Strategies for Enhancement in Food Production

Improvement In Crop Yields

With the increasing global population, enhancing food production, particularly crop yields, is a major challenge. Various strategies are employed to improve the quantity and quality of crop production.

Improvement in Crop Yields is broadly addressed by:

1. Crop Variety Improvement: Developing better varieties of crops.
2. Crop Production Management: Improving the management practices during crop cultivation.
3. Crop Protection Management: Protecting crops from pests, diseases, and weeds.

Crop Variety Improvement

This involves selecting or breeding crop varieties that give high yields and have other desirable characteristics.

• Objectives: Higher yield, improved quality (e.g., protein content in pulses, oil quality in oilseeds, vitamin content in fruits/vegetables), resistance to diseases and pests, tolerance to environmental stresses (drought, salinity, heat, cold), responsiveness to fertilisers, shorter maturity period.
• Methods:
  • Hybridisation: Crossing genetically different parent plants to combine desirable traits into a hybrid variety. Can be intervarietal (between varieties), interspecific (between two different species of the same genus), or intergeneric (between two different genera).
  • Mutation Breeding: Inducing mutations (changes in DNA) using mutagens (like radiation or chemicals) to create new variations and selecting desirable mutants.
  • Polyploid Breeding: Inducing polyploidy (having more than two sets of chromosomes) to increase cell size and potentially yield or other traits.
  • Genetic Engineering (Biotechnology): Introducing genes from other organisms into crops to confer desirable traits (e.g., Bt crops for insect resistance, herbicide tolerance, improved nutritional value). This results in Genetically Modified (GM) crops.
• Developing high-yielding varieties (HYVs) through these methods has been crucial for increasing food grain production (e.g., Green Revolution in India with HYVs of wheat and rice).

Crop Production Management

This involves optimising the conditions and practices for growing crops to maximise yield and efficiency.

• It includes aspects like nutrient management, irrigation, and cropping patterns.

Nutrient Management

Ensuring that plants receive adequate essential nutrients from the soil in the right balance. Plants require 17 essential nutrients (9 macronutrients and 8 micronutrients).

• Sources of nutrients: Soil, air ($CO_2$ for C and O), water ($H_2O$ for H and O), fertilisers, manures.
• Manures: Organic matter derived from decomposition of animal excreta and plant waste. They are rich in organic nutrients and improve soil structure, water holding capacity, and aeration. Examples: Farmyard manure (FYM), compost, green manure.
• Fertilisers: Commercially produced inorganic salts or organic compounds containing specific nutrients (e.g., urea for Nitrogen, superphosphate for Phosphorus, muriate of potash for Potassium). Fertilisers provide nutrients in a readily available form and are essential for achieving high yields, but their excessive use can cause environmental problems (pollution, soil degradation).

Irrigation

Providing water to crops through artificial means. Proper irrigation is essential, especially in areas with insufficient or irregular rainfall, to ensure optimal soil moisture for plant growth.

• Sources of irrigation: Wells, canals, rivers, tanks, dams.
• Methods of irrigation: Traditional methods (moat, chain pump, rahat, dhekli - often less efficient in water use) and modern methods (sprinkler system, drip system - more efficient in water conservation).
• The choice of irrigation method depends on the water availability, type of soil, topography, and the crop being grown.

Cropping Patterns

Different ways of growing crops in the same field to maximise yield, reduce pest/disease incidence, improve soil fertility, and efficiently use resources.

• Mixed Cropping: Growing two or more crops simultaneously on the same field (e.g., wheat + gram, groundnut + sunflower). Benefits: Reduces risk of crop failure, provides different nutrients.
• Inter-cropping: Growing two or more crops simultaneously in the same field in definite row patterns (e.g., soybean + maize, finger millet + cowpea). Benefits: Better utilisation of resources, less competition, can reduce pest/disease spread.
• Crop Rotation: Growing different crops on the same field in a planned sequence. Benefits: Improves soil fertility (e.g., including legumes), helps control pests and diseases, prevents nutrient depletion.

Crop Protection Management

Protecting crops from damage caused by pests, diseases, and weeds to prevent yield losses.

• Pests: Insects, rodents, mites that damage crops.
• Diseases: Caused by pathogens like bacteria, fungi, viruses.
• Weeds: Unwanted plants that grow in the field and compete with crops for resources.

Methods of crop protection:

• Weed control: Mechanical removal, using herbicides (weedicides).
• Pest and disease control: Using pesticides (insecticides, fungicides), biological control (using natural enemies of pests), developing resistant varieties through breeding, proper seed selection, timely sowing.
• Integrated Pest Management (IPM): A holistic approach that combines various methods (cultural practices, biological control, chemical control) to manage pests and diseases in an environmentally friendly and sustainable way.

Animal Husbandry

Animal husbandry is the scientific management of domestic animals for their products and for human welfare. It includes breeding, feeding, housing, and disease control of farm animals.

Animal husbandry deals with the management of livestock such as cattle, goats, sheep, pigs, poultry, and fisheries.

Cattle Farming

Management of cattle (cows and buffaloes) for milk and draught labour (agricultural work, transport). Dairy animals are managed for milk production, and draught animals for labour.

• Milk Production (Dairy Farming): Aims to increase milk yield and improve the quality of milk. Involves breeding improved varieties (e.g., high-yielding indigenous breeds like Sahiwal, Red Sindhi; exotic breeds like Jersey, Holstein-Friesian), providing proper nutrition, maintaining hygiene, and controlling diseases.
• Housing: Should be clean, well-ventilated, and provide protection from rain, heat, and cold.
• Feeding: Requires a balanced diet including roughage (fibre-rich fodder) and concentrate (protein-rich feed).
• Disease Control: Regular check-ups by a veterinary doctor, vaccination, and prompt treatment of sick animals.

Poultry Farming

Raising domestic fowl (chickens, ducks, turkeys, geese) for eggs and meat.

• Eggs (Layers): Varieties selected for high egg production (e.g., White Leghorn).
• Meat (Broilers): Varieties selected for rapid growth and good meat quality.
• Housing: Clean, well-ventilated houses with adequate space and lighting (especially for layers).
• Feeding: Specific feed mixes are provided for layers (for egg production) and broilers (for rapid weight gain). Feed should be rich in protein and vitamins.
• Disease Control: Maintaining hygiene, preventing diseases, and vaccination are crucial in poultry farming as diseases can spread rapidly.

Fish Production

Rearing and catching fish for food. Fish is a rich source of protein.

Fish production can be categorised into:

• Capture fishing: Catching fish from natural water bodies (seas, rivers).
• Culture fishing (Aquaculture): Rearing fish in confined water bodies (ponds, tanks).

Marine Fisheries

Catching fish from seas and oceans. India has a long coastline and large marine areas.

• Includes catching commercially important fish like sardines, mackerel, pomfret, tuna.
• Technologies like echo-sounders and satellite navigation are used to locate large schools of fish.
• Mariculture is the culture of marine fish, prawns, oysters, etc., in coastal waters.

Inland Fisheries

Catching and culturing fish in freshwater bodies (rivers, lakes, ponds, reservoirs) and brackish water bodies (estuaries, lagoons).

• More fish culture is done in inland waters compared to capture fishing.
• Composite fish culture systems involve culturing different species of fish in the same pond, each occupying a different ecological niche, to utilise all the available food resources efficiently (e.g., Indian major carps like Catla, Rohu, Mrigal, along with exotic carps like Grass Carp, Common Carp).

Bee-keeping (Apiculture)

Rearing honey bees for honey and beeswax.

• Honey is a nutritious food and has medicinal uses. Beeswax is used in various industries.
• Most common species in India is Apis indica (Indian bee). Other species include Apis dorsata (rock bee) and Apis florea (little bee). Apis mellifera (Italian bee) is also popular due to high honey yield and gentle nature.
• Factors important for successful bee-keeping: Knowledge of bee habits and lifecycle, selection of site for bee-keeping, catching and hiving of swarms, management of bee colonies during different seasons, handling and collection of honey and beeswax.
• Providing flora (flowering plants) for nectar and pollen collection is essential.

Management Of Farms And Farm Animals

Effective management practices are essential for increasing productivity and maintaining the health of farm animals.

Management Practices:

• Housing: Providing clean, spacious, well-ventilated shelters suitable for the climate. Preventing overcrowding.
• Feeding: Ensuring a balanced diet that meets the nutritional requirements of the animals for growth, production (milk, eggs, meat), and maintenance. This includes providing adequate quantities and quality of feed and clean water.
• Breeding: Selecting and breeding animals with desirable traits (e.g., high yield, disease resistance, fast growth).
• Disease Prevention and Control:
  • Maintaining hygiene in the farm environment.
  • Regular cleaning and disinfection of sheds and equipment.
  • Isolation of sick animals.
  • Regular health check-ups by a veterinary doctor.
  • Vaccination against common diseases.
  • Prompt diagnosis and treatment of illnesses.
• Handling and Care: Gentle handling of animals, providing opportunities for exercise, monitoring their behaviour for signs of illness or distress.

Examples of Farm Management:

• Dairy Farm Management: Ensuring healthy, high-yielding breeds, providing proper feed and water, regular milking practices, maintaining hygiene during milking and storage of milk, regular veterinary check-ups.
• Poultry Farm Management: Selecting suitable breeds (layers or broilers), providing appropriate feed, maintaining temperature and light conditions in sheds, vaccination against diseases like Bird Flu, timely removal of litter.
• Fishery Management: Selecting suitable species for culture, managing pond ecosystem (water quality, oxygen levels), providing supplementary feed, controlling predatory fish and weeds, harvesting fish at appropriate times.
• Bee Colony Management: Monitoring the health of the queen bee, workers, and drones, checking for diseases and pests (e.g., mites), providing supplementary food if needed, protecting from predators, ensuring availability of adequate flora.

Scientific management practices contribute significantly to enhanced productivity, profitability, and sustainability in animal husbandry.

Animal Breeding

Animal breeding aims at improving the genotype of domesticated animals to increase yields and improve desirable qualities (e.g., milk production, growth rate for meat, disease resistance, quality of wool/eggs).

Objectives of Animal Breeding:

• Increasing the yield of animals (e.g., more milk, eggs, meat).
• Improving the desirable qualities of the products (e.g., protein content in milk, lean meat).
• Producing animals resistant to diseases.
• Producing animals tolerant to environmental stresses.
• Increasing the growth rate and efficiency of feed conversion.
• Developing new breeds with specific characteristics.

Methods of Animal Breeding:

Two main breeding approaches are used:

1. Inbreeding: Mating of more closely related individuals within the same breed for 4-6 generations.
   • Procedure: Identify superior males and superior females within the same breed. Mate them. Select superior progeny from the F$_1$ generation and mate them among themselves. Repeat for several generations.
   • Effects: Increases homozygosity (bringing together recessive alleles). Helps in accumulating superior genes and eliminating undesirable recessive genes (by selection against them).
   • Inbreeding depression: Continued inbreeding can lead to reduced fertility and productivity. This can be overcome by outcrossing (mating selected inbred animals with unrelated superior animals of the same breed).
2. Outbreeding: Mating of unrelated individuals.
   • Outcrossing: Mating of individuals within the same breed but having no common ancestors on either side of their pedigree for 4-6 generations. Helps in overcoming inbreeding depression.
   • Cross-breeding: Mating of superior males of one breed with superior females of another breed. Aims to combine desirable traits of two different breeds (e.g., crossing exotic breeds with indigenous breeds for increased milk yield and disease resistance). Example: Hisardale is a new breed of sheep developed in Punjab by crossing Bikaneri ewes and Merino rams.
   • Interspecific hybridisation: Mating between male and female animals of two different species. Progeny often sterile. Example: Mule is produced by crossing a male donkey and a female horse.

Other Breeding Techniques:

• Artificial Insemination (AI): Semen from a superior male is collected and artificially introduced into the reproductive tract of a selected female. Allows wider use of superior males, improves success rate, helps overcome problems of natural mating.
• Multiple Ovulation Embryo Transfer Technology (MOET): Technique to increase success in cattle breeding. A superior female is given hormonal treatment to induce multiple ovulation (producing 6-8 eggs instead of one per cycle). The female is then artificially inseminated with semen from a superior male. The fertilised eggs (embryos) are recovered at 8-32 cell stage and transferred to surrogate mothers. The genetic mother can then be superovulated again. This allows a superior female to produce several offspring in a year.

Animal breeding, through planned mating and reproductive technologies, plays a vital role in enhancing animal productivity to meet human demands for food and other products.

Plant Breeding

Plant breeding is the purposeful manipulation of plant species to create desired plant types that are better suited for cultivation, give better yields, and are disease resistant.

What Is Plant Breeding?

• Plant breeding is the science of improving plants for human benefit.
• It involves selecting and breeding plants with desirable traits to develop new and improved varieties.
• It has been practiced for thousands of years (since the beginning of settled agriculture).
• Classical plant breeding involves hybridisation of pure lines and selection of hybrids with desirable traits.
• Modern plant breeding also uses molecular techniques (genetic engineering) to introduce specific genes for improved traits.

Steps in a typical Plant Breeding Program:

1. Collection of variability: Gathering diverse genetic resources (e.g., wild relatives of the crop, cultivated varieties, landraces) to identify potential parents with desirable traits.
2. Evaluation and selection of parents: Evaluating the collected material for desired traits and selecting the best plants to be used as parents for hybridisation.
3. Cross hybridisation among the selected parents: Crossing selected parents to combine desirable traits. This is done using artificial hybridisation techniques (emasculation and bagging).
4. Selection and testing of superior recombinants: Screening the progeny of the hybrid cross (F$_1$, F$_2$, etc.) to select plants with the desired combination of traits (recombinants).
5. Testing, release and commercialisation of new cultivars: The selected superior lines are tested for their performance (yield, resistance, quality) in various environments over several seasons. If found superior, they are released as new varieties (cultivars) and multiplied for distribution to farmers.

India's Green Revolution (in the mid-20th century) was largely based on the development and widespread adoption of high-yielding, disease-resistant varieties of wheat and rice through plant breeding efforts (e.g., varieties developed by Dr. M.S. Swaminathan in India, inspired by Norman Borlaug's work).

---

Plant Breeding For Disease Resistance

Diseases cause significant losses in crop yield. Developing disease-resistant varieties is a cost-effective and environmentally friendly way to minimise these losses.

• Sources of resistance genes: Resistance genes may be present in wild relatives of the crop or in existing cultivated varieties. Induced mutations can also create new resistance genes.
• Breeding methods:
  • Hybridisation followed by selection: Crossing a disease-resistant variety with a high-yielding but susceptible variety, then selecting hybrid progeny that are both high-yielding and resistant.
  • Mutation breeding: Inducing mutations and selecting for resistance mutants. Example: Resistance to yellow mosaic virus in mung bean was achieved by mutation breeding.

Examples of Disease Resistant Varieties developed in India:

• Wheat: Himgiri (resistant to leaf and stripe rust, hill bunt).
• Brassica (Rapeseed Mustard): Pusa Swarnim (Karan Rai) (resistant to white rust).
• Cauliflower: Pusa Shubhra, Pusa Snowball K-1 (resistant to black rot and curl blight black rot).
• Cowpea: Pusa Komal (resistant to bacterial blight).

---

Plant Breeding For Developing Resistance To Insect Pests

Insect pests cause huge damage to crops. Developing pest-resistant varieties reduces the need for chemical pesticides.

• Mechanism of resistance: Can be morphological (e.g., hairy leaves deter pests), biochemical (e.g., presence of toxins), or physiological.
• Breeding methods: Hybridisation and selection, mutation breeding, genetic engineering (e.g., Bt cotton expresses a toxin gene from bacterium *Bacillus thuringiensis* that is toxic to certain insect pests).

Examples of Insect Pest Resistant Varieties developed in India:

• Brassica (Rapeseed Mustard): Pusa Gaurav (resistant to aphids).
• Flat bean: Pusa Sem 2, Pusa Sem 3 (resistant to jassids, aphids, fruit borer).
• Okra (Bhindi): Pusa Sawani, Pusa A-4 (resistant to shoot and fruit borer).

---

Plant Breeding For Improved Food Quality

Breeding crops not just for yield but also for improved nutritional quality (Biofortification). This aims to make staple crops more nutritious and address micronutrient deficiencies (hidden hunger).

• Objectives: Increasing protein content and quality, oil content and quality, vitamin content, micronutrient content (iron, zinc, iodine).

Examples of Biofortified Varieties:

• Maize hybrids with twice the amount of amino acids (lysine and tryptophan).
• Wheat variety (Atlas 66) with a high protein content.
• Iron-fortified rice varieties.
• Vitamin A-rich carrots, spinach, pumpkin.
• Vitamin C-rich bitter gourd, Bathua, mustard, tomato.
• Protein-rich beans, lablab, garden peas.
• Iron and calcium-rich spinach and Bathua.

---

Plant breeding has played a vital role in increasing food production and improving nutritional security, and it continues to be essential for addressing future challenges in agriculture.

Single Cell Proteins

Single Cell Protein (SCP) refers to edible protein produced from single-celled or simple multicellular organisms like bacteria, algae, yeasts, and fungi.

Concept and Potential:

• The increasing demand for protein for human and animal nutrition, coupled with limitations of traditional agriculture, has led to the exploration of alternative protein sources.
• SCP offers a potential solution as it can be produced rapidly on a large scale using relatively simple methods and various low-cost raw materials (substrates).
• Microorganisms can grow on various waste materials like wastewater from potato processing plants, straw, molasses, animal manure, sewage.

Examples of Microorganisms used for SCP production:

• Bacteria: *Methylophilus methylotrophus*
• Algae: Spirulina (can be grown easily on wastewater, rich in protein, minerals, vitamins, carotenoids), Chlorella
• Yeasts: Saccharomyces cerevisiae (brewers yeast)
• Fungi: *Fusarium graminearum* (used to produce Quorn, a mycoprotein)

Advantages of SCP:

• High protein content (40-80% or more).
• Rapid growth rate of microorganisms.
• Can be produced year-round, regardless of climate or season.
• Requires less land and water compared to traditional protein sources.
• Can be produced from waste materials, helping in waste recycling and pollution reduction.
• Can provide a good source of vitamins and minerals.

Challenges in SCP Production:

• High nucleic acid content in some microbial biomass, which needs to be reduced for human consumption.
• Cell wall components in some organisms may be indigestible.
• Palatability and consumer acceptance issues.
• Cost-effectiveness of large-scale production.

Despite challenges, SCP holds promise as a supplementary protein source to address nutritional needs.

Tissue Culture

Tissue culture is a technique of growing plant cells, tissues, or organs in vitro (in a sterile laboratory environment) on a synthetic nutrient medium.

Concept and Totipotency:

• The basis of plant tissue culture is the property of totipotency, which is the ability of a single plant cell (explant) to divide and differentiate to regenerate a whole plant.
• The plant part used for tissue culture (cell, tissue, organ fragment) is called the explant.
• The synthetic nutrient medium provides inorganic salts, vitamins, amino acids, sugars, and often plant growth regulators (auxins and cytokinins).

Micropropagation:

• Micropropagation is the method of producing a large number of plants in a short time using tissue culture techniques.
• A small explant is cultured on a nutrient medium, where it grows into a mass of undifferentiated cells called callus.
• The callus is then transferred to different media containing specific plant growth regulators (manipulating auxin:cytokinin ratio) to induce the formation of shoots and roots.
• Plantlets are then transferred to soil.

Micropropagation allows for rapid multiplication of desired plant varieties.

*(Image shows a diagram illustrating the steps of tissue culture: explant $\rightarrow$ callus formation $\rightarrow$ shoot/root development $\rightarrow$ plantlet transfer to soil)*

Somatic Hybridisation:

• Tissue culture techniques can also be used for somatic hybridisation, which involves the fusion of protoplasts (cells without cell walls) from two different plant varieties or species.
• Protoplasts are isolated by removing cell walls using enzymes.
• Protoplasts are fused (using chemicals or electrofusion) to form a somatic hybrid cell.
• The somatic hybrid cell is then cultured using tissue culture to regenerate a whole new plant (somatic hybrid).
• This allows for combining desirable traits from two different species that cannot be crossed sexually.
• Example: Pomato, a somatic hybrid of potato and tomato (though not commercially successful due to undesirable traits).

Advantages of Tissue Culture:

• Production of a large number of plants in a short time (micropropagation).
• Production of genetically identical plants (clones).
• Production of disease-free plants: If the explant is taken from a meristematic region (shoot apex, root apex), which is usually virus-free, disease-free plants can be produced (meristem culture).
• Somatic hybridisation allows for combining traits of sexually incompatible species.
• Can be used for producing haploid plants (from pollen grains) for breeding programs.
• Production of secondary metabolites in large quantities using cell cultures.

Tissue culture is a powerful tool in plant biotechnology, contributing to rapid plant multiplication, disease eradication, and crop improvement.