Relationships of organisms in agricultural systems. Traditional extensive ways to increase the productivity of agroecosystems The calculation is carried out according to the formula

Earlier we considered (chapter 4.1) that every minute 2 calories of solar energy enter 1 cm 2 of the upper layer of the earth's atmosphere - the so-called solar Constant, or constant. The use of light energy by plants is relatively small. Only a small part of the solar spectrum, the so-called PAR (photosynthetically active radiation with a wavelength of 380-710 nm, 21-46% of solar radiation) is used in the process of photosynthesis. In the temperate climate zone on agricultural lands, the efficiency of photosynthesis does not exceed 1.5-2%, and most often it is 0.5%.

In the developing world agriculture, several types of ecosystems differ in the amount of energy supplied and used by man and its source (MS Sokolov et al. 1994).

1. natural ecosystems. The only source of energy is solar (ocean, mountain forests). These ecosystems are the main pillar of life on Earth (energy inflow is on average 0.2 kcal/cm 2 year).

2. Highly productive natural ecosystems. In addition to solar, other natural energy sources are used ( coal, peat, etc.). These include estuaries, large river deltas, tropical rainforests and other highly productive natural ecosystems. Here, organic matter is synthesized in excess, which is used or accumulated (energy inflow, on average, 2 kcal/cm 2 year).

3. Agroecosystems close to natural ecosystems. Along with solar energy, additional sources created by man are used. These include agricultural and water management systems that produce food and raw materials. Additional energy sources - fossil fuels, the energy of the metabolism of people and animals (energy inflow on average 2 kcal / cm 2 year).

4. Agroecosystems of intensive type. Associated with the consumption of large quantities of petroleum products and agrochemicals. They are more productive in comparison with the previous ecosystems, differing in high energy intensity (energy inflow on average 20 kcal/cm2 year).

5. Industrial(urban) ecosystems. Get ready-made energy (gas, coal, electricity). These include cities, suburbs and industrial zones. They are both generators of life improvement and sources of environmental pollution (since direct solar energy is not used):

These systems are biologically related to the previous ones. Industrial ecosystems are very energy intensive (energy inflow is on average 200 kcal / cm 2 year).

The main distinguishing features of the functioning of natural ecosystems and agroecosystems.

1. Different direction of selection. For natural ecosystems, natural selection is characteristic, which leads to their fundamental property - sustainability, sweeping aside unstable, non-viable forms of organisms in their communities.

Agroecosystems are created and maintained by man. The main thing here is artificial selection, which is aimed at increasing crop yields. Often, the yield of a variety is not related to its resistance to environmental factors, harmful organisms.

2. Diversity of ecological composition of phytocenosis ensures the stability of the product composition in the natural ecosystem during fluctuations in weather conditions in different years. The suppression of some plant species leads to an increase in the productivity of others. As a result, the phytocenosis and the ecosystem as a whole retain the ability to create a certain level of production in different years.

The agrocenosis of field crops is a monodominant community, and often a single-varietal one. On all plants of agrocenosis, the effect of unfavorable factors is reflected in the same way. The inhibition of the growth and development of the main crop cannot be compensated for by the increased growth of other plant species. And as a result, the stability of agrocenosis productivity is lower than in natural ecosystems.

3. The presence of species diversity composition of plants with different phenological rhythms allows the phytocenosis as an integral system to carry out the production process continuously throughout the entire growing season, fully and economically consuming the resources of heat, moisture and nutrients.

The growing season of cultivated plants in agrocenoses is shorter than the growing season. Unlike natural phytocenoses, where species of different biological rhythms reach their maximum biomass at different times of the growing season, in agrocenosis, plant growth is simultaneous and the sequence of developmental stages is usually synchronized. Hence, the time of interaction of the phytocomponent with other components (for example, soil) in the agrocenosis is much shorter, which naturally affects the intensity of metabolic processes in the whole system.

The diversity of development of plants in a natural (natural) ecosystem and the simultaneity of their development in an agrocenosis lead to a different rhythm of the production process. The rhythm of the production process, for example, in natural grassland ecosystems, sets the rhythm for destruction processes or determines the rate of mineralization of plant residues and the time of its maximum and minimum intensity. The rhythm of destruction processes in agrocenoses to a much lesser extent depends on the rhythm of the production process, due to the fact that terrestrial plant residues enter the soil and into the soil for a short period of time, as a rule, at the end of summer and early autumn, and their mineralization is carried out mainly way for next year.

4. A significant difference between natural ecosystems and agroecosystems is degree of compensation of circulation substances within an ecosystem. The cycles of substances (chemical elements) in natural ecosystems are carried out in closed cycles or are close to compensation: the arrival of a substance in a cycle for a certain period is on average equal to the exit of a substance from a cycle, and hence, within a cycle, the arrival of a substance in each block is approximately equal to the exit of a substance from it (Fig. .18.5).

Rice. 18.5. Nutrient cycling in

natural ecosystem (according to A. Tarabrin, 1981)

Anthropogenic impacts violate the closed nature of the circulation of substances in ecosystems (Fig. 18.6).

Rice. 18.6. Nutrient cycling in

agroecosystem (according to A. Tarabrin, 1981)

Part of the substance in agrocenoses is irretrievably withdrawn from the ecosystem. At high rates of fertilizer application for individual elements, a phenomenon can be observed when the input of nutrients into plants from the soil is less than the input of nutrients into the soil from decaying plant residues and fertilizers. With economically useful products in agrocenoses, 50-60% of organic matter is alienated from its amount accumulated in products.

5. Natural ecosystems are systems, so to speak, autoregulatory, and agrocenoses - controlled by man. To achieve his goal, a person in an agrocenosis changes or controls to a large extent the influence of natural factors, gives advantages in growth and development, mainly to the components that produce food. The main task in this regard is to find conditions for increasing productivity while minimizing energy and material costs, increasing soil fertility. The solution of this problem consists in the most complete use of natural resources by agrophytocenoses and the creation of compensated cycles of chemical elements in agrocenoses. The completeness of the use of resources is determined by the genetic characteristics of the variety, the duration of the growing season, the heterogeneity of the components in joint crops, the sowing layering, etc.

Therefore, concludes M.S. Sokolov et al. (1994), the strictest control of the state of agroecosystems, which requires significant energy costs, can only be carried out in a closed space. This category includes semi-open systems with very limited channels of communication with the external environment (greenhouses, livestock complexes), where temperature, radiation, and the circulation of mineral and organic substances are regulated and largely controlled. This - managed agroecosystems. All other agroecosystems - open. On the human side, the effectiveness of control is higher, the simpler they are.

IN semi-open And open systems, human efforts are reduced to providing optimal conditions for the growth of organisms and strict biological control over their composition. Based on this, the following practical problems arise:

First, if possible, the complete elimination of unwanted species;

Secondly, the selection of genotypes with high potential productivity.

In general, the circulation of substances connects the various species that inhabit a ^-ecosystems (Fig. 18.7).

Rice. 18.7. Energy flow in pasture agroecosystem

(according to N.A. Urazaev et al., 1996):

Note: white arrows show the migration of substances from producers to primary and secondary consumers, black arrows show the mineralization of organic remains of plants and animals

In the biosphere, many circulating substances of biogenic origin are also energy carriers. Plants in the process of photosynthesis convert the radiant energy of the Sun into the energy of chemical bonds of organic substances and accumulate it in the form of carbohydrates - potential energy carriers. This energy is included in the nutrition cycle from plants through phytophages to consumers of higher orders. The amount of bound energy as it moves along the trophic chain is constantly decreasing, since a significant part of it is spent to maintain the vital functions of consumers. Energy cycling maintains a variety of life forms in an ecosystem and keeps the system stable.

According to M.S. Sokolov et al. (1994) the consumption of photosynthetic energy of plants in the agroecosystem on the example of grasslands in central Russia is as follows:

About 1/6 of the energy used by plants is spent on respiration;

About 1/4 of the energy enters the body of herbivorous animals. At the same time, 50% of it is in the excrement and corpses of animals;

In general, together with dead plants and phytophages, about 3/4 of the initially absorbed energy is contained in dead organic matter and a little more than 1/4 is eliminated from the ecosystem during respiration in the form of heat.

Once again, we note that the energy flow in the food chain of the agroeco-system obeys the law of energy conversion in ecosystems, the so-called Lindemann's law or law 10%. According to Lindemann's law, only part of the energy received at a certain trophic level of agrocenosis (biocenosis) is transferred to organisms located at higher trophic levels (Fig. 18.8).

Rice. 18.8. Loss of energy in the food chain (according to T. Miller, 1994)

The transfer of energy from one level to another occurs with a very low efficiency. This explains the limited number of links in the food chain, regardless of one or another agrocenosis.

The amount of energy produced in a particular natural ecosystem is a fairly stable value. Thanks to the ability of the ecosystem to produce biomass, a person receives the food he needs and many technical resources. As already noted, the problem of providing numerically growing humanity with food is mainly the problem of increasing the productivity of agroecosystems (agriculture), fig. 18.9.

Fig.18.9. Agroecosystem Productivity Flowchart

Human impact on ecological systems, associated with their destruction or pollution, directly leads to an interruption in the flow of energy and matter, and hence to a decrease in productivity. Therefore, the first task facing humanity is to prevent a decrease in the productivity of agroecosystems, and after its solution, the second most important task can be solved - increasing productivity.

In the 90s. 20th century the annual primary productivity of cultivated lands on the planet was 8.7 billion tons, and the energy reserve was 14.7 × 1017 kJ.

One of the main trends in the development of human society is the continuous increase in the level of production, and ultimately, labor productivity. This allowed man throughout his history to gradually increase the "capacity of the environment." However, if all the power of the human mind is manifested in this, then in filling the increasing capacity of the environment, Homo sapiens behaves like any other biological species. The species fills this capacity to the level at which biological factors again turn out to be regulators. Thus, according to UN estimates for 1985, almost 500 million people, or approximately 10% of the world's population, were threatened with starvation; in 1995, about 25% of people suffered from intermittent or permanent hunger. Hunger is the main evolutionary factor of mankind.

A great contribution to understanding the danger of hunger was made by the work of the international non-governmental organization, the so-called Club of Rome, created in the 60s of the 20th century on the initiative of Aurelio Peccei. The Club of Rome developed a number of successively refined models, the study of which made it possible to consider some scenarios for the possible development of the future of the Earth and the fate of mankind on it. The results of these works alarmed the whole world. It became clear that the path of development of civilization, focused on a constant increase in production and consumption, leads to a dead end, because it is not consistent with the limited resources on the planet and the ability of the biosphere to process and neutralize industrial waste. This threat to the Earth's biosphere due to the violation of the stability of ecosystems is called the ecological crisis. Since then and in scientific literature, and in the general press, in the media, various problems associated with the threat of a planetary, global environmental crisis are constantly discussed.

Although, after the publication of the works of the Club of Rome, many optimists came out with "refutations" and "revelations", not to mention the scientific criticism of the predictions of the first global models (and indeed not quite perfect, like any model of a complex system), in 20 years it will be possible to It was stated that the real level of the population of the Earth, the lag in food production from the growth in demand for it, the level of pollution of the natural environment, the growth of morbidity, and many other indicators turned out to be close to what these models predicted. And since it was ecology that turned out to be a science that has a methodology and experience in analyzing complex natural systems, including the influence of anthropogenic factors, the crisis predicted by global models began to be called "environmental".

Although the land area is half that of the oceans, the annual primary carbon production of its ecosystems is more than twice that of the world's oceans (52.8 billion tons and 24.8 billion tons, respectively). In terms of relative productivity, terrestrial ecosystems are 7 times higher than the productivity of ocean ecosystems. From this, in particular, it follows that the hopes that the full development of the biological resources of the ocean will allow mankind to solve the food problem are not very well founded. Apparently, the opportunities in this area are small - even now the level of exploitation of many populations of fish, cetaceans, pinnipeds is close to critical, for many commercial invertebrates - mollusks, crustaceans and others, due to a significant drop in their numbers in natural populations, it has become economically viable. breeding them on specialized marine farms, development of mariculture. The situation is approximately the same with edible algae, such as kelp (seaweed) and fucus, as well as algae used in industry to obtain agar-agar and many other valuable substances (Rozanov, 2001).

Developing countries and countries with economies in transition strive primarily for food independence. They want to produce food themselves, and not depend on other countries, because food is perhaps the most formidable political weapon and pressure weapon in the modern world so far (for example, Russia, which imports up to 40 percent of food). Doubling food production and removing dependence requires new technologies, knowledge about the genes that determine yield and other important consumer properties of staple crops. Serious work must also be done to adapt these crops to the specific environmental conditions of these countries. In other words, we have to rely on transgenic or genetically modified organisms (GMOs), the cultivation of which is much cheaper, pollutes the environment less and does not require the attraction of new territories.

The world was as imperfect as it was. The first World Food Conference took place over 30 years ago, in 1974. It estimated that there were 840 million victims of chronic malnutrition in the world. Against the opposition of many, she proclaimed for the first time "the inalienable right of man to be free from hunger."

The results of the implementation of this right were summed up at the World Food Forum in Rome 22 years later. It recorded the collapse of the hopes of the world community to curb hunger, as the situation on the front of the fight against this social evil remained unchanged. In this regard, the Rome meeting outlined more modest goals - to reduce the number of hungry people by 2015 to at least 400 million people.

Since then, this problem has become even worse. As noted in the report of the UN Secretary General Kofi A. Anan "Prevention of wars and disasters", today the subsistence level is over 1.5 billion people. - less than a dollar a day, 830 million suffer from hunger. For the period 1960-2000. the production of all types of agricultural products increased from 3.8 billion to 7.4 billion tons. However, the amount of food produced on average per person remained unchanged (1.23 tons / person). Almost half of the world's population is currently undernourished, and a quarter are starving. In the countries of Western Europe, North America and Japan, where the predominantly chemical-technogenic intensification of agriculture is most widespread and less than 20% of the world's population lives, 50 times more resources are spent per person compared to developing countries and are emitted into environment, about 80% of all hazardous industrial waste (WHO commission report), which puts all of humanity on the brink of an environmental catastrophe.

Agriculture is a unique human activity that can be considered both an art and a science. And the main goal of this activity has always been the growth of production, which has now reached 5 billion tons per year. To feed the growing population of the Earth, by 2025 this figure will have to increase by at least 50%. But agricultural producers can achieve this result only if they have access to the most advanced methods of growing the highest-yielding crop varieties anywhere in the world. To do this, they also need to master all the latest achievements in agricultural biotechnology, in particular, the production and cultivation of genetically modified organisms.

From cannibalism to GMOs

In order to feed mankind, the intensification of agriculture is required. However, such intensification affects the environment and causes certain social problems. However, to judge the harm or benefit modern technologies(including crop production) is possible only taking into account the rapid growth of the world's population. It is known that the population of Asia has more than doubled in 40 years (from 1.6 to 3.5 billion people). What would be an additional 2 billion people if society did not intensively use the achievements of the "green revolution"? While the mechanization of agriculture has reduced the number of farms and in this sense contributed to the growth of unemployment, the benefits of the "Green Revolution", associated with a multiple increase in food production and a steady decline in the price of bread in almost all countries of the world, are much more significant for humanity.

Currently, there is a slowdown in the growth of yields, a reduction in arable land from 0.24 hectares in 1950 to 0.12 hectares per person, a shortage and pollution of water resources, and climate change are clearly beginning to be felt. Under these conditions, the search for new methods of agricultural intensification, in particular, the widespread introduction of genetically modified organisms into practice, is so far the only alternative to traditional farming.

Genetically modified organisms (GMOs) are organisms whose genetic apparatus has been altered to improve their properties. Otherwise, genetic engineering is the creation of new forms of organisms by "transplanting" genes from one biological system to another. In crop production, transgenic plants are obtained, and in animal husbandry, the so-called "gentaurs". In animal husbandry, so far, progress has been more than modest. As far as crop production is concerned, here the successes, one might say, are enormous. Hundreds of varieties of transgenic plants are already being cultivated, which have features that are not characteristic of them due to the functioning of foreign genes in them. These are various varieties of potatoes resistant to the Colorado potato beetle, corn - resistant to certain herbicides, strawberries - more productive, and much more.

Opponents of GMOs call them "Frankenstein food", "the new slow-acting Chernobyl", forgetting that they eat "Frankenstein food" every day, in the form of bread, which is a product of natural genetic engineering. And supporters modestly remind that in a quarter of a century without GMOs it will simply be impossible to provide the continuously growing humanity with food and medicine. Moreover, medicines, vitamins, antibiotics - they are all in more, over the past more than 60 years, are products of biotechnology, the results of genetic engineering developments. Does that mean they should be banned too? It is not clear how medicines differ from plants in this respect. Both those and others serve to prolong human life, and, most importantly, not only the number of years lived, but also their quality. At the same time, it is obvious that genetically modified agricultural products, before getting into the fields, go through a lot of the most severe, most thorough tests.

It can be expected that GMOs will play a special role in the new green revolution. The flow of information about GMOs suggests that GMOs can help solve a variety of problems, from providing food for a growing world population to preserving biodiversity on the planet and reduce the pressure of pesticides on the environment. One of the arguments for the use of GMOs is that it is "traditional" agricultural production that is now the main source of environmental pollution.

The solution to this problem can be obtained through the active use of the achievements of biotechnology, especially in the cultivation of genetically modified varieties of cereals that do not require significant use of pesticides. GMO farmers use fewer pesticides than "traditional" farmers. As you know, about 85 million people are added to the planet every year, and the increase in food production is only enough for half.

The transition to transgenic plants (GMOs) is a change from the "one pest - one chemical" model to the "one pest - one gene" paradigm.

Pests quickly adapt to new conditions and acquire resistance to new generations of insecticides. For example, the Colorado potato beetle acquires sufficient resistance in 2 generations.

Good example the impact of modern technology on human life - the creation of "golden" rice. It took 10 years and $100 million to develop golden rice. Now scientists from the International research institute rice located in Philadelphia are satisfied, and given the fact that all this time 900 million people living below the poverty line (mainly in Asia, where rice is the main food) will continue to suffer from hunger and numerous diseases, the staff of the institute are ready to transfer new rice free of charge to any state that wishes to engage in its cultivation. In addition, with one modifier, the so-called "iron" rice, which, thanks to its high iron content, is able to help two billion people suffering from anemia.

Food production per capita in 1998 exceeded the figures of 1961 by a quarter and turned out to be 40% cheaper. However, the problems of food production and the fight against hunger cannot be considered solved.

The problem of hunger and genetic technologies - is there an alternative for humanity?

"Green revolution"

The forerunner of the biotechnological revolution, based on gene-chromosome manipulation in plants, was the green revolution. It ended 30 years ago and for the first time gave impressive results: the productivity of cereals and legumes almost doubled.

The expression "green revolution" was used for the first time in 1968 by the director of the US Agency for international development V. Goud, trying to characterize the breakthrough achieved in food production on the planet due to the wide distribution of new highly productive and low-growing varieties of wheat and rice in Asian countries suffering from food shortages. Many journalists then sought to describe the "green revolution" as a massive transfer of advanced technologies developed in the most developed and consistently high-yield agricultural systems to the fields of farmers in the Third World. It marked the beginning of a new era in the development of agriculture on the planet, an era in which agricultural science was able to offer a number of improved technologies in accordance with the specific conditions that characterize farms in developing countries. This required large doses. mineral fertilizers and ameliorants, the use of a full range of pesticides and mechanization, the result was an exponential increase in the cost of exhaustible resources for each additional unit of crop, including a food calorie.

This was achieved by transferring target genes into the developed varieties in order to increase the strength of the stem by shortening it, to achieve neutrality to the photoperiod to expand the cultivation area and efficient utilization of minerals, especially nitrogen fertilizers. The transfer of selected genes, albeit within species, using traditional methods of hybridization, can be considered as a prototype of transgenesis.

The ideologist of the Green Revolution, Norman Borlaug, who received the Nobel Prize for its results in 1970, warned that increasing crop yields by traditional methods could provide food for 6-7 billion people. Maintaining demographic growth requires new technologies in the creation of highly productive plant varieties, animal breeds and strains of microorganisms. In an address to a genetic engineering forum held in March 2000 in Bangkok, Thailand, Borlaug stated that "either we have developed or we are in the final stages of developing technologies that will feed a population of more than 10 billion people."

The work begun by N. Borlaug and his colleagues in Mexico in 1944 demonstrated the exceptionally high efficiency of purposeful breeding in creating high-yielding varieties of agricultural plants. By the end of the 60s, the wide distribution of new varieties of wheat and rice allowed many countries of the world (Mexico, India, Pakistan, Turkey, Bangladesh, the Philippines, etc.) to increase the yield of these important crops by 2-3 or more times. However, the negative aspects of the Green Revolution were soon revealed, caused by the fact that it was mainly technological, and not biological. The replacement of genetically diverse local varieties with new high-yielding varieties and hybrids with a high degree of nuclear and cytoplasmic homogeneity significantly increased the biological vulnerability of agrocenoses, which was an inevitable result of the impoverishment of the species composition and genetic diversity of agroecosystems. The mass spread of harmful species, as a rule, was also facilitated by high doses of nitrogen fertilizers, irrigation, thickening of crops, the transition to monoculture, minimum and zero tillage systems, etc.

A comparison of the "green revolution" with the ongoing biotechnological revolution was carried out in order to show the socially significant component that underlies all gene-chromosomal manipulations. We are talking about how to provide the population of the Earth with food, create more efficient medicine, and optimize environmental conditions.

Modern cultivars allow for higher average yields due to more efficient ways of growing and caring for plants, due to their greater resistance to insect pests and major diseases. However, they only allow to get a noticeably larger yield when they are provided with proper care, implementation of agricultural practices in accordance with the calendar and the stage of plant development (fertilization, watering, soil moisture control and pest control). All these procedures remain absolutely necessary for last years transgenic varieties.

Moreover, radical changes in plant care and crop culture become essential if farmers start growing modern high-yielding varieties. For example, fertilization and regular watering, so necessary for obtaining high yields, at the same time create favorable conditions for the development of weeds, insect pests and a number of common plant diseases. With the introduction of new varieties, additional measures are needed to combat weeds, pests and diseases, the dependence of the productivity of agroecosystems on technogenic factors increases, processes accelerate and the scale of environmental pollution and destruction increases.

Despite the significant successes of the Green Revolution, the battle for food security for hundreds of millions of people in the poorest countries is far from over.

The exhaustion of the possibilities of the green revolution

The rapid growth of the population of the "Third World" as a whole, even more dramatic changes in demographic distributions in certain regions, ineffective programs to combat hunger and poverty in many countries "ate" most of the achievements in the field of food production. For example, in the countries of Southeast Asia, food production is still clearly not enough to overcome hunger and poverty, while China has made a tremendous leap. China's success in the fight against hunger and poverty (in particular, in comparison with India) is attributed to the fact that the Chinese leadership allocates huge funds for education, health care and science. With a healthier and better educated rural population, the Chinese economy has been able to grow twice as fast as India's over the past 20 years. Today average income per capita in China is almost twice that of India.

In general, the world community has managed to achieve progress in the fight against hunger even without genetically modified organisms. From 1950 to 1990, the production of cereals, as well as beef and mutton, increased almost three times (respectively from 631 to 1780 million tons and from 24 to 62 million tons), the production of fish products - almost 4.5 times (from 19 to 85 million T). Despite the more than doubling of the world's inhabitants during the same period, this allowed for a 20% increase in world food production per capita from 1961 to 1994 and a slight increase in the level of nutrition in developing countries.

However, the "Green Revolution" did not bring much change in the quantity and quality of nutrition in poor countries. Per capita consumption of cereals in direct and indirect form in the modern world ranges from 200 to 900 kg per year. Unlike the populations of developed countries, who consume their grain crops mainly in the form of meat, milk and eggs, the peoples of the Third World are content with a meager diet. In 1995, the average American ate 45 kg of beef, 31 kg of pork, 46 kg poultry and 288 liters of milk, and the annual diet of the average Indian included only 1 kg of beef (it should be noted that Hindus do not eat it), 0.4 kg of pork, 1 kg of poultry and 34 liters of milk.

At present, the Homo sapiens population of 6 billion people is the largest in all highly productive biotopes of the Earth.

Man uses about 7% of the 180 billion tons of photosynthesis products - the organic matter of the biosphere. If it took 80 years (for the period from 1850 to 1930) to double the number from 1 to 2 billion people, then at present it is 40 years. 20% of the population of "prosperous" countries account for 77% of the pollutants emitted into the biosphere.

It so happened that rational decisions were made by experts convinced that they were working in the name of reason and progress, and did not take into account the protests of the local population, considering them to be unfounded superstitions. This approach often leads to detrimental results that balance and even outweigh their beneficial results. Thus, the "Green Revolution", carried out in order to stimulate the development of third world countries, greatly increased their food resources and largely avoided crop failures. However, it is now clear that the initial idea, which was to select and propagate over very large areas a single breeding variety (quantitatively the most productive) turned out to be dangerous in its consequences. The lack of genetic diversity made it possible for the pathogenic factor, which this variety could not resist, to destroy the entire seasonal crop. It has become clear that some genetic diversity needs to be restored in order to optimize rather than trying to maximize yields more and more.

Intensive technology leads to soil degradation; irrigation, which does not take into account the characteristics of the soil, causes their erosion; the accumulation of pesticides destroys the balance and regulatory systems between species - destroying beneficial species along with harmful ones, sometimes stimulating the uncontrolled reproduction of a harmful species that has become resistant to pesticides; toxic substances contained in pesticides pass into food and worsen the health of consumers, etc.

Deficiency of fertile soils

In recent years, the problem of deficiency of fertile soils has become aggravated. If we compare world crop production in 1950 and 1998, then with the yield in 1950, to ensure such growth, it would have been necessary to sow not 600 million hectares, as now, but three times more. Meanwhile, an additional 1.2 billion hectares is, in fact, nowhere to get, especially in Asian countries, where the population density is extremely high. In addition, the lands involved in agricultural turnover are becoming more depleted and environmentally vulnerable every year.

Of the exporting countries, only the United States and Russia can expand grain crops. Neither Australia, nor Argentina, nor Canada, nor the EU countries have reserves - everything is plowed up there. In the USA, as well as in Russia, there are also lands that have been taken out of circulation, so that by using them, Americans can get another 100 million tons per year. This is an impressive export reserve, because the United States more than meets its needs in the current areas. But what does the US supply to the global market? Mostly corn and soybeans - they almost do not export wheat. Russia, using modern technologies, can potentially export more than 100 million tons.

The impact of soil erosion, deforestation and meadows on biodiversity is becoming more and more noticeable; the dependence of the productivity of agroecosystems on technogenic factors is increasing. With the failures of the countries of the "third world" and international organizations contributing to their development, it is not easy to accept in an attempt to achieve an adequate return on investment in agriculture, since throughout history no nation has been able to increase prosperity and achieve economic development without first dramatically increasing food production, the main source of which has always been agriculture. Therefore, according to many experts, in the XXI century. the second "green revolution" is coming. Without this, it will not be possible to ensure human existence for everyone who comes into this world.

Clearly, significant efforts, both traditional breeding and modern agricultural DNA technology, will be required to achieve the genetic improvement of food plants at a pace that would satisfy the needs of 8.3 billion people by 2025. For further growth in agricultural production, a lot of fertilizers will be needed, especially in the countries of Equatorial Africa, where fertilizers are still applied no more than 10 kg per hectare (tens of times less than in developed countries and even in developing Asian countries).

According to experts who study nitrogen cycles in nature, at least 40% of the 6 billion people currently inhabiting the planet are alive only thanks to the discovery of ammonia synthesis. Adding that much nitrogen to the soil with organic fertilizers would be completely unthinkable, even if we were all doing just that.

« Green revolution”created the prerequisites for solving the food problem, but did not turn the promise of defeating hunger into XXI century into reality. A drought in the US and Canada in 1989 burned almost a third of the crop and reminded the world of the unsustainability of agriculture in the face of global warming. In the 90s of the 20th century, the rate of grain production slowed down, and in a number of regions it decreased compared to the 80s.

If we take the index of world food production in 1979-1981. for 100, then the dynamics of its movement in 1993-1995. acquired a negative value and amounted to 95.9 in Africa, 95.4 in North and Central America, and 99.4 in Europe. This jeopardized the achievements of the "Green Revolution" and required the creation of fundamentally new methods for breeding new varieties.

The situation in agriculture became more complicated due to the decrease in fertility and the reduction of arable land. According to a study conducted in 1991, the loss of the top layer of the earth due to its degradation in various regions of the world was 16-300 times higher than the ability of the soil to naturally regenerate. Another study estimated that land degradation from 1945 to 1990 resulted in a 17% decline in world food production. Attempts to compensate for these losses through irrigation and chemicalization had a certain effect, but had a devastating effect on the environment.

In agriculture, there is an annual removal with a harvest of significant amounts of biogenic elements, the soil is gradually depleted of them, depleted. The application of mineral fertilizers compensates for these losses and makes it possible to obtain relatively stable high yields. At the same time, not being bound in humus, mineral salts are easily washed out by soil waters, gradually flow into reservoirs and rivers, and go into underground aquifers. In the soil itself, an excess of mineral salts changes the composition of soil animals and microorganisms that create humus, it becomes less and less, and the soil, losing its natural fertility, becomes something like a dead porous material for impregnation with mineral salts. And industrial fertilizers always contain impurities of heavy metals, which tend to accumulate in the soil.

The process of soil destruction is significantly accelerated by the use of pesticides, which, together with pests, kill soil insects, worms, mites, without which the formation of humus is greatly inhibited.

Gradually, products from such fields become more and more contaminated with nitrates and nitrites from excess fertilizers, pesticides and heavy metals. Such an intensification of agriculture, of course, gives short-term positive results, but more and more aggravates the problem of loss of soil fertility and reduction of land resources.

Further expansion of cultivated areas will lead to a catastrophic acceleration in the extinction of species. Biological methods of maintaining soil fertility - organic fertilizers, change and optimal combination of crops, the transition from chemical plant protection to biological, methods of soil cultivation strictly corresponding to local soil and climate characteristics (for example, non-moldboard plowing) - the necessary conditions conservation and improvement of soil fertility and stabilization of food production of sufficiently high quality and safe for human health.

Finding a way out using genetically modified organisms

Medical problems associated with the action of plant pathogens, in particular fungi, on the human body are widely known. So, the waste products of the fungus Aspergillus - aflatoxins - are dangerous carcinogens. Today, this indestructible fungus infects cereal crops around the world - 20-25% of the area, depending on the crop and region. And we consume these aflatoxins without knowing it, for example, with bread. PMO varieties with resistance to fungal diseases do not carry any toxic load.

Taking into account the growing interest of farmers and other producers in biotechnological products, the increase in sown areas under GMO crops, within the framework of state initiatives, it is planned to deepen scientific research on risk assessment of biotechnological products. Scholars tend to favor the principle of "careful attitude". Risk perception, risk assessment undoubtedly depend on the level of culture of the nation. For example, even the "greens", actively protesting against the use of GM plants in agriculture, as a rule, do not even mention the use of GMOs in medicine and pharmacology. The same Friends of the Earth recognize the safety of herbicide-resistant plants.

It never occurs to anyone to protest against genetically engineered (human) insulin, which diabetics in their mass prefer to domestic "pork".

In many countries of the world, the so-called transgenic (more precisely, another term - genetically modified) plants are already widely used in crop production - soybeans, corn, cotton, rapeseed, potatoes and many others that are resistant to certain pesticides or insects. In 1995, a modified NewLeaf potato variety resistant to the Colorado potato beetle (Monsanto) was registered in the United States. Already in the next two years, a modified potato variety was registered in Canada, Japan, and Mexico. Many countries in Europe, South America, Australia are now testing modified plant varieties.

The positive aspects of plant modification are obvious. This is a simplification of technologies for growing crops, a significant reduction in energy costs. And, most importantly - reducing environmental pollution with pesticides. In addition, GM plants give a significant increase in yield by reducing the harmful effects of insects and microorganisms, reducing production costs, and hence food prices.

The hopes placed on genetically modified (GM) plants can be divided into two main areas:

1. Improvement of the qualitative characteristics of crop production.

2. Increasing the productivity and stability of crop production by increasing the resistance of plants to adverse factors.

The creation of genetically modified plants is most often performed to solve the following specific problems.

1) In order to increase productivity by increasing:

a) resistance to pathogens;

b) resistance to herbicides;

c) resistance to temperatures, different soil quality;

d) improving productivity characteristics (taste, easier digestibility).

2) For pharmacological purposes:

a) obtaining producers of therapeutic agents;

b) producers of antigens, providing food "passive" immunization.

The main tasks of DNA technology in the creation of GM plants in the modern conditions of the development of agriculture and society are quite diverse and are as follows:

1. Obtaining hybrids (compatibility, male sterility).

2. Growth and development of plants (changes in plant habitus - for example, height, shape of leaves and root system, etc.; change in flowering - for example, structure and color of flowers, flowering time).

3. Plant nutrition (fixation of atmospheric nitrogen by non-legume plants; improved absorption of mineral nutrients; increased efficiency of photosynthesis).

4. Product quality (changes in the composition and/or amount of sugars and starches; changes in the composition and/or amounts of fats; changes in taste and smell food products; obtaining new types of medicinal raw materials; changing the properties of fibers for textile raw materials; change in the quality and timing of ripening or storage of fruits).

5. Tolerance to abiotic stress factors (drought and salinity tolerance, heat resistance; flood resistance; cold adaptation; herbicide resistance; resistance to soil acidity and aluminum; resistance to heavy metals).

6. Resistance to biotic stress factors (resistance to pests; resistance to bacterial, viral and fungal diseases).

In practice, among the traits controlled by the transferred genes, herbicide resistance ranks first. The share of resistant to viral, bacterial or fungal diseases among industrially grown transgenic plants is less than 1%.

Among the genes that determine herbicide resistance, genes for resistance to such herbicides as glyphosate (Roundup), phosphimothricin (Bialafos), ammonium glyphosimate (Basta), sulfonylurea and imidozoline drugs have already been cloned. With the use of these genes, transgenic soybeans, corn, cotton, etc. have already been obtained. Transgenic crops resistant to herbicides are also being tested in Russia. The Bioengineering Center has developed a potato variety resistant to Basta, which is currently undergoing field trials.

The need to create GMOs in the modern world is due to the fact that many varieties are characterized by insufficient adaptability to local features of soil, climatic and weather conditions, cultivation technologies (varietal agricultural technology) and market requirements, violation of the principles of agroecological macro-, meso- and microzoning of agricultural territory. A one-sided focus on the "technogenic" intensity of varieties and hybrids that can ensure yield growth only with ever-increasing costs of exhaustible resources (mineral fertilizers, ameliorants, pesticides, irrigation, etc.) inevitably leads to a decrease in resource and energy efficiency coefficients, a disproportionate increase in the cost of irreplaceable resources , pollution and destruction of the natural environment.

An essential direction in obtaining GM plants are attempts to create biofuels. The problem of creating biofuels arose a long time ago. Henry Ford dreamed about it. Future gasoline could be made from genetically modified soybeans or corn. Those. there will be plants-factories for the production of given substances (for example, the mentioned vegetable oil, which in the near future will successfully replace oil as a fuel). As a result, the area under crops and the impact of the extracted fuel on the environment will be sharply reduced. The transition to fuel plantations should start with biodiesel fuels - their molecular structure is so close to that of some vegetable oils that at first it will be possible to do without genetic engineering.

It should be emphasized that with the help of genetic engineering, new varieties are not created, but only improved, made more adapted to specific breeding conditions and tasks. That is, the original variety must already be adapted to certain environmental conditions, as well as cultivation technologies. Therefore, in complex breeding and agrotechnical programs, the goals and stages of using classical and bioengineering methods for managing hereditary variability in the implementation of one or another morphophysiological model of a variety (hybrid) should be initially determined. Usually released varieties used for genetic engineering work are characterized by ideal agro-ecological "fitting" of its genome and cytoplasm (plasmon) to specific conditions.

In principle, transgenic plants should markedly increase the diversity of crops. For example, maize selection in the United States has so far been based on a small number of cultivated varieties, and as a result, the gene pool used is rather poor. Seeds of varieties in seed banks are practically not used; several high-yielding varieties are used for crossing. And if we have genes responsible for the necessary properties, then by introducing them into these varieties, we will increase the biodiversity of the varieties used.

The main problem of natural genetic engineering is its slowness.

Nature itself is engaged in genetic engineering. Over the past millennia (with the help of artificial selection), she has achieved a lot. So, in particular, it is believed that due to gene mutations and natural genetic engineering, nature has put a lot of new products on the table for humans, ranging from soft wheat (the fusion of three genomes) to corn. But how can a normal breeder compress millions of years of what nature has been doing into decades and even years? How to shorten the time as much as possible? Can genetics and selection be able to cope with all this? The adaptive system of plant breeding, based on the mobilization of the gene pool, heredity management, variety testing and seed production, provides an increase in the size and quality of agricultural crops in most of the agricultural territory of the Earth. At the same time, it is plant breeders who play the role of strategists in improving crops and ensuring food security, mastering new technologies, including transgenic ones. Therefore, the immediate problem in the field of breeding is to integrate and cooperate the efforts of breeders and molecular biologists to solve a common problem - increasing the size and quality of the crop, resource and energy efficiency, environmental reliability, safety and profitability of crop production.

Hybridization, although its molecular mechanisms are still not fully understood, plays an important role in improving the efficiency of agriculture. So, with cross-pollination of corn, stronger and more productive hybrids are formed. At the Plant Genetic System in Ghent, such hybrids have been obtained not only for corn, but also for rapeseed. China has once again shown its capabilities, which apparently underlie its thousand-year stability: regardless of the political system in the country, it has fully ensured its food security.

For example, it is in China that great success has been achieved in rice breeding. First of all, these are high-yielding hybrids based on traditional local varieties, yielding 10-11 t/ha instead of the usual 2.5-3. Farmers are happy with these varieties, and they are now grown in vast areas in China, Vietnam and other countries in Southeast Asia. If all these areas were sown with one variety, then soon it would be very susceptible to various diseases. The hybrid, derived from various GM varieties, has become an important milestone on the path to consistently high rice yields, ensuring food security and well-being for half the world's population. In each area where a variety is grown, it would not hurt to use GM varieties and hybrids based on them to produce a wide range of high-yielding locally adapted varieties.

An analysis of yield growth in the 20th century shows that, along with mineral fertilizers, pesticides, and mechanization, the main role in this process was played by the genetic improvement of plants.

Thus, the contribution of selection to increasing the yield of the most important agricultural crops over the past 30 years is estimated at 40-80%. It is thanks to selection over the past 50 years, for example in the USA, that an annual yield increase of 1-2% was ensured for the main field crops. There is every reason to believe that in the foreseeable future the role of the biological component, and primarily the selection improvement of varieties and hybrids, in increasing the size and quality of the crop will continuously increase.

However, in order to feed the world, even such numbers are small today. Breeding design of a new variety is a difficult scientific process. This business requires monstrous perseverance from breeders, decades of work, and success most often comes to them only in their declining years. How many breeders did not live to see the time when their efforts began to bear fruit, and many were left without varieties at all. And the problem of hunger is still the main one for many countries. Time does not wait, we are talking about millions of living people, they need help.

The complexity of ways to create varieties becomes clear if, for example, we take into account the list of requirements for a new wheat variety according to the classical calculation of Nikolai Ivanovich Vavilov. Among the features that must be new variety, includes forty-six items.

We list some of them: the shape of the grain; high weight of 1000 seeds; large, not crumbling ear when ripe; grain that does not germinate on the vine and in sheaves; strong, non-lodging straw; the optimal ratio of the mass of grain and straw; immunity to pests, diseases; drought resistance; suitability for mechanized harvesting, etc. and so on.

And this is by the standards of the past decades. Now the number of requirements has grown even more. The more traits the breeder seeks to combine in one variety or hybrid, the lower the rate of artificial selection, the more time it takes to create a new variety.

The presence of negative genetic and bioenergetic in nature correlations between traits significantly reduces the rate of creation of new varieties. In addition, according to Zhuchenko (2001), increasing the efficiency of the modern breeding process involves the control of a whole complex of population genetic characteristics. The most important of them include: the selection of pairs for crossing, taking into account their recombination potential, the choice of the direction of crossing and the conditions for obtaining F1 hybrids, taking into account the different ability of macro- and microspores to transfer chromosome aberrations, as well as the elimination of recombinant gametes in the process of selective selective fertilization; choice of background for growing hybrids, taking into account the influence of environmental factors on the level and spectrum of recombination variability at the stages of premeiosis, meiosis and postmeiosis; the use of effective selective media for the selection of recombinant genotypes at the cellular level (In vitro), as well as moving genetic elements; transfer of foreign DNA by transgenesis; reduce the selective elimination of recombinant gametes and zygotes, and yet a number of environmental problems require particular international attention, such as soil salinization caused by poorly designed and maintained irrigation systems, and soil and surface water pollution due largely to excessive use of fertilizers and chemical means of protection.

At the same time, the plant genome has a great potential for their improvement in various ways, including the increase in yield. This is an important aspect not taken into account by the "greens". They believe that the agricultural productivity of developing countries and countries with economies in transition depends on social and economic conditions, which is hard to disagree with, but do not take into account that today this is no longer enough to increase productivity and new technologies are needed to realize the hidden in agricultural types of genetic potential. Only they will make it possible to approach sustainable agriculture, sustainable industry and responsibly, to overcome the ecological crisis.

Nearly all of our traditional foods are the result of natural mutations and genetic transformation that drive evolution. Don't be these fundamental processes perhaps we would still be in the bottom sediments of the primitive ocean. Fortunately, from time to time mother nature took charge and made genetic modifications. Thus, wheat, which plays such a significant role in our modern diet, acquired its present qualities as a result of unusual (but quite natural) crosses between various types herbs. Today's wheat bread is the result of the hybridization of three different plant genomes, each containing a set of seven chromosomes. In this sense, wheat bread should be classified as transgenic, or genetically modified, products. Another result of transgenic hybridization is modern maize, most likely due to the crossing of Teosinte and Tripsacum species.

The prospects for solving the problem of hunger using traditional breeding approaches do not inspire hope. By 2015, about 2 billion people will be living in poverty. Plant breeders have been trying to solve this problem for a long time, having long been engaged in the development of new, highly productive varieties, traditional ways using crossbreeding and selection, that is, natural ways, the main disadvantages of which are unreliability and a low probability that the breeder will get what he planned, and too much time.

Disadvantages of traditional breeding and modern ways to overcome them

Usually, hybridization and methods of radiation and chemical mutagenesis are used to obtain new varieties and breeds of animals. Among the problems that limit the possibilities of traditional breeding, the following can be distinguished: desirable genes are transmitted along with undesirable ones; the acquisition of one desired gene is often accompanied by the loss of another; some genes remain linked to each other, making it much more difficult to separate the good from the bad.

The methods of radiation and chemical mutagenesis used in the daily practice of a breeder lead to the appearance of a huge number of unknown genetic rearrangements. A plant bred as a result of such impacts, if it is viable and does not have pronounced toxic properties, may carry unidentified mutations, since mutant varieties are studied only to study the characteristics relevant to solving a specific breeding problem.

The main advantages of genetic engineering methods are that they allow the transfer of one or more genes from one organism to another without complex crosses, and the donor and recipient do not have to be closely related. This dramatically increases the diversity of variable properties, speeds up the process of obtaining organisms with desired properties, and, very importantly, makes it easier to trace genetic changes and their consequences. And most importantly, the modified variety or breed is immediately adapted - inscribed in specific environmental conditions.

It is difficult to imagine the future of agriculture, but we can speak with great certainty about the strategic tasks that we would like to solve. Here we must understand that the goals of nature and man are different. For people, let's say, it is more profitable to get wheat or barley with a large grain, with a light threshing with tew. Nature is more important not the size, but the number of grains; but the tendency to light threshing - this sign can even be harmful for the plant.

Such discord in the views of nature and man, whose power is ever growing, cannot but have a detrimental effect on the biosphere. Of the huge variety of plants that fed humans 10 thousand years ago, today the basis of nutrition (85%) is only five plant species. And out of 5,000 cultivated plant species, man currently uses only 20 to satisfy 90% of his food needs, of which 14 belong to only two families.

To understand how far evolutionary changes have gone under the influence of human selection work, it is enough to look at corn cobs (their age is 5 thousand years) found during excavations in the Tehuacan cave (Mexico). They are about 10 times smaller than modern varieties. And this is a real example of the work of geneticists and breeders.

G.D. Karpechenko (1927) synthesized for the first time a new species form Raphanobrassica unknown in nature, a constant polyploid intergeneric hybrid between radish and cabbage. Quite rightly N.N. Vorontsov (1999) calls the synthesis of Rafanobrassica the first case of constructing a new genome, what was called genetic engineering in the late 70s.

Three years later, the Swedish geneticist Arne Muntzing for the first time carried out the resynthesis of an allopolyploid wild rosemary species that grows wild in nature.

Natural chromosome engineering creates hybridogenic polyploid species complexes, discovered and studied by the American botanist Ledyard Stebbins. In these complexes, the genomes of several diploid parent species can enter into all sorts of hybrid allotetraploid combinations. Several genomes can be combined at once, so that not one, but several species can be the ancestor of one species, as, for example, in ordinary soft wheat, in cotton species.

Hybridogenic speciation is also found in vertebrates and invertebrates. But animals reproduce sexually, which is difficult or even impossible for interspecific hybrids. Therefore, interspecific animal hybrids reproduce in unusual ways, which we might call reproductive technologies. These include: parthenogenesis (sperms are not needed for the development of eggs of hybrid species); gynogenesis (sperms are needed only to activate development, but development occurs on the basis of female gametes and matroclinal inheritance); and actually hybridogenesis, when a hybrid species is formed on the basis of hybrid fertilized eggs, but one of the parental genomes is selectively eliminated.

Thanks, in part, to breeding work, the ancient natural diversity of local species has now been replaced by a small number of specially bred and almost forcibly introduced varieties grown over vast areas. 96% of the US pea crop comes from just two varieties, and 71% of the corn crop comes from six varieties. Plants that are excellent in terms of productivity are used, but unfortunately they are becoming more susceptible to various diseases, such as potato rot. Plants have to be intensively “treated” with pesticides and other means dangerous to the environment and the person himself. One of the most important goals of DNA technology is not to change the environment for plants, but on the contrary - to change the plant in such a way that it is the most adaptive to this environment. In addition, the vegetable kingdom must return to diversity, to an immense wealth of species. It is obvious, however, that in this case, the main thing is to ensure access to food for all social groups of the population (“the health of the nation”), since up to 70% of the population’s income is spent on the purchase of food.

Breeders, watching the work of bioengineers, experience a feeling of envy from the simplicity and clarity of experiments. Although many of them believe that genetic engineering is a kind of hobby, the fashion that it will pass, and the practitioner will not receive any special benefit from it.

Slow, patient, stubborn, sacredly observant of the rules, long since decreed by nature, of a rural, so to speak, warehouse, breeders are suspicious of the hasty, clearly urban methods of bioengineering. They are annoyed by zeal, haste, advertising noise, excessive promises, a clear desire to break the rituals, quickly overturn the barriers set by nature, bypass them, climb through the “back door”, go “out of turn”. This old dispute between rural slowness, solidity and urban bustle and optionality, apparently, will not be resolved soon, because the bioengineer, in the end, passes on his findings to breeders, it is they who must judge whether the next gene “trick” has succeeded or not.

Whatever miracles molecular biologists come up with, breeders argue, it's up to us to decide what they did. That is why high-speed methods of reworking agriculture are a myth. It takes from five to fifteen years to obtain the desired traits from this plant. And then another, at least three to eight years of work using traditional methods to fix these traits in a plant, and then its zoning, and so on. But it should be recognized that bioengineering, unlike traditional breeding methods, has the greatest opportunity to technologize the achievements of fundamental knowledge, and, in particular, molecular biology. In addition, biotechnology methods are a qualitatively new tool for the direct study of the structural and functional organization of genetic material. And this, in turn, suggests that genetic engineering of plants will have the greatest impact in breeding on such adaptively and economically valuable traits as the intensity of net photosynthesis, yield index, etc. Most promising directions in the field of plant protection include the production of transgenic varieties resistant to herbicides and harmful species, biopesticides, new forms of microorganisms, etc. It is also obvious that genetic engineering itself, having become an experimental testing ground for evolution, will continuously improve and become more complex, expanding human capabilities in purposeful transformation of organisms , and it is likely that the further development of molecular biology methods, including transgenosis, will raise modern plant breeding to a qualitatively new level.

Although there are many difficulties for genetic engineering, for example, in the fact that the selection of new varieties affects the properties of the plant, controlled not by one, but by many genes at once. For example, scientists want to design plants that can "fertilize" themselves.

The idea is persistently promoted to transfer to grain crops - the main food of mankind - a group of nrf genes from bacteria that can capture atmospheric nitrogen, and thereby get rid of the need to apply nitrogen fertilizers to the soil. And it will. But when is still unknown, because it is necessary to transfer whole complex at least 17 genes. And if everything goes well, to make all these genes work (for example, in the wheat genome), then, according to experts, such plants will reduce the yield by 20-30 percent of dry weight due to the need to incur additional energy costs for nitrogen fixation ...

The problem of production and consumption of genetically modified plant products is becoming more and more acute. Proponents of the widespread use of such products for food say that they are completely safe for the human body, and their advantages are enormous - large yields, increased resistance to weather changes and pests, and better preservation. At the same time, there are long-distance links between genes in the plant genome, and one should be very careful when interfering with the operation of the gene machine. It is possible to inadvertently transfer the gene mechanisms of a plant from one mode to another, which is completely undesirable for humans.

Although there are a lot of such examples in traditional breeding, not to mention how many breeders did not receive anything at all. For example, the story of the opaque 2 gene is known. This gene was wanted to be used in the USA (Pardew University) to enrich corn kernels with the amino acid lysine, which would dramatically increase the nutritional value of corn grain.

The gene transfer was successful, the joy was great, but ... the yield of the transformed varieties fell by 15 percent, and the grains themselves became fragile and susceptible to pathogens. Of course, it is a pity that selection armed with genetic engineering methods cannot solve all problems at once, but it guarantees, although modest, but strong, continuous and effective successes in agriculture.

Among priority areas The use of plant resources is also the problem of introducing new species and ecotypes of plants into the culture. And although the processes of natural and artificial selection are interrelated, the latter has a number of features. It is known, for example, that in the natural flora the yield index does not play a leading role in selection. Meanwhile, in natural populations there is genotypic variability for this trait, the significance of which for cultivated plants is obvious. Thus, according to Primack, when studying populations of 15 annual and perennial Plantago species, annual species showed higher rates of “reproductive effort” (number of bolls and seeds, seed weight per unit leaf area) compared to perennial species. Moreover, in spring annual species, they turned out to be more than in summer ones. There is reason to believe that many of the species and ecotypes selected by man had high rates of "reproductive effort", and the level of genotypic variability for this trait had a decisive influence on the effectiveness of targeted selection.
In most cases, the extremely high ecological plasticity of plant species is combined with their very low productivity. Thus, in many wild species, the strategy of adaptation to adverse environmental conditions is based on a low rate of growth processes. It's no coincidence, Stuart notes, that even with excessive nutrient intake by wild plant species, their growth rate remains unchanged. Among the huge variety of plant species, there are those whose growth rate is almost not affected by certain environmental factors. Examples are some types of tundra vegetation, the growth rate of which does not depend on temperature; Plantago coronopus only slightly reacts to the content of nutrients in the soil; the growth rate of Carex limosa is not affected by changes in the concentration of K + in the 100-fold range, etc. It is obvious that people preferred those plant species that had a positive growth response to the optimization of environmental conditions (plowing, high soil fertility, irrigation, etc.). d.). The leading role was played not only by the features of the ontogenetic adaptation of wild species, but also by the potential of their genotypic variability.
The nature of the relationship between the high ecological plasticity of plants and their low productivity, noted above, deserves special attention. It is possible that it was precisely this feature of the adaptive capabilities of plants that served as the basis for posing the question: “adaptation or maximum yield?” spectrum of genotypic variability, an increase in plant yield is unthinkable. Moreover, this opposition makes sense only in relation to general and wide adaptation of plants, while specific and narrow adaptations are an indispensable condition for increasing yields for most cultivated plant species.
A high degree of genetic and morphophysiological integration of the general ecological stability of each plant species in most cases negates the attempts of breeders to achieve the ecological stability of varieties inherent in other species through hybridization (including interspecific hybridization). No less difficult is the task of combining high potential productivity and environmental sustainability in one variety (and even hybrid). Varieties with high potential productivity and low environmental resistance provide high yields only under favorable environmental conditions, while they sharply reduce it under stressful conditions. Therefore, in breeding practice, especially when using wild species as donors, methods of induced recombinogenesis, reducing the elimination effect of “selection sieves” due to gamete and zygote selection, and using the possibilities of an ecological-geographic breeding and variety testing network are of paramount importance. An important role is given to the methods of creating F1 hybrids, mixed, synthetic and multiline varieties.
In general, there are very different points of view regarding the possibilities of combining high potential productivity and environmental sustainability in one genotype. Thus, according to Adamer, the increase in the value of some components of yield due to selection usually reduces the value of others. And yet, the difficulties of the selection combination of potential productivity and environmental sustainability, even at the interspecific level, should not be exaggerated, much less absolutized. As is known, the possibility of solving this problem was demonstrated in the works of I.V. Michurin, L. Burbank, N.V. Tsitsin and other researchers. Data on the independent segregation of traits that determine the potential productivity and ecological stability of plants, known since the 1930s, are currently supported by a sufficient number of data on a certain physiological, biochemical and genetic independence of the main components of the plant ontogenetic adaptation potential. Many traits that characterize plant resistance to water stress (strong root system, wax coating, spatial orientation of leaves, their pubescence, etc.), as a rule, are not negatively correlated with potential and biological productivity or their components. Moreover, for example, a large branching of the root system, the depth of its penetration provide not only high (moreover, active) resistance of plants to drought, but also the possibility of better use of mineral nutrition elements by them, thus determining the greater potential and biological productivity of the cultivated species. A typical example in this regard is alfalfa.
The fact that potential productivity and ecological resistance are controlled by different complexes of genes indicates the real possibility of combining them in one variety or hybrid. Coyne provides data on the components of bean yield (number of pods per plant, number of seeds per pod, and average seed weight) that have almost the same effect on overall seed yield and are controlled by different genetic systems. Therefore, the most effective for this culture was not individual, but mass selection in terms of yield in later splitting generations.
The combination of high potential productivity and ecological stability in one variety or F1 hybrid requires the use of not only special breeding methods (interspecific hybridization, recombination induction, etc.), but also the choice of special backgrounds for assessing the productive yield of the original forms and promising lines. According to Johnson and Frey, Vela-Cardenas and Frey, Allen et al., ecological and genetic variants of plant yields are higher in favorable environmental conditions for their cultivation. Moreover, if in an optimal environment the heritability of yield and its components (and the advantage of appropriate selection) is high, then in unfavorable conditions it is extremely low, and the selection efficiency decreases sharply. Therefore, selection for high productive yields, provided incl. and due to greater environmental sustainability, it is better to conduct in a supportive rather than a stressful environment. In practical terms, this means that it is advisable to evaluate the ecological stability of varieties and hybrids under appropriate stressful conditions only after their high potential yield under favorable environmental conditions has already been proven.
An effective approach in breeding, for example, for plant resistance to drought is the combined use of an optimal and stressful environment in terms of water supply. This approach is based on the assumption that potential productivity and drought tolerance are controlled by different genetic systems and therefore can be selected independently from each other in the breeding process. In this regard, the author considers it expedient to carry out selection for drought resistance in an appropriate stressful environment, and selection for high potential productivity under conditions of optimal water supply. An example of independent inheritance of resistance to water stress is the cuticular layer, the greater thickness of which provides better drought resistance of plants and is not associated with a negative correlation with yield or its components. By alternating selection under conditions of water stress (for better manifestation of one or another trait of resistance) and optimal water supply (for maximum manifestation of potential yield or its components), it is possible to combine high potential productivity and resistance in one variety. A similar possibility is confirmed by our earlier information that the differences between species and varieties in their ability to absorb, accumulate and use mineral nutrition elements, as well as edaphic resistance, are determined by different gene complexes. For example, significant differences between varieties of tomato, beans, corn and other crops in terms of the efficiency of using N, P and K are shown, high-yielding varieties of wheat, sorghum and rice resistant to acidic and low-productive soils are created.
Lu, Chiu, Tsai et al., Oka, by sequential selection for high productivity in the offspring of soybean hybrids grown at different sowing dates (disruptive seasonal selection), obtained eurypotent varieties, i.e. capable of providing high yields in a wide range of changes in environmental conditions. Thus, the relationship between the adaptability of plants to seasonal and regional variability of environmental conditions and the effectiveness of the disruptive seasonal selection method in increasing the overall adaptability of soybean varieties were proved. Due to the fact that soybean is more sensitive to changes in day length and temperature than other crops, when growing different varieties in different ecological zones and/or in different years, it is necessary to take into account the significant interaction in the “genotype-environment” system, which masks genotypic variability. . In order to increase the ecological sustainability of wheat, Borlaug made extensive use of the possibility of greater ecological differentiation of breeding material due to different sowing dates and growing it at different heights above sea level.
Finlay and Wilkinson have found barley genotypes that are highly tolerant in a wide range of environments, and intensive varieties of rice that are adapted to high fertilizer rates and thickening, maintaining tolerance to varying weather conditions at local cultivar levels. It was shown that some high-yielding varieties selected under optimal environmental conditions retained their advantage even under less favorable environmental conditions, and the yield value in different environments and its stability are largely independent of each other.
In cross-pollinated forage crops, unlike self-pollinated wheat and rice, Suzuki was unable to find combinations of high potential productivity and resistance to environmental stressors in one variety, and high-yielding forage varieties, as a rule, showed a strong response to changing environmental conditions. The author explains this feature by the fact that the adaptability of cross-pollinated crops is due not only to the adaptability of individual plants (homeostasis individual development), but also the heterogeneity of the genetic composition of the population (genetic or population homeostasis). Moreover, genetic homeostasis apparently has a more significant effect on ontogenetic adaptation, which contributes to a better adaptability of cross-pollinated plants to natural environments than self-pollinating ones. In this regard, in our opinion, the possibility of more efficient use of genetic homeostasis to increase the potential productivity and environmental sustainability of cross- and self-pollinating crops by creating mixed species and varietal crops, as well as synthetic and multiline varieties deserves special attention.
F, hybrids play a particularly important role in increasing the potential productivity and environmental sustainability of cultivated plants. Not only their high potential productivity was noted, but also greater stability, as well as higher ecological homeostasis compared to parental lines. And although Griffing and Zsiros rightly believe that environmental stresses usually minimize heterosis effects, there are often cases of greater resistance of F hybrids to environmental stressors. It has been shown, for example, that the homeostasis of the individual development of maize hybrids is due to their heterozygosity, and a significant part of the heterotic effect of hybrids of maize, wheat, barley, Phalaris tuberosa x P. arundinacea, and other crops is associated with their increased resistance to thermal stress. According to Langridge's suggestion, the latter is due to the greater stability of F, hybrid proteins. Recall that in the general complex of ecological stability of higher plants, tolerance to extreme temperatures is the most deficient property. In addition to resistance to the temperature factor, F1 hybrids have a higher overall adaptability. According to Quinby, "strong" sorghum hybrids, adapted to conditions of different latitudes and different altitudes, at the same time show specific adaptations, incl. by maturity.
Thus, the advantages of F1 hybrids are based on the positive heterosis effect not of individual components, but of the entire system of ontogenetic adaptation. As a result, phenotypic variability in heterozygotes is usually less pronounced than in inbred lines. The latter are more susceptible to changes under the influence of external conditions, physiologically less able to compensate for the influence of adverse environmental factors, while heterozygotes in this situation have a wider range of protective and compensatory reactions, greater morphogenetic plasticity, and more effective developmental homeostasis.
Note that the widespread use of F1 hybrids is due not only to the phenomenon of "true heterosis", but also the ability to quickly combine the most important economically valuable traits, including those between which there are negative genotypic and ecological correlations and which usually cannot be combined with varietal selection. . It is important to combine high potential productivity and environmental sustainability. In addition, by creating F1 hybrids, it is possible to overcome the difficulties associated with the use of valuable dominant genes linked to unfavorable recessive genes (for example, Tm-2 and nv in tomato), and in a shorter time to provide a combination of valuable dominant genes, including . controlling resistance to new races of pathogens.
Crop heterogeneity plays an important role in determining potential productivity and environmental sustainability. Literature data on this issue are very contradictory. Thus, in the experiments of Schnell and Becker, the heterogeneity of corn crops had the same effect on yield stability as heterozygosity, although their combination provided only a slight advantage over the effect of heterozygosity. However, along with the superiority of the mixture of genotypes noted by many researchers, incl. heterozygous, over homogeneous crops, in a number of works such advantages were not recorded.
Taking into account the practical difficulties of breeding change in the idiotype of plants, indicators of the evolutionarily determined ecological stability of cultivated species should be considered as a fundamental factor in determining the species structure of crop production in unfavorable soil and climatic zones and the priorities of crops in breeding work. In this connection Special attention should be given to increasing the productive yield of such plant species as sorghum, millet, rapeseed, rye, etc., which have a high constitutive resistance to a lack of moisture and / or heat, which to the greatest extent limit the size and quality of the crop in many regions of our country. This approach is not only realistic, but still the most effective in solving the problem of increasing the resistance of intensive agrocenoses to weather fluctuations (droughts, dry winds, frosts, frosts, a short growing season, etc.).
In increasing the potential productivity and ecological stability of varieties and agrocenoses, both general and specific fitness, which characterizes their ability to effectively use favorable environmental conditions and/or resist the action of abiotic and biotic stressors, plays an important role. Moreover, as already noted, the overall potential productivity and environmental sustainability cannot be reduced to the sum of the corresponding specific adaptations, but are the integrative properties of the plant and the agrocenosis as a whole. In addition, general resistance can be weakened or, conversely, strengthened due to one or another specific resistance, and both positive and negative correlations can exist between different types of the latter.
Supporting these assumptions are Briggle and Vogel's findings on high-yielding, widely adapted Pacific Northwest dwarf wheat varieties that proved unsuitable for growing in the dry conditions of the Great Plains, as well as Quisenberry and Roark's findings on cotton varieties that use water efficiently in an optimal way. humid environment, but do not show this ability under water stress. Select lines for wide adaptation, i.e. adaptability to a wide range of ecological environments, according to Reitz, means breeding for mediocre and even low yields. According to Matsuo, varieties with high potential productivity that provide high yields in favorable environmental conditions are more responsive to changes in them, sharply reducing yields in unfavorable conditions. According to Hurd, in varieties that have a well-developed root system under favorable environmental conditions, its power is significantly reduced under water stress. Barley genotypes with broad adaptability tend to provide intermediate yields, while environment-adapted genotypes show the highest productivity. In general, the highest productive yield of an F1 variety or hybrid can be achieved if they are specifically adapted to growing conditions. In cases where selection is aimed at maximizing one particular trait and ends after a number of generations, the population is given the opportunity to reach its own genetic equilibrium, the intensively selected trait very often loses part, and often more, of the phenotypic success (improvement) achieved during the previous period of intensive selection.
In the process of natural and artificial selection, which go through the entire phenotype of the plant, and not according to individual traits, their associated variability is inevitable. This provision is realized to the greatest extent and first of all for such usually complex and integrated in their genetic and physiological-biochemical nature components of productivity as potential productivity and environmental sustainability. That is why the problem of the ratio of potential productivity and environmental sustainability of varieties is gaining more and more theoretical and practical importance.

Tasks:

1. To get acquainted with the concept of agrocenosis.
2. To reveal the ecological features of agrocenoses;
3. Ways to increase their productivity;
4. Ecological ways to increase their sustainability and biological diversity;
5. Cultivate a correct, careful attitude towards nature.

Equipment: support scheme; instructional cards, pictures of various agrocenoses, video film "Hurry up to save the planet" textbook "Fundamentals of Ecology" Chernova N.M.

During the classes

I. Repetition of the past:

II. Jump to topic:

As a result of human activity, artificial biogeocenoses have arisen.

Russia is a country with developed agriculture. Agricultural lands (arable land, hayfields, pastures, orchards) occupy more than 40% of its territory, all of which are agrocenoses.

Agrocenoses are biocenoses that have arisen on agricultural land. Give examples of agrocenoses.

III. Topic message:

Today in the lesson we will learn: (I refer to the plan written on the board).

On the desk:

Plan.

1. The main ecological signs of agrocenosis.
2. Ways to increase the productivity of agrocenosis.

IV. Learning new:

Independent work in groups.

I suggest that you find out the main ecological signs of agrocenosis.

We work in groups.

To answer, use the text of §18 p. 117 and the instruction card. Each group is offered an illustration. (1 group - potato field; 2 group - apple orchard; 3 group - beet field;)

Guidance Card Questions:

1. What agrocenosis is shown?
2. Name the species included in the agrocenosis?
3. Make 2 power supply circuit diagrams (remembering that a person can be an obligatory link).
4. Make a conclusion about the stability of agrocenosis.?

V. Conclusion:

On the basis of what has been said, we will draw a conclusion.

I am posting a chart on the board:

Agrocenoses arose as a result economic activity person.

1. They include a few types.
2. Differ in short food chains.
3. These are unstable systems. to. consist of a small number of species. The instability of agrocenosis is caused by the fact that the protective mechanisms of cultivated plants are weaker than those of wild species.

VI. Ways to increase the productivity of agrocenosis.

A person is constantly striving to increase the stability of agrocenosis, to increase productivity, i. harvest more produce.

Think about how this is achieved? What does a person do to increase the yield?

(Student answers).

So, a person spends additional energy: applies fertilizers, cultivates the soil, irrigates, fights pests, rotates crops, i.e. crop rotation applies. Today in the lesson we will get acquainted with individual agricultural practices for increasing the productivity of agrocenosis. Each group received homework. It was proposed to find out (assignments to groups):

1. Pesticides. Pros and cons of using pesticides. Biological struggle.
2. What does the use of mineral fertilizers lead to? Is there a way out?
3. Monocultures. Crop rotations.

Each group reports on the work done. A conclusion is made for each message.

VII. Conclusions:

1) One of the most modern trends in agriculture.: conservation species diversity. Man should strive to preserve diversity soil organisms responsible for soil-forming processes, to maintain the cycle of substances, due to the correct crop rotation, the introduction of organic fertilizers into the soil.

Question: What agricultural methods are anti-ecological, i.e. harmful?

2) Many modern ways industrial agricultural production are anti-environmental, that is, harmful.

These are: a) Monocultures.

b) The use of pesticides.

c) Large doses of mineral fertilizers.

This list can be continued: overgrazing, improper plowing of fields, the use of heavy equipment.

Why are they harmful? They contribute to the accumulation of toxic substances in soil, water, the accumulation of poisons in plants, animals. At present, people are increasingly aware of the harm of these methods and refuse them, moving on to environmentally friendly agricultural practices, methods of increasing fertility.

VIII. I propose to watch the film and answer the question: what ecological agro-methods are used to increase the productivity of agrocenoses?

Film screening. "Hurry up to save the planet."

Work in notebooks. Filling in the table.

IX. Summary of the lesson.

Questions for students:

1. What happens as a result of using these ecological or organic methods.
2. What is the result?

(The result of these methods: pure products, no chemical impurities. Clean land, save natural resources, stable harvest for several years.)

Conclusion:

Rational environmental management in agriculture provides for:

• obtaining a high yield while maintaining soil fertility;
• production of environmentally friendly products;
• no pollution of soil, water, atmosphere, animals, plants;

Let the motto in a person's life be: "Working with nature and on nature is a pass to the future."

“If we are destined to breathe the same air
Let's all unite forever
Let's save our souls
Then we ourselves on Earth will be preserved.”
(N. Starshinov)

X. Homework: Questions are discussions.

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