Outline: Increasing Food Production Options

• Introduction

  • Overview of the three options for increasing food production.

• Agro-chemical Based Agriculture

  • Use of fertilizers and pesticides.

  • Improved crop varieties.

  • Better management practices.

  • Challenges in developing countries due to high costs.

• Organic Agriculture

  • Focus on natural methods.

  • Avoidance of synthetic chemicals.

  • Sustainable farming practices.

  • Potential benefits for health and the environment.

• Genetically Engineered Crop-Based Agriculture

  • Genetic modification for desired traits.

  • Increased resistance to pests and diseases.

  • Potential for higher yields.

  • Controversies surrounding GMOs.

• Comparison and Challenges

  • Green Revolution's impact on food supply.

  • Limitations of existing crop varieties.

  • Affordability and accessibility issues in developing countries.

• Conclusion

  • Need for a balanced approach.

  • Consideration of environmental and social impacts.

  • Importance of research and innovation in food production.

Outline: Tissue Culture in Crop Improvement

• Introduction

  • Traditional breeding techniques vs. tissue culture

  • Development of tissue culture technology

• Definition of Tissue Culture

  • Regeneration of whole plants from explants

  • Totipotency: ability to generate a whole plant from any cell/explant

• Process of Tissue Culture

  • Explants: any part of a plant grown in a test tube

  • Sterile conditions and special nutrient media

  • Importance of carbon source (sucrose), inorganic salts, vitamins, amino acids, and growth regulators (auxins, cytokinins)

• Significance of Tissue Culture

  • Fast and efficient systems for crop improvement

  • Potential for generating new plant varieties

  • Application in higher classes for students to learn

• Conclusion

  • Emphasis on the importance of nutrient medium components

  • Future prospects and advancements in tissue culture technology

Tissue Culture and Micro-propagation

• Introduction

  • Definition of micro-propagation

  • Production of genetically identical plants (somaclones)

• Applications of Tissue Culture

  • Commercial scale production of food plants (tomato, banana, apple)

  • Recovery of healthy plants from diseased plants

• Meristem Culture

  • Meristem as virus-free

  • Culturing meristems of banana, sugarcane, potato

• Protoplast Isolation

  • Isolation of naked protoplasts

  • Fusion of protoplasts from different varieties to obtain hybrid protoplasts

• Somatic Hybridisation

  • Formation of somatic hybrids

  • Process of somatic hybridisation

• Conclusion

  • Importance of tissue culture in plant propagation

  • Potential for creating new plant varieties through somatic hybridisation

Outline: Genetically Modified Organisms (GMOs)

• Introduction

  • Fusion of protoplasts of tomato and potato to create pomato

  • Pomato not meeting desired characteristics for commercial use

• Alternative Path for Maximum Yield

  • Utilizing understanding of genetics for improved crop traits

  • Development of genetically modified crops for enhanced yield

• Minimizing Chemical Usage

  • Reducing fertilizers and chemicals to mitigate environmental harm

  • Potential solution: adoption of genetically modified crops

• Genetically Modified Organisms (GMOs)

  • Definition: organisms with altered genes through manipulation

  • Examples: plants, bacteria, fungi, and animals

• Conclusion

  • GMOs as a potential solution for maximizing yield and reducing chemical usage

  • Importance of responsible and ethical use of genetically modified crops

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Outline: Genetic Modification in Plants

• Introduction

  • Genetic modification (GM) has been beneficial in various ways in agriculture.

• Advantages of Genetic Modification

  • Increased tolerance to abiotic stresses:

    • Cold, drought, salt, heat.

  • Reduced reliance on chemical pesticides:

    • Pest-resistant crops.

  • Decreased post-harvest losses.

  • Enhanced mineral usage efficiency:

    • Prevents soil fertility exhaustion.

  • Improved nutritional value:

    • e.g., Golden rice (Vitamin A enriched).

• Applications of Genetic Modification

  • Tailor-made plants for alternative resources:

    • Starches, fuels, pharmaceuticals.

  • Production of pest-resistant plants:

    • Decreases pesticide usage.

  • Bt toxin:

    • Produced by Bacillus thuringiensis (Bt).

    • Cloned and expressed in plants for insect resistance.

    • Examples: Bt cotton, Bt corn, rice, tomato, potato, soybean.

• Conclusion

  • Genetic modification in plants offers various benefits in agriculture and food production.

Outline: Bt Cotton

• Introduction to Bacillus thuringiensis (Bt)

  • Mnemonic: "Some Tigers Attack Cute Birds Daily."

    Some strains produce proteins that kill certain insects (tobacco budworm, armyworm),coleopterans (beetles) and dipterans (flies, mosquitoes).

  • Protein crystals contain toxic insecticidal protein

• Mechanism of Action

  • Inactive protoxins converted to active form in insect gut

  • Activated toxin binds to midgut epithelial cells, causing cell lysis

  • Resulting in insect death

• Incorporation into Crop Plants

  • Specific Bt toxin genes isolated from Bt

  • Genes incorporated into crop plants like cotton

  • Choice of genes depends on crop and targeted pest

• Examples of Bt Toxin Genes

  • cryIAc and cryIIAb control cotton bollworms

  • cryIAb controls corn borer

• Conclusion

  • Bt cotton offers pest resistance through genetic modification

  • Provides a sustainable and effective method for insect control

BIOTECHNOLOGICAL APPLICATIONS IN AGRICULTURE

Let us take a look at the three options that can be thoughtfor increasing food production(i) agro-chemical based agriculture (ii) organic agriculture; and(iii) genetically engineered crop-based agriculture.The Green Revolution succeeded in tripling the food supply but yetit was not enough to feed the growing human population. Increased yieldshave partly been due to the use of improved crop varieties, but mainlydue to the use of better management practices and use of agrochemicals(fertilisers and pesticides). However, for farmers in the developing world,agrochemicals are often too expensive, and further increases in yield withexisting varieties are not possible using conventional breeding.As traditional breeding techniques failed to keep pace with demand andto provide sufficiently fast and efficient systems for crop improvement,another technology called tissue culture got developed. What doestissue culture mean? It was learnt by scientists, during 1950s, thatwhole plants could be regenerated from explants, i.e., any part of aplant taken out and grown in a test tube, under sterile conditions inspecial nutrient media. This capacity to generate a whole plant fromany cell/explant is called totipotency. You will learn how to accomplishthis in higher classes. It is important to stress here that the nutrientmedium must provide a carbon source such as sucrose and alsoinorganic salts, vitamins, amino acids and growth regulators like auxins,cytokinins etc. By application of these methods it is possible to achievepropagation of a large number of plants in very short durations. Thismethod of producing thousands of plants through tissue culture iscalled micro-propagation. Each of these plants will be geneticallyidentical to the original plant from which they were grown, i.e., they aresomaclones. Many important food plants like tomato, banana, apple,etc., have been produced on commercial scale using this method. Try tovisit a tissue culture laboratory with your teacher to better understandand appreciate the process.Another important application of the method is the recovery ofhealthy plants from diseased plants. Even if the plant is infected with avirus, the meristem (apical and axillary) is free of virus. Hence, onecan remove the meristem and grow it in vitro to obtain virus-free plants.Scientists have succeeded in culturing meristems of banana, sugarcane,potato, etc.Scientists have even isolated single cells from plants and afterdigesting their cell walls have been able to isolate naked protoplasts(surrounded by plasma membranes). Isolated protoplasts from twodifferent varieties of plants – each having a desirable character – can befused to get hybrid protoplasts, which can be further grown to form anew plant. These hybrids are called somatic hybrids while the process is called somatic hybridisation. Imagine a situation when a protoplastof tomato is fused with that of potato, and then they are grown – to formnew hybrid plants combining tomato and potato characteristics. Well,this has been achieved – resulting in formation of pomato; unfortunatelythis plant did not have all the desired combination of characteristics forits commercial utilisation.Is there any alternative path that our understanding of genetics canshow so that farmers may obtain maximum yield from their fields? Isthere a way to minimise the use of fertilisers and chemicals so that theirharmful effects on the environment are reduced? Use of geneticallymodified crops is a possible solution.Plants, bacteria, fungi and animals whose genes have been altered bymanipulation are called Genetically Modified Organisms (GMO). GMplants have been useful in many ways. Genetic modification has:(i) made crops more tolerant to abiotic stresses (cold, drought, salt, heat).(ii) reduced reliance on chemical pesticides (pest-resistant crops).(iii) helped to reduce post harvest losses.(iv) increased efficiency of mineral usage by plants (this prevents earlyexhaustion of fertility of soil).(v) enhanced nutritional value of food, e.g., golden rice, i.e., Vitamin ‘A’enriched rice.In addition to these uses, GM has been used to create tailor-madeplants to supply alternative resources to industries, in the form of starches,fuels and pharmaceuticals.Some of the applications of biotechnology in agriculture that you willstudy in detail are the production of pest resistant plants, which coulddecrease the amount of pesticide used. Bt toxin is produced by abacterium called Bacillus thuringiensis (Bt for short). Bt toxin gene hasbeen cloned from the bacteria and been expressed in plants to provideresistance to insects without the need for insecticides; in effect created abio-pesticide. Examples are Bt cotton, Bt corn, rice, tomato, potato andsoyabean etc.Bt Cotton: Some strains of Bacillus thuringiensis produce proteins thatkill certain insects such as lepidopterans (tobacco budworm, armyworm),coleopterans (beetles) and dipterans (flies, mosquitoes). B. thuringiensisforms protein crystals during a particular phase of their growth. Thesecrystals contain a toxic insecticidal protein. Why does this toxin not killthe Bacillus? Actually, the Bt toxin protein exist as inactive protoxins butonce an insect ingest the inactive toxin, it is converted into an active formof toxin due to the alkaline pH of the gut which solubilise the crystals.The activated toxin binds to the surface of midgut epithelial cells andcreate pores that cause cell swelling and lysis and eventually cause death Specific Bt toxin genes were isolated from Bacillus thuringiensis andincorporated into the several crop plants such as cotton (Figure 10.1).The choice of genes depends upon the crop and the targeted pest, asmost Bt toxins are insect-group specific. The toxin is coded by a genecryIAc named cry. There are a number of them, for example, the proteinsencoded by the genes cryIAc and cryIIAb control the cotton bollworms,that of cryIAb controls corn borer