Selection methods I. Michurin. Breeding methods I.V. Michurin The main breeding work of Michurin was the method

In his work, IV Michurin widely used hybridization. In doing so, he took into account the complex nature of hybrids. He believed that hybrid seedlings go through critical periods at various stages of development, during which the realization of parental genes of different quality occurs.

Based on this assumption, I.V. Michurin applied the methods of raising seedlings, influencing them with environmental factors. He used various methods of tillage, fertilization, the mentor method.

The mentor method consists in the fact that a plant is grafted into the crown of a hybrid seedling, the properties of which must be transferred to the hybrid. Sometimes a hybrid is grafted onto an appropriate rootstock.

Remote hybridization in the works of Michurin

I.V. Michurin also widely used. He found that the hybridization of southern varieties with local varieties usually dominates the characteristics of local varieties. To avoid this, he came to the conclusion that it was necessary to select parents from different geographical areas.

So, he brought out the winter pear variety Bere due to the hybridization of the South European pear Bere royal with the Ussuri pear. With such hybridization in a hybrid, the hereditary basis of both initial parental forms turns out to be in unusual natural conditions.

By changing the conditions for growing hybrids, Michurin brought up in them economically valuable traits, borrowed from both one and the other of the parents. In this particular case, the Bere winter variety inherited large-fruitedness, high taste qualities and the possibility of long-term winter storage from the southern parent, and cold resistance from the Ussuri parent.

Due to the fact that organisms under the influence of the environment can change within the normal range of reaction, external factors can influence the phenotypic manifestations of signs. This was used by Michurin when growing hybrids of fruit trees, changing certain conditions at various stages of ontogenesis. The dominance of traits that find the most favorable conditions for development in the environment, Michurin called dominance control.

To overcome non-crossing during distant hybridization, Michurin developed a number of methods.

Michurin methods

Method of vegetative convergence consists in the preliminary grafting of one plant species onto another. As a result, the chemical composition of tissues changes, which, apparently, promotes the germination of pollen tubes in the pistil of the mother plant. In this way, fertilization can be achieved by hybridizing species that do not usually interbreed.

Mediator method consists in the fact that if it is necessary to obtain a hybrid between non-crossing species A and B, first the hybridization of the crossing of species B with C is carried out, and already the hybrid is crossed with species A.

Pollination method with a mixture of pollen from different species may also favor the germination of pollen tubes in the pistil of the flower and promote fertilization.

Most of the varieties bred by Michurin are heterozygous by genotype, therefore they cannot be propagated sexually, they will split. They are propagated vegetatively.

Michurin paid much attention to the acclimatization of southern fruit plants and initiated the northward movement of grapes, apricots, cherries, etc.

Much has been done by breeders to develop new varieties of agricultural plants. The merit of N.V. Tsitsin, P.P. Lukyanenko, V.N. Remeslo, F.G. Kirichenko, V.E. Pisarev, who bred new varieties of wheat, is great in this. V.S. Pustovoit created high-oil varieties of sunflower, I.M. Khadzhinov achieved great success in corn breeding.

Dream

Pavel Savvich is from Kazan. Born in 1858 in the family of a yeast factory master. But the Komissarovs had a family hobby - a garden. Parents did not even give their indispensable assistant to study. Then, all his life, Pavel Savvich comprehended the sciences on his own. Most of all he was fascinated by books and magazines on gardening. And so Pavel read that in Siberia, near Omsk, the first agronomists of the region, Osip Obukhov and Pyotr Shcherbakov, work on the Experimental Farm near Cheredovoye Lake, and next to the Cadet Corps there is a Practical Garden. The young man had a dream to go to Siberia, to start an unprecedented business - gardening in a harsh land.

And life went on as usual. Five years after starting work at the yeast factory, at the age of 22, Pavel received a first-hand master's diploma. He was even put in charge of the workshop, and his father was his subordinate. The family was proud of Paul.

But he didn't sit still. First he went to the Volga cities, then settled in Yekaterinburg for three years. The owner of the local yeast factory liked it so much that he found an apartment for Pavel and paid for it himself. And most importantly, the smart, well-read girl Fedosya lived here. They fell in love with each other and got married. Fedosya's parents gave her a decent dowry. Live and be happy. And Pavel decided that it was time to realize the dream of his own garden in Siberia. What gardening is in the Urals: not earth - stone. Pavel perceived the dream as the mission of his life.

In 1885 the Komissarovs went to Tobolsk. And for five years Pavel Savvich fought there for his idea with cold winds, from which seedlings froze, and with a misunderstanding of both local residents and officials. And in 1890 the family moved to the south of Siberia, to the provincial Omsk - now forever.

The first gardens have already been planted in Omsk. They belonged to the most famous townspeople: Shanina, Terekhov, Yasherov ... But there was no particular success. With whomever Pavel Savvich spoke about his dream, he heard in response: “Yes, in Siberia, potatoes instead of apples will give birth to more than a fist, and this is enough. And apples will be brought to us from the south.” But Pavel Savvich stubbornly went to his goal. He wrote a petition to the Cossack Military Administration with a request to let him rent twenty acres of land on the condition that in twenty years he would return the land with a flowering garden. Bonded, I must say, the condition: to do everything and give. But Komissarov was not thinking about increasing property.

Siberian climate winner

The first garden was far from the Irtysh, which created a problem with watering. And hares in winter damaged the trunks of seedlings. Without losing hope of success, Pavel Savvich moved the garden to the south. The family bought a house in Omsk, sold it, and put a modest hut in the garden.

To protect the garden from the winds, Pavel Komissarov planted willows from the Irtysh side, and pine trees from the north. He divided the entire site into squares and created borders between them - backstage from dozens of different plants: from oak and cedar to elder, acacia, lilac. Inside the squares were thermophilic grapes, cherries, pears, apple trees, honeysuckle, strawberries, currants, raspberries. Everything that pleases Omsk residents in their dachas today, but at that time was a curiosity. Pavel Savvich nurtured this planting plan for many years. He grafted creeping apple trees of European large-fruited varieties onto Siberian wild animals. In late autumn, he wrapped the trees with straw, burlap and matting.

He, self-taught, corresponded with IV Michurin. By 1905 he already had twenty varieties of his selection. Fourteen years later, 64 varieties of apple trees, 15 varieties of cherries, 6 varieties of barberry, about 60 varieties of currants, Kazan walnut, plum, Pennsylvania cherry, 12 species of hawthorn bore fruit in the garden.

The pride of Komissarov is white mulberry. He grew 34 varieties of one lilac. Since then, lilac has become a sign of Omsk, a favorite floral motif of artists-countrymen of different generations. About three hundred different biological species made up the wealth of this garden. IV Michurin supported the enthusiast.
Inspired, Pavel Savvich distributed seedlings to everyone who wished, welcomed the guests. Who just wasn't here! They sailed from the city on steamboats with an orchestra for pleasant walks along shady alleys. And, for example, businessman S. Kh. Randrup came with his family by car, one of the first in Omsk. The guests drank tea with fragrant herbs, ate fruits, and received bouquets of flowers at parting.

Today, when working on five acres seems to Omsk residents, especially young people, not an easy task, it is impossible to imagine how one family managed a garden of twenty acres. Moreover, it was experimental, where each type of plant needed to be acclimatized. Here is a fragment from the memoirs of the daughters of Pavel Savvich: “Father did not give money, everything went to the garden. All winter the earth soared in cast iron. I sowed seeds in jars, more than a thousand jars with sprouts stood. Forty tubs of water were poured through the garden. In the morning, trees were watered from tubs, seven hundred buckets each. And that’s all… running… My father was crawling on his knees, loosening the ground around the trees with his hands. He drank tea on the go, so he walked around the garden with a mug ... At night he jumped up, wrote in his book, paced back and forth, thought.

Hard labor. And all the worries fell on the shoulders of Pavel Savvich, his wife Fedosya Alexandrovna and the children of Fedor, Sergey, Uliana and Maria. Nothing for myself. Pavel Savvich did not even have a second pair of boots. Alone - and only on the way out. I went barefoot all summer.

In 1907, the Governor-General of the Steppe was at the highest reception of Nicholas II and presented the emperor with a box of Komissarov's apples and photographs of the garden, saying: "Yermak conquered the Siberian land, and Komissarov conquered the Siberian climate." The tsar ordered to thank Pavel Savvich and grant him a gold watch with a chain and the state emblem.

The minister shook hands

At the first West Siberian Agricultural, Forestry and Commercial and Industrial Exhibition, the exhibits of Pavel Savvich Komissarov were presented in the Forest Pavilion. For some reason, everyone admired the American maple. It was believed that maple could not grow in Siberia. Pavel Savvich brought to the exhibition a collection of pickles and jams from his garden. And also luxurious bouquets of flowers.

The exhibition was visited by the Minister of Railways Krivoshein, who, as reported in the newspapers, “examined the exposition of the famous gardener with visible interest” and “thanked him for the successful fight against the harsh nature of Siberia, shaking his hand twice.” “But the expert commission on horticulture almost did not notice him. The circumstance is at least strange,” the journalist notes. The press loved Pavel Savvich and tried to support him in everything. What a fuss was raised in the Omsk press when, following the results of the exhibition, Komissarov was awarded not a gold, but a silver medal!

I can assume that the scientific world was confused by the simplicity and ... popularity of the Siberian Michurin. During the exhibition, an agricultural congress was held, at which Pavel Savvich was also given the floor. During his speech, laughter was heard in the hall. Yes, he was not speechless, he formulated thoughts in a peasant way. But his amazing garden was then the only one in Siberia! None of the learned gentlemen was ready for such a feat: to live in hardship, creating the future.

"I will die, but my surname will live"

The sons of Pavel Savvich were mobilized for the German war. This means: minus two assistants. But he did not leave experiments. As before, he ordered seeds from all over the world: from North and South America, Japan, Manchuria, Western Europe. The trouble happened during the Civil War. In the late autumn of 1919, the retreating White Army with a herd of horses passed through the Komissarov garden. Not only did she pass, she made a stop in the garden. Before the eyes of the owner, the horses broke seedlings, grazed in the beds. There was a conflict.

According to one version, the warriors beat the gardener, then he caught a cold and died of pneumonia. According to another, when he saw the ruin of the garden, Pavel Savvich fell into despair, got a nervous breakdown and, visiting his affected trees in the bitter cold, caught pneumonia. Be that as it may, we can say that he fell ill, fell ill and died of grief. Relatives buried Pavel Savvich in his garden. The garden was nationalized in the same 1920. Became popular, and therefore no one's. The children continued to take care of the plants for several years. But it ended with the fact that the sons had to flee from the new government, they went to hell. And the daughters got married.

The famous Hirel garden. Only in 1948 it was recognized as a park and botanical reserve, but traces of desolation were obvious. The garden was overgrown with weeds, cattle grazed in it. And all the distinguished guests of Omsk were still brought to Komissarov's garden. Nikita Khrushchev, and Leonid Brezhnev, and Joseph Broz Tito, and Walter Ulbricht have been here.

Omsk agricultural scientists, biologists, geographers sounded the alarm: the garden was disappearing. But not their voice, but a critical article in the Pravda newspaper in 1970 gave impetus to restore order. The Chapaev collective farm was assigned to look after the garden, and a museum building was built.

The second time it was opened in 1999. The garden was given the status of an arboretum named after P. S. Komissarov. And in 2008, the arboretum was declared a natural monument of regional significance. Today there is a monument with a portrait of Pavel Savvich, work is underway to restore the former beauty. The Day of the Siberian Garden, art festivals are held.

Once Pavel Savvich spoke about his hard labor: "If there were no hope, my heart would burst." He addressed the youth with a poetic order (he dabbled in composing poetry): "Do not waste your golden time, be useful, do not be lazy, and for the future tribe, spare no effort, work." And he noticed: "I will die, but my surname will live." As it turned out, the words were prophetic.

The outstanding Russian scientist-breeder Ivan Vladimirovich Michurin spent most of his life in the county town of Kozlov (Tambov province), which was later renamed Michurinsk in recognition of his work. He is considered one of the founders of the science of breeding fruit crops. From a young age, he was fascinated by gardening. His whole life was devoted to one goal: to develop new high-yielding varieties of agricultural crops in the climatic conditions of Russia. And he managed to achieve the realization of this dream, despite the incredible difficulties and hardships.

One of the most important results of his many years of work was the original practical methods he developed for obtaining hybrids with new, valuable properties. In addition, on the basis of the work done, he made very important theoretical conclusions.

Initially, Michurin set himself the task of acclimatizing southern varieties of fruit trees in the conditions of central Russia. However, failure awaited him here, due to the fact that the heat-loving southern varieties of plants, even if grown in new conditions, did not endure the harsh winter. This is due to the fact that one change in the conditions of existence of an organism cannot change a phylogenetically developed stable genotype, moreover, in a certain direction.

Thus, Michurin realized that the acclimatization method did not give the desired results. This led him to the idea that it is possible to obtain varieties with the required properties if one variety is crossed with another, that is, by engaging in selection work. Michurin used three main types of influence in his work: hybridization, education of a developing hybrid in various conditions, and selection.

hybridization method

Obtaining a variety with new, improved characteristics is called hybridization.

As a rule, it is carried out by crossing a local variety with a southern one with higher palatability. However, due to the historical adaptation of the local variety to the conditions of existence in the area, the resulting hybrids were dominated by the characteristics of the local variety.

In order for hybridization to be successful, Michurin took parents from very distant geographical areas for crossing. Michurin believed that in this case unilateral dominance would not occur, since the conditions of existence would not be familiar to any of the parental forms. Based on this, the development of the newly obtained hybrid can be controlled.

Subsequently, Michurin practically proved the validity of the above statement, having received a completely new pear variety Bere winter Michurina. It was distinguished by large, light fruits with good taste, while the hybrid plant itself endured cold down to -36 °. As a father, a southern variety of pear Bere was taken - a piano with large juicy fruits, and as a mother - a wild Ussuri pear with small fruits and high winter hardiness. For both parents, the conditions of central Russia were unusual.

Michurin also selected and crossed local frost-resistant varieties with southern heat-loving varieties, which differed in other ways. He strictly monitored that the resulting hybrids were frost-resistant. Thanks to this, the apple variety Slavyanka was obtained from crossing Antonovka with the southern variety Ranet pineapple.

Michurin's experiments on crossing plants of different species were also widely known, and interspecific and intergeneric hybrids were obtained, such as hybrids between cherries and bird cherry (cerapadus), between apricot and plum, plum and sloe, mountain ash and Siberian hawthorn, etc.

Under natural conditions, crossing of different species plants does not occur due to the fact that alien pollen of another species is not perceived by the mother plant. Michurin used several methods to overcome non-crossing in distant hybridization.

Method of preliminary vegetative approach

This method was used by Michurin when crossing mountain ash and pear. It consists of two stages.

First, a one-year-old stalk of a hybrid rowan seedling (graft) is grafted into the crown of a plant of another species or genus, for example, to a pear (rootstock). After 5 - 6 years of nutrition due to the substances produced by the stock, there is some change, the convergence of the physiological and biochemical properties of the scion.

Then, during the flowering of mountain ash, its flowers are pollinated with the pollen of the rootstock. This is where the crossover takes place.

Mediator method

The essence of this method is that in case of impossibility of direct hybridization of two forms of plants, the third one is used. This plant is crossed with one of the first two, and then the resulting hybrid is crossed with the second, resulting in a hybrid of the first two forms. The third form acts as an intermediary.

The intermediary method was used by Michurin when crossing a cultivated peach with a wild Mongolian almond bean (to increase the frost resistance of a peach). Since direct crossing of these forms was not possible, Michurin crossed the beaver with the semi-cultivated peach David. Their hybrid crossed with a cultivated peach, for which he was called an intermediary.

Pollination method with a mixture of pollen

I. V. Michurin used various variants of the pollen mixture. A small amount of pollen from the mother plant was mixed with pollen from the father. In this case, its own pollen irritated the stigma of the pistil, which became capable of accepting foreign pollen. When pollinating apple flowers with pear pollen, a little apple pollen was added to the latter. Part of the ovules was fertilized by its own pollen, the other part - by someone else's (pear).

Non-crossing was also overcome when the flowers of the mother plant were pollinated with a mixture of pollen from different species without the addition of pollen of their own variety. Essential oils and other secretions secreted by foreign pollen irritated the stigma of the mother plant and contributed to its perception.

Throughout his many years of work on breeding new varieties of plants, IV Michurin showed the importance of the subsequent education of young hybrids after crossing.

When raising a developing hybrid, Michurin paid attention to the composition of the soil, the method of storing hybrid seeds, frequent replanting, the nature and degree of nutrition of seedlings, and other factors.

The mentor method

This method was developed by Michurin and widely used by him in practice. It consists in the fact that the seedling is grafted onto a plant that has the necessary qualities for nurturing the desired qualities in the hybrid seedling. As a result, the desired qualities are enhanced in the hybrid, and its further development is under the influence of substances produced by the parent plant (mentor). In this case, in the process of development of hybrids, a change in the properties of dominance occurs. At the same time, both a rootstock and a scion can be a mentor.

Using the method of a mentor, Michurin bred two varieties - Bellefleur-Chinese and Kandil-Chinese.

Kandil-Chinese is the result of crossing Kitaika with the Crimean variety Kandil-Sinap. Michurin grafted the hybrid into the crown of the frost-resistant Kitaika mother in order to develop and consolidate the trait of frost resistance. Thanks to the nutrition of the mother's substances, the hybrid has the desired quality.

The second variety, Bellefleur-Chinese, was bred to prevent the hybrid from deviating towards the frost-resistant and early ripe Kitayka, and therefore the fruits of the hybrid could not be stored for a long time. Michurin grafted several cuttings of late-ripening varieties into the crown of the Bellefleur-Chinese hybrid seedling in order to increase the keeping quality in the hybrid. As a result of the hybridization carried out, the fruits of Bellefleur-Chinese became more late-ripening and keeping quality.

This method can be controlled in the following ways:

The duration of the mentor.

The ratio of the age of the mentor and the hybrid.

The quantitative ratio of mentor foliage and hybrid.
The older the age of the mentor, the richer the foliage of the crown and the longer it acts, the higher the intensity of its action. When carrying out breeding work, Michurin made repeated and rather rigorous selection, which made it possible to obtain hybrids of excellent quality. Hybrid seeds were selected for their roundness and size; hybrids - according to the configuration and thickness of the leaf blade and petiole, the shape of the shoot, the location of the lateral buds, the winter hardiness and resistance to fungal diseases, pests and many other features, and, finally, the quality of the fruit.

As a result of his research, I. V. Michurin created several hundred new varieties of plants. New cold-resistant varieties of apple trees and berry crops were bred. These plants are characterized by high palatability and at the same time are perfectly adapted to local conditions. One of these species is the apple variety Antonovka six hundred grams, which yields up to 350 kg from one tree. Grapes, bred by Michurin, withstood the winter without powdering the vines, which is done even in the Crimea. At the same time, he did not reduce his commodity indicators.

I. V. Michurin, with his work, turned the idea of human capabilities and laid a solid foundation for further research in plant breeding.

Bibliographic list

Biology manual for university students. - Minsk: Higher School, 1978

Encyclopedic Dictionary of a Young Naturalist. - Moscow: Pedagogy, 1981

Initially, Michurin set himself the task of acclimatizing southern varieties of fruit trees to the conditions of central Russia. However, failure awaited him here, due to the fact that the heat-loving southern varieties of plants, even if grown in new conditions, could not stand the harsh winter. This is due to the fact that one change in the conditions of existence of an organism cannot change a phylogenetically developed stable genotype, moreover, in a certain direction.

hybridization method

Obtaining a variety with new, improved characteristics is called hybridization. As a rule, it is carried out by crossing a local variety with a southern one with higher palatability. However, due to the historical adaptation of the local variety to the conditions of existence of the given area, the obtained hybrids were dominated by the characteristics of the local variety.

Subsequently, Michurin practically proved the validity of the above statement, having received a completely new pear variety Bere winter Michurina. It was distinguished by large, storable fruits with good taste, while the hybrid plant itself endured cold up to -36 °. The southern pear variety Bere royale with large juicy fruits was taken as the father, and the wild Ussuri pear with small fruits and high winter hardiness was taken as the mother. For both parents, the conditions of central Russia were unusual.

^ Method of preliminary vegetative approach

This method was used by Michurin when crossing mountain ash and pear. It consists of two stages.

First, a one-year-old stalk of a hybrid rowan seedling (graft) is grafted into the crown of a plant of another species or genus, for example, to a pear (rootstock). After 5-6 years of nutrition, due to the substances produced by the rootstock, there is some change, the convergence of the physiological and biochemical properties of the rootstock.

Then, during the flowering of mountain ash, its flowers are pollinated with the pollen of the rootstock. This is where the crossover takes place.

^ Mediator method

^ Pollination method with a mixture of pollen .

Throughout his many years of work on breeding new varieties of plants, IV Michurin showed the importance of the subsequent education of young hybrids after crossing.

The mentor method

Using the method of a mentor, Michurin bred two varieties - Bellefleur-Chinese and Kandil-Chinese.

The second variety, Bellefleur-Chinese, was bred to prevent the hybrid from deviating towards the frost-resistant and early ripe Kitayka, and therefore the fruits of the hybrid could not be stored for a long time. Michurin planted several cuttings of late-ripening varieties into the crown of the Bellefleur-Chinese hybrid seedling in order to increase the keeping quality in the hybrid. As a result of the hybridization carried out, the fruits of Bellefleur-Chinese became more late-ripening and keeping quality.

This method can be controlled in the following ways:

1) the duration of the mentor; 2) the ratio of the age of the mentor and the hybrid; 3) the quantitative ratio of the leaves of the mentor and the hybrid.

The older the age of the mentor, the richer the foliage of the crown and the longer it acts, the higher the intensity of its action. When carrying out breeding work, Michurin made repeated and rather rigorous selection, which made it possible to obtain hybrids of excellent quality. Hybrid seeds were selected for their roundness and size; hybrids - according to the configuration and thickness of the leaf blade and petiole, the shape of the shoot, the location of the lateral buds, the winter hardiness and resistance to fungal diseases, pests and many other features, and, finally, the quality of the fruit.

As a result of his research, I. V. Michurin created several hundred new varieties of plants. New cold-resistant varieties of apple trees and berry crops were bred. These plants are characterized by high palatability and at the same time are perfectly adapted to local conditions. One of these species is the apple variety Antonovka six hundred grams, which yields up to 350 kg from one tree. The grapes bred by Michurin withstood the winter without powdering the vines, which is done even in the Crimea. At the same time, he did not reduce his commodity indicators.

I. V. Michurin, with his work, turned the idea of human capabilities and laid a solid foundation for further research in plant breeding

Bibliography

Biology manual for university students. Minsk, I., Higher School, 1978

Encyclopedic Dictionary of a Young Naturalist. Moscow, I., Pedagogy. 1981

Equipment: tables on general biology, illustrating the methods of plant breeding, methods of breeding work by I.V. Michurin and achievements in plant breeding.

DURING THE CLASSES

I. Knowledge Test

A. Card work

№ 1. Scientists have obtained a wheat-rye hybrid of triticale. How did you manage to create such a hybrid that successfully reproduces sexually?

№ 2. Bezostaya 1 (bred by P.P. Lukyanenko) and Mironovskaya 808 (bred by V.N. Remeslo) are recognized as the highest-yielding (up to 100 c/ha) wheat varieties. Their ears and grains are very large, the stems are thick, strong. These varieties are soft, polyploid ( 6n) wheat. The highest yield and large fruits in strawberries are also given by polyploid (8n) plants. Using this data, answer the questions:

a) how does polyploidy affect fruit size and other morphological features of wheat and strawberries?
b) how does polyploidy affect the productivity of these plants?
c) what is the economic significance of polyploidy for humans?

№ 3. Evolutionary theory was confirmed by the studies of the Danish geneticist V. Johansen. He studied the action of selection in populations and pure lines. It turned out that within the limits of a pure line, selection by size, seed weight, and other traits is inefficient. At the same time, selection in freely crossing populations is effective. Explain what pattern of evolutionary theory is supported by the results of this study.

№ 4. Currently, a hybrid tomato variety resistant to two viruses is widely used in the USA and England. The variety is obtained as a result of the fusion of germ cells of a wild tomato and a cultivated variety. Explain the importance of preserving the genes of wild species for breeding.

B. Oral knowledge test

1. What are the biological characteristics of plants taken into account in breeding?
2. What is inbreeding and interbreeding?
3. What is intervarietal and interspecific crossbreeding?
4. What is the phenomenon of heterosis and what are its genetic bases?
5. What is the method of G.D. Karpechenko on overcoming the infertility of interspecific hybrids?
6. What is mass and individual selection in plant breeding?
7. What is induced mutagenesis and what is the method of obtaining polyploids in plant breeding.

II. Learning new material

1. Methods of selection work I.V. Michurin

Ivan Vladimirovich Michurin (1855–1935) is an outstanding practical breeder, the author of 300 varieties of fruit and berry crops. At the beginning of his activity, I.V. Michurin was engaged in acclimatization according to the Grell method, grafting southern varieties into the crown of hardy and cold-resistant varieties in order to achieve their adaptation to new conditions. But it was impossible to change the genotype of southern varieties by a similar method. Michurin was convinced of this by testing about 200 foreign varieties: after 35 years, not a single tree remained of them, although Michurin lived and worked in the relatively mild climate of the Black Earth Zone of Russia (Kozlovsk, now Michurinsk, Tambov province).
Convinced of the futility of attempts at simple acclimatization, I.V. Michurin began to develop new breeding methods based on hybridization, selection and education (the impact of environmental conditions on developing hybrids). In their implementation, he used a variety of approaches (many of them for the first time in world breeding practice), the most important of which are as follows.

biologically distant hybridization - crossing representatives of different species to obtain varieties with the desired properties or crossing representatives of different genera. So, for example, Michurin crossed the Vladimirskaya cherry with the white Winkler cherry. In further work with hybrids, he developed the Krasa Severa cherry variety, which had good taste and winter hardiness. When crossing cherry with bird cherry, Michurin received a hybrid called cerapadus. He also obtained hybrids of blackberry and raspberry, plum and blackthorn, mountain ash and Siberian hawthorn, etc.

Geographically distant hybridization - crossing of representatives of contrasting natural zones and geographically remote regions in order to instill in the hybrid the desired qualities. For example, the well-known pear variety Bere winter Michurina was obtained as a result of hybridization of the wild Ussuri pear and the southern French variety Bere-royal.

The mentor method - one of the methods of "education" of hybrids developed by I.V. Michurin. It is based on the fact that the characteristics of a developing hybrid change under the influence of a scion or rootstock. Michurin used this method in two versions. In the first case, the hybrid seedling served as a scion, and it was grafted onto an adult fruit-bearing plant (rootstock), the properties of which it was desirable to obtain from the hybrid. In the second case, a stalk of a variety was grafted into the crown of a young hybrid seedling (rootstock), the characteristics of which they would like to obtain from the hybrid.
This method was applied by Michurin, for example, when creating the Bellefleur-Chinese apple variety. In the first year of fruiting hybrids, it turned out that their fruits are small and sour. To direct the further development of the hybrid in the right direction, Bellefleur cuttings were grafted into the crown of young trees. Under the influence of cuttings, the fruits of the hybrid began to acquire the taste qualities of Bellefleur.
The influence of the mentor should be seen as a change in dominance during the development of the hybrid. In this case, the mentor contributed to the phenotypic manifestation (dominance) of the genes obtained from the Bellefleur variety, without changing the genotype of the hybrid.

Mediator method was used by Michurin for distant hybridization. It consists in using the wild species as an intermediary to overcome inbreeding. By crossing the wild Mongolian almond with the wild peach of David, Michurin obtained the Posrednik almond, which he later used to cross with the cultivated peach. The hybrid peach he received acquired winter hardiness, due to which he was promoted to the north.

Mixing pollen was used by Michurin to overcome interspecific inbreeding (incompatibility). The essence of the method was that when pollinated with a mixture of one's own pollen and pollen of another species, one's own pollen irritated the stigma of the pistil, and it perceived foreign pollen.

Exposure to environmental conditions . When "educating" young hybrids, Michurin used changes in the methods of storing seeds, the nature of nutrition and soil properties, exposure to low temperatures, and used frequent transplants. As a result, hybrids hardened and could endure adverse environmental conditions.

Selection – repeated and rigorous selection of plants in terms of size, shape, winter hardiness, immune properties, quality, taste, fruit color, etc.
Most of the varieties obtained by I.V. Michurin, were complex heterozygotes. To preserve their qualities, they are propagated vegetatively: by layering, grafting, etc.

2. Achievements in plant breeding

Selection work is of great national economic importance. Replacing low-yielding varieties with high-yielding breeding varieties is one of the main ways to increase yields. At present, both in our country and abroad, selection and genetic work leads to remarkable results.
Let's take a look at some of the latest advances in breeding for major crops.

Winter wheat . For Russia, wheat is the main grain crop. Academician Pavel Panteleimonovich Lukyanenko (1901–1973) created a number of high-yielding varieties of winter wheat, covering millions of hectares both in Russia and in other countries. Especially popular are the varieties Avrora and Kavkaz, yielding up to 100 c/ha, and Bezostaya 1 with a yield of up to 50 c/ha. On the basis of the latter variety, the varieties Krasnodarskaya 57 and Odessa semi-dwarf were bred.
No less high-yielding varieties were bred at the Mironovskaya breeding experimental station by Academician Vasily Nikolaevich Remeslo (1907–1983): Mironovskaya 264, Mironovskaya 808, etc. Over the past 50 years, the yield of winter wheat varieties has increased from 25 to 65 c/ha, i.e. 2.5 times. Ilyichevka also belongs to the new high-yielding varieties of winter wheat, bred at the same station. In 1974, this variety was released in 15 regions of Ukraine and, with proper irrigation and high agricultural technology, yields up to 100 c/ha.
Among the new varieties, perennial wheats are very promising, bred under the guidance of Academician Nikolai Vasilievich Tsitsin (1898–1980) on the basis of interspecific hybridization of wheat and wheatgrass. They are high-yielding, drought-resistant, withstand frosts down to -35 oC.

Spring wheat . Among the spring varieties, the most valuable is the high-yielding variety Saratovskaya 29, created by Alexei Pavlovich Shekhurdin (1886–1951) and Valentina Nikolaevna Mamontova (1895–1982), which is distinguished by high baking qualities. We have already mentioned the Novosibirskaya 67 spring wheat variety with a shortened and thickened straw, bred at the Institute of Cytology and Genetics of the Siberian Branch of the Russian Academy of Sciences. The yield of this variety in Western Siberia reaches 40 q/ha.

Sunflower . In this area of plant breeding, the achievements of academician Vasily Stepanovich Pustovoit (1886–1972) are remarkable. Until the middle of the XX century. The best varieties of sunflower oil content did not exceed 33%. Currently, the average oil content of seeds reaches 50%.

Sugar beet . In recent years, the sugar content and yield of sugar beets have increased dramatically. A large role in the selection of this culture was played by polyploidy (works by A.N. Lutkov, V.P. Zosimovich).

Corn . When creating new promising varieties of this crop, self-pollinating homozygous lines are used with their subsequent hybridization (M.I. Khadzhinov and G.S. Galeev).

III. Consolidation of knowledge

Generalizing conversation in the course of learning new material.

IV. Homework

To study the paragraph of the textbook (methods of breeding work by I.V. Michurin and the achievements of plant breeding).

Lesson 8–9. Animal breeding, its methods and achievements

Equipment: tables on general biology, illustrating the methods of selection work by I.V. Michurin, achievements in plant breeding, methods of animal breeding.

DURING THE CLASSES

I. Knowledge Test

A. Card work

№ 1. What important pattern of trait dominance in hybrids was established by I.V. Michurin? What is the significance of this pattern for selection? Give examples.

№ 2. What are the positive and negative aspects of self-pollination in the selection of cultivated plants?

№ 3. There is an expression: "A person is fed and clothed by polyploids." How should it be understood?

№ 4. When selecting parent pairs for hybridization, I.V. Michurin made extensive use of geographically distant forms. So, for example, the apple-tree variety Bellefleur-Chinese was created, obtained as a result of hybridization of a Chinese apple tree from Siberia and the American variety Bellefleur yellow. Why did Michurin pay much attention to the crossing of geographically distant forms?

B. Oral knowledge test

1. What breeding methods did I.V. Michurin?
2. What are the latest advances in plant breeding?

II. Learning new material

1. Features of animal biology taken into account in breeding

When selecting animals, it is necessary to take into account the following features:

- a small number of offspring in a pair of parents;
- long life expectancy;
- the impossibility of vegetative reproduction of highly organized animals and the presence of only sexual reproduction in them;
- dichotomy;
- often late puberty;
- more complex than in plants, relationships with the environment due to the presence of the nervous system;
- the difficulty of studying the genotype, because it contains a large number of heterozygotes, and genes are in complex interaction (meat, milk, wool productivity, fertility, fur density in fur animals and other economically valuable traits are very difficult to inherit).

2. Types of crosses and breeding methods used in animal husbandry

In breeding work, it is important to represent the ultimate goal that the breeder is striving for. Whether it is desirable to increase milk production, increase its fat content, or change the meat qualities of livestock - all this requires different directions for the selection and selection of producers, the use of various crossing systems.
When selecting breeders, it is important to consider their pedigrees. In breeding farms, pedigree books are always kept, in which the exterior features and productivity of parental forms are taken into account in detail over a number of generations. According to the signs of the ancestors, one can judge the genotype of the producers.
The types of crossbreeding in breeding work with animals are varied. There are mainly two types of crossing: unrelated and related.

unrelated crossbreeding , or outbreeding (from English. out- outside and breeding- breeding) is carried out between individuals of the same breed or between individuals of different breeds of animals. With strict selection, it leads to the maintenance of properties or their improvement in the next generations of hybrids, tk. in the offspring, a successful combination of genes can be obtained, which ensures the formation of a number of economically important traits.

Inbreeding, or inbreeding, held between siblings or parents and offspring. This type of crossing is used in those cases when they want to transfer most of the genes of the breed to a homozygous state, i.e. to obtain pure lines, preserve economically important traits, increase the stability of these traits for subsequent crossing and obtain the effect of heterosis.
To a certain extent, such crossing is similar to self-pollination in plants, since. leads to an increase in homozygosity. With closely related crossing, weakening of animals, loss of resistance to external factors, to diseases is often observed. All these negative manifestations of inbreeding are called depression.

Interline crossing is carried out between representatives of pure homozygous lines in order to avoid the adverse effects of recessive genes, transfer them to a heterozygous state and cause the effect of heterosis. Usually representatives of several lines are used for crossing.

distant hybridization , i.e. interspecific crossing has been known in animals since ancient times. Most often, interspecific hybrids are sterile, because. they have disrupted meiosis, which leads to disruption of gametogenesis. Since ancient times, man has been using a hybrid of a mare with a donkey - a mule, which is distinguished by endurance and long life expectancy. Overcoming the infertility of interspecific hybrids of animals is an important task of breeding.
Sometimes gametogenesis in distant hybrids proceeds normally, and this made it possible to obtain new valuable breeds of animals. An example is the archa-merino, which can graze high in the mountains like argali and, like merino, produce good wool. Prolific hybrids have been obtained from crossing local cattle with yaks and zebu (a subspecies of cattle common in Asia and Africa). Productive hybrids of beluga and sterlet (bester), ferret and mink (honorik) , carp and carp. Also prolific are the offspring obtained by crossing between one-humped and two-humped camels, domestic horses and Przewalski's horses, bison and bison.
In animal husbandry, two main breeding methods are used: interbreeding and interbreed.

Inbreeding, or breeding in oneself , aimed at preserving and improving the breed. In practice, it is expressed in the selection of the best producers, the culling of individuals that do not meet the requirements of the breed.

Interbreeding used to create a new breed. In this case, inbreeding is often carried out, which helps to obtain a large number of individuals with the desired properties.

To be continued