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CH-9: STRATEGIES FOR ENHANCEMENT IN FOOD PRODUCTION NEET BOTANY VOL- II 64 NARAYANA GROUP 9 STRATEGIES FOR ENHANCEMENT IN FOOD PRODUCTION C O N T E N T S NEET SYLLABUS · INTRODUCTION · PLANT BREEDING · BREEDING PROCESS · AGRICULTURE & GREEN REVOLUTION · MUTATIONAL BREEDING · BREEDING FOR RESISTANT TO INSECTS PESTS · BREEDING FOR BIOFORTIFICATION · SINGLE CELL PROTEIN · TISSUE CULTURE · SOMATIC HYBRIDISATION · REVIEW POINTS · EXERCISE Improvement in food production; Plant breeding, tissue culture, single cell protein, Biofortification;
NEET BOTANY VOL-II CH-9: STRATEGIES FOR ENHANCEMENT IN FOOD PRODUCTION NARAYANA GROUP 65 INTRODUCTION  Biology is the youngest of the formalised disciplines of natural science.  Progress in physics and chemistry proceeded much faster than in Biology.  Applications of physics and chemistry in our daily life also have a higher visibility than those of biology.  However, twentieth century and certainly twenty-first century has demonstrated the utility of biological knowledge in furthering human welfare, be it in health sector, and agriculture.  The discovery of antibiotics, and synthetic plant-derived drugs, anaesthetics have changed medical practice on one hand and human health on the other hand. Life expectancy of human beings have dramatically changed over the years.  Agricultural practices, food processing and diagnostics have brought socio-cultural changes in human communities. * M.S. Swaminathan born in August 1925 in Kumbakonam in Tamil Nadu. * He did his graduation and post-graduation in Botany from Madras University. * He worked in different capacities in large number of institutions in India and abroad gained experience in genetics and plant breeding. * The School of Cytogenetics and Radiation Research established at the IARI enabled Swaminathan and his team to develop short duration high yielding varieties of rice including scented Basmati. * He is also known for developing of the concept of crop cafeteria, crop scheduling and genetically improved the yield and quality. * He initiated collaboration with N. E. Borlaug, who is the father of ‘Green Revolution’ through introduction mexican varieties wheat in India i.e., Sharbati Sanora from Semi dwarf Maxican variety Sanora-64 by using gamma radiation. It was highly recognised and appreciated. * M.S. Swaminathan is also the initiator of ‘Lab-to-Land’, food security and several other environmental programmes. * M.S. Swaminathan has been honoured with Padma Bhushan and several other prestigious awards, medals and fellowships by institutions of excellence. * Plants are the sources of food, medicine and other useful products. * More than 840 million people in the world do not have adequate food to meet their daily food and nutritional requirements * With ever increasing population of the world, enhancement of food production is a major necessity. Biological principles as applied to animal husbandry and plant breeding have a major role in our efforts to increase food production. * Several new techniques like embryo transfer technology and tissue culture techiniques are going to play a pivotal role in further enhancing food production are – Mutation breeding, tissue culture and r-DNA technology etc...
CH-9: STRATEGIES FOR ENHANCEMENT IN FOOD PRODUCTION NEET BOTANY VOL- II 66 NARAYANA GROUP PLANT BREEDING: * Traditional farming inadequate to support the increasing global population because it yields a limited biomass, as food for humans and animals. * Adaption of better management practices and increase in acreage is also inadequate to support the increasing global population because they increase yields only to a limited extent. * The technology that helped us in increase yields to a very large extent is Plant breeding * After independence, during 1960’s, the concept helped us in meeting the national requirements in food production and even to export it was Green revolution. * In the development of high yielding and disease resistant varieties in wheat, rice, maize, etc... Green revolution relied to a large extent on plant breeding techniques * The purposeful manipulation of plant species in order to create desired plant types that are better suited for cultivation, give better yields and are disease resistant is Plant breeding * Conventional plant breeding is an age old technology practiced for thousands of years, since the beginning of human civilisation with recorded evidence of plant breeding dates back to 9,000-11,000 years ago. * The process of bringing wild varieties under human management is called domestication * Many present day crops are the result of domestication in ancient times and all our major food crops are derived from domesticated varieties. * Classical plant breeding involves crossing or hybridisation of pure lines, followed by artificial selection to produce plants with desirable traits of higher yield, nutrition and resistance to diseases. * With advancements in genetics, molecular biology and tissue culture, plant breeding is now increasingly being carried out by using - molecular genetic tools. * The desirable traits or characters that would be incorporated by the breeders into crop plants are - Increased crop yield and improved quality, Increased tolerance to environmental stresses (salinity, extreme temperatures, drought) , Resistance to pathogens (viruses, fungi and bacteria) and Increased tolerance to insect pests etc... * Plant breeding programmes are carried out in a systematic way worldwide in government institutions and commercial companies. The main steps in breeding a new genetic variety of a crop are:- (i) Collection of variability :  The main steps in breeding a new genetic variety of a crop are collection of variability: * Genetic variability is the root of any breeding programme. * In many crops pre-existing genetic variability is available from wild relatives of the crop. * Collection and preservation of all the different wild varieties, species and relatives of the cultivated species (followed by their evaluation for their characteistics)
NEET BOTANY VOL-II CH-9: STRATEGIES FOR ENHANCEMENT IN FOOD PRODUCTION NARAYANA GROUP 67 * It is a pre-requisite for effective exploitation of natural genes available in the populations of all the different wild varieties, species and relatives of the cultivated species is collection and preservation of Genetic variability  The entire collection (of plants/seeds) having all the diverse alleles for all genes in a given crop is called Germplasm collection. (ii) Evaluation and selection of parents: * The germplasm is evaluated so as to identify plants with desirable combination of characters. * The selected plants are multiplied and used in the process of hybridisation. Purelines are created wherever desirable and possible.  The progeny of a single self-pollinated homozygous plant is known as pure line  The progeny of a single cross-pollinated heterozygous plant produced through self pollination is inbreed line  If the plants selected as parents are in heterozygous condition they are made homozygous through continuous inbreeding for a number of generations. (iii) Cross hybridisation among the selected parents:  The method of producing new crop varieties by crossing two genetically different parents is Artificial hybridisation  Incorporation of desirable qualities from various varieties into a single variety is possible through Cross hybridisation * The desired characters have very often to be combined from two differenet plants (parents) * For example high protein quality of one parent and disease resistance from another parent can be incorporated into one plant through cross hybridisation. * Since the pollen grains from the desirable plant chosen as male parent have to be collected and place on the stigma of the flowers selected as female parent * The limitations in Cross hybridization are This is a very time consuming and tedious process  Inferior success rate(one in few hundred to a thousand crosses)  Removal of anthers from the flower buds of the bisexual flowers of female parent before the anther dehiscence is called Emasculation  In Artificial hybridisation, the undesired self pollination is prevented through Emasculation  In Artificial hybridisation, the undesired cross pollination is prevented through Bagging  Method of plant breeding in which there is a control on pollination is Artificial hybridisation. * Also it is not necessary that the hybrids do combine the desirable characters; usually only one in few hundred to a thousand crosses shows the desirable combination. (iv) Selection and testing of superior recombinants: * This step consists of selecting among progeny of the hybrids, those plants that have the desired character combination * The selection process is crucial to the success of the breeding objective and requires careful scientific evaluation of the progeny. * This step yields plants that are superior to both of the parents (very often more than one superior progeny plant may become available) * These are self-pollinated for several generations till they reach a state of uniformity (homozygosity) * So that the characters will not segregate in the progeny.