sub-tropical plains. After the establishment of CPRI, collection of potato germplasm was made mandatory. Presently there are over 2,700 accessions including 133 wild species (related to potato) in the germplasm collection of CPRI. Despite the large collection of potato germplasm at the institute the genetic base of all 41 Indian potato varieties released so far can be traced to only about 50 parents and most of these represent tetraploid potato cultivars while only a few of the exotic diploid wild species have been used in improvement of potato varieties in India. Under utilization of wild species could be mainly due to the pre- and post zygotic crossability barriers inherent in many species of genus solanum. Nevertheless, about seven wild species have been used in potato breeding for introgression of resistance genes for various biotic and abiotic stresses in the improved Indian potato varieties.

Introduction

‘Cole crops’ is a general term used to describe several vegetables in the Brassicaceae family. It is an important and highly diversified group of vegetable crops grown worldwide that belongs to Brassica oleracea (Monteiro and Lunn, 1998) and includes particularly six Brassica crops (cabbage, cauliflower, Brussels sprouts, broccoli, kale and knol kohl). All of these crops can trace their history to a common ancestry of wild cabbage originating in the Mediterranean and Asia Minor regions. Cole crops are one of the oldest cultivated plant groups in the world. They are cultivated in Europe since very ancient time from where they have spread to other parts of the world (Nieuwhof, 1969). All the cole crops (except few cauliflower, broccoli and cabbage types) require chilling temperatures for about two months to transform from vegetative phase into reproductive phase. However, the period of chilling requirement differs according to the kind of crop and varieties. Cole crops are also commonly called as European or biennial vegetables due to their cool temperatures requirements and two season requirement to complete their life cycle.

Major Resources of Cole Crop Germplasm

Germplasm is any form of the hereditary material from an organism. Genetic resources encompass all the various forms of germplasm that are available for collection, storage and use. The genetic diversity of crops, represented by traditional local cultivars and wild relatives has been disappearing rapidly during recent decades. Initial concern was noted by H.V. Harlan in the 1930s (Harlan and Martini, 1936) but by the 1960s, modern plant breeding and land-use changes accelerated loss and stimulated the realization that genetic resources in regions of diversity were being lost at an alarming rate. To conserve the genetic variation within the cole group, a comprehensive base collection of the cultivated forms of Brassica oleracea has been established at the vegetable gene bank of Horticulture Research International (HRI), Wellesbourne, (U.K.). Gene banks have also been established at Instiuut de veredeling van Tuinbouwgewssen, Wageningen, the Netherlands and the Instituto del Germoplasm, Bari, Italy (Van der Meer et al., 1984) for conservation of genetic resources. The International Board for Plant Genetic Resources (IBPGR) has recognized HRI as an international centre for conservation of Brassica oleracea (Innes, 1975). Large number of collections of cole crops is also available with the United States Department of Agriculture, Plant Introduction Service. In India, National Bureau of Plant Genetic Resources (NBPGR), New Delhi has been assigned the duty of conserving the germplasm of all crops, including vegetables. Germplasm of all the cole crops is being maintained at the Indian Agricultural Research Institute, New Delhi (tropical types) and its regional station at Katrain (temperate types). Other major institutes maintaining germplasm of cole crops include Punjab Agriculture University, Ludhiana, G. B. Pant University of Agriculture & Technology, Pantnagar, Indian Institute of Vegetable Research, Varanasi, Dr. Y.S. Parmar University of Horticulture and Forestry, Solan and SKUAS&T, Srinagar.

Introduction

Cowpea, {Vigna unguiculata (L.) Walp.} is an important food legume in the semi-arid tropics covering Asia, Africa, Southern Europe and Central and South America (Henriet et al., 1997; Mortimer et al., 1997; Van Ek et al., 1997). It is a drought tolerant and warm weather crop. Therefore, well adapted to the drier regions of the tropics where other food legumes do not perform as well. It fixes atmospheric nitrogen and grows well even in the poor soils with more than 85% sand and with less than 0.2% organic matter and low levels of phosphorus (Kolawale et al., 2000 and Sanginga et al., 2000). Also, it is shade tolerant and therefore, compatible as an intercrop with maize, millet, sorghum, sugarcane and cotton as well as with several plantation crops (Singh and Emechebe, 1998). Coupled with these attributes, its quick growth and rapid ground cover checks soils erosion and in situ decay of its roots and nitrogen rich residues improves soil fertility and structure which together have made cowpea an important component of cropping system in the dry savannas of the sub-Saharan Africa (Carsky et al., 2001 and Mortimer et al., 1997).

Cowpea is cultivated in about 14 million ha world wide with about 5 million tons annual production. However, a substantial part of the cowpea production comes only from few countries. Nigeria is the largest producer and consumer of cowpea with about 5 million ha area and about 3 million tons production annually. Niger Republic is the next largest producer with 3 million ha and over 1 million ton production. Northeast Brazil grows about 1.5 million ha of cowpea with about 500.000 tons production. In the southern USA about 40,000 ha of cowpea is grown with an estimated 45,000 tons annual production of dry cowpea seed and a large amount of frozen green cowpeas. Even though exact statistics are not available, India is the largest cowpea producer in Asia and together with Sri Lanka, Pakistan, Nepal, Bangladesh, Thailand, Indonesia and other far eastern countries, there may be over 1.5 million hectares under cowpea in Asia.

Introduction

Radish (Raphanus sativus L., 2n=2x=18) is a root cum leafy vegetable suitable for sub tropical and temperate climate. Radish probably originated in Europe and Asia. It has been under extensive cultivation in Egypt since long. It was introduced to England and France in the beginning of 16^th century. In 1806, it was introduced to America. Radish does not exist in wild stack. It is believed to have originated from R. raphanistrum which is widely distributed as weed in Europe. Radish is primarily a winter crop but with the development and release of new varieties, it can be grown all the year round. The new varieties can withstand heat and does not bolt in spring. Radish is a favourite crop because of its quick growth and availability in 4-7 weeks.

Its fleshy roots are modified roots, developed from both the primary root and hypocotyl. The leaves and roots are consumed both as salad and cooked. The radish root is a good appetizer; its different preparations are useful in curing liver and gall bladder problems. Roots are also used in treating urinary complaints and piles. The juice of fresh leaves is useful as diuretic and laxative. Pungency in radish is due to volatile isothiocyanates while pink colour is due to pigment anthocyanin.

Radish is a good source of vitamin C containing 15-40 mg per 100g of edible portion. Roots also contain proteins, fat, minerals, fibre and carbohydrates, besides trace elements like aluminium, barium, lithium, manganese, silicon, titanium, fluorine and iodine. Pink skinned radish is generally richer in vitamin C than the white skinned type. Radish contains glucose as the major sugar and also contains fructose and sucrose in smaller quantities. Pectin and pentosans are also reported to be present. The leaves are good source of extraction of protein on a commercial scale and seeds are potential source for non-drying fatty oil suitable for soap making, illuminating and for the edible purposes.

Introduction

Peas (Pisum sativum L., 2n = 2x =14) are consumed as fresh vegetables or dry seeds throughout the world. In India, peas are grown as winter vegetable in plains and as summer vegetable in the hills. As field pea, it occupies about 0.45 m ha area in India, accounting for only about 2% of the total pulse area. About 90% of its area and production is limited to Uttar Pradesh alone. The area under vegetable peas is on increase. The acreage of vegetable pea in India is 2.72 lakhs ha with a productivity of 9.9 tons/ha. Pea is a rich source of protein (7.2% in green pea & 20 % in dry pea) and minerals (0.8%).

The geographical region comprising of Central Asia, the Near East, Abyssinia and the Mediterranean is considered as centre of origin based on genetic diversity. According to Blixt (1970), the Mediterranean is the primary center of diversity with secondary centers in Ethiopia and the Near East.

Garden pea, seeds have been observed in archeological excavations of Mohan Jodaro and Harappa, there are distinct hot weather tolerant and round-seeded varieties which carry high resistance to fusarium wilt and powdery mildew (Erysiphe polygoni). These varieties have a different use as a pulse crop for meeting protein requirements of common people. These are considered as intermediate stages of domestication of the present day vegetable (garden) pea, which is sweet and wrinkled-seeded. In fact, the quick spread of Arkel variety, an introduction from England in seventies, has displaced some of the native round-seeded varieties like Asauji, Hara Bonia, Hoshiarpuri, Kaparkheda, Kalanagni, Lucknow Bonia etc. there is need to conserve these valuable germplasm, before they are swept away by genetic erosion.

Introduction

Potato is a wonder crop that can be grown under diverse range of agro-climatic conditions. Short duration; high yield per unit area and time and wide flexibility in planting and harvesting time are important virtues of potato that enable its inclusion in intensive cropping systems.

Potato is not an Indian crop but is a native of high Andean region of South America. It was introduced in India perhaps in 16^th or early 17^th century by either the Portuguese traders or the British missionaries. The present day cultivated potatoes (tetraploid, 2n=4x=48) in most of the world represent Solanum tuberosum spp. tuberosum and S. tuberosum spp. andigena, although it’s numerous diploid (2n=2x=24) relatives are still under cultivation in and around its primary and secondary centers of origin in South America (Pandey and Sarkar, 2005). The great Irish famine in the 19^th century, caused by late blight disease, nearly wiped out all the earliest potato introductions in the Europe and dramatically changed the potato cultivation and production scenario in rest of the world.

Unlike in European Countries 80% of the potato is grown in India under short day conditions as a short duration crop i.e. 70-90 days. The tubers are exposed to high temperatures during planting (September-October) and harvesting (February-May). The crop is irrigated and suffers mid day water stress. The potato varieties introduced from Europe were unsuitable for growing under the above conditions. Systematic potato research in India spanned over the last half-a-century of the 20^th century in the past millennium. The Central Potato Research Institute (CPRI), which was established in 1949, has bean mainly responsible for tremendous growth of potato production in the country. The indigenous technological advances made it possible to extend potato cultivation in almost all part of the country. Now in India, compared to the production, area and yield of potato in 1949-50, the increase over the same period was 1513%, 559% and 270% respectively (Naik and Thakur, 2007). According to the FAO, potato production worldwide stands at 329 million tones and covers more then 19 million ha.

The Cucurbitaceae family is characterized by long training viny stems. There is variation for flower size and colour among the species but all of them have similar general morphology. The species are open pollinated and self compatible. Most of them are either monoecious (eg. Cucurbita spp.) Or andromonoecious (e.g. common in melon). Other species show gynomonoecy, androgynomonoecy, androecy, gynoecy, hermaphrodite or dioecy. Chow-chow is the only member of the Cucurbitaceae that is viviparous, contains single seed and propagated by planting whole fruit. The Indian gene centre has rich diversity in genetic resources of ridgegourd (Luffa acutangula), bottlegourd (Lagenaria siceraria), bittergourd (Momordica charantia), ashgourd (Benincasa hispida), snakegourd (Trichosanthes anguina), pointed gourd- parval (Trichosanthes dioica), pumpkin (Cucurbita spp.) and roundgourd (Praecitrullus vulgaris). Cucurbits are of tremendous economic importance and are cultivated throughout the world from tropical to sub-temperate zones. China, Turkey, India and Iran are important cucurbit growing countries. In India, this diversity is concentrated in Indo-Gangatic plains, north eastern region, north western Himalayas, the Western and Eastern Ghats and sporadically in the tribal dominant belts of central India.  More diversity occurs in Cucurbita spp. in the north east as also for ashgourd, bottlegourd while for Luffa, it is more concentrated in the eastern peninsular tract.

Plant genetic resource (PGR) is fundamental to crop improvement programme and key to establish future food and nutritional security. In recent times there is a worldwide awakening about the conservation of natural resources viz., land, water and plant genetic resources for the sustainable development of mankind. With the increasing risk from the events like climatic change, natural resource degradation,habitat destruction and environmental pollution etc, now there is an worldwide  debate asking many questions - where the humanity is heading in the this 21st century? Whether the present form of indiscriminate growth pattern is sustainable over a long run?

INTRODUCTION

Potato belongs to a genetically diverse genus Solanum having nearly 235 tuber bearing species. These speciesform a polyploid series ranging from diploids (2n=2x=24)tohexaploids (2n=2x=72), with12 asthebasic chromosome number. There is also arichdiversity within the cultivatedspecies of potato and they were initially grouped under six different species. Later studies, however, recognized those species as land race populations of S. tuberosum, with the eight groups: Ajanhuiri, Andigenum, Chaucha, Chilotanum, Curtilobum, Juzepczukii,Phurejaand Stenotomum(Spooner & Salas, 2006). Thisrich genetic diversity of the species is available in the Andean mountain where potato originated. In India,however, it was quite natural that genetic variability within the locally available material will be meager since, it was introduced here only about 400 years ago. On the contrary, more than 500 differentvarieties existed in India by 1940. This paradoxical situation was primarily due to assigning different local names toasingle variety in different parts ofthe country. The available local varieties in India consisted of both early introductions belonging to either pure Solanum tuberosum ssp. andigenum or their hybrids with S. tuberosumssp.tuberosumas well as later European introductions belonging to S. tuberosum ssp. tuberosum.

Germplasm collection and conservation are crucial for maintaining the genetic diversity and ensuring the long-term sustainability of spice crops. Here’s a general approach for spices:
A. Germplasm collection
a. Identification and selection
• Identify key spices and their varieties.
• Select diverse genetic material, including wild relatives and landraces.
b. Field collection
• Collect samples from diverse locations to capture genetic variation.
• Document the collection site, local environment, and plant characteristics.
c. Data recording
• Maintain detailed records on the collected germplasm, including geographic origin, agronomic traits, and any special characteristics.
d. Quality assessment
• Ensure the collected material is healthy and viable.
• Assess quality traits relevant to the spice industry.

Tripura is situated between 22º 56’to 240 32’ N latitude and 91010’ to 92021’E longitude with tropic of cancer passing through it. The total geographical area of state is about 10,491 km2 of which 57.98 % area is under forest cover.  Agriculture is an important sector in the state, which contributes 26 % of the State GDP of which the major contribution is from horticultural crops like fruits (pineapple, litchi and oranges), vegetables (potato TPS), plantation crops (cashew nut, coconut, rubber and tea) and spices (ginger, turmeric and black pepper). More than 75 % of the population either directly or indirectly depends on agriculture. The small and marginal farmers constitute about 90 % of total farming community and the average size of land holding is 0.97 ha (1990-91) in comparison to 1.25 ha (1976-77), which is the lowest among the seven other North Eastern states.

Introduction

The North-eastern region comprises of eight states viz. Assam, Arunachal Pradesh, Meghalaya, Manipur, Mizoram, Nagaland, Tripura and Sikkim lying between 21.5^o N - 29.5^o N latitudes and 85.5 ^o E - 97.3 ^o E longitudes. It has a total geographical area of 262180 Km² which is nearly 8 % of the total geographical area of the country. In the whole of NE region, about 35 % area is plain and the remaining 65 % area is under hills. Whereas in Assam plains account for 84.44 % of its total geographical area and the remaining 15.56 % area is under hills. Net sown area is highest in Assam (34.12 %) followed by Tripura (23.48 %), however, Arunachal Pradesh has lowest net sown area in the region. Cropping intensity is highest in Tripura (173 %) followed by Manipur (152.1 %), Mizoram (136.36 %) and Assam (123.59 %). About 0.5 million hectare area is under shifting cultivation in the NE region. Out of 4.4 million hectare net sown area, roughly 1.4 million hectare lies in hilly sub region and at least 1.3 million hectare suffer from serious soil erosion problem.

The diverse agro climatic conditions, varied soil type and abundance of rainfall offers immense scope for cultivation of different types of horticultural crops, including fruits, vegetables, flowers, plantation crops, tuber and rhizomatous crops and crops of medicinal and aromatic importance. The region has rich diversity of different vegetable crops and both indigenous tropical vegetables and temperate vegetables are grown to a considerable extent. The major vegetables grown in the region are brinjal, cabbage, cauliflower, okra, onion, pea, potato, tomato, knol-khol, radish, carrot, French bean and different cucurbitaceous crops. Tuber and rhizomatous crops like tapioca (cassava), sweet potato, Dioscorea, colocasia, ginger and turmeric grow abundantly in the region.

Introduction

A delicate balance between human sustenance and ecological preservation has always been at play in the vast expanse of our oceans and freshwater bodies. The world's fisheries have long served as a critical source of nourishment and economic livelihood for millions, yet the sustainability of these resources faces ever-increasing challenges. As fish populations dwindle due to overfishing, habitat degradation, and the looming uncertainties of climate change, innovative solutions are more urgently required than ever before. Enter Marker-Assisted Selection (MAS), a groundbreaking technology that is poised to revolutionize the realm of fisheries management and aquaculture.

Artificial seeds have been widely used for micro-propagation of many plant species. Establishment of gene banks for ex situ conservation of plant germplasm in the form of field gene banks, seed gene banks, in vitro collections, and cryogenically preserved tissues is a common practice (Withers 1983; Rao, 2004; Borner, 2006). Alginate encapsulation provides a viable approach for in vitro germplasm conservation as it combines the advantages of clonal multiplication with those of seed propagation and storage (Standardi and Piccioni, 1998; Ara et al., 2000).

The main aim of artificial seeds is to obtain true to type plants to maintain the germplasm, but, however, during tissue culture, there is a chance of genetic aberration which is commonly known as somaclonal variations. Larkin and Scowcroft (1981) for the first time used the word ‘somaclonal variation’ to describe these variations as displayed among the plants derived from tissue culture. It is clearly understood that genomes modify themselves when exposed to unfamiliar conditions, and these modifications are best described as programmed loss of cellular control (Phillips et al., 1994).

Abstract

The present investigation was carried out in okra consisting of 11 diverse genotypes (8 lines & 3 testers) and their 24 F1 hybrids. Phenotypic and genotypic correlation indicated positive association of average fruit length with average fruit weight while negative association between days taken to first flower with number of fruits per plant. The maximum positive direct effect on yield was due to number of fruits per plant followed by average fruit weight. The F₁ hybrid VRO-6 × Parbhani Kranti exhibits highest negative heterobeltiosis for days taken to 1^st flowering while D-1-87-5 × Pusa A-4 and Arka Abhay × Parbhani Kranti are earliest heterobeltiotic hybrids for days taken to 1st harvest. The hybrid Arka Abhay × Pusa A-4 represents highest heterobeltiosis for average fruit length, number of fruits/ plant and average yield. Among all parents, only Akra Abhay exhibits better GCA effect. The highest SCA effect for average yield observed in VRO-6 × Arka Anamika, while VRO-6 × Pusa A-4 for per cent infestation of YVMV. The cross Arka Abhay × Pusa A-4 incurred the highest net returns/ ha and B: C ratio (3.21) followed by that of D-1-87-5 × Parbhani Kranti and the parent Hisar Unnat gave the higher net returns/ ha with B: C ratio of 2.02 among the parents. These elite hybrids may be tested for yield and other quality traits under different agro-climatic conditions for commercial exploitation of hybrid vigour.

Genetic Transfer and Mapping in Bacteria a

Bacteria can transfer genetic material during conjugation

Hfr strains contain an F factor integrated into the bacterial chromosome

Hfr strains can transfer a portion of the bacterial chromosome to recipient cells

Conjugation experiments can map genes along the E. coli chromosome

A genetic map of the E. coli chromosome has been obtained from many conjugation studies

Bacteria may contain different types of plasmids

Bacteriophages transfer genetic material from one bacterial cell to another via transduction

Cotransduction can be used to map genes that are within 2 minutes of each other

Bacteria can also transfer genetic material by transformation

Bacteria may acquire new genes by horizontal gene transfer

1. INTRODUCTION

Plants produce an array of natural products, the secondary metabolites, which play a variety of roles such as pollinator attractants e.g. pigments and scents and defense molecules against attacks by animals and microorganisms. These substances are very much important as a source of pharmaceuticals, fragrances, agrochemicals and food additives. Great efforts have been made by the chemical industry to mimic and synthesise these compounds. However little success has been achieved and plants still remain the major source of these vital compounds (Wink, 1990). In the late 1970s plant cell culture was thought to be an alternative or additional way of producing these compounds (Alfermann and Peterson, 1995). The low yields obtained with cultured cells and inferior to the amounts present in intact plants, provided a major drawback to their commercial exploitation. The plant derived pharmaceuticals represent a large market value; about 25% of today’s pharmaceuticals contain at least one active ingredient of plant origin. So only a minute fraction of the enormous biosynthetic potential of plant cells is being exploited. The most popular analgesic drug aspirin and the most valuable anti-cancer drugs paclitaxel and vinblastine are derived solely from plant sources (Pezzuto, 1996).

Over the last 10-15 years, the successful genetic transformation of plants has been reported in about 200 species including agricultural crops, trees, ornamentals, fruits and vegetables. Such genetic modification has improved specific crop traits, such as resistance to pathogens, to herbicides and to various environmental factors including drought and floods (Bajaj and Ishimaru, 1999). Following on from this success genetic transformation of medicinal plants has been attempted, primarily to enhance the production of various pharmaceuticals, flavours and pigments. During the early 90’s it was suggested that metabolic engineering of biosynthetic networks might be achieved by application of recombinant DNA methods.

Genetic variations

Genetic variation is the presence of differences in gene sequences between individual organisms of a species.

Enables natural selection, one of the major forces driving the evolution of life.

When an individual’s offspring exhibit mutations in the traits of their parents, such offspring are called variants.

Any crop improvement programme primarily depends on the amount of genetic variability available and the extent to which the economic traits are heritable. A wide survey of genetic variability and a thorough understanding of the genetic makeup of the crop with the biometrial tools is very much indispensable for initiating an effective breeding programme.

Effectiveness in breeding programme depends upon three main factors viz., (i) the extent of genetic variation available, (ii) heritabiity of the variation and (iii) intensity of the selection pressure that can be applied. As most of the characters of economic importance and related characters which influence the performance of the economic character in a given set of environment are highly influenced by the environmental conditions, the heritable (genotypic) variation usually masked by non-heritable (environmental) variation and thereby creates difficulty in exercising the selection. Hence, it becomes necessary to partition the overall variability into heritable and non-heritable components to enable the breeders to plan for proper breeding programme.

The estimates of mean, variance and standard error are worked out by adopting the standard methods of Panse and Sukhatme (1961). Usually, randomized block design is the choice of the statistical design. Various genetic parameters are worked out from the mean squares. Assessment of genetic variation is usually made through the computation of genotypic variance and genotypic coefficient of variation. The proportion of the total genetic variance expressed as percentage of total phenotypic variance has been used as a measure of genetic variability of heritability in broad sense.

Introduction
Prenatal development is a crucial phase in the life of an organism during which the foundation for its future health and survival is established. In animals, the prenatal development is influenced by a complex interaction of genetic, chromosomal and environmental factors. These factors play a pivotal role in determining the phenotype, viability and overall health of the developing organism. The abnormalities of the structure or function of cells, tissues or organs present at birth are termed as congenital defects. These developmental defects can be caused by genetic, chromosomal and environmental factors.
A. Genetic Factors
Genes are the fundamental units of inheritance and their expression controls the development and functioning of all living organisms. In prenatal development, genetic factors provide the blueprint on which the formation and differentiation of tissues and organs is depend. These factors influence a range of developmental processes which include the timing and coordination of cell division and the development of specific structures.
1. Gene Expression and Regulation: Proper gene expression and regulation are essential for normal prenatal development. Genes are activated or suppressed at specific times during development and the precise regulation of these genes ensures the correct formation of tissues and organs. The mutations in key developmental genes can lead to malformations or developmental disorders.
2. Inherited Traits and Developmental Variation: Inherited genetic traits can influence the rate of prenatal development and the eventual size and characteristics of the offspring. For example, certain breeds of animals have genetic predispositions for faster growth rates, larger body sizes or distinct physical features which are evident even during prenatal development. Selective breeding practices in domesticated animals often aim to enhance these traits but they can also accidently introduce genetic disorders or vulnerabilities.
3. Epigenetic Modifications: Epigenetic factors such as DNA methylation and histone modifications also plays a crucial role in regulating gene expression during

Abstract
The use of Genetically Modified Microorganisms (GMMs) and Genetically Engineered Microorganisms (GEMs) offers a groundbreaking solution for tackling environmental pollution, especially in highly contaminated areas. These microorganisms, engineered for enhanced degradation of pollutants, offer significant potential for restoring polluted environments such as soil, groundwater, and wastewater. However, concerns regarding their uncontrolled persistence, gene transfer, and potential environmental risks have prompted the need for further research and the development of safer, more efficient strategies. Key advancements in the field include the use of suicidal genes to ensure the safe removal of GMOs post-degradation, as well as the use of bioluminescent signals to monitor microbial activity in real-time. Furthermore, composting has proven to be an effective strategy for reducing the risks associated with horizontal gene transfer. Despite these innovations, the widespread field application of GMOs for bioremediation remains limited to controlled systems. This article explores the challenges and advancements in utilizing GMOs for bioremediation, underscoring the importance of ongoing research to ensure their safe and effective application.
Keywords: Genetically Modified Microorganisms (GMOs), Bioremediation, Environmental Pollution, Biosafety, Biodegradation.

Male-sterility
Normal development of the male reproductive organ (stamen) and male gametophyte (pollen grain) is essential for successful completion of sexual reproduction in angiosperms. Abnormalities at any stage of stamen and pollen development can result in male sterility. Male sterility in plants implies the inability to produce or to release functional pollen. Male sterility is caused due to failure in the formation or development of functional stamens, microspores or gametes and /or release of pollens from the anther. Male-sterility can result from mutations in nuclear genes alone or mitochondrial genes or mitochondrial genes coupled with nuclear genes. The resulting conditions are known as genic male sterility (GMS), cytoplasmic male sterility (CMS) and cytoplasmic-genic male sterility (CGMS), respectively.
Classification of male-sterility
1. Genetic male-sterility
This male-sterility is caused due to mutations in nuclear genes alone or mitochondrial genes or mitochondrial genes coupled with nuclear genes which results abnormalities at any stage of stamen and pollen development.

The potential yield levels in major crops have reached almost to a plateau. The current world population of 7 billion is likely to reach 9 billion by 2050 putting huge pressure to produce more from the available arable lands as acreage of major crops is predicted not to increase any further. The deficit of food requirements will have to be met partly by bridging the gap between farm yield (the average yield of the crop in a particular region/country/world) and the potential yield (the yield obtained usually in the breeders’ plots grown across the region of interest with the best yielding new varieties and without biotic stresses as diseases and pests, and abiotic stresses such as drought, flooding, salinity, heat and cold and partly by increasing potential yield per se.

Even after public concern the scientists feel that the GMO foods are quite safe. According to them the genetically-engineered crops are very safe to eat as much as the non-GE of the same crop. According to them the environment has improved by reducing the use of pesticides. GMO stands for genetically modified organism. Soy, corn, or other crops are very common as GM crops which are made by genetically engineered DNA. Many have come to the conclusion that GM foods are safe, healthy and sustainable. However, some people are against them. There are many benefits of GM crops like less water or pesticides to be used. Genetically engineered crops fight diseases to save the foods. At the same time the industries/ farmers that grow them are also benefitted. These foods have higher nutritional profiles, both in the US and abroad like corn which is one of the most prominent GMO foods. Soy is found in tofu, vegetarian products, soybean oil, soy flour and many other products. The other major crops taken for genetic modification are Papayas, Canola and Cotton. For dairy products a lot of work is being done on the genetic engineering of animals in a big way. This is going to be the most intractable environmental challenge of the 21^st Century. Presently, around 92% of the U. S. corn (GE), 94% of soybeans and 94% of cotton are genetically engineered.

GENETIC ENGINEERING

Genetic engineering is a means of improving the food supply even before harvest or slaughter by improving yields, increasing disease resistance, and enhancing the nutritional qualities of various foods. Broadly speaking, genetic engineering refers to any deliberate alteration of an organism’s DNA. Genetic engineering has been practiced for thousands of years, ever since humans began selectively breeding plants and animals to create more nutritious, better tasting foods. In the past two decades, genetic engineering has become increasingly powerful as scientific advances have enabled the direct alteration of genetic material. Genetic engineering is alternately called as ‘ recombinant DNA technology’ or ‘gene cloning’. Genes have been cut and pasted from one species to another, yielding, for example, disease- resistant squash and rice, frost-resistant potatoes and strawberries, and tomatoes that ripen-and therefore spoil-more slowly.

Genetically modified organism (GMO) is a microbe or more complex plant or animal in which DNA has been altered for a particular purpose such as manufacturing proteins, making improvement to the organism, research into the nature of genes and biological process, correcting genetic defects.

Transgenic plants are those plants, in which a foreign gene(s) has/have been introduced and stably integrated into the genome. The inserted gene sequence is known as Transgene. Almost three decades ago, in early 1983, the first cloning of the recombinant genes in tobacco signified the beginning of plant molecular biology in its own right. Since then the number of genes transferred and studied in plants has increased exponentially and the first transgenic crop (‘FlavrSavr’ tomato) was commercialized on May 18, 1994. However, the impact of transgenic crops was perceptible only after 1995 when transgenic maize, soybean and cotton were released for cultivation in USA.

MENDEL’S RULES OF GENETICS DO NOT ALWAYS WORK

Mendel’s rules:

Segregation of alleles

Independent assortment of genes for different characters

Hold for characters:

Which have dominant & recessive traits

Determined by single genes

Genes are on separate chromosomes

Different types of chromosomes, or

Different homologues of same type of chromosome

These conditions are not always met, so there are many complications

This chapter introduces genetic principles used to improve wool production and quality. It examines heritable traits including fibre diameter, clean fleece weight, staple length, staple strength, diameter variability and freedom from faults. Selection differential, response to selection, selection indices and crossbreeding strategies are discussed. The chapter also introduces objective measurement, genomic selection, reproductive technologies and electronic recording systems as modern tools for accelerating genetic improvement and producing more valuable and uniform fleeces.