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Introduction |
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One of the primary objectives of agriculture is to produce food. In the entire history of agriculture, food production has remained a prime objective. |
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Technologies to Improve Food Production |
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Many technologies are generated out of intensive agricultural research, to increase the food production. They are grouped in three broad groups namely crop improvement, crop protection and crop production. There are three methods of crop improvement namely, selection, breeding and tissue culture - each one contributing for crop improvement in its own way. Basically, crop improvement refer to improving the genotypic characters - which are expressed phenotypically to ultimately increase the crop yield or improve the quality. |
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Crop Improvement |
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Each crop is, in fact, an adaptation from wild type to a cultivated type. Wild types or wild species of each crop can be traced to their natural habitat where such species are grown naturally without human interference. |
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Introduction as Crop Improvement |
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When a cultivated variety of a species is attempted to be grown outside its well adapted climatic periphery - such variety is said to be introduced to new area. This method of introduction was followed by many ancient travellers, diplomats, warriors, kings almost inadvertently in many crops. Introduction- as a crop improvement method has led to introduction of crop itself to the new region or introduction of new cultivated variety to an already existing crop of such region. For e.g., potato is an introduced crop to India. |
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Selection |
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It is a process of selective improvement of a crop. In selection, a plant is selected based on its genotypic and phenotypic characters in order to improve some of its characters in its next generation. |
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Mass Selection |
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Desirable plants are selected purely based on phenotype and pooled. They are allowed to be grown in mass in next generation. Further selections are made in 3-4 such generations to consolidate desirable characters by ignoring plants with undesirable character at each selection. Individual progeny is not tested and propagated. This method is generally suitable for highly cross pollinated crops like maize. |
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Breeding |
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Crop improvement by deliberate attempt to cross two parents of desirable characters to incorporate such characters in next generations is called breeding. |
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Hybridization |
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It is a breeding method, where in two known parents are crossed with the objective of achieving hybrid vigour or heterosis. Parents may belong two varieties of same species or two species of same genus. |
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Filial Generations |
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The offsprings of a hybrid is called filial generation. The first filial generation after hybridization is called F1. |
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Commercial Utility of Hybridization |
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A commercial hybrid is a hybrid, where in seeds of F1 generation are used to grow the crop - so that heterosis is available to improve the performance of crop. |
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Ploidy Breeding |
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An organism, in which number of complete chromosome sets is more than the diploid number is called polyploid. |
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Mutation Breeding |
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Mutations are defined as heritable changes in structure number of genes or chromosomes. Mutations can be natural (spontaneous) or induced. Many natural mutations are recorded. But, stability of mutant expression needs a thorough testing over generations, as many mutants have tendency to revert to normalcy. |
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Beneficial Mutations |
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Crop - Reported benefits after mutations. Barley - Reduction in height, increased yield and day neutrality. |
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High Yielding Varieties / Hybrids |
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As a result of sustained research in agriculture, many high yielding varieties /hybrids have been released in our countries (India 2000). In rice, more than 600 high yielding, early maturing, dwarf disease resistant varieties have been evolved. |
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Plant Tissue Culture |
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It refers to culture or growing the plant tissues. Plant tissue culture is developed as a separate branch of science - ever since the potentiality of each cell or tissue of plant to grow into a separate organism has been recognised. Tissue culture technique has opened up new opportunities in evolving new hybrids/varieties, besides solving many difficult problems - conventionally difficult to tackle by other known methods. In a sense, tissue culture technique has created a revolution in agricultural research. |
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Micropropagation |
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It refers to artificial propagation of plants vegetatively through the culture of cell or tissue. It is most useful, when normal propagation takes long time or the success in fertilization is very poor as seen in many valuable plants useful in agriculture, horticulture and forestry. |
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Embryo Culture |
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Embryo mortality and seed failure associated with embryo development are most common reasons for failure of interspecific hybridization due to incompatability. In such instances, fertilization and zygote formation may not suffer but embryo development does not take place and seeds are aborted. |
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Creation of Variations |
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The plants developing from callus have shown large variations in their characters. Such variations are called somaclonal variations. Such variations occur as a part of mutation or as a part of clonal development. |
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Protoplast Culture |
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Protoplast is a cell without cell wall. In plants, the cells are invariably surrounded by thick cell wall made of cellulose and pectin. During the process of tissue culture and using it for crop improvement, cell wall acts as a barrier to induce mutations or some times to develop the callus. |
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Crop Production |
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Crop improvement technologies improve the potentialities of higher yield and food quality in crops. New varieties and hybrids of various crops released by various crop improvement techniques are ultimately aimed to increase the yield and better quality. |
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Concept of Nutrient Availability |
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Soil is a living medium consisting of physical part - called as soil particles, chemical part - consisting of various compounds as well as biological part - consisting of various microbes, vertebrates, invertebrates inhabiting in soil. Unless all these components are kept in harmony, the crop plants would suffer by poor nutrient availability. |
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Biofertilizers |
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Any living organism supplying plant nutrients directly or indirectly is regarded as biofertilizer. They are not synthetically manufactured in factory. Many organisms with a potentiality to supply plant nutrients - have been recognised. |
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Nitrogen Fixing Organisms |
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Some bacteria are known to fix the atmospheric nitrogen for their own biological activity. This natural phenomena is commercially utilized to increase the nutrient supply to crops. |
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Azolla |
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Azolla is a fast growing aquatic plant often observed in many water bodies. It itself is not much useful, except that it can add organic matter on decomposition. But an algae called Anabaena Azollae inhabits in the cavities of Azolla leaves and fix atmospheric nitrogen. Thus, Azolla leaves acts as excellent source of nitrogen, besides their capacity to act as source of organic matter. |
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Blue Green Algae (BGA) |
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Blue green algae are autotrophic and nitrogen fixing organisms unlike heterotrophic and symbiotic nitrogen fixing microbes discussed above. They manufacture their food by photosynthesis, as they have chloroplasts. Hence, they can live independently. BGA like Anabaena and Nostoc are found to live on soil, rocks. They have potentiality to fix large atmospheric nitrogen (upto 20 - 25 kg/ha). |
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Phosphate Solubalising Bacteria |
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Some bacteria like Aspergillus awamori have the capacity to solubalise the phosphates fixed in soil. It must be recalled here that most of applied phosphorus is fixed in soil, and a small part of it is available to plants every year as labile phosphorous. |
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Crop Protection |
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Most of the food crops are subjected to damage by insects and diseases. Large number of insects and diseases are recognized on every food crop. Control of insects and diseases is one of the great challenge posed to human knowledge. |
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Diseases of Crop |
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Plant diseases are improvement because of the loss they cause. In the history of mankind plant disease have played an important role. A good example would be the Irish potato famine caused due to late blight of potato, a disease affecting the potato crop. |
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Insects of Food Crops |
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The growth and yield of food crops are also seriously damaged by various insects. Each insect attacks the crop in its own style and damage the crop to complete its own life cycle. The insects attack almost all parts of crop and the damage may be direct loss of economic product or may be indirect through the reduced growth. |
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Biopesticides |
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Biopesticides are the pesticides of biological origin or the biological control agents, which are used to control the weeds and pests; they are of 2 types bio herbicides and bio insecticides. |
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Integrated Pest Management |
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Integrated pest management (IPM) refers to techniques of managing the pest by making use of cultural, chemical and biological methods in the form of integrated module (specific to each crop and each situation). |
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Recent Advances in Applied Biology |
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Applied biology is playing major role in many facets of our society in terms of facility, technology and danger. Some of them are discussed here. |
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Organic Food |
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With world wide awareness about dangers of persisting pesticides in food crops, enormous interest is shown in food grown on organic farming principles. Such food is called organic food. |
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Bio - war |
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Bio - war refers to biological war. It means that biological organisms are used as weapons to carry out the war. It is latest form of war. It is carried out by spreading the pathogens in specific part of geographical region to deliberately spread a deadly disease. The diseases spread through bio war may bring skin disorders, respiratory disorders, muscular disorders or digestive disorders. |
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Bio-piracy |
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Bio piracy refers to unauthorised and unlawful access to biological secret and use of such secrets for specific gain. |
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Bio-patent |
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Patenting was considered exclusively in industrial domain. Inventions, production processes were patented since long. But recently patenting is extended to biological field too. Bio-patent is the result of TRIPS (Trade related intellectual property right) as a part of WTO agreement signed by most of countries during 1994. |
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Biotechnology |
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Biotechnology is science of manufacturing useful substances, chemicals, medicines by use of living organisms and their life process. In fact, biotechnology is not a new science. Alcohol was the first product manufactured by ancient biotechnologist. |
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Enzymes |
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Amylase is an enzyme to degrade starch. It is produced from Bacillum subtilis, Bacillus polymya (bacteria) as well as Aspergillus niger, Aspergillus oryzae, Rhizopus oryzae (fungi). Amylase is widely used pharmaceutical, beverage, textile confectionary industries. |
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Antibiotics |
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Antibiotics are substances obtained from microorganisms - which are antagonistic to growth of other pathogenic bacteria.; |
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Antibodies |
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Monoclonal antibodies are pure, high affinity, antigen specific, proteinaceous bodies derived outside the organism from clonal cultures of hybrid cells called hybridomas. |
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Production of Vitamins |
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Vitamins can be produced on industrial scale by microorganisms. |
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Steroids |
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Steroids are commonly found in human body in the form of cholesterol, testesterone, oestrogen, progesterone and cortisterone. Cholesterol acts as precursor for other body steroids - which are hormones. Steroids are normally prepared by activated hydroxylation. Rhizopus stolonifer effectively mediates the process of hydroxylation. |
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Crop Diseases |
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Plant diseases are improvement because of the loss they cause. In the history of mankind plant disease have played an important role. A good example would be the Irish potato famine caused due to late blight of potato, a disease affecting the potato crop. |
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Sustainable Agriculture |
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Crop yields remaining stagnant, pesticides polluting the eco-systems, increasing cost of fertilizers, reducing soil fertility, imbalance in host - parasite and predator - parasite relationships have pushed agriculture into dangerous mode. Scientists have looked back into the technologies evolved and used to increase the crop yields. Long term projections have indicated that agriculture is pushing itself towards stagnation with severe damage to eco-systems. |
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Summary |
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Although India's food production has increased by 300 percent, percapita availability of food has reduced, in the last 50 years. |
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Some Important Facts to know |
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Scientists connected with improvement of crop varieties are called Plant Breeders. |
