Michurin's main method of breeding work was. Methods of selection and genetic work I.V. Michurina. B. Oral knowledge test

08.03.2020

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

DURING THE CLASSES

I. Test of knowledge

A. Working with cards

№ 1. Scientists have obtained a wheat-rye triticale hybrid. How was it possible to create such a hybrid that successfully reproduces sexually?

№ 2. The highest yielding (up to 100 c/ha) wheat varieties are recognized as Bezostaya 1 (bred by P.P. Lukyanenko) and Mironovskaya 808 (bred by V.N. Remeslo). Their ears and grains are very large, the stems are thick and strong. These varieties are soft, polyploid ( 6n) wheat. Most high yield (and strawberries also produce large fruits that are polyploid 8n

) plants. Using this data, answer the questions: a) how polyploidy affects the size of fruits and others morphological characteristics
wheat and strawberries?
b) how does polyploidy affect the productivity of these plants? in which economic importance

№ 3. has polyploidy for humans? Confirmation evolutionary theory

№ 4. were the studies of the Danish geneticist V. Johansen. He studied the action of selection in populations and pure lines.

It turned out that within a pure line, selection for size, weight of seeds and other characteristics is ineffective. At the same time, selection in freely interbreeding populations is effective. Explain what pattern of evolutionary theory is supported by the results of this study.

Currently, a hybrid variety of tomatoes that is resistant to two viruses is widespread 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 selection. B. Oral knowledge test 1. What are
biological features
plants taken into account in breeding?
2. What is inbreeding and interline crossings?
5. What is the G.D. method? 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 for obtaining polyploids in plant breeding.

II. Learning new material

1. Methods of selection work I.V. Michurina

Ivan Vladimirovich Michurin (1855–1935) - an outstanding practical breeder, author of 300 varieties of fruits berry crops. At the beginning of his activity I.V. Michurin worked on acclimatization using 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 change the genotype southern varieties this method was impossible. Michurin became 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 selection methods based on hybridization, selection and education (the impact of environmental conditions on developing hybrids). When implementing them, he used a variety of approaches (many for the first time in world breeding practice), the most important of which are the following.

Biologically distant hybridization – crossing of representatives different types to obtain varieties with the desired properties or crossing representatives different genera. For example, Michurin crossed Vladimir cherry with Winkler white cherry. At further work With hybrids, he developed the Krasa Severa cherry variety, which had good taste and winter hardiness. When crossing cherries with bird cherry, Michurin obtained a hybrid called cerapadus.

He also obtained hybrids of blackberries and raspberries, plums and sloe, rowan and Siberian hawthorn, etc. Geographically distant hybridization – crossing representatives of contrasting natural areas and geographically remote regions in order to instill in the hybrid necessary qualities

. For example, the famous winter pear variety Bere Michurina was obtained as a result of hybridization of wild Ussuri pear and the southern French variety Bere royal. - one of the methods of “raising” 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 were desired to be obtained from the hybrid. In the second case, a cutting of a variety whose characteristics would be obtained from the hybrid was grafted into the crown of a young hybrid seedling (rootstock).
This method was used by Michurin, for example, when creating the Bellefleur-Chinese apple tree variety. In the first year of fruiting of the hybrids, it turned out that their fruits were 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 the cuttings, the fruits of the hybrid began to acquire the taste qualities of Bellefleur. The influence of the mentor should be considered as a change in dominance during the development of the hybrid. IN in this case

the mentor promoted the phenotypic manifestation (dominance) of genes obtained from the Bellefleur variety, without changing the genotype of the hybrid. Mediator method

was used by Michurin for remote hybridization. It consists of using a wild species as an intermediary to overcome uncrossability. By crossing the wild Mongolian almond with the wild David peach, Michurin obtained the Mediator almond, which he later used to cross with the cultivated peach.

The hybrid peach he obtained acquired winter hardiness, thanks to which it was promoted to the north. Pollen mixing used by Michurin to overcome interspecific incompatibility (incompatibility). The essence of the method was that when pollinated with a mixture of one’s own pollen and pollen of another species, the own pollen irritated the stigma of the pistil, and it perceived foreign pollen. Exposure to environmental conditions . When “raising” young hybrids, Michurin used changes in methods seed storage, nutritional patterns and soil properties, impact

low temperatures , used frequent transplants. As a result, the hybrids were hardened and could tolerate
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 economic importance. Replacing low-yielding varieties with high-yielding breeding varieties is one of the main ways to increase productivity. Currently, both in our country and abroad, selection and genetic work leads to remarkable results.
Let's get acquainted with some of the latest achievements in breeding for major agricultural crops.

Winter wheat . For Russia, wheat is the main grain crop. Academician Pavel Panteleimonovich Lukyanenko (1901–1973) created a number of high-yielding varieties winter wheat, occupying millions of hectares both in Russia and in other countries. Particularly popular are the varieties Aurora and Kavkaz, which produce a yield of up to 100 c/ha, and Bezostaya 1 with a yield of up to 50 c/ha. Based on the latter variety, the varieties Krasnodarskaya 57 and Odesskaya semi-dwarf were bred.
No less high-yielding varieties 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 is one of the new high-yielding varieties of winter wheat bred at the same station. In 1974, this variety was zoned in 15 regions of Ukraine and, with proper irrigation and high agricultural technology, produces yields of up to 100 c/ha.
Among the new varieties, perennial wheats bred under the leadership of Academician Nikolai Vasilyevich Tsitsin (1898–1980) based on interspecific hybridization of wheat and wheatgrass are very promising. They are high-yielding, drought-resistant, and can 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), characterized by high baking qualities. We have already mentioned the spring wheat variety Novosibirskaya 67 with shortened and thickened straw, bred at the Institute of Cytology and Genetics of the SB RAS. The yield of this variety is Western Siberia

reaches 40 c/ha. Sunflower . In this area of plant breeding, the achievements of Academician Vasily Stepanovich Pustovoit (1886–1972) are remarkable. Until the middle of the 20th century. 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 sharply. Polyploidy played a major role in the selection of this crop (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

Summarizing conversation while learning new material.

IV. Homework

Study the paragraph of the textbook (methods of selection work of I.V. Michurin and achievements of plant breeding).

Equipment Lesson 8–9. Animal selection, its methods and achievements

DURING THE CLASSES

I. Test of knowledge

A. Working with cards

№ 1. : tables on general biology illustrating the methods of selection work by I.V. Michurin, achievements in plant breeding, methods of animal breeding.

№ 2. 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. What are the positive and negative sides self-pollination during selection?

№ 3. cultivated plants

№ 4. There is an expression: “Man is fed and clothed by polyploids.” How should it be understood?

It turned out that within a pure line, selection for size, weight of seeds and other characteristics is ineffective. At the same time, selection in freely interbreeding populations is effective. Explain what pattern of evolutionary theory is supported by the results of this study.

When selecting parental pairs for hybridization I.V. Michurin widely used geographically distant forms. For example, the Bellefleur-Chinese apple tree variety was created, obtained as a result of the hybridization of a Chinese apple tree from Siberia and the American Bellefleur yellow variety. Why did Michurin pay great attention to crossing geographically distant forms?
1. What methods of breeding work did I.V. use? Michurin?

II. Learning new material

2. What are the latest advances in plant breeding?

1. Features of animal biology taken into account in selection

When breeding animals, it is necessary to take into account the following characteristics:
– small number of offspring per pair of parents;
– long life expectancy; – impossibility vegetative propagation
highly organized animals and the presence of only a sexual method of reproduction;
– dioeciousness;
– often late puberty; – more complex relationships with plants than in plants external environment
due to the presence of the nervous system; – difficulty in studying the genotype, because he contains a large number of

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

In breeding work it is important to represent final goal, which the breeder strives 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 of selection and selection of manufacturers, applications various systems crossing.
When selecting producers, it is important to take into account their pedigree. In breeding farms, stud books are always kept, which take into account in detail the exterior characteristics and productivity of the parent forms over a number of generations. Based on the characteristics of the ancestors, one can judge the genotype of the producers.
The types of crossbreeding during breeding work with animals are varied. There are mainly two types of crossbreeding: unrelated and related.

Unrelated crossing , or outbreeding (from English out– out and breeding- breeding), carried out between individuals of the same breed or between individuals different breeds animals. With strict selection, it leads to the maintenance of properties or their improvement in a number of subsequent generations of hybrids, because it may happen in the offspring good combination genes, ensuring 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 cases where they want to transfer the majority 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.
Such crossing up to to a certain extent similar to self-pollination in plants, because leads to increased homozygosity. When closely related crossings occur, weakening of animals and loss of resistance to the effects of external factors, to diseases. 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. Typically, 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 their meiosis is disrupted, which leads to disruption of gametogenesis. Since ancient times, people have been using a hybrid of a mare and a donkey - a mule, which is distinguished by its endurance and long life expectancy. Overcoming the infertility of interspecific animal hybrids is an important task of selection. Sometimes gametogenesis in distant hybrids proceeds normally, and this made it possible to obtain new valuable species animals. An example is the Arharomerinos, which can graze high in the mountains, like Argali, and, like Merinos, produce good wool , . Fertile hybrids have been obtained by crossing local cattle with yaks and zebu (a subspecies of cattle common in Asia and Africa). Hybrids of beluga and sterlet (Bester), ferret and mink (Honorik) are productive.
carp and crucian carp. Also fertile are the offspring obtained from crosses between one-humped and two-humped camels, domestic horses and Przewalski's horses, bison and bison. There are two main breeding methods used in livestock farming: intrabreed And.

interbreed, Intrabreeding or , breeding "inside" aimed at preserving and improving the breed. In practice, it is expressed in selection the best manufacturers

, 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 Ivan Vladimirovich Michurin, an outstanding Soviet scientist and breeder, dedicated himself to the development of new varieties fruit trees

and other cultivated plants 60 years of hard work. His work began back in the 70s of the last century in a small nursery in the city of Kozlov (now Michurinsk) in the former Tambov province. Widely expand the research of I.V. Michurin was able only after October revolution when his nursery was turned into a large government agency . V.I. was interested in Michurin’s activities. Lenin, who gave her great importance

I.V. Michurin did not immediately come to those methods and views that led to great success. In the first period of his activity, he spent a lot of time and effort on experiments on simple acclimatization (accustoming) of southern varieties to the relatively harsh climate of the Tambov province with cold winters. These attempts were unsuccessful. All southern varieties froze in winter.

Convinced of the futility of the simple acclimatization method, I.V. Michurin began to develop new methods for changing the nature of plants.

The works of I.V. are based on Michurin lies in a combination of three main methods: hybridization, selection and influence of environmental conditions on developing hybrids(their “education” in the desired direction).

Much attention to I.V. Michurin paid attention to the selection of initial parental forms for hybridization. He used crossbreeding of local frost-resistant varieties with the best southern ones. The resulting seedlings were subjected to strict selection. I.V. Michurin kept the hybrids obtained in this way in relatively harsh conditions, without giving them rich soil. I.V. Michurin points out the possibility of controlling the dominance of traits during the development of a hybrid, and the influence of external factors on dominance is effective only on early stages hybrid development. The varieties obtained by this method include, for example, the Slavyanka apple tree, bred as a result of the hybridization of Antonovka with the southern variety Ranet pineapple.

Of particular importance in the selection of parental forms for hybridization I.V. Michurin emphasized the crossing of geographically distant forms that do not grow in the area where hybridization takes place. He wrote about this: “The farther the pairs of crossed producer plants are separated from each other in the place of their homeland and environmental conditions, the easier it is for the hybrid seedlings to adapt to the environmental conditions in a new area.” This way I.V. Michurin created a number of first-class varieties of fruit trees. These include the Bellefleur-Chinese apple tree variety, obtained as a result of the hybridization of the Chinese apple tree originally from Siberia and the American variety Bellefleur yellow. The Chinese variety is characterized by its hardiness to frost and resistance to disease, while Bellefleur is characterized by the remarkable taste of its fruit. Received I.V. Michurin new variety It has excellent taste and significant frost resistance.

The widely known Michurin pear variety Bere winter Michurina was obtained as a result of hybridization of wild Ussuri pear and the southern French variety Bere-royal.

Among the “education” methods developed by I.V. Michurin, it should be pointed out mentor method. Its essence boils down to the fact that the characteristics of the developing hybrid change under the influence of the scion or rootstock. This method was used by Michurin in two versions.

The first of them boiled down to the fact that the hybrid seedling served as a scion and was grafted onto an adult fruit-bearing plant (rootstock), in the direction of whose properties it was desirable to change the properties of the hybrid.

The second version of the mentor method was that a cutting from the variety in the direction of which it was desirable to change the properties of the hybrid was grafted into the crown of a young hybrid seedling, which in this case served as a rootstock.

The mentor method was applied by I.V. Michurin, for example, when creating the already mentioned apple variety Bel Fleur-Chinese. In the first year of fruiting of the hybrids that gave rise to the variety, it turned out that in terms of fruit quality they deviate towards Kitayka, which has small sour fruits. In order to change the further development of the hybrid in the desired direction, Bellefleur cuttings were grafted into the crown of young hybrids, under the influence of which the formation of the hybrid trait in subsequent years went towards acquiring the high taste qualities of Bellefleur. This method was applied by I.V. Michurin and when creating some other varieties, but wide application he didn't receive it. The influence of the mentor should obviously be considered as a change in the property of dominance during the development of the hybrid. In this case, the mentor promoted the phenotypic expression (i.e., dominance) of genes obtained from the Bellefleur variety.

In his work I.V. Michurin also used distant hybridization - crossing between different species and even genera, and thus obtained several valuable new fruit crops.

He obtained hybrids of blackberries and raspberries, plums and sloe, rowan and Siberian hawthorn, etc.

Most of the received I.V. Michurin varieties were complex heterozygotes. To preserve their qualities, they reproduced vegetatively: by layering, grafting, etc.

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 fruit crop breeding. 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 climatic conditions Russia. And he managed to achieve this dream, despite incredible difficulties and hardships.

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

Initially, Michurin set himself the task of acclimatizing southern varieties of fruit trees to conditions middle zone Russia. However, here he met with failure due to the fact that the heat-loving southern varieties of plants, even if grown in new conditions, could not tolerate the harsh winter. This is due to the fact that one change in the conditions of existence of an organism cannot change the 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 was possible to obtain varieties with the required properties by crossing one variety with another, that is, by engaging in breeding work. Michurin used three main types of influence in his work: hybridization, raising a developing hybrid in different conditions and selection.

Hybridization method

Obtaining a variety with new, improved characteristic characteristics is called hybridization. As a rule, it is carried out by crossing a local variety with a southern variety with higher taste. However, due to the historical adaptability of the local variety to the conditions of existence of a given area, the traits of the local variety were dominant in the resulting hybrids.

In order for the 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 parent forms. Based on this, the development of the new resulting hybrid can be controlled.

Subsequently, Michurin practically proved the validity of the above statement by obtaining a completely new pear variety, Bere winter Michurina. It was distinguished by large, shelf-stable fruits with good taste, while the hybrid plant tolerated cold down to - 36°. The southern pear variety Bere Royal with large juicy fruits, and as a mother - a wild Ussuri pear with small fruits and high winter hardiness. For both parents, the conditions in central Russia were unusual.

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

Michurin’s experiments in crossing plants of different species also became widely known, resulting in interspecific and intergeneric hybrids, such as hybrids between cherry and bird cherry (cerapadus), between apricot and plum, plum and sloe, rowan and Siberian hawthorn, etc.

IN natural conditions Crossing of different species of plants does not occur due to the fact that foreign pollen of another species is not accepted by the mother plant. Michurin used several methods to overcome uncrossability in distant hybridization.

Method of preliminary vegetative rapprochement

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

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

Then, during the flowering of rowan, its flowers are pollinated by pollen from the rootstock. In this case, crossing occurs.

Mediator method

The essence of this method is that if direct hybridization of two plant forms is impossible, a 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 plays the role of an intermediary.

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

Pollination method with pollen mixture

I. V. Michurin used various options pollen mixtures. A small amount of pollen from the mother plant was mixed with pollen from the father plant. In this case, its own pollen irritated the stigma of the pistil, which became capable of receiving foreign pollen. When pollinating apple flowers with pear pollen, a little apple pollen was added to the latter. Some of the ovules were fertilized with their own pollen, the other part with foreign pollen (pear pollen).

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

With all his many years of work on breeding new plant varieties, I. V. Michurin showed the importance of raising young hybrids following crossing.

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

Mentor method

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

Using the mentor's method, Michurin developed two varieties - Bellefleur-Chinese and Kandil-Chinese.

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

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

Action this method can be adjusted 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 foliage of the mentor and the hybrid.

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

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

With his works, I. V. Michurin revolutionized the idea of human capabilities and laid a solid foundation for further research in plant breeding

Bibliography

A textbook on biology for applicants to universities. Minsk, I., “Higher School”, 1978
encyclopedic Dictionary young naturalist. Moscow, I., “Pedagogy”. 1981

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Students, graduate students, young scientists who use the knowledge base in their studies and work will be very grateful to you.

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Selection methods I.V. Michurina

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 fruit crop breeding. 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 this dream, despite incredible difficulties and hardships.

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

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

Hybridization method

Subsequently, Michurin practically proved the validity of the above statement by obtaining a completely new pear variety, Bere winter Michurina. It was distinguished by large, shelf-stable fruits with good taste, while the hybrid plant itself tolerated cold down to - 36°. The southern pear variety Bere Royal 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 in central Russia were unusual.

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

method selection hybridization pollination mentor

Method of preliminary vegetative rapprochement

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

Then, during the flowering of rowan, its flowers are pollinated by pollen from the rootstock. In this case, crossing occurs.

Mediator method

Pollination method with pollen mixture

I.V. Michurin used various pollen mixtures. A small amount of pollen from the mother plant was mixed with pollen from the father plant. In this case, its own pollen irritated the stigma of the pistil, which became capable of receiving foreign pollen. When pollinating apple flowers with pear pollen, a little apple pollen was added to the latter. Some of the ovules were fertilized with their own pollen, the other part with foreign pollen (pear pollen).

With all his many years of work on breeding new plant varieties, I.V. Michurin showed the importance of the education of young hybrids following 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 the seedlings and other factors.

Mentor method

Using the mentor's method, Michurin developed 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-ripening 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 of the hybrid. As a result of the hybridization, the fruits of Bellefleur-Chinese became later ripening and shelf-stable.

The effect of this method can be regulated by the following techniques:

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

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

I.V. With his works, Michurin revolutionized the idea of human capabilities and laid a solid foundation for further research into plant breeding

Posted on Allbest.ru

Michurin's main method of breeding work was. Methods of selection and genetic work I.V. Michurina. B. Oral knowledge test

Read also

I. Test of knowledge

A. Working with cards

It turned out that within a pure line, selection for size, weight of seeds and other characteristics is ineffective. At the same time, selection in freely interbreeding populations is effective. Explain what pattern of evolutionary theory is supported by the results of this study.

II. Learning new material

1. Methods of selection work I.V. Michurina

2. Achievements in plant breeding

. 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).

Summarizing conversation while learning new material.

Study the paragraph of the textbook (methods of selection work of I.V. Michurin and achievements of plant breeding).

I. Test of knowledge

A. Working with cards

It turned out that within a pure line, selection for size, weight of seeds and other characteristics is ineffective. At the same time, selection in freely interbreeding populations is effective. Explain what pattern of evolutionary theory is supported by the results of this study.

II. Learning new material

2. What are the latest advances in plant breeding?

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

Hybridization method

Method of preliminary vegetative rapprochement

Mediator method

Pollination method with pollen mixture

Mentor method

Bibliography

Send your good work in the knowledge base is simple. Use the form below

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