Breeding: characteristics of methods and achievements. Plant breeding methods What is a breed in breeding

"Biology selection" - On the website of the gymnasium, view presentations of students in grade 10 B on the topic "Trends in biotechnology." Centers of origin of cultivated plants. Effects of radiation and chemicals on plants and animals. selection tasks. hybridization method. mutagenesis method. selection method. selection methods. Homework.

"Basic breeding methods" - Heterotic animals are characterized by precocity and increased meat productivity. 10. Brewing. 8. Polyploidy is extremely rare in animals. 7. 4. Using the effect of heterosis. Preparation of many dairy products. Selection.

"Plant selection" - Kudoyarova G.R. Plant Physiology Laboratory, Institute of Biology. A correlation was found between plant productivity under conditions of moderate drought and relative water content (RWC, left) and ABA content (right) RWC=(wet weight - dry weight)/(turgor weight - dry weight). Productivity of Mexican corn varieties.

"Selection in Biotechnology" - What do we know about the use of microorganisms? Root cancer of fruit crops. Sterlet. The mule is the result of crossing a donkey and a mare. More than 300 varieties of different plants! Beltyukova K.I.). Kyiv: Naukova Dumka, 1966. A.A. Kamensky, E.A. Kriksunov, V.V. Pasechnik General biology grade 10-11 Ed. "Drofa" 2006

"Methods of breeding animals and plants" - Methods of breeding plants and animals. Selection methods: selection, hybridization, mutagenesis. Biotechnology. MOU Bazhenov secondary school. selection of microorganisms. Viruses are sometimes referred to as microorganisms. Biology presentation on the topic: Completed by: Kormina Irina, a student of grade 10.

"Vavilov the basics of selection" - The structure of the lesson. A method of organizing the educational process based on the block-modular presentation of educational information. Works by N.I. Vavilov. modular block "Selection". Complex didactic goal (CDC): Teacher of biology at Lyceum No. 11 Volkova M.P. Selection basics.

There are 26 presentations in total in the topic

breed And sort called a population of organisms artificially created by man and having certain hereditary characteristics.

All individuals within the breed and variety have very similar hereditarily fixed productivity indicators, biological properties and morphological features.

For example, white leghorn chickens are characterized by a certain constitution and exterior - they are light in weight, but have high egg production. For chickens of this breed, it is characteristic that with the improvement of the conditions of keeping and feeding, their egg production increases without a significant change in live weight. There are breeds of general-use chickens that combine high live weight and high egg production, for example, Australorps (black), New Hampshires of red-brown color, white and striped Plymouth Rocks, etc. Each of these breeds is characterized by a certain constitution, productivity, egg weight, resistance to diseases . These breeds also differ in certain properties of higher nervous activity: in the strength of the excitatory and inhibitory processes. The morphological and physiological properties of an animal and plant are, as it were, hereditary markers of a given breed or variety, by which their “portrait” is recognized. The properties of a breed or variety that determine its productivity depend to a large extent on external conditions (feeding, maintenance, agricultural technology). Morphological markers (markers) of the breed and variety are more stable. For example, coloring, comb, constitution in chickens can be preserved in a variety of climatic conditions. However, it must be borne in mind that the properties of a breed and variety appear in the most typical form only under those conditions of keeping and feeding in which this breed was created.

Each breed and variety is created to obtain a certain type of product from them. The value of a variety is determined by the nutritional or fodder properties of the plant or the quality of the raw materials obtained for industry, the adaptation of the variety to the technique of mechanized cultivation and harvesting of a given crop, responsiveness to applied fertilizers, etc. At present, each variety is created in relation to a specific method and cultivation technique. So, for example, glomeruli - seedlings of sugar beet varieties usually give several seedlings. To obtain a full-fledged root crop, you have to spend a lot of work on thinning seedlings. Multigerm makes it difficult to carry out a complete machine processing of this culture. Soviet breeders created a variety of hereditary single-sprout beets.

In animals, productivity is also determined by the quality and quantity of the product obtained. Breeds of dairy cattle are characterized by the amount of milk yield, percentage of fat and protein in milk, live weight, etc., breeds of the Meat direction - growth rate, slaughter yield. Sheep breeds are distinguished by the yield of wool, its quality, as well as by fertility and live weight. Breeds of chickens are characterized by egg production, egg weight, early maturity, etc.

The following world records can serve as an illustration of the success of animal breeding. In 1960 (USA), a cow of the Holstein-Friesian breed produced 16,702 kg of milk with an average fat content of 5.1% in 365 days of lactation. In 1962, in Denmark, one of the Jersey cows on the ninth lactation gave 7,269 kg of milk with a fat content of 7.29%. In Japan, a herd of 1000 hens was presented at competitive trials, of which 33 hens laid 365 eggs in 365 days of counting and 423 hens laid about 300 eggs. In pigs, modern world record holders (boars) reach 550 kg of live weight. From the above data, it can be seen that the productivity of domestic animals is many times higher than the productivity of wild representatives of the same species.

Plants and microorganisms also have high-yielding varieties and strains. As a rule, the properties of productivity are determined by the complex interaction of genes in the genotype system. Due to the polygenic hereditary determination of valuable economic traits, the nature of their inheritance is very complex. It is obvious that the more genes are involved in determining the trait, the more different types of their combinations are possible. Depending on how traits of productivity are inherited and changed under different environmental conditions, the methods of artificial selection may be different.

At the same time, we must remember that despite the leading role of artificial selection carried out by the breeder, natural selection is constantly acting on cultivated plants and domestic animals. Sometimes its action can be opposite to the action of artificial selection. So, for example, when selecting for high fertility in multiparous animals (pigs, sheep, fur-bearing animals), natural selection leads to a reduction in the number of fertilized eggs and even embryos.

Everything that has been said about animal breeds applies to plant varieties. Based on the biology of plant reproduction and the characteristics of this variety, systems of seed production and cultivation of the variety under production conditions are built. For each region with certain climatic conditions, as well as certain possibilities for the mechanization of agricultural production, it is necessary to have its own varieties and breeds.

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1. What is called a variety, breed, strain?

Breed, variety, strain are artificially obtained populations of animals, plants, fungi and bacteria with traits that are necessary for humans.

2. What features are characteristic of heterotic organisms?

For heterotic organisms, the superiority of the first generation of hybrids in a number of characteristics and properties over both parental forms is characteristic.

3. What is the relationship between artificial selection and selection?

Artificial selection is the choice by a person of the most valuable for him individuals of animals and plants of a given species, breed or variety in order to obtain offspring from them with desirable properties. It is the basis of selection. Breeding is a science that studies the biological foundations and methods for creating and improving animal breeds, plant varieties and strains of microorganisms.

4. What role does the selection of microorganisms play in the national economy?

Microorganisms are used in various industries (in bakery and winemaking, in the production of feed protein, lactic acid products, antibiotics, vitamins, hormones, amino acids, enzymes), in agriculture (in the production of silage), for biological plant protection and wastewater treatment. In this regard, industrial microbiology is developing and intensive breeding work is underway to develop new strains of microorganisms with increased productivity, which produce substances necessary for humans.

5. Name the main selection methods.

Artificial selection, hybridization, mutagenesis, polyploidy.

6. Name the varieties of fruit or vegetable plants, animal breeds known to you.

Apple varieties: Antonovka, White filling. White and red cabbage, cauliflower and Brussels sprouts.

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Explain why a variety, breed or strain cannot be considered a separate species?

Species - a set of individuals characterized by a hereditary similarity of morphophysiological features, freely interbreed and produce fertile offspring, adapted to certain living conditions and occupying a certain area (territory). A species is a taxonomic category that is used in taxonomy to determine the diversity of life on Earth.

Breed - a group of farm animals of the same species, common origin, similar in appearance, constitution, productivity and other economically useful traits that are transmitted to offspring.

A variety is a form (variety) of cultivated plants artificially created in the process of selection, which, under specific growing conditions, has certain biological and economic properties.

Strain - a pure culture of a microorganism created under control conditions from a single source cell with the desired characteristics, acquired mainly due to mutation.

Speciation occurs in natural conditions without human influence, and the formation of breeds, varieties and strains is artificially created organisms due to mutations that humans use.

biology.kiev.ua

Answer to question 2 in biology from Sivoglazov's textbook for grade 10 on the topic § 32. Selection: basic methods and achievements

• Varieties of Antonovka apples, Severyanka pear, dog breeds: Rottweiler, Miniature Poodle, Collie....
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• What are the main selection methods you know?...
• Select criteria and compare mass and individual selection....
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Basics of selection | Study-Easy.RF - the largest study portal

Breeding is a science that studies the possibilities of obtaining new breeds of animals, plant varieties, strains of microorganisms, with signs that are necessary for humans.

Breed, variety, strain are populations of animals, plants, microorganisms created by man with the help of breeding methods, which have the characteristics necessary for a person, fixed by heredity in a number of subsequent generations of individuals.

Mass selection is a method of plant breeding when a genetically homogeneous population of individuals with the necessary traits is selected.

Individual selection - a method of plant breeding, when individual individuals with certain characteristics are selected.

Inbreeding is a method of plant breeding when the preservation of a variety of self-pollinating plants is carried out by protecting it from the ingress of pollen from other plants.

Cross-pollination of self-pollinating plants is a method of plant genetics aimed at obtaining varieties with new traits. Distant plant hybridization is a plant breeding method in which plants of different species are crossed.

Inbreeding is a method of animal genetics when new breeds of animals are obtained by carrying out closely related crosses.

Outbreeding is a method of animal genetics, when new breeds of animals are obtained by carrying out unrelated crosses.

Inbreeding is a method of animal genetics when new breeds of animals are obtained by crossing the most suitable individuals of the same breed.

Progeny testing is a method of animal genetics when new breeds of animals are obtained by selecting males whose offspring are considered productive for one or another trait. The same goal is pursued by artificial insemination.

Distant hybridization of animals is a method of animal breeding in which animals of different species are crossed.

Genetic engineering is a method of genetics of microorganisms, which is based on the transfer of genes from one type of microorganism to another.

Selection basics. Selection Methods

Selection is one of the most important areas of practical application of genetics, that is, genetics - theoretical basis selection, since genetics helps to rationally plan breeding work, based on from the laws of heredity and variability and specific features of the inheritance of a particular trait.

In addition, selection is based on the achievements of other sciences, for example, plant systematics and geography, cytology, embryology, biochemistry and physiology of plants and animals, molecular biology, etc.

Breeding is the science of methods for creating new and improving existing breeds of domestic animals and cultivated plant varieties and strains of microorganisms.

Selection- this is an evolutionary process in which a person is the main acting factor and directs the entire process in accordance with his needs.

Breed, variety, strainis a population of organisms artificially created by man, which is characterized by certain hereditary characteristics. All individuals within a variety, breed or strain have a similar genotype, phenotype and the same type of reaction to the influence of environmental factors, for example, dairy breeds of cattle differ in milk yield, fat percentage and protein content in milk.

Variety valuedetermined by yield, food and fodder properties.

Breed value determined by the quality and quantity of the output.

The main tasks of selection:

• yield increase varieties of cultivated plants, increasing the productivity of breeds of domestic animals and strains of microorganisms;
• quality improvement products (flax properties, gluten content in grain, sugar content in beets, etc.);
• improvement of physiological properties (precocity, frost resistance, etc.);
• promotion intensity of development (for plants - for feeding, for animals - for keeping conditions).

conditions for successfulselection work:

Source material (variety, breed or species);

Studying the role of mutations in the appearance of a certain trait;

Study of patterns of inheritance in hybridization;

The role of the environment in the development of the trait;

Application of artificial selection.

(A striking example of selection based on market needs is fur farming, as the cultivation of mink, sable, fox is in line with the changing fashion. Insect breeding is of particular importance for biological control methods. For the manufacture of biscuits, soft varieties of wheat are needed, and for the manufacture of pasta, hard ones. Breeds of chickens have been bred that do not reduce productivity in conditions of high overcrowding in poultry farms.For Belarus, it is important to create plant varieties that are productive in conditions of snowless frosty winters and in conditions of late frosts.)

The success of breeding work is verystrongly depends on the genetic diversity of the original group of organisms.The gene pool of existing breeds and varieties is much smaller than the gene pool of wild species.

In order to study the diversity and geographical distribution of cultivated plants, N. I. Vavilov conducted a number of expeditions around the globe, a huge seed material was collected and isolatedcenters of origin of cultivated plants:

1) South Asian ( India ) - the birthplace of rice, bananas, citrus fruits, sugar cane;

2) East Asian(China) - the birthplace of soybeans, dew, buckwheat, apple, pear;

3) southwest Asian(Central Asia) - the birthplace of wheat, peas, grapes;

4) mediterranean- the birthplace of cabbage, beets, olives;

5) abyssinian(Africa) - the birthplace of durum wheat, barley, coffee tree;

6) Central American(Mexico) - the birthplace of corn, cocoa, pepper, beans, cotton;

7) South American(South America) - the birthplace of potatoes, tobacco, sunflower.

Vavilov's research allows breeders to quickly select the source material and, to a certain extent, to foresee the results.

Raw material:

Wild forms (they differ in a number of useful properties, for example, resistance to sharp fluctuations in climatic factors, to diseases, have high fecundity, but are inferior to cultivated ones in productivity);

Artificially obtained mutant forms;

Forms obtained as a result of combinative variability;

Varieties and breeds obtained in other climatic conditions.

Basic selection methods:

• - hybridization;
• obtaining clean lines;
• use of the phenomenon of heterosis;
• induced mutagenesis;
• use of polyploid forms;
• artificial selection.

G inbreeding

A) inbreeding - closely related crossing;

b) outbreeding - unrelated crossing that is, crossing individuals of the same or different breeds or the same or different varieties.

artificial selection This is the process by which better adapted individuals are left for reproduction.

In the early stages of human evolution, selection was unconscious, it started with domestication, that is, at first it was probably carried out behavior selection(those individuals who were able to contact a person survived), and later, other signs began to be affected, the best individuals were left for the tribe.

At the present stage, breeding uses methodical selection:

A) mass- carried out according to external phenotypic features in the direction chosen by the breeder, its disadvantage is that it does not give genetically homogeneous material, repeated selection is always necessary;

b) individual- based on genotype assessment.

With artificial selection, a hybrid simultaneously acts and natural selection, which increases its adaptability to specific environmental conditions.

Currently, breeding is increasingly usinginduced mutagenesis, which consists in increasing the number of mutations as a result of exposure to various mutagens on the body.

A significant place in plant breeding is given mainly to obtainingpolyploid forms, since they are characterized by higher yields, colchicine is usually used, which destroys the fission spindle threads and prevents the homologous chromosomes from separating during meiosis.

Breeding process goes along the way: starting material → selection → hybridization → selection → hybridization → selection, etc.

plant breeding:

1) setting a specific task;

2) selection of source material, (if it is not possible to find the necessary parental forms, artificial mutagenesis is used, and among the mutations that have appeared, useful ones are found, which are used in further work);

3) hybridization- this is the production of hybrids from the crossing of genetically heterogeneous organisms.

a) it is based on artificial pollination of usually cross-pollinated plants with its pollen, such pollination leads to an increase in homozygosity and the consolidation of hereditary properties, and the offspring obtained from one homozygous plant by self-pollination is clean line.

Clean line is different reduced viability and reduced yields.

If then cross two clean lines between themselves - interline hybridization, we get the phenomenon heterosis

Heterosis explained the transition of most genes V heterozygous state. The phenomenon of heterosis can be fixed by vegetative propagation;

b) outbreeding- crossing unrelated organisms, however, such hybridization is carried out with difficulties, and interspecific and intergeneric hybrids are sterile, since conjugation of chromosomes of different species or genera during meiosis is impossible. For the first time, Karpechenko managed to overcome the infertility of interspecific hybrids, who received a hybrid of cabbage and radish (9 "rare" and 9 "cabbage" chromosomes), sterile, then the scientist received a polyploid form of the hybrid, which had 18 "rare" and "cabbage" chromosomes, became conjugation of homologous chromosomes of cabbage with "cabbage" and radish with "rare" is possible, and each gamete carried 18 chromosomes (9 "rare" and 9 "cabbage"), such a hybrid became fertile. Thus, polyploidy has become one of the ways to restore fertility in interspecific plant hybrids.

distant hybridization allows combine in one organism valuable features of different species and even genera.

Difficulties in the implementation of distant hybridization:

Mismatch of breeding cycles;

Incompatibility of pollen tubes.

Coping Methods:

Method of vegetative convergence (pre-grafting of one species onto another) (hybrid of mountain ash and pear);

Pollination with a mixture of pollen (apple + pear);

Intermediary method (hybrid of a wild species with a wild one, then with a cultivated one to increase frost resistance).

4) artificial selection is to preserve for reproduction plants with the desired characteristics:

A) mass selection

b) individual selection

In artificial selection, a variety is simultaneously affected by natural selection, which increases the adaptability of plants to specific environmental conditions.

The created variety is the result of human activity and the environment.

Breeding of new high-yielding varieties of plants makes it possible to sharply intensify agricultural production.

Breeding successes:

Academician P. P. Lukyanenko - winter wheat Bezostaya 1 - yield up to 100 kg / ha, Aurora;

Shekhurdin and Mamontova - Saratovskaya29, Saratovskaya -36;

Academician N. V. Tsitsyn - a hybrid of wheat and rye - triticale - high flour-grinding qualities are combined with the ability to grow on poor soils;

Academician V.S. Pustovoit - a sunflower variety with an oil content in seeds of over 20%;

AN Lutkov - new varieties of sugar beet with increased sugar content and yield;

M. I. Khadzhinov - high-yielding varieties of corn;

P. I. Icemik - high-yielding varieties of potatoes - Temp, Spark, Lasunak, Synthesis, etc.;

A. L. Semyonov - perennial herbs;

A. G. Voluznev - blackcurrant varieties: Belarusian sweet, Katyusha, Partizanka, red currant: Beloved, gooseberry: Generous

Great contribution to plant breeding introduced by I. V. Michurin(1855-1935), devoted 60 years to the breeding of new varieties, worked in the city of Kozlov (now Michurinsk) of the Tambov region. At the beginning of his activity, he tried to acclimatize the southern varieties by hardening in the northern regions, but they froze, then he used breeding methods. His work is based on a combination of three main methods:

- hybridization;

- selection;

- the impact of environmental conditions on developing hybrids (their "education" in the desired direction.

Michurin attached great attention selection of initial parent forms for hybridization. He crossed local frost-resistant varieties with southern ones, subjected the resulting seedlings to strict selection and kept in relatively harsh conditions. This method was used to obtain the variety Slavyanka, a hybrid of Antonovka and southern pineapple Ranet.

Michurin attached particular importance to crossing geographically distant forms, not growing in the area where hybridization is carried out. This method was used to breed the Bellefleur-Chinese variety, a hybrid of the Chinese apple tree from Siberia and the American variety Bellefleur yellow.

Michurin widely used distant hybridization:

He got hybrids of raspberries and blackberries;

Rowan and hawthorn.

Michurin used to overcoming in the implementation of distant hybridization, the following methods are used:

- method of vegetative convergence(preliminary grafting of one species to another leads to a change in the chemical composition of tissues, including generative organs, which increases the likelihood of germination of pollen tubes in the pistil) (hybrid of mountain ash and pear);

- pollination with a mixture of pollen to stimulate the germination of pollen tubes, that is, “own” pollen irritates the stigma of the pistil and it perceives “foreign” pollen (apple + pear);

- mediator method(a hybrid of a wild species with a wild one, then with a cultivated one to increase frost resistance).

Most varieties bred by Michurin are complex heterozygotes, so to save them use only vegetative propagation(layering, vaccinations).

Animal breeding:

The basic approaches do not differ from those in plant breeding, but there are peculiarities:

a) animals reproduce only sexually;

b) puberty occurs rather late;

c) a small number of offspring.

1) setting a specific task;

2) selection of parental couples, when selecting animals, it is important to take into account exterior- this is a set of external signs of animals, their physique and the ratio of body parts. Different breeds of animals unequally react to changes in external conditions, for example, in meat breeds, improved nutrition leads to an increase in body weight, and in dairy breeds, to an increase in milk yield;

3) hybridization- this is the production of hybrids from the crossing of genetically heterogeneous organisms.

A) inbreeding - inbreeding, it is based on crossing individuals of the same generation or parents and offspring, which leads to an increase in homozygosity and the consolidation of hereditary properties. Prolonged inbreeding leads to weakening and even death, since many recessive mutations are detected in the homozygous state, to overcome these problems, after several inbreeding, outbreeding is used to increase heterozygosity;

If then cross two clean lines with each other - we get the phenomenon heterosis or hybrid power - this is increased viability and fertility in hybrids of the first generation, which decreases in subsequent generations.

There are 3 types of heterosis:

- reproductive- greater fertility than parents;

- somatic- increase in vegetative mass;

- adaptive- hybrids are better adapted.

Heterosis explained the transition of most genes V heterozygous state, since mutant alleles do not appear in the heterozygous state.

The phenomenon of heterosis can be fixed by alternately crossing a hybrid with one or the other initial form.

b) outbreeding- crossing individuals of different breeds;

4) artificial selection is to preserve for reproduction animals with the desired traits:

A) mass selection- selection of a group of organisms with the desired characteristics and obtaining offspring, and the selection is repeated from generation to generation, since individuals can give splitting;

b) individual selection- growing the offspring of one individual, the selection is faster, but the number of offspring is less.

In artificial selection, the breed is simultaneously affected by natural selection, which increases the adaptability of animals to specific environmental conditions;

5) method for determining the quality of producers by offspring(quantity and fat content of milk, egg production).

The created breed is the result of human activity and the environment.

Breeding new highly productive breeds of domestic animals can dramatically increase the quantity and quality of food products.

Breeding successes:

M. F. Ivanov - white steppe Ukrainian pig;

Breeds of fine-fleeced sheep;

Sterile horse-donkey hybrids are mules;

MP Grin - selection of cattle black-and-white breed;

V. T. Gorin - selection of pigs;

- interspecific hybrids- a mule (a hybrid of a mare and a donkey - sterile, but hardy, strong, long-lived), a hybrid between a beluga and a sterlet, a hybrid of carp and crucian carp, a hybrid of a bull and a yak.

Biotechnology- this is the use by man of living organisms and biological processes for the industrial production of various products.

Biotechnology uses microorganisms (prokaryotes - bacteria and blue-green algae) and eukaryotes - fungi, microscopic algae.

The use of microorganisms in such processes as winemaking, baking, cheese making, etc., has been known since antiquity, but modern biotechnology emerged in the mid-1970s.

Features selection of microorganisms consist in the fact that scientists are practically not limited by either time or space, since microorganisms:

b) have simple regulation gene activity;

c) very fast multiply;

d) have haploid set, so any mutation appears already in the first generation;

e) in a small number of test tubes and Petri dishes, millions of individuals can be grown in a few days, that is, easy to get several generations of organisms in almost a short time.

In the selection of microorganisms, they are used natural ability to synthesize substances useful to humans.

Selection stages:

Isolation from the wild nature of microorganisms capable of synthesizing the desired compounds;

Selection of the most productive strains;

Induced mutagenesis and use selective media(environments on which mutants grow well, but the original wild-type parent individuals die);

Productivity selection.

As growth medium for microorganisms, non-food products are used: liquid fractions of oil, synthetic alcohols, waste from the woodworking industry, etc.

Currently in biotechnology great importance got methods of cell and genetic engineering, which open up wide opportunities in the rearrangement of the genome to obtain organisms with desired properties:

So the gene responsible for the formation of insulin was included in the genome of Escherichia coli;

Bacterial strains capable of destroying petroleum products have been constructed and are used to clean water during oil spills;

Bacterial strains were constructed that produce large amounts of amino acids, vitamins, interferon, etc.

Method genetic engineering- This construction of new genetic structures according to a predetermined plan

Genetic engineering method includes:

• selection from cells of individual genes or synthesis of genes outside cells;
• synthesizing or gene cloning or the transfer and integration of these genes into the genome using vectors;
• selection of cells with recombinant genome.

This method became possible as a result of the discovery of enzymes restrictase, which cut the DNA molecule in the right place and enzymes ligase, that stitch together pieces of different DNA molecules and open vectors.

Vector- This is a short circular DNA molecule that can independently multiply in a bacterial cell (virus, bacteriophage, specially designed plasmid). First, the desired gene is inserted into such a vector, and then into the genome of the host cell.

Transgenic plants and animals- organisms whose genome has been modified by genetic engineering operations.

Cell engineering allows you to design whole cells, as well as their individual fragments based on their cultivation, hybridization and reconstruction

• body cells are cultured, and these cells synthesize the substances necessary for a person, for example, ginseng cells transferred to culture synthesize medicinal raw materials, and with such cells, induced mutagenesis or distant hybridization can be carried out to increase their productivity, for example, hybridomas of cells synthesizing antibodies with cancer cells that are capable of to infinite synthesis;
• from cultivated and hybridized cells get regenerated plants, for example, hybrids of tomato and potato, apple and cherry.

(However, manipulations at the genome level can lead to the appearance of strains with unpredictable properties, so progressive scientists held a conference calling for a moratorium on genetic engineering work, scientists began to work on obtaining mutant strains that cannot live in the natural environment, and such organisms were obtained, they can live only on a nutrient medium and are not dangerous for living organisms).

Breeding is the science of improving the individual qualities of animals and plants necessary for man, as well as breeding new plant varieties, animal breeds, strains of microorganisms. Plant breeding methods are used to create cultivars.

Selection

Most of the plants that modern mankind eats are a selection product (potato, tomato, corn, wheat). For several centuries, people have been cultivating wild plants, moving from gathering to farming.

Selection areas are:

• high yield;
• plant nutrition (eg protein content of wheat);
• improved taste;
• resistance of crops to weather conditions;
• early ripening of fruits;
• intensity of development (for example, "responsiveness" to fertilizers or watering).

Rice. 1. Comparison of wild and agricultural corn.

Breeding has solved the problem of food shortage and continues to develop, introducing genetic engineering methods. Breeders not only improve the taste and increase the nutritional value of plants, but also make them healthy, rich in vitamins and chemical elements important for metabolism.

For successful selection, it is necessary to understand the patterns of inheritance of traits, the features of the influence of the environment, the morphological structure and methods of reproduction of cultivated plants.

Methods

The main selection methods are:

TOP 4 articleswho read along with this

• artificial selection- human choice of the most valuable crops for breeding;
• hybridization- the process of obtaining offspring from crossing different genetic forms;
• artificial mutagenesis- changes in DNA.

Artificial selection includes two types - individual (by genotype) and mass (by phenotype).

In the first case, the specific qualities of plants are important, in the second, the most adapted individuals are selected.

Hybridization is of two types:

• intraspecific or closely related - inbreeding;
• distant (interspecies) - outbreeding.

Classical plant breeding methods are described in the table.

Rice. 2. Examples of hybrids.

Unsuccessful breeding experience - Sosnovsky's hogweed. The plant was cultivated as feed for livestock. However, later it turned out that the new hogweed easily penetrates ecosystems, displacing natural plants, and also contains substances that increase sensitivity to ultraviolet radiation. Once on the skin, the juice causes a burn in the sun.

Rice. 3. Sosnovsky's hogweed.

What have we learned?

From the lesson we learned about why breeding is necessary and what methods are used in plant breeding. Considered the classical methods of breeding - individual and mass selection, intraspecific and distant hybridization, mutagenesis.

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