eChapters

Introduction
Farm mechanization represents a pivotal shift in agricultural practices, marking the transition from traditional, labor-intensive methods to modern, technologydriven farming systems. This chapter explores the various dimensions of farm mechanization, highlighting its critical role in enhancing agricultural productivity, ensuring food security, and addressing the challenges of global warming. The chapter begins by examinin65g the different types of agricultural machinery and equipment used in modern farming. This includes tractors, plows, harvesters, seeders, and other essential tools that have revolutionized the way crops are cultivated, harvested, and processed. The mechanization of these processes has significantly increased efficiency, reduced labor costs, and improved the overall productivity of agricultural systems. Precision farming and remote sensing are discussed as integral components of modern farm mechanization. These technologies enable farmers to optimize the use of resources such as water, fertilizers, and pesticides, thereby increasing yields while minimizing environmental impacts. Key components of precision farming, such as GPS-guided machinery, soil sensors, and aerial imaging, are explored in detail, along with their applications and benefits. The chapter also delves into machinery management and maintenance, emphasizing the importance of regular upkeep and proper management of farm equipment. Effective machinery management ensures the longevity and reliability of agricultural machinery, reduces downtime, and lowers operating costs, all of which contribute to more sustainable and profitable farming practices. Farm mechanization is highlighted as a crucial factor in enhancing food security. By increasing the efficiency and scalability of food production, mechanization plays a vital role in meeting the growing global demand for food. The chapter discusses how mechanization extends growing seasons, improves crop quality, and diversifies crop choices, thereby contributing to a more stable and resilient food supply. The impact of farm mechanization on global warming is also a key focus of this chapter. While mechanization has led to increased productivity, it has also contributed to greenhouse gas emissions and other environmental challenges. The chapter explores strategies for mitigating these impacts, including the adoption

Introduction
Water management is a critical aspect of agricultural science and environmental sustainability, influencing not only the efficiency of food production but also the health of ecosystems and the balance of global water resources. This chapter delves into the principles, techniques, and modern advancements in water management, emphasizing its significance in ensuring food security, conserving vital resources, and combating global warming. The chapter begins by exploring the foundational principles of irrigation, a key component of water management in agriculture. Various irrigation techniques, such as surface, sprinkler, and drip irrigation, are discussed in detail, along with the factors that influence irrigation efficiency, such as soil type, crop needs, and climatic conditions. The importance of optimizing irrigation practices to enhance water use efficiency and minimize waste is underscored. Water use efficiency and conservation strategies form the next major focus of the chapter. As global water resources face increasing pressure from population growth, industrialization, and climate change, the need for efficient water use in agriculture becomes ever more critical. The chapter discusses various methods to improve water use efficiency, including advanced irrigation technologies, crop selection, and soil management practices. Conservation strategies, such as rainwater harvesting, groundwater recharge, and the use of drought-resistant crops, are also explored. Effective drainage systems and waterlogging control are essential for maintaining soil health and agricultural productivity. The chapter provides an overview of drainage system principles, techniques for assessing soil drainage, and strategies for controlling waterlogging, a condition that can severely impact crop yields. The benefits of well-managed drainage systems, including improved soil structure, reduced salinity, and enhanced crop performance, are highlighted. Water quality and salinity management are crucial for sustaining agricultural productivity and preventing soil degradation. The chapter discusses methods for assessing water quality, the impact of salinity on soils and crops, and techniques for managing salinity, such as the use of salt-tolerant crops and soil amendments. Effective water quality management ensures that crops receive the nutrients they need while preventing harmful buildup of salts and other contaminants

Introduction
Plant breeding and genetics are at the forefront of agricultural innovation, playing a crucial role in enhancing crop traits to meet the ever-growing demands for food, fiber, and fuel. This chapter delves into the scientific principles, methods, and modern advancements in plant breeding and genetics, providing a comprehensive understanding of how these disciplines contribute to global food security and environmental sustainability. The chapter begins by exploring the fundamental principles of plant breeding, including heredity, genetic variation, selection, and hybridization. These concepts form the foundation for developing new plant varieties that exhibit desirable traits such as improved yield, disease resistance, and environmental adaptability. The importance of genetic variation is emphasized as a key driver of plant improvement, with discussions on the sources of genetic variation, the role of germplasm resources, and the impact of genetic diversity on plant adaptation. As the chapter progresses, various breeding techniques and strategies are examined, including mass selection, pedigree breeding, backcrossing, and markerassisted breeding. These methods are crucial for developing new plant varieties that can withstand the challenges posed by climate change, pests, and diseases. The chapter also addresses the role of genomics in plant breeding, highlighting the significance of genomic selection, gene editing, and bioinformatics in accelerating the breeding process and enhancing crop traits. The chapter further explores the controversial topic of genetically modified organisms (GMOs), discussing the principles of genetic engineering, the rise of genetically modified crops, and the associated controversies and concerns. The importance of GMOs in addressing global food security and environmental challenges is also discussed, providing a balanced perspective on their potential benefits and risks. The chapter concludes by emphasizing the critical role of plant breeding and genetics in ensuring food security and combating global warming. By developing climate-resilient crop varieties, improving water efficiency, and enhancing disease and pest resistance, plant breeding and genetics can contribute to sustainable agricultural practices that reduce greenhouse gas emissions and conserve natural resources

Introduction
Horticulture, the science and art of cultivating fruits, vegetables, and ornamental plants, is a vital component of agriculture that contributes significantly to food security, economic growth, and environmental sustainability. This chapter provides a comprehensive overview of horticulture, exploring its various branches, including fruit and vegetable production, floriculture, landscape design, and greenhouse management. Horticulture is unique in its integration of scientific principles, artistic design, and business acumen, making it a dynamic and multifaceted field.
The chapter begins by introducing the fundamental concepts of horticulture and its importance in modern agriculture. It delves into the specifics of fruit and vegetable production, emphasizing the techniques and practices that enhance yield and quality. Floriculture and landscape design are also discussed, highlighting the aesthetic and environmental benefits of ornamental plants. The chapter further explores post-harvest handling and storage, crucial aspects that ensure the longevity and marketability of horticultural products.
In addition to traditional practices, the chapter addresses modern horticultural techniques, such as greenhouse management, which plays a crucial role in extending growing seasons and improving crop quality. Sustainable horticultural practices are also emphasized as key strategies for addressing global challenges like climate change and food security.
Horticulture is a branch of agriculture that focuses on the cultivation, production, and management of plants, particularly fruits, vegetables, ornamental plants, and flowers. This chapter explores various aspects of horticulture, including an introduction to horticulture, fruit and vegetable production, greenhouse management, floriculture and landscape design, and post-harvest handling and storage. Horticulture plays a vital role in agriculture, encompassing the science and art of growing plants for food, aesthetics, and environmental enhancement. This chapter delves into the exciting world of horticulture, exploring the cultivation and management of fruits, vegetables, ornamental plants, and flowers. Horticulture combines scientific knowledge, practical skills, and artistic creativity to maximize plant growth, yield, and aesthetic appeal. By studying horticulture, we can gain insights into the principles and practices that contribute to successful fruit and vegetable production, greenhouse management, floriculture and landscape

Introduction
Environmental science plays a critical role in understanding and addressing the complex interactions between human activities and the natural world. This chapter explores the intersection of environmental science and agriculture, emphasizing the importance of ecological balance for sustainable development. As agriculture continues to be a major driver of environmental change, understanding its impacts on ecosystems, biodiversity, and climate is crucial for developing strategies that promote sustainability.
The chapter begins by examining the environmental impacts of agriculture, including land degradation, deforestation, and pollution. It then explores agroecology and biodiversity, highlighting the importance of maintaining diverse ecosystems to support sustainable agricultural practices. Sustainable resource management is discussed as a key approach to conserving natural resources and minimizing the environmental footprint of agriculture.
Climate-smart agriculture, a modern concept that integrates environmental sustainability with agricultural productivity, is introduced as a solution to mitigate the effects of climate change while ensuring food security. The chapter also covers environmental regulations and policies, which are essential for guiding sustainable agricultural practices and protecting the environment.
As the chapter progresses, it delves into the importance of environmental science in food security, the impact of environmental factors on global warming, and various modern concepts in environmental science, including sustainable food systems, circular economy, and ecosystem-based approaches. The chapter concludes with a discussion on combating food security and global warming challenges through sustainable practices and policies.
Environmental science plays a crucial role in agriculture by studying the interactions between agricultural practices and the natural environment. This chapter explores various aspects of environmental science in agriculture, including the environmental impacts of agriculture, agroecology and biodiversity, sustainable resource management, climate-smart agriculture, and environmental regulations and policies. Agriculture and the environment are inherently interconnected, as agricultural practices have both direct and indirect impacts on the natural environment. Environmental science in agriculture aims to understand these impacts and develop sustainable practices that minimize negative environmental

Introduction Soil, often referred to as the “skin of the earth,” is a critical component of our planet’s ecosystem, serving as the foundation for all terrestrial life. This chapter explores the science of soil, delving into its formation, classification, and the complex properties that define its role in agriculture and environmental sustainability. Understanding soil is fundamental to addressing global challenges such as food security, climate change, and sustainable land management. The chapter begins with an examination of soil formation and classification, providing insights into the diverse types of soils that exist across different landscapes. It then discusses the physical and chemical properties of soil, including their impact on soil health and fertility. The role of soil microbiology is highlighted, emphasizing the importance of microorganisms in maintaining soil health and promoting plant growth. As we progress through the chapter, we explore modern concepts in soil science, including sustainable soil management practices and their significance in mitigating the effects of global warming. The chapter also addresses the crucial role of soil in food security, demonstrating how effective soil management can enhance agricultural productivity and resilience in the face of climate change. Finally, the chapter touches upon the threats to soil health and the importance of sustainable soil management in ensuring a prosperous future for all. Soil science is a vital discipline within agriculture that focuses on the study of soils and their properties. This chapter delves into various aspects of soil science, including soil formation and classification, soil physical and chemical properties, soil fertility and nutrient cycling, soil conservation and erosion control, and soil microbiology and soil health. Soil is the foundation of agriculture, providing the medium for plant growth and supporting the intricate web of life that sustains our ecosystems. Understanding the science of soil is essential for optimizing crop production, protecting natural resources, and ensuring sustainable land management practices. In this chapter, we will explore the fascinating world of soil science, delving into its various aspects to gain insights into soil formation, composition, fertility, and conservation. By understanding the principles and processes underlying soil science, we can make informed decisions to enhance soil health, maximize nutrient availability, mitigate erosion, and promote sustainable agricultural practices.

Introduction
Agronomy, the science of crop management, is a cornerstone of agricultural sciences, focusing on the principles and practices that optimize crop production. This chapter delves into the core principles of agronomy, exploring how these practices have evolved over time to meet the challenges of modern agriculture. As the global demand for food intensifies, agronomy has emerged as a critical field that integrates various scientific disciplines to improve crop yields, enhance sustainability, and ensure food security. The chapter begins by outlining the fundamental principles of agronomy, which serve as the foundation for crop management. It then transitions into an exploration of new concepts and innovations that are reshaping the agricultural landscape. These include precision agriculture, vertical farming, agroforestry, urban agriculture, organic farming, and sustainable agriculture practices, all of which contribute to more efficient and environmentally friendly farming systems. The chapter also discusses the role of digital agriculture, climate-smart agriculture, and regenerative practices in addressing the pressing issues of climate change and food security.
By examining these cutting-edge developments, this chapter highlights the importance of agronomy in the context of global challenges such as food security, environmental degradation, and climate change. The role of agronomy in ensuring sustainable food production and its impact on global warming are also discussed, providing a comprehensive overview of the field’s relevance in the 21st century. In the intricate tapestry of agriculture, where the hands of farmers and the mysteries of nature converge, stands a pivotal discipline that orchestrates the dance of growth and sustenance – agronomy. Rooted in science and guided by the rhythms of the seasons, agronomy is the art of orchestrating nature’s symphony to yield the harvests that nourish the world. It’s a testament to human ingenuity and a profound understanding of the intricate balance between the forces that shape our planet.
At its essence, agronomy is the vanguard of crop production, embracing the ever-evolving dialogue between humans and plants. It’s a discipline that transcends mere cultivation, delving into the profound intricacies of plant life, the dynamics of ecosystems, and the manipulation of natural elements to ensure bountiful yields. It’s a synergy of knowledge that marries the wisdom of generations with the cutting-edge revelations of science, all in pursuit of ensuring the sustenance of humanity.

Agriculture is one of the oldest and most fundamental activities of human civilization, serving as the bedrock upon which societies and economies have been built. In its simplest definition, agriculture is the science and practice of cultivating the soil, growing crops, and raising livestock. However, its significance extends far beyond mere food production; it is integral to the economic, social, and environmental fabric of nations. This chapter provides a comprehensive overview of agriculture, beginning with its basic definition and expanding to cover its critical role in human civilization. It delves into the diverse agricultural practices observed in Pakistan, a country where agriculture is not only a tradition but also a cornerstone of the economy. The discussion covers how climate, geography, and government policies influence these practices and shape the challenges and opportunities within the sector. Moreover, this chapter explores the economic impact of agriculture on Pakistan, particularly in terms of employment, poverty alleviation, and rural development. It also addresses the role of agriculture in ensuring food security, the environmental implications of farming practices, and the need for sustainable methods to secure the future of this vital industry. Finally, the chapter touches on the technological advancements and innovations that are driving modern agricultural practices and the broader implications of these changes for the future of farming. In the heartlands of progress and sustenance, where the earth meets the sky, lies a discipline that stands as the foundation of civilizations throughout history – agriculture. More than just a vocation, agriculture is an intricate science that has shaped societies, provided nourishment, and propelled the evolution of humanity. It intertwines the art of nurturing the land with the precision of scientific inquiry, producing a symphony of growth and harvest that sustains life itself. At its core, agriculture is the embodiment of a delicate balance between nature’s offerings and human ingenuity. It’s the art of coaxing the earth’s potential, and the science of unraveling its secrets. From the rhythmic dance of seasons to the intricacies of soil composition, every facet of agriculture is woven into the tapestry of life on Earth. And as we stride into an era where global challenges like population growth, climate change, and resource scarcity loom, the importance of understanding the science behind farming has never been more crucial.

Introduction
India has vast animal genetic resources with a wide variety of indigenous farm animals including cattle. The cattle breeds have evolved over generations to adapt to the agro-climatic and socio-economic needs of the people. Domestic animal diversity is defined as the spectrum of genetic differences within each breed and across all breeds within each domestic animal species, together with the species differences; all of which are available for the sustainable intensification of food and agriculture production . The domestic animal diversity has evolved over millions of years through the processes of natural selection forming and stabilizing each of the species used in food and agriculture. Over the more recent millennia the interaction between environmental and human selection has led to the development of genetically distinct breeds. Selection processes, directed by both humans and the environment, together with the random sampling processes causing genetic populations to drift over generations, have accelerated the development of the diversity within species leading to the creation of distinct genetic differences amongst breeds.
India is the seventh largest country in the world and it is recognized as one of the 12-mega biodiversity centres of the world. It is well marked off from the rest of Asia by mountains and the sea, which gives the country a distinct geographical entity. Due to diverse agro-ecological regions and topographic conditions, India has rich repository of both flora and fauna. India has vast animal genetic resources with a wide variety of indigenous farm animals. Indigenous animal breeds are now 53 for cattle, 20 for buffalo, 39 for goat, 45 for sheep, 8 for horses & ponies, 9 for camel, 14 for pig, 3 for donkey, 3 for dog, 1 for yak, 20 for chicken, 3 for duck, and 1 for geese, besides many other non-descript and mixed populations. Livestock husbandry is an age-old important occupation for Indian farmers. The unique and rich animal biodiversity is extensively referred to in Indian scriptures.

Understanding Immunogenetics
The study of genetic basis of the immune response is known as immunogenetics. The term was introduced with the discovery of ABO blood groups and were first demonstrated through the existence of “natural” antibodies i.e., isoantibodies. The broad field of immunogenetics include study of normal immunological pathways as well as identification of genetic variations that result in immune defects, which may facilitate detection of new therapeutic targets for immune diseases. Hence, understanding and subsequent manipulation of host immune response (immunomodulation) is the most precise and effective tool to reduce disease incidences and nullify the limitations associated with antibiotic treatment or vaccination. Therefore, breeding for disease resistance has gained considerable attention from researchers in the recent past.
Immune Response Genes
Often it was observed that individuals respond differently to same infectious agent. A possible explanation may be the genetic variability between them. Indeed, many studies have looked for associations between genes involved in immunity and disease outcome and it has been found that certain immune response (Ir) genes play the crucial role. This concept was discovered in the mid-1960s and this discovery introduced an apparently new level of antigen recognition whose diversity and specificity had to be explained in addition to those of familiar immunoglobulins. Hence immune response (Ir) genes were defined as antigenspecific genes that control the ability of an animal to raise an immune response, either humoral or cellular to a particular antigen .

Reproduction is the backbone of animal production and productivity is the key to development. Reproductive inefficiency is one of the most important causes of economic losses in animal industries and it is realized throughout the world. Despite the remarkable advancement that has been made in the field of reproductive physiology in recent years, infertility due to low conception rate and high embryonic mortality rate remains a major problem. To meet future needs and to be able to sustain agricultural production, agricultural research and its applications need to use all emerging technologies one of which is modern reproductive biotechnologies.5 Thus, various assisted-reproductive techniques have been developed and refined to obtain a large number of offspring from genetically superior animals or obtain offspring from infertile (or sub-fertile) animals in addition to disease control. Reproductive biotechnologies intend to be used routinely to shorten generational intervals and to propagate genetic material among breeding animal populations. To achieve this goal, reproductive technologies have been developed in generations over the years, namely artificial insemination (AI), embryo transfer (ET), manipulation of fertilization in vitro (IVF), cloning and transgenesis. These, together with sperm separation techniques, including that of selection of spermatozoa for chromosomal sex (commonly named sex-sorting) all face today a strong wave of increasing commercialization.9 Hence, this review paper highlighted the reproductive biotechnology options and their roles in the improvement of livestock production.
Roles of Reproductive Biotechnology in Animal Production
Biotechnology is defined as a technique that uses living organisms to make or modify and improve products. The emergence and development of reproductive technologies have been driven by the economic gain offered by the potential increase in the number of offspring from genetically superior animals or simply to safeguard the genetic pool of infertile or sub-fertile animals. In other words, reproductive technologies were developed to offer possibilities for wider use of superior germplasm.In recent times, there has been increasing challenges for

Animal husbandry programmes have been run through the State schemes. Each State has to evolve its own breeding policy deciding on choice of breed, cross breeding strategy, optional mixture of animals of different breeds required, breeding goals in terms of expected genetic progress to be achieved, specific breeding programmes and the control measures that should be adopted to achieve the desired genetic gains in the population.
General parameters in the breeding policy formulated by various States are
• Indigenous milch breeds such as Shaiwal, Red Sindhi and Gir, should be selectively developed for dairy traits in their native tracts.
• Indigenous dualpurpose breeds such as Hariana, Tharparkar, Rathi, Kankrej, Gaolao, Ongole Deoni etc. should be developed selectively in their native tracts for dairy and draft traits.
• Indigenous draft breeds like Kangayam, Hallikar, Khillari, Amrit Mahal etc. should be developed selectively for draft traits in their native tract.
• Non-descript cattle will be bred with exotic semen to produce cross breed with Holstein Friesian or jersey and maintaing 50% exotic impenitence. In some States Red Sindhi, Tharparkar and Hariana have also been used upgrading non-descript cattle.
• Development of indigenous breeds
• To develop indigenous breeds Government of India has initiated three schemes namely National Project for Cattle and Buffalo Breeding, Central Herd registration scheme, Central Cattle Breeding Farms.
• Central Herd Registration Scheme
• For identification and location of superior germplasms of cattle and buffaloes, propagation of superior genetic stock, regulating sale and purchase, help in formation of breeders societies and to meet requirement of indigenous bulls in the different parts of the country. Government of India

The global demand for high producer animals is rising, and cattle producers are looking for ways to improve productivity and efficiency. One method for developing cattle with enhanced traits is crossbreeding – combining the desirable qualities of two or more cattle breeds into one animal.
Crossbreeding allows cattle producers to take advantage of breed differences and heterosis while managing unwanted traits.
Implementing an effective breeding strategy can help cattle producers select for optimum performance in their herd.
Benefits of Crossbreeding Cattle
Crossbreeding offers commercial beef producers several advantages compared to using only straight-breed animals. Some key benefits include:
1. Heterosis – Crossbred animals exhibit hybrid vigour or heterosis, which is the increased performance for traits like growth rate, fertility, and longevity compared to purebred animals.
The heterosis effect results from the increase in heterozygosity or genetic diversity from combining divergent breeds. Heterosis levels are highest in first-cross animals (the initial cross between two pure breeds.
2. Complementarity – An additional advantage of crossbreeding is combining the strengths of two or more breeds to produce an animal with the ideal blend of traits.
For example, crossing a breed known for high intramuscular fat and marbling, like Angus, with a lean breed that excels in meat yield and growth, like Charolais, can result in an animal with both good marbling and leanness.
3. Breed Complementation – Crossbred animals also benefit from breed complementation. This occurs when the strengths in one breed offset or complement the weaknesses in the other breed. For example, British maternal breeds tend to be lower in milk production but exhibit excellent maternal behaviour

Closed Nucleus Breeding Scheme (CNBS)
In the CNBS the germplasm flows in only one direction. That is from the nucleus to the cooperating herds or flocks. In the traditional pyramid there is only one way of flow of genes with in the pyramid, downwards from top to bottom. This means that the only some of cumulative genetic progress in commercial production is improvement that occurs at the top of the pyramid. If the nucleus tier makes no genetic improvement then no improvement will be noticed in the root of the tiers. However even if the nucleus tier thus make improvement progress is not seen immediately at lower levels in the pyramid. It takes time for the genetic progress in one tier to be transmitted to the next tier. The resultant difference in performance between any two adjacent tiers is called IMPROVEMENT LAG.
It is usually expressed in terms of no. of years of genetic improvement that are represented by the difference in performance between adjacent tiers. There are two factors that affect the size of the improvement. Age structure in the lower tiers. Source and merit of dams used in the lower tiers, e.g. Lag can be reduced by keeping the sires and dams in lower tiers for shorter periods of time before replacing them with younger stock. Lag can be reduced by transferring females downwards tiers. Even greater reduction result if some nucleus parent can be transferred directly to commercial tier. Only downward flow of genes from nucleus to lower tiers. No gene flow into nucleus tier, e.g. Most traditional breed of livestock modern pig and poultry breeding programme have CNBS structure.

There is urgent need to increase the production in order to meet the demand for the exploding population. This could be achieved by applying various modern methodologies in selection and breeding of livestock. Increasing the productivity through genetic improvement requires adequate identification and intensive selection of genetically superior sires. About 93 per cent of the total herd improvement comes from breeding of young bulls from tested sires and only six per cent from selection of dams.
With the advances in artificial insemination and cryopreservation of semen, a sire has a potential of serving 3/4th million cows and producing 1/4th million progenies.
Thus, selection of bulls is of great importance in dairy herd improvement.
For maximising the genetic gain by sire selection, it is essential that the method of estimating breeding values of sires should be unbiased and efficient. The breeding value refers to the average genetic effect of the genes passed on by the individual to its offspring and is estimated to know whether the individual is genetically superior to other individuals or not for the trait concerned.

The sheep population in India is estimated to be about 65.07 million ranking second in the world (Anonymous, 2019). There are 42 descript breeds of sheep distributed in various agro climatic zones of the country (Anonymous, 2017). It is well-known that the sheep rearing provides nutritional security and insurance to the farmer at the time of crisis due to crop failure. Therefore, sheep is seen as, “finance elevator” by the countryside poor farmer (Sharif et al., 2011). Two major sources of income; meat and wool make sheep industry a very profitable enterprise. In addition, a rich source of nitrogen, phosphorus and potash present in the droppings of sheep improves the soil fertility. Indian sub-continent isa rich source of diverse ovine germ plasm.
The native breeds of sheep of from India are well adapted to geo-physical and agro-climatic conditions. Most of the breeds of sheep in India have evolved through natural selection. Most of the breeds have generally been named after their place of origin and on the basis of prominent characters. This vast ovine biodiversity in India is being eroded rapidly and more than 50% of sheep breeds are currently under threat.
Sheep biodiversity in India is characterized by high degree of endemism and variations in agro-climatic conditions of the different regions have led to the development of various breeds/strains. Selecting for breeding animals with superior EBV in growth rate, meat, milk, or wool production, or with other desirable traits has revolutionized livestock production through out the world.
Breeding means, the manner in which selected males and females are mated. The breeders identify and select desirable qualities in animals for future mating and discard less desirable qualities. For the improvement of livestock (farm animals) selection and breeding must be practiced simultaneously. Continuous selective breeding leads to homozygosity in a population resulting in loss of variability. If all the individuals are alike, the breeder cannot make progress in future. Hence, there is a need to create variability in population. This can be achieved by breeding. Therefore, selection and breeding go hand in hand for the improvement of livestock.

It is imperative that the country should develop strategic planning so that available resources in different agro ecological zones of the country to exploited judiciously and utilize sustainably for further enhancing the productivity of cattle and buffaloes. Therefore, agroclimatic region and animal production system-based breeding policy strategies with a focus on large scale implementations of improved animal genetics and breeding innovations by development organizations with active participation of farmers/breeders are discussed here. Before developing sustainable breeding strategies for improving the productivity performance of a particular breed/genetic group of animal population in a given agro-climatic region, it is necessary to have a comprehensive details of population size of breed along with analysis of existing activities such as farmer/breeder’s perceptions and socio-economic levels, agriculture and livestock production systems, available feed and fodder resources, animal genetic resources, their production potentials and utilization pattern, breeding organizations, infrastructure and development facilities . The Quinquennial All India Livestock Census contains information on the herd/flock structure, sex, age, etc. and it does not reflect the factual situation about the status of breeds in terms of their population. Hence, the actual population of each breed and their geographical distribution is not clearly known. The correct picture about these breeds would be available only when breed-wise census of the livestock is carried out and status and performance of breeds are surveyed in their natural habitat and the same has been initiated in the recent survey . In the back ground of the collected and collated information on all above aspects, following region specific animal breeding strategies can be planned for conservation and genetic improvement of bovine genetic resources under different animal production systems.
Genetic Improvement of Non-Descript Zebu Cattle by Crossbreeding
The most rapid and effective approach to genetically improve the largest chunk of non-descript zebu cattle population is through crossbreeding with exotic dairy cattle breeds particularly in milk shed areas around peri-urban and industrial towns

Combining Ability Estimation
Crosses made in a definite fashion are a prerequisite for combining ability estimation. Estimated by half-sib (GCA) and full-sib (SCA) mating. Various steps like parent selection for crosses, performing crosses, their evaluation, and interpretation are involved while estimating of combining ability. For analysis of crosses, biometrical techniques like diallel analysis, partial diallel, and Line x tester analysis are used. If GCA variance is higher than SCA variance the importance of AGA & parent selection will be effective for the improvement of such traits. If SCA variance is higher than GCA variance there is importance of NAGA( dominance & epistasis) & Heterosis breeding may be rewarding. If GCA=SCA variance then AGA & NAGA are equally important in the expression of character, In this situation reciprocal recurrent selection may be adopted for population improvement.
Selection for GCA
General combining ability (GCA) is the average value of the inbred line based on its behavior in crosses with other lines. The mean performance of the line is expressed as deviation from the mean of all crosses.GCA is owing to the activity of genes which are largely additive in their effects as well as additive × additive interactions.

Definition: Heterosis is defined as the percent increase in the performance of outbred animals over the average of their parents.
The mean superiority of hybrids over the average of their parental lines is called heterosis. Heterosis or hybrid vigor is the increased vigor of the offspring over that of the parents when unrelated individuals are mated. Hybrid vigor includes greater viability, faster growth rate, greater milk production and greater wool production in domestic animals. The amount by which the hybrids exceed the mean performance of better parent is called heterobeltiosis or Euheterosis. The term heterosis was coined by G.H. Shull (1914). Heterosis or hybrid vigour is synonym to each other. However, the heterosis is a phenomena exhibited by an individual or a group of individuals due to heterozygosity of genes. Heterosis in quantitative terms can also be defined as the non-additive gene action. While “hybrid vigour” is the resultant of heterosis phenomena expressed phenotypically by an increase in vigour, size, production, reproduction, survival rate, growth, and economic returns etc. the heterosis is a measure of extent magnitude of out breeding.
In livestock, hybrids may be produced by crossing between two species/breeds/ lines/strains. Technically, heterosis may be positive or negative. However, the desirability of a trait is more important than the sign of heterosis. In some cases, the negative heterosis could be a desirable one (e.g. age at first lay, age at first calving, calving interval, back fat thickness etc.). The amount of heterosis obtained usually depends upon the extent of heterozygosity attained by the hybrids, which in turn is based on the diversity of sire and dam lines crossed. It also depends upon the degree of dominance, over dominance and/ or for which the heterosis is exhibited. Thus, the main causes of heterosis are directional dominance, over dominance and epistasis.

Under the selected breeding system selected males and females are mated. The breeding system can be classified into five different ways depending on their phenotypic and genotypic relations.
The five Breeding Systems are
(1) Random mating,
(2) Phenotypic assortive mating,
(3) Phenotypic disassortive mating,
(4) Genetic assortive mating and
(5) Genetic disassortive mating.
1. Random mating or Panmixia: It is a system of mating in which each male individual has an equal opportunity to mate with the female individual and vice versa. This mating system generally takes place in nature where the number of males and females are assumed to be equal.
2. Phenotypic assortive mating: In this type of mating animals which are phenotypically alike are allowed to mate among themselves. This is also called “like to like” mating.
3. Phenotypic disassortive mating: Here individuals which are phenotypically unlike are allowed to mate. It is also called “unlike to unlike” mating. For example, mating of tall with short individuals.
4. Genetic assortive mating: In this system individuals, which are closely related genetically are allowed to mate. This is also known as inbreeding.
5. Genetic disassortive mating: This system is just opposite to the previous system where mating takes place between less closely related individuals. This is also called as out breeding.