《可持续发展的理论与实践》（英文版） Lecture 8 OrganicFarmingandTransgenicAgriculture.doc_大学文库

Organic Farming and Transgenic Agriculture bicultural Ecology NCP=- - PH Where: NCP= Net Community Productivity History of Agricultural Development Food Gathering Green Revolution Organic Farming High inputs of energy subsidies including fertilizers, pesticides, fossil fuels, mechanization, imigation& advanced technol ogy High outputs at the expense of environmental integrity Contamination of ground water surface water by agrochemicals sediments ete resurgence ad and animal health(e.g. residual effect of methamidophos in vegetables, Agent orange in ietnam, cr oss-Atlantic DDT contamination) Hazards to h esistance and animals Problems of Conventional due to Erosio Salinization Loss of organic matter Problems of Conventional Farming Problems of Conventional Farming It is an altemative agriculture in which the use of chemical fertilizers and pesticides is replaced by Organic Matter(e.g. crop residues, green manures, farmy ard manures)& biological control. The objectives an produce quality and safe fo to minimize health hazards 1. Organic wastes heterogeneous in property and are highly variable in nutritive value Limitations of Organic Agriculture 2. Mineral ization of organic matter C: Nratio(nitrate depression period) Limitations of Organic Agriculture Limitations of Organic Agriculture 4. Acceptance by farmers ctant to give up the use of agrochemical Soil adjustment after prolonged years of conventional farming Productivity decline& sustainability 8. Carcinogenic due to elevated nitrogen level in farm products Organic Farming in Hong Kong Organic Farming in Hong Kong 2. Daily Consumption of Fresh Food Organic Farming in Hong Kong long Kong 4. Advantages Disadvantages of Agncultural Development in Hong Kong Modemization, specialization, market-oriented and competitive Full use of market information Development of specialized agriculture, e.g. organic farming and protected farming 6. what has aFCd done? rovide efiective and efficient marketing channel Provide low-interest loans to farme Organic Farming in Hong Kong 7. Current Trend of Organic Farming

1 Organic Farming and Transgenic Agriculture Agricultural Ecology Photosynthesis: Productivity: NCP = PG – PR –PH Where: NCP = Net Community Productivity PG = Gross Productivity PR = Respiration PH = Heterotrophic consumption History of Agricultural Development Food Gathering Domestication of Crops Green Revolution Organic Farming Transgenic Farming Conventional Agriculture (since Green Revolution) Also known as high input agriculture, capitalist agriculture & industrialized agriculture High inputs of energy subsidies including fertilizers, pesticides, fossil fuels, mechanization, irrigation & advanced technol ogy High outputs at the expense of environmental integrity Palaeotechnic Agriculture Neotechnic Agriculture Pest Control & Pest Fluctuations Problems of Conventional Farming Contamination of ground water & surface water by agrochemicals & sediments Hazards to human and animal health (e.g. residual effect of methamidophos in vegetables, Agent orange in Vietnam, cross-Atlantic DDT contamination) Pest resurgence and resistance Loss of genetic diversity in plants and animals Problems of Conventional Farming 5. Destruction of wildlife species 6. Reduced soil productivity due to: Erosion Salinization Loss of organic matter Compaction Acidification Problems of Conventional Farming Problems of Conventional Farming Organic Agriculture It is an alternative agriculture in which the use of chemical fertilizers and pesticides is replaced by Organic Matter (e.g. crop residues, green manures, farmyard manures) & biological control. The objectives are: to protect and preserve the agricultural and natural environments to preserve biodiversity to produce quality and safe foods so as to minimize health hazards to recycle and reuse organic wastes Limitations of Organic Agriculture 1. Organic wastes heterogeneous in property and are highly variable in nutritive value Limitations of Organic Agriculture 2. Mineralization of organic matter Time Lapse C : N ratio (nitrate depression period) Limitations of Organic Agriculture 3. Labour, delivery & storage Limitations of Organic Agriculture 4. Acceptance by farmers Farmers reluctant to give up the use of agrochemical Loss of agricultural export 5. Soil adjustment after prolonged years of conventional farming 6. Social & value adjustment 7. Productivity decline & sustainability 8. Carcinogenic due to elevated nitrogen level in farm products Organic Farming in Hong Kong 1. Physical Setting Organic Farming in Hong Kong 2. Daily Consumption of Fresh Food Organic Farming in Hong Kong 3. Productivity in 1999 Organic Farming in Hong Kong 4. Advantages & Disadvantages of Agricultural Development in Hong Kong Organic Farming in Hong Kong 5. Agricultural Development Principles Modernization, specialization, market-oriented and competitive Safe, quality farm produce with high add-on values Full use of market information Development of specialized agriculture, e.g. organic farming and protected farming Organic Farming in Hong Kong 6. What has AFCD done? Provide infrastructure Provide effective and efficient marketing channel Technological support Provide low-interest loans to farmers Search for new market Organic Farming in Hong Kong 7. Current Trend of Organic Farming

2 Infancy stage of development, fewer than 10 organizations/farms, accounting for less than 0.1% of the total agricultural productivity Sales at specific locations or directly to members The focus of some farms is on the promotion of environmental education, not production Hong Kong Organic Farm Association established in mid-1999. Organic Farming in Hong Kong 8. Prospect of Organic Farming in Hong Kong Growing understanding of organic farm produce Growing awareness of the need for health food and environmental preservation Strong economy and high education level of the people help promote organic farming Another option for consumers Plant Resources & Improvements (Past – Present – Future) Summary Keeping the world fed, healthy, happy Limits to plant productivity and global population Genetic options and resources Wild germplasm Breeding/selecting new genotypes Molecular biotechnology Plant Resources & Improvements Earth at its limits Accelerated expansion since industrialization Human population cannot grow indefinitely Expectation beyond subsistence living The environment cannot sustain conventional agriculture No more forests to slash and burn Accelerated topsoil erosion Salt accumulation Plant Resources & Improvements What do humans want from plants? Food Fuel Fiber Pharmaceuticals Industrial products Plant Resources & Improvements What are the threats? Population growth Insufficient land / water Loss of biodiversity Pollutants Politics/economics Plant Resources & Improvements What has been lost already? Animal and plant extinction began with human civilization First North Americans 20,000 years ago rapidly hunted large mammals to extinction First Hawaiians 2,000 years ago exterminated 39 species of birds But now greater threats to many more species Plant Resources & Improvements Future trends 10% of species to extinct in next 20 years Up to 50% to extinct in 50 years What can be saved? Temperate developed countries have already lost most of their native vegetation Forest clearing for pastures and agriculture Urbanization Most of undocumented diversity is in tropics Conservation strategies possible for all countries Plant Resources & Improvements Finding new genes Wild germplasm New uncultivated species New hybrids with distant relatives New genotypes of cultivated species Plant Resources & Improvements History of plant cultivation Hunter-gatherer Useful plants for food, fuel, fiber, shelter Minimal cultivation Ancient civilizations Aztecs, Mayans Chinese Egyptians, Greek, Romans Plant Resources & Improvements Genetic selection by early farmers (domestication) Cereals Seed collected from grasses with largest heads Repeated selection over many generations Major crops are wheat, barley and oat Possibly also selected for disease resistance

uman Population Plant Resources Improvements in the next 40 years (i.e 80 m net e per year) ed for food productie So clearly, biotechnology with its ability to improve yield, quality and nutritional value will help us in feeding today s and tomorrows population. Plant Implications 1. Food consumption in 2000 6 billion pe 3 billion in absolute poverty(<SUS 1/day) 0.071 land and simple ve lifestyle larger areas needed if marginal lands used Unsustainable systems degrade farmland Erotic 4. Many farmlands are already marginal Farming 1. 4 billion ha(11%total land on earth) Consuming 40% of terrestrial photosynthate 5. By 2050: 38 countries(4 billion people) below 0.07 ha Plant Resources Improvements Food Crisis In the next 2 generations, we will consume twice as much food as has been consumed in the entire previous history of humankind How and where to produce it? Only one planet There are no simple solutions ethics, consensus, population, education, distribution, conservation, invention, science, biotechnology Shift emphasis to global sustainability Plant Resources Improvements are for a sm sustanable agriculture cultivation sy hat sustain most of humanity Sustain farmed and natural environments for future generations Combine the best technologies for safe, efficient and sustainable production(e g. gene technologies) Plant Resources Improvements 235, 000 species of angiosperm 5,000 12 species provide 75% of food 1% increase in wheat yield is good Greater gains from breeding unimproved species opical(less research effort to date) ant Resources Improvements Why can t be done by normal breeding? Make hybrids between unrelated plants Introduce single genes into species om non-plants This is molecular biotechnology or genetic engineering Genetic Engineering Genetic Engineering is the transfer of specific useful segments of genetic materials between unrelated organisms. It is used to: crease plant and animal production medical treatment produce vaccines and other useful drugs enetic Engineering Transgenic Technology Recombinant DNA Technology

3 Plant Resources & Improvements Human Population Plant Resources & Improvements Projections (USDA) Doubling of population in the next 40 years (i.e. 80 m net increase per year) Need for food production increases of 250% However, resources are dwindling “ So clearly, biotechnology with its ability to improve yield, quality and nutritional value will help us in feeding today’s and tomorrow’s population.” Plant Resources & Improvements Implications 1. Food consumption in 2000 6 billion people 1.3 billion in absolute poverty (<$US 1/day) 840 million malnourished 2. Sustainable carrying capacity 0.07 ha per human, only with high quality land and simple vegetarian lifestyle larger areas needed if marginal lands used Plant Resources & Improvements Implications 3. Unsustainable systems degrade farmland Erosion Salinity 4. Many farmlands are already marginal Farming 1.4 billion ha (11% total land on earth) Consuming 40% of terrestrial photosynthate Consuming 30% of coastal shelf production 5. By 2050: 38 countries (4 billion people) below 0.07 ha Plant Resources & Improvements Food Crisis In the next 2 generations, we will consume twice as much food as has been consumed in the entire previous history of humankind. How and where to produce it? Plant Resources & Improvements Problems & Solutions Only one planet “ The problems are complex” “ food, poverty, pollution, climate change, biodiversity, inequality of opportunity” “ space-ship earth” “ There are no simple solutions” “ ethics, consensus, population, education, distribution, conservation, invention, science, biotechnology” “ Shift emphasis to global sustainability” Plant Resources & Improvements Agriculture for a Small Planet Sustainable agriculture to: Enhance ecological footprint of cultivation systems that sustain most of humanity Enhance quality of human life through reliable production of safe and affordable food Sustain farmed and natural environments for future generations Combine the best technologies for safe, efficient and sustainable production (e.g. gene technologies) Plant Resources & Improvements How many species do we need? 235,000 species of angiosperm 5,000 species cultivated 103 species provide 90% of food 12 species provide 75% of food Plant Resources & Improvements Gains from plant breeding 1% increase in wheat yield is “good” yield plateau. Greater gains from breeding unimproved species perennials (slow to breed) tropicals (less research effort to date) Plant Resources & Improvements Why can’t be done by normal breeding? Make hybrids between unrelated plants Introduce single genes into species from other plants from non-plants Delete or down-regulate existing genes This is molecular biotechnology or genetic engineering Genetic Engineering Genetic Engineering is the transfer of specific & useful segments of genetic materials between unrelated organisms. It is used to: increase plant and animal production diagnose disease improve medical treatment produce vaccines and other useful drugs Genetic Engineering It is synonymous to: Molecular Biotechnology Genetic Transformation Transgenic Technology Recombinant DNA Technology &

Genetic Modification Technology GM technology was first developed in the 1970s. One of the most prominent developments, apart from the medical applications, has been the dev elopment of ovel transgenic crop plant varieties including soybean, cotton, tobacco, potato and maize Genetic Need for GM technology in Agncul By 2030, the world population will increase from todays 6 billion to 8 billion. Today there ar 800 million people(18% of the population in the developing world) who do not have access to sufficient food to meet their needs due to Need for GM technology in Agriculture Lack of food ed for GM technology in Agriculture Global climate change and alterations in the use of land will exacerbate the problem of regional production and demands for food. Increasing the amount of land to cultivate crops without having a serious impact on the environment and natural resources is a limited option(c f. marginal lands) Need for GM technology in Agrculture developing countries, about 650 million ofthe poorest people live in rural areas where the local production of food is their main activity he three most important elements in rural community are increase in crop yield income generation and more effective distr bution of food stocks. GM Need for GM technology in Agriculture High input agriculture involves large-scale use of pesticides and fertilizers that are expensive and can potentially affect human health or damage the ecosystem What is Transgenic Agriculture Transgenic agriculture aims selectively to alter, add or remove a characteristic of choice in a plant It brings in not only desirable characteristics fiom other varieties of the plant, but also adds characteristics from other unrelated species. Thereafter the transgenic plant becomes a parent for use in traditional breeding Properties of GM Foods Correct micro-nutrient deficiencies reduces expenses and resources required to implement supplementation programs pest, herbicide, and viral, bacterial and fungal disease of GM Foods on of plant architecture(e.g. height) and development (e.g. early or late flowering), tolerance to stresses (e.g. salinity and drought, production of ndustrial chemicals, use of biomass for fuel; flexibility in crop management, enhanced yields, easier harvesting and higher proportions of the crop for trading Stable and increased length of storage due to delayed ripening or softening Pest Transgenic crops(e.g. cotton, papaya) containing insect-resistance ge om Bacillus thuringiensis reduces significantly the amount of insecticide application In the USA, there was a reduction of 2 million hectare treatments of about I million kilograms of chemical insecticides in 1999 compared to 1998(US National st resistance gene transfer is, however, pest-, region- and cultivar-specific Resistance of pest to the transgenic crop can still happe Examples of GM Technology Crop yield can be increased by modifying growth patten of the plant parts Typical example is the high-yielding semi-dwarf wheat with the added "Japanese NORIN 10 genes Two benefits of these dwarfing genes o more fertilizer without collapsing crease yield directly by reducing cell elongation in the plant vegetative plant parts, thereby allowing the plant to invest more in the reproductive plant parts These genes can be used to transform other crop species(Peng et al. 1999) erance to Biotic Abiotic stresses Most of the examples are concemed with viruses, bacteria selected soil limiting factors Tolerance to Biotic Abiotic Stresses These sources of resistance need to be more stable than the traditional intra-species sources Examples of GM Technology Marginal lands suffer from different problems including salinity and alkalinity ples of GM Technology itamin A deficiency causes half a million children to become partially or totally blind each year( Conway 999). Researchers introduced 3 genes into rice(2 from daffodils and 1 from a bacterium called Erw exhibit tamin a and the seed is yellow in color hence know as golden rice (Ye et al. 2000). See also the February issue of TImE magazine Examples of GM Technology Examples of GM Technology en. About 400 million child-bearing age suffer and give birth to underweight hildren and to mortality at childbirth. Anemia contributes to over 20% of matemal deaths (after giving birth) in Asia and Africa(Conway 1999). Transgenic facilitates iron availability in the human diet( Goto et al. 1999) educed Environmenta GM technology is a useful tool for the introduction of root disease resistance for conditions of reduced tillage. This will help reduce soil erosion pharmaceuticals vaccines fiom T M technology has the potential of pi 1995)

4 Genetic Modification Technology Genetic Engineering GM technology was first developed in the 1970s. One of the most prominent developments, apart from the medical applications, has been the development of novel transgenic crop plant varieties including soybean, cotton, tobacco, potato and maize Genetic Engineering Need for GM technology in Agriculture By 2030, the world population will increase from today’s 6 billion to 8 billion. Today there are some 800 million people (18% of the population in the developing world) who do not have access to sufficient food to meet their needs due to poverty and unemployment. Need for GM technology in Agriculture Each year nearly 12 million children under 5 in developing countries die because of Malnutrition Lack of food Deficiencies in micro-nutrients (vitamin A, iodine and iron) Need for GM technology in Agriculture Global climate change and alterations in the use of land will exacerbate the problem of regional production and demands for food. Increasing the amount of land to cultivate crops without having a serious impact on the environment and natural resources is a limited option (c.f. marginal lands) Need for GM technology in Agriculture In developing countries, about 650 million of the poorest people live in rural areas where the local production of food is their main activity The three most important elements in rural community are: increase in crop yield, income generation and more effective distri bution of food stocks.GM technology are relevant to these elements of food security Need for GM technology in Agriculture High input agriculture involves large-scale use of pesticides and fertilizers that are expensive and can potentially affect human health or damage the ecosystem What is Transgenic Agriculture? Transgenic agriculture aims selectively to alter, add or remove a characteristic of choice in a plant, bearing in mind regional needs and opportunities It brings in not only desirable characteristics from other varieties of the plant, but also adds characteristics from other unrelated species. Thereafter the transgenic plant becomes a parent for use in traditional breeding Properties of GM Foods More nutritious – improves human health addressing malnutrition and under-nutrition Correct micro-nutrient deficiencies – reduces expenses and resources required to implement supplementation programs Resistant to pest, herbicide, and viral, bacterial and fungal disease Properties of GM Foods Modification of plant architecture (e.g. height) and development (e.g. early or late flowering); tolerance to stresses (e.g. salinity and drought); production of industrial chemicals; use of biomass for fuel; flexibility in crop management, enhanced yields, easier harvesting and higher proportions of the crop for trading etc Stable and increased length of storage due to delayed ripening or softening Examples of GM Technology Pest resistance Transgenic crops (e.g. cotton, papaya) containing insect-resistance genes from Bacillus thuringiensis reduces significantly the amount of insecticide application. In the USA, there was a reduction of 2 million hectare-treatments of about 1 million kilograms of chemical insecticides in 1999 compared to 1998 (US National Research Council 2000) Pest resistance gene transfer is, however, pest- , region- and cultivar-specific. Resistance of pest to the transgenic crop can still happen Examples of GM Technology Improve yield Crop yield can be increased by modifying growth pattern of the plant parts Typical example is the high-yielding semi-dwarf wheat with the added “Japanese NORIN 10 genes” Two benefits of these dwarfing genes Shorter, stronger plant that could respond to more fertilizer without collapsing Increase yield directly by reducing cell elongation in the plant vegetative plant parts, thereby allowing the plant to invest more in the reproductive plant parts that are eaten These genes can be used to transform other crop species (Peng et al. 1999) Examples of GM Technology Tolerance to Biotic & Abiotic Stresses Most of the examples are concerned with viruses, bacteria & selected soil limiting factors Examples of GM Technology Tolerance to Biotic & Abiotic Stresses These sources of resistance need to be more stable than the traditional intra-species sources Examples of GM Technology Use of Marginalized Lands Marginal lands suffer from different problems including salinity and alkalinity Examples of GM Technology Nutritional Benefits Vitamin A deficiency causes half a million children to become partially or totally blind each year (Conway et. Al. 1999). Researchers introduced 3 genes into rice (2 from daffodils and 1 from a bacterium called Erwinia uredovora). The transgenic rice exhibits an increased production of beta-carotene as a precursor to vitamin A and the seed is yellow in color hence know as golden rice (Ye et al. 2000). See also the February 12, 2001 issue of TIME magazine Examples of GM Technology Examples of GM Technology Nutritional Benefits Iron deficiency causes anemia in pregnant women and young children. About 400 million women of child-bearing age suffer and give birth to underweight children and to mortality at childbirth. Anemia contributes to over 20% of maternal deaths (after giving birth) in Asia and Africa (Conway 1999). Transgenic rice with elevated iron levels has been produced using genes involved in the production of an iron-binding protein and in the production of an enzyme that facilitates iron availability in the human diet (Goto et al. 1999) Examples of GM Technology Reduced Environmental Impacts GM technology is a useful tool for the introduction of root disease resistance for conditions of reduced tillage. This will help reduce soil erosion Examples of GM Technology Pharmaceuticals & Vaccines from Transgenic Plants GM technology has the potential of producing vaccines and pharmaceuticals in plants. This will allow easier access, cheaper production, and an alternative way to generate income. For instance, vaccines against infectious diseases of the gastro-intestinal tract have been produced in potatoes and bananas (Thanavala et al. 1995)