Heterosis usually does not persist in subsequent generations. Heterosis. What is called a breed, variety, strain

The method is intended for use in agriculture. The goal is to significantly increase the efficiency of crop hybridization. Heterosis of hybrids appears only in the first generation. It has been established that the attenuation of heterosis in subsequent generations Hybridization mainly occurs due to the transition of recessive lethals, semilethals and subvitals into a homozygous state and disruption of a complex of favorable coordinately acting genes. Elimination of these phenomena leads to the consolidation of heterosis in subsequent generations. It is carried out by backcrossing a hybrid with artificially obtained absolutely homozygous androgenetic sons, after which the genetically transformed hybrid is almost completely cleared of harmful genes and at the same time preserves intact the complex of favorable genes that determine heterosis. This makes it possible to completely preserve heterosis in subsequent industrial generations obtained as a result of simple intrahybrid crossings, which has been proven by experiments on silkworms. The method is also intended for agricultural plants, in which it is possible to obtain androgenetic absolutely homozygous individuals. 3 salary, 4 ill.

The invention relates to methods used in agriculture. A well-known natural way of preserving heterosis in subsequent generations is through vegetative propagation in plants that additionally have sexual reproduction. Numerous studies in this area on other plants that are not capable of vegetative propagation and animals were not completely successful (1), because the nature of heterosis was still a great genetic mystery (2). The literature has not even expressed any real theoretical approaches to a radical solution to this important problem. In some animals, heterosis can be fixed by cloning. However, only a few offspring identical to the mother are obtained using this method. U silkworm cloning has been developed more successfully, but for practical use in terms of preserving heterosis, it is not acceptable for two reasons: due to the high labor intensity of mass production of parthenogenetic offspring and the lower productivity of the female sex, which makes up the clones, compared to males (3). Promising results were obtained by the authors after they developed the method of meiotic parthenogenesis and obtained absolutely homozygous male silkworms from parthenogenetic clones (4). Their backcrossing with a parthenogenetic clone of hybrid origin made it possible to consolidate heterosis in backcross generations (5). But this was the discovery of only the fundamental possibility of fixing heterosis. This method had no practical significance and, therefore, could not be patented as a method. This was explained by the fact that homozygous males could only be obtained from highly viable female parthenoclones with a high propensity for parthenogenesis. It was practically impossible to obtain absolute homozygotes in commercial breeds and hybrids, so meiotic parthenogenesis was used only for reconnaissance experiments aimed at determining the possibility of solving the problem. The invention of a method for fixing heterosis in the silkworm, suitable for production, became possible after the authors discovered monospermic androgenesis (1998, unpublished). The essence of the invention. Heterosis appears only in the first generation of the hybrid. In subsequent generations, starting from the second, it sharply fades. Therefore, in order to grow a heterotic hybrid, it is necessary to repeat intervarietal or interbreed hybridization each time. This process is technically complex and very labor-intensive, and for many plant crops it is simply not feasible, although their hybrids, if they were obtained, would give surprisingly high yields compared to the parent forms. This is exemplified by many agricultural plants. These problems would be radically solved if it were possible to develop effective method consolidation of heterosis in subsequent generations. Such a method would simultaneously open up completely new approach to the creation of even more outstanding hybrids in terms of heterosis. It is known that any industrial hybrid is obtained by crossing a huge mass of individuals of two parental forms. And these individuals are very differentiated in their combinative ability. Therefore, production is content with average heterosis for all individual hybrids taken together, each of which comes from the germ cells of two parents. While rare individual hybrids have truly fantastic heterosis, it is irretrievably lost in the next generation. The proposed method will make it possible to consolidate this powerful heterosis in subsequent generations of the hybrid and propagate it in unlimited quantities. One of the reasons for heterosis was considered to be the beneficial effect on the development and vital activity of the organism of heterozygosity of all genes in general, regardless of their specificity (the “overdominance” hypothesis). Using silkworms, the authors experimentally proved that heterosis occurs as a result of two main reasons. The first is integration in the genotype of hybrids large quantity favorable genes that control viability are coordinated in their action. The second is the transition to a heterozygous state not of all genes of the genotype, but only of recessive details, hemilethals and subvitals (4). In fig. 1 provides evidence of this. Consequently, the decrease in heterosis in subsequent generations of hybrids is mainly explained by the inevitable transition of some recessive parts and semi-lethals into a homozygous state when crossing a hybrid within its limits and the disruption of a complex of favorable genes that increase viability during meiosis. Therefore, the authors came to the conclusion that it is possible to consolidate heterosis in subsequent generations if the complex of all favorable genes in the hybrid genotype is completely preserved or even improved and the recessive lethal and semi-lethal ones are almost completely removed from the genotype. This problem was solved by the authors in the following way. Two genetically distant breeds are selected as the starting material, from crossing which the most highly heterotic hybrids arise. These two breeds produce a series of individual hybrids, each of which comes from only two parents. Through comparative tests, the 10 best individual hybrids in terms of heterosis are selected. From each hybrid, absolutely homozygous descendants are obtained by the method of monospermic androgenesis, which is available to breeders. For this purpose, uninseminated females of any breed are irradiated with rays at a dose of 80 kr. The females then mate with males of the individual hybrids. Layed eggs at the age of 60-80 minutes after laying at a temperature of 25 o C are heated for 210 minutes in water heated to 38 o C. The overwhelming majority of absolute homozygotes die at different stages of development due to the fact that in the haploid genotype they inherited from father, contains many lethal, semi-lethal and subvital genes. When the pronucleus nucleus diploidizes, they pass into a homozygous state, which is most often incompatible with the normal development of the organism. Only those homozygotes survive who, during meiosis, did not receive or received, but very few, harmful genes, mostly of weak effect (5). The grown absolutely homozygous individuals are backcrossed with the original hybrid, thus obtaining the first backcross generation (Fig. 2). The maturation of the original hybrid and absolute homozygotes must be synchronized by delaying the start of growing the first for a time equal to the duration of the development cycle of the selected object. Simple calculations show that in backcross offspring new homozygotes of strong harmful genes cannot appear, and homozygotes of subvital genes, if they were not eliminated from the surviving homozygous androgens, are suppressed by a complex of favorable genes inherited from the original hybrid. This is why heterosis persists in all backcross generations (Fig. 3). The first and subsequent backcross generations are dealt with in exactly the same way as with the original hybrid (Fig. 2). Further backcrosses lead, firstly, to the almost complete removal of details and semi-lethals from the hybrid genotype and, secondly, to the preservation of the numerically predominant part of the genes that provided heterosis in the original hybrid. After 5 or 6 backcrosses, the hybrid, cleared of harmful genes, is massively propagated by intrahybrid crossing. In the offspring obtained as a result of such reproduction, heterosis not only remains at the level of the original hybrid, but even increases somewhat (Fig. 4), which indicates a complete solution to the problem of fixing heterosis in the silkworm. The complete commonality of the genetic basis of heterosis and its attenuation in animals and plants allows this invention to be recommended for consolidating heterosis in agricultural plants, in which it is possible to obtain absolutely homozygous individuals of androgenic origin from hybrids. They are obtained by stimulating the embryonic development of haploid pollen, followed by the transformation of its germ cells into diploid ones, which develop into viable fertile plants. The technique varies depending on the biological characteristics of the crop. Graphic materials. Fig. 1 A. A direct relationship is shown between the yield of silkworm cocoons - the main indicator of heterosis (1) and the levels of heterozygosity (2) of genetic variants of the hybrid that are not purified from lethals and semi-lethals. The yield and heterozygosity indicators of the original hybrid of the first option (1) are taken as 100%. B. It has been shown that there is a complete absence of dependence between the cocoon yield (1) and the levels of heterozygosity (2) in genetic variants purified from lethals and semi-lethals. This proves the inconsistency of the “overdominance” hypothesis of heterosis and the possibility of maintaining heterosis in backcross generations. Fig. 2. Scheme for purifying silkworm hybrids from recessive lethals and semi-lethals through backcrossing of hybrids with absolutely homozygous males of breed A and B obtained from them. F 1, F 2 - hybrid of the first and second generation. F b1, F b2 - first and second backcross generations. Fig. 3. Viability of the original hybrid (1) and backcross generations (II), obtained according to the scheme presented in Fig. 2. Fig. 4. Demonstrates indicators of the frequency of harmful genes in the heterozygous state (1), cocoon mass (2), viability (3) in the original hybrid (I) and the transformed hybrid after four consecutive backcrosses with homozygous males (II), as well as in three consecutive inbred generations (III-V). Each genetic variant was reared simultaneously with a control parthenogenetic hybrid, the indicators of which were taken as 100%. In all genetic variants, heterosis is higher than in the original hybrid, which indicates a radical solution to the problem of fixing heterosis. The stable preservation of heterosis in all backcross generations has already indicated the fundamental effectiveness of the developed method. But backcross generations are not practical due to the difficulty of obtaining them. Therefore, in the final experiment on silkworms, they studied the possibility of fixing heterosis not in backcross, but in normal generations. In this final experiment, the original hybrid was first subjected to four backcrosses with homozygous males. As a result, the frequency of heterozygotes for lethals and semi-lethals decreased to 6.2% from 100% in source material. Next, backcross generations were propagated by inbreeding. Each inbred generation was obtained by crossing a brother with a sister within each individual family. As a result, the frequency of harmful genes suppressed by normal alleles decreased in the first inbred generation to 4.7, and in the second and third - to 3.5 and 2.6%, respectively. Inbred reproduction has an extremely detrimental effect on all economic indicators of normal inbred offspring. But in our experiment, it not only did not have a depressing effect on the inbred offspring, but, on the contrary, led to an increase in its average weight of one cocoon and viability compared to the original, control hybrid (Fig. 4). Consequently, the problem of fixing heterosis in hybrids of subsequent generations has been radically solved. BIBLIOGRAPHICAL DATA

1. Inge-Vechtomov S.I. 1989. Genetics with the basics of selection. M. " graduate School", on page 557. 2. Hutt F. 1969. Animal genetics. Translated from English, edited by Doctor of Biological Sciences Ya. L. Glembotsky. M., "Spike", on page 322. 3 . Strunnikov V. A. 1998. Cloning of animals: theory and practice. - Nature, N 7, pp. 3 -9. 4. Strunnikov V. A. Genetic methods selection and regulation of silkworm sex. M. VO "Agropromizdat", on page 35. 5. Strunnikov V.A. 1994. The nature of heterosis and new methods for its enhancement. - M. Nauka, 108 p.

CLAIM

1. A method of consolidating the heterosis of a hybrid in subsequent generations, including the use of backcrossings with absolutely homozygous males, characterized in that in order to preserve favorable genes that determine heterosis in the genotype of the hybrid, and at the same time to remove lethals and semi-lethals, backcrossings of hybrids with those obtained from them are used monospermic androgenesis by androgenetic absolutely homozygous males and then, after several backcrosses, switch backcross generations to conventional mass bisexual reproduction through intrahybrid crosses. 2. The method according to claim 1, characterized in that absolutely homozygous male silkworms are obtained by the method of monospermic androgenesis, performed by irradiating eggs in the female’s body with rays at a dose of 80 cr, subsequent mating with males of the original individual hybrids and heating the irradiated inseminated eggs in aged 60 - 80 minutes in water heated to 38 o C for 210 minutes. 3. The method according to claim 1, characterized in that, in order to sharply increase the heterosis of hybrids for industrial use, heterosis is fixed only in individual hybrids arising from two parents that have shown maximum heterosis in comparison with other simultaneously tested hybrids. 4. The method according to claim 1, characterized in that the method of fixing heterosis is used on hybrids of agricultural plants in which it is possible to obtain androgenetic absolutely homozygous individuals by varying methods known for each species of stimulating pollen to embryonic development and converting the germ cells developing from it into absolutely diploid homozygous cells that develop into fertile plants.

Heterosis

The concept of heterosis.

Inbreeding is accompanied by inbreeding depression, increased homozygosity of inbred offspring and increased genetic similarity of the descendant to the ancestor. Heterosis has opposite biological and genetic properties.

Under heterosis understand the superiority of the first generation offspring over the parental forms in viability, endurance, productivity, which arises when crossing different races, animal breeds, and zonal types.

The phenomenon of heterosis, or “hybrid vigor,” was noticed in the practice of animal husbandry in ancient times, in particular when producing mules by crossing a donkey with a mare, Charles Darwin first gave scientific explanation“hybrid vigor”, which occurs in offspring when unrelated organisms are crossed. He explained this effect by the biological dissimilarity of male and female gametes, which is caused by the influence of differences in the environment in which the parents live.

Genetic theories of heterosis

The term " heterosis"was introduced by G. Schell (1914), and explained the presence of “hybrid vigor” by the state of heterozygosity in the genotype of an organism, formed as a result of crossing. The heterosis hypothesis, formulated by G. Schell, E. East and H. Hayes, explains the phenomenon of heterozygosity by the presence of heterozygosity of various loci and the resulting overdominance, that is, when the action of a heterozygote Ahh the manifestation of the phenotype is stronger than that of the homozygous dominant genotype AA(that is, the effect of the action Ahh more action AA) The significance of heterozygosity was confirmed by the works of N. P. Dubinin, M. Lerner and other scientists,

Another explanation of heterosis, formulated by Keibl and Pellew (1910), is based on the fact that when crossing organisms carrying different homozygous genes in the genotype, for example AAbb) And aaBB, y crossbred offspring, recessive alleles transform into a heterozygous form of the genotype AaB, in which the harmful effects of recessive genes are eliminated. The influence of dominant genes on the manifestation of heterosis can be explained by the simple cumulative effect of a large number of dominant genes, that is, there is an additive effect.

K. Davenport (1908) and D. Jones (1917) proposed to explain heterosis based on the hypothesis of the interaction of non-allelic dominant genes of both parents, which gives a total effect that causes heterosis.

An ecological type of heterosis has been identified (Merkuryeva and 1980), which is caused by the process of acclimatization and manifests itself in animals of the first ecological generation. This type of heterosis manifested itself in increased milk production of offspring born in the Ryazan region from Ayrshire cows imported from Finland. In subsequent generations, milk yield decreased to a level corresponding to the genetic potential of the introduced group of cows.

Modern ideas about the causes of heterosis are based on the fact that heterosis is the result of the interaction of many genes. Their multiple action leads to a heterotic effect. This explanation is called balance heterosis (Dobzhansky, 1952). Subsequently, Lerner (1954), N.V. Turbin (1961-1968) continued to develop this position. According to their statements, hegerosis is caused by the action of many genes, mutually balanced in the genome in the process of evolution, which determines the optimal development and adaptability of the organism to environmental conditions.

If, during crossing, the optimal genomes of both parents are combined, then the descendants of the first generation have the most favorable situation in the combination of genomes, which leads to the manifestation of heterosis. Consequently, heterozygosity accompanying crossing undergoes pressure from various factors and thereby creates a balanced interaction of genes in the genome ,

In the practice of animal husbandry, so-called negative heterosis is sometimes observed, when the offspring have a level of a trait below the average of the parents, but is slightly higher than the level of the trait of the parent in whom it is less developed. The higher the differences in the trait level of the parental forms, the more the average trait level of the descendants approaches the trait level of the worst parent. This feature of inheritance was described by Ya L, Glembotsky in relation to the cutting of wool in crosses obtained from crossing Angora goats with coarse-haired goats. The wool clipping of the first generation crossbreeds was slightly greater than that of coarse-haired goats, but significantly less than that of Angora goats, in which it was 4-5 times greater compared to coarse-haired and crossbred goats.

Research to elucidate the biological basis of heterosis has been carried out at the Institute of Experimental Biology of the Academy of Sciences of the Kazakh SSR since 1962 under the leadership of Academician F. M. Mukhametgaliev. The research results are summarized in the monograph by A. S. Sareenova (1982), which can serve as additional material for understanding heterosis and the effect of crossing. In the process of work, the amount of DNA, RNA, proteins and the activity of a number of enzymes in the tissues and subcellular structures of cells (nuclei, chromosomes) of purebred and crossbred sheep was determined. Features of metabolic processes and heterosis in animals differing in origin were identified. It turned out that the heterotic effect is not associated with a change in the amount of hereditary substance in a single cell, nucleus or chromosomes. Crossing does not cause the activation of previously inactive genes obtained through the chromosomes of the parents in crossbreeds, and does not lead to a radical restructuring of metabolic processes. Instead, there is only stimulation of the level of intensity of metabolic processes. In the process of ontogenesis, this tension decreases and the effect of heterosis in crossbreeds decreases.

The biochemical effect of heterosis in crossbreds manifested itself in the stimulation of the activity of tissue enzymes (DNAase, RNase, etc.), which affect the synthesis of nucleic acids. The activity of enzymes in crossbreeds occurs in a wider pH range of the environment, which increases the ecological plasticity of crossbred organisms and adaptability to environmental conditions. Consequently, crossing affects the mechanism of regulation of enzyme activity.

RNA synthesis in the cell nucleus and translation of RNA-guided synthesis of protein molecules in the cytoplasm occur at a higher level in crossbreeds. This is facilitated by the enrichment of cell nuclei with non-histone chromatin proteins, which are a specific stimulator of genome activity. Consequently, the crossing stimulated the synthesis of ribosomal RNA, that is, it enhanced the transcription process. It is hypothesized that with the help of biologically active substances (hormones, metabolites), which can influence the activity of the genetic apparatus, it is possible to prolong the effect of heterosis over a longer period of ontogenesis.

There are other biochemical explanations for heterosis. It is believed that main reason Hybrid power is served by the formation of sensitive copies of structural genes on chromosomes, which form an excess of information in cells and determine the high compatibility of metabolic processes (Severin, 1967).

Explanations for the heterosis effect can be found in the assumption that crossbreeds have polymorphic types of proteins (isoenzymes), which differ in some properties.

The parental forms do not have polymorphism of enzymes, and when they are crossed, polymorphism and the number of polymorphic loci y are formed in crossbreeds. therefore there are more of them than their parents. This, according to some scientists (Fincham, 1968; Kirpichnikov, 1974), explains the effect of overdominance. F. M. Mukhametgaliev (1975) believes that the mutual stimulation of genomes during fertilization is equivalent to the additive effect of united genetic systems and is the basis for the appearance of heterosis, but is not the cause of the emergence of new qualities in the genetic material, therefore heterosis manifests itself in quantitative changes in characteristics and has a polygenic type inheritance.

A new approach to explaining the heterosis effect is proposed by V. G. Shakhbazov (1968). He believes that heterosis has a biophysical basis, since during fertilization an exchange of electrical charges of homologous chromosomes occurs, which increases the activity of chromosomes in hybrid zygotes. This leads to the accumulation of acidic proteins and RNA, increases the nucleolus-nuclear ratio and increases the rate of mitotic division.

The above explanations of the causes of the heterosis effect indicate a lack of unity in the scientific explanation of the phenomenon of heterosis, and therefore the problem remains for further study and consideration. Despite this, in animal husbandry practice, animal selection techniques are used to consolidate and enhance the effect of heterosis. There are several techniques for calculating the magnitude of the heterosis effect. The so-called true type of heterosis is distinguished, which is determined by the magnitude of the superiority of the trait in crossbred animals over both parental forms. Another type of heterosis is hypothetical, when the characteristics of the crossbred offspring exceed the arithmetic average level of the trait of both parents.

If there is no data on one of the breeds from which the crossbreeds are obtained, then their performance is compared with the parent breed, and the improved performance of the crossbreed is called not heterosis, but the effect of crossing.

Summarizing the modern understanding of the phenomena of inbreeding depression and heterosis, we can draw conclusions about the need to use both phenomena in practical breeding work.

Practical application of heterosis

Modern livestock farming is characterized by the use of crossbreeding, accompanied by a heterotic effect, especially for egg and broiler poultry farming . This system includes two main stages; breeding inbred poultry lines using different types inbreeding and crossing (crossing) lines to obtain a so-called hybrid bird that exhibits heterosis. For example, in the Netherlands, the Eurybrid company works with two crosses of egg-laying chickens: “Hisex White” (white shell, based on Leghorns) and “Hisex Brown” (with the participation of Rhode Island and New Hampshire with a brown shell). These two crosses occupy a leading position in the world egg production.

Work on creating hybrid egg and meat poultry is also being carried out in our country. To carry out selection for heterosis, inbred lines are bred by mating according to the “brother x sister” type for 3-4 generations or more, combining this with strict culling of undesirable individuals. Of the large number of established lines, about 10-15% of lines remain at the end, with an inbreeding coefficient on average of 37.5% (mating of full sibs for three generations). Next, the remaining lines are crossed with each other to check their compatibility, then the most successful combinations are left for production crossing and 2-, 3-, 4-line hybrids are obtained,

The use of the heterosis effect is also used in working with other types of animals, especially in beef cattle breeding, sheep farming, camel farming, and fish farming. Methods for obtaining the effect of heterosis are varied. Heterosis manifests itself during interspecific crossing of animals: obtaining mules from crossing a donkey with a mare, breeding new heterotic breeds by obtaining hybrids from crossing cattle with zebu (Santa Gertrude, Beefmaster, Charbray, Bridford - in the USA; Sao Paulo - in Brazil; Haup Holstein - in Jamaica). In our country, distant hybridization was carried out between fine-wool sheep and argali and a new breed was developed - arharomerinos. In Kyrgyzstan and Altai, hybrids of yak with Simmental cattle were obtained.

Distant hybridization is accompanied by the manifestation of heterosis for a number of economically valuable traits.

The problem of obtaining and enhancing the effect of heterosis has not been fully resolved. The main obstacle that cannot be overcome is the loss of the heterotic effect in the second generation, that is, the heterosis obtained in the first generation is not consolidated, but is lost in subsequent generations when breeding crosses “in themselves.” Some methods allow heterosis to be maintained over several generations. One of the most accessible and effective methods is variable crossing, used in commercial livestock farming. At the same time, from the first-generation crossbreeds obtained from crossing queens of breed A with sires of breed B, the best part of the queens is isolated and crossed with the sire of breed C, and second-generation crosses are obtained, with the manifestation of heterosis when three breeds are combined (A, B, C). Next, the second generation crossbreeds can be crossed with the sire of breed D and obtain more complex crossbreeds, which represent the heredity of the original maternal breed A and the heredity of the paternal breeds B, C and B. No other methods have been developed in animal husbandry to preserve the effect of heterosis.

In the practice of modern animal husbandry, it has been proven that the effect of heterosis is diverse and is expressed in the improvement of valuable economic characteristics. The main indicators of heterosis are an increase in embryonic and postembryonic viability; reduction of feed costs per unit of production; increasing early maturity, fertility, productivity; manifestation of greater opportunities for adaptation to changing conditions and new elements of technology. The wide range of heterotic effect, manifested in a variety of reacting characteristics, is a reflection of physiological and biochemical processes caused by the peculiarities of the genetic apparatus of heterotic animals.

The use of Heterosis in crop production is an important technique for increasing plant productivity. The yield of heterotic hybrids is 10-30% higher than that of conventional varieties. For the use of hydrocarbons in production, cost-effective methods have been developed for obtaining hybrid seed n corn, tomatoes, eggplants, peppers, onions, cucumbers, watermelons, pumpkins, sugar beets, sorghum, rye, alfalfa and other agricultural products. plants. A special position is occupied by a group of vegetatively propagated plants in which it is possible for G. to be established in the offspring, for example, varieties of potatoes and fruit and berry crops bred from hybrid seeds. To use genetics for practical purposes, intervarietal crossings of homozygous varieties of self-pollinating plants, intervarietal (interpopulation) crossings of self-pollinating lines of cross-pollinating plants (paired, trilineal, double-quadrilineal, multiple) and varietal-lineal crossings are used. The advantage of certain types of crossing for each agricultural product. culture is established on the basis economic assessment. Elimination of difficulties in obtaining hybrid seeds can be facilitated by the use of cytoplasmic male sterility (CMS), the property of incompatibility in some cross-pollinating plants and other hereditary features in the structure of the flower and inflorescence, eliminating the high costs of castration. When choosing parental forms for producing heterotic hybrids, their combinative ability is assessed. Initially, selection in this direction was reduced to selecting the best genotypes in terms of combinational value from populations of open-pollinated varieties based on inbreeding in the form of forced self-pollination. Methods have been developed for assessing and increasing the combinative ability of lines and other groups of plants used for crossings.

The greatest effect in using G. was achieved on corn. The creation and introduction into production of corn hybrids made it possible to increase the gross grain yield by 20-30% on the vast areas occupied by this crop in different countries peace. Corn hybrids have been created that combine high yields with good seed quality, drought resistance and immunity to various diseases. Heterotic hybrids of sorghum (Hybrid Early 1, Hybrid Voskhod), heterotic intervarietal hybrids of sugar beet have been zoned, of which the Yaltushkovsky hybrid is the most widespread. To obtain heterotic forms, sugar beet lines with sterile pollen are increasingly used. G. phenomena have also been established in many vegetable and oilseed crops. The first results in the study of G. in first-generation wheat hybrids were obtained, sterile analogues and fertility restorers were created, and sources of CMS in wheat were identified.

The method is intended for use in agriculture. The goal is to significantly increase the efficiency of crop hybridization. Heterosis of hybrids appears only in the first generation. It has been established that the attenuation of heterosis in subsequent generations of the hybrid is mainly due to the transition of recessive lethals, semilethals and subvitals into a homozygous state and disruption of a complex of favorable coordinately acting genes. Elimination of these phenomena leads to the consolidation of heterosis in subsequent generations. It is carried out by backcrossing a hybrid with artificially obtained absolutely homozygous androgenetic sons, after which the genetically transformed hybrid is almost completely cleared of harmful genes and at the same time preserves intact the complex of favorable genes that determine heterosis. This makes it possible to completely preserve heterosis in subsequent industrial generations obtained as a result of simple intrahybrid crossings, which has been proven by experiments on silkworms. The method is also intended for agricultural plants, in which it is possible to obtain androgenetic absolutely homozygous individuals. 3 salary, 4 ill.

The invention relates to methods used in agriculture. A well-known natural way of preserving heterosis in subsequent generations is through vegetative propagation in plants that additionally have sexual reproduction. Numerous studies in this area on other plants that are not capable of vegetative propagation and animals were not completely successful (1), because the nature of heterosis was still a great genetic mystery (2). The literature has not even expressed any real theoretical approaches to a radical solution to this important problem. In some animals, heterosis can be fixed by cloning. However, only a few offspring identical to the mother are obtained using this method. In the silkworm, cloning has been developed more successfully, but for practical use in terms of preserving heterosis, it is not acceptable for two reasons: due to the high labor intensity of mass production of parthenogenetic offspring and the lower productivity of the female sex, which makes up the clones, compared to males (3 ). Promising results were obtained by the authors after they developed the method of meiotic parthenogenesis and obtained absolutely homozygous male silkworms from parthenogenetic clones (4). Their backcrossing with a parthenogenetic clone of hybrid origin made it possible to consolidate heterosis in backcross generations (5). But this was the discovery of only the fundamental possibility of fixing heterosis. This method had no practical significance and, therefore, could not be patented as a method. This was explained by the fact that homozygous males could only be obtained from highly viable female parthenoclones with a high propensity for parthenogenesis. It was practically impossible to obtain absolute homozygotes in commercial breeds and hybrids, so meiotic parthenogenesis was used only for reconnaissance experiments aimed at determining the possibility of solving the problem. The invention of a method for fixing heterosis in the silkworm, suitable for production, became possible after the authors discovered monospermic androgenesis (1998, unpublished). The essence of the invention. Heterosis appears only in the first generation of the hybrid. In subsequent generations, starting from the second, it sharply fades. Therefore, in order to grow a heterotic hybrid, it is necessary to repeat intervarietal or interbreed hybridization each time. This process is technically complex and very labor-intensive, and for many plant crops it is simply not feasible, although their hybrids, if they were obtained, would give surprisingly high yields compared to the parent forms. This is exemplified by many agricultural plants. These problems would be radically solved if it were possible to develop an effective way to consolidate heterosis in subsequent generations. This method would simultaneously open up a completely new approach to creating hybrids that are even more outstanding in heterosis. It is known that any industrial hybrid is obtained by crossing a huge mass of individuals of two parental forms. And these individuals are very differentiated in their combinative ability. Therefore, production is content with average heterosis for all individual hybrids taken together, each of which comes from the germ cells of two parents. While rare individual hybrids have truly fantastic heterosis, it is irretrievably lost in the next generation. The proposed method will make it possible to consolidate this powerful heterosis in subsequent generations of the hybrid and propagate it in unlimited quantities. One of the reasons for heterosis was considered to be the beneficial effect on the development and vital activity of the organism of heterozygosity of all genes in general, regardless of their specificity (the “overdominance” hypothesis). Using silkworms, the authors experimentally proved that heterosis occurs as a result of two main reasons. The first is the integration in the genotype of hybrids of a large number of favorable genes, coordinated in their action, that control viability. The second is the transition to a heterozygous state not of all genes of the genotype, but only of recessive details, hemilethals and subvitals (4). In fig. 1 provides evidence of this. Consequently, the decrease in heterosis in subsequent generations of hybrids is mainly explained by the inevitable transition of some recessive parts and semi-lethals into a homozygous state when crossing a hybrid within its limits and the disruption of a complex of favorable genes that increase viability during meiosis. Therefore, the authors came to the conclusion that it is possible to consolidate heterosis in subsequent generations if the complex of all favorable genes in the hybrid genotype is completely preserved or even improved and the recessive lethal and semi-lethal ones are almost completely removed from the genotype. This problem was solved by the authors in the following way. Two genetically distant breeds are selected as the starting material, from crossing which the most highly heterotic hybrids arise. These two breeds produce a series of individual hybrids, each of which comes from only two parents. Through comparative tests, the 10 best individual hybrids in terms of heterosis are selected. From each hybrid, absolutely homozygous descendants are obtained by the method of monospermic androgenesis, which is available to breeders. For this purpose, uninseminated females of any breed are irradiated with rays at a dose of 80 kr. The females then mate with males of the individual hybrids. Layed eggs at the age of 60-80 minutes after laying at a temperature of 25 o C are heated for 210 minutes in water heated to 38 o C. The overwhelming majority of absolute homozygotes die at different stages of development due to the fact that in the haploid genotype they inherited from father, contains many lethal, semi-lethal and subvital genes. When the pronucleus nucleus diploidizes, they pass into a homozygous state, which is most often incompatible with the normal development of the organism. Only those homozygotes survive who, during meiosis, did not receive or received, but very few, harmful genes, mostly of weak effect (5). The grown absolutely homozygous individuals are backcrossed with the original hybrid, thus obtaining the first backcross generation (Fig. 2). The maturation of the original hybrid and absolute homozygotes must be synchronized by delaying the start of growing the first for a time equal to the duration of the development cycle of the selected object. Simple calculations show that in backcross offspring new homozygotes of strong harmful genes cannot appear, and homozygotes of subvital genes, if they were not eliminated from the surviving homozygous androgens, are suppressed by a complex of favorable genes inherited from the original hybrid. This is why heterosis persists in all backcross generations (Fig. 3). The first and subsequent backcross generations are dealt with in exactly the same way as with the original hybrid (Fig. 2). Further backcrosses lead, firstly, to the almost complete removal of details and semi-lethals from the hybrid genotype and, secondly, to the preservation of the numerically predominant part of the genes that provided heterosis in the original hybrid. After 5 or 6 backcrosses, the hybrid, cleared of harmful genes, is massively propagated by intrahybrid crossing. In the offspring obtained as a result of such reproduction, heterosis not only remains at the level of the original hybrid, but even increases somewhat (Fig. 4), which indicates a complete solution to the problem of fixing heterosis in the silkworm. The complete commonality of the genetic basis of heterosis and its attenuation in animals and plants allows this invention to be recommended for consolidating heterosis in agricultural plants, in which it is possible to obtain absolutely homozygous individuals of androgenic origin from hybrids. They are obtained by stimulating the embryonic development of haploid pollen, followed by the transformation of its germ cells into diploid ones, which develop into viable fertile plants. The technique varies depending on the biological characteristics of the crop. Graphic materials. Fig. 1 A. A direct relationship is shown between the yield of silkworm cocoons - the main indicator of heterosis (1) and the levels of heterozygosity (2) of genetic variants of the hybrid that are not purified from lethals and semi-lethals. The yield and heterozygosity indicators of the original hybrid of the first option (1) are taken as 100%. B. It has been shown that there is a complete absence of dependence between the cocoon yield (1) and the levels of heterozygosity (2) in genetic variants purified from lethals and semi-lethals. This proves the inconsistency of the “overdominance” hypothesis of heterosis and the possibility of maintaining heterosis in backcross generations. Fig. 2. Scheme for purifying silkworm hybrids from recessive lethals and semi-lethals through backcrossing of hybrids with absolutely homozygous males of breed A and B obtained from them. F 1, F 2 - hybrid of the first and second generation. F b1, F b2 - first and second backcross generations. Fig. 3. Viability of the original hybrid (1) and backcross generations (II), obtained according to the scheme presented in Fig. 2. Fig. 4. Demonstrates indicators of the frequency of harmful genes in the heterozygous state (1), cocoon mass (2), viability (3) in the original hybrid (I) and the transformed hybrid after four consecutive backcrosses with homozygous males (II), as well as in three consecutive inbred generations (III-V). Each genetic variant was reared simultaneously with a control parthenogenetic hybrid, the indicators of which were taken as 100%. In all genetic variants, heterosis is higher than in the original hybrid, which indicates a radical solution to the problem of fixing heterosis. The stable preservation of heterosis in all backcross generations has already indicated the fundamental effectiveness of the developed method. But backcross generations are not practical due to the difficulty of obtaining them. Therefore, in the final experiment on silkworms, they studied the possibility of fixing heterosis not in backcross, but in normal generations. In this final experiment, the original hybrid was first subjected to four backcrosses with homozygous males. As a result, the frequency of heterozygotes for lethals and semi-lethals decreased to 6.2% from 100% in the original material. Next, backcross generations were propagated by inbreeding. Each inbred generation was obtained by crossing a brother with a sister within each individual family. As a result, the frequency of harmful genes suppressed by normal alleles decreased in the first inbred generation to 4.7, and in the second and third - to 3.5 and 2.6%, respectively. Inbred reproduction has an extremely detrimental effect on all economic indicators of normal inbred offspring. But in our experiment, it not only did not have a depressing effect on the inbred offspring, but, on the contrary, led to an increase in its average weight of one cocoon and viability compared to the original, control hybrid (Fig. 4). Consequently, the problem of fixing heterosis in hybrids of subsequent generations has been radically solved. BIBLIOGRAPHICAL DATA 1. Inge-Vechtomov S.I. 1989. Genetics with the basics of selection. M. "Higher School", on page 557. 2. Hutt F. 1969. Animal genetics. Per. from English edited by Doctor of Biology Sciences Ya.L. Glembotsky. M., "Spike", on page 322. 3. Strunnikov V. A. 1998. Cloning of animals: theory and practice. - Nature, N 7, pp. 3 -9. 4. Strunnikov V.A. 1987. Genetic methods for selection and sex regulation of silkworms. M. VO "Agropromizdat", on page 35. 5. Strunnikov V.A. 1994. The nature of heterosis and new methods for its enhancement. - M. Nauka, 108 p.

Claim

Detailed solution to paragraph § 32 in biology for 10th grade students, authors V.I. Sivoglazov, I.B. Agafonova, E.T. Zakharova. 2014

Remember!

What is selection?

Give examples of animal breeds and plant varieties known to you.

Antonovka apple varieties, Severyanka pear, dog breeds: Rottweiler, miniature poodle, collie.

Review questions and assignments

1. What is selection?

Selection (from Latin selectio - selection) is the science of creating new and improving existing plant varieties, animal breeds and strains of microorganisms. At the same time, selection is understood as the process of creating varieties, breeds and strains. Theoretical basis selection is genetics.

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

A breed, variety or strain is a collection of individuals of the same species, artificially created by man and characterized by certain hereditary properties.

5. What difficulties arise when performing interspecific crosses?

Distant hybridization involves crossing different species. In plant growing, with the help of distant hybridization, a new grain crop has been created - triticale, a hybrid of rye and wheat. This crop combines many of the properties of wheat (high baking qualities) and rye (the ability to grow on poor sandy soils). A classic example of interspecific hybrids in livestock breeding is a mule, obtained by crossing a donkey with a mare, which is significantly superior to its parents in endurance and performance. In Kazakhstan, by crossing wild mountain argali sheep with fine-wool sheep, the famous argali sheep breed was created. However, the use of interspecific crosses has certain difficulties, because the resulting hybrids often turn out to be infertile (sterile) or low-fertility. The sterility of hybrids is associated with the absence of paired homologous chromosomes. This makes the conjugation process impossible. Therefore, meiosis cannot be completed and no germ cells are formed.

6. Are interspecific hybrids produced and used in your region? Using additional sources of information, find out which species are hybrids of organisms such as bester, honorik, hinny, and raphanobrassica. What interest do they have for Agriculture?

Think! Remember!

2. Why do each region need its own plant varieties and animal breeds? What varieties and breeds are typical for your region? What are their features and advantages?

Since environmental conditions are different in different regions, varieties and breeds must be adapted to specific conditions. Features of crop production in the Southern Urals

3. Of the wide variety of animal species living on Earth, humans have selected relatively few species for domestication. What do you think explains this?

The process of domesticating wild animals begins with the artificial selection of individual individuals to produce offspring with certain characteristics necessary for humans. Individuals are typically selected for certain desirable characteristics, including reduced aggression towards humans and members of their own species. In this regard, it is customary to talk about taming a wild species. The purpose of domestication is to use an animal in agriculture as a farm animal or as a pet. If this goal is achieved, we can talk about a domesticated animal. The domestication of an animal radically changes the conditions for further development kind. Natural evolutionary development is replaced by artificial selection based on breeding criteria. Thus, as part of domestication, the genetic properties of the species change.

4. Heterosis usually does not persist in subsequent generations and fades away. Why is this happening?

When crossing different breeds of animals or plant varieties, as well as during interspecific crossings in the first generation, the viability of hybrids increases and powerful development is observed. The phenomenon of superiority of hybrids in their properties of parental forms is called heterosis, or hybrid vigor. It appears in the first generation, and fades away in the second.

5. Why do you think ligers are born only in zoos and are not found in the wild? Explain your point of view.

Ligers - interspecific hybrids between a lion and a tigress - look like huge lions with blurry stripes. Consequently, his parents belong to the same biological genus of panthers, but different types. In appearance, it is noticeably different from its opposite hybrid, the tigrol. It is the largest representative of the cat family currently existing. Looks like a giant lion with blurred stripes. Ligers are not found in the wild mainly because lions and tigers have little chance of meeting in the wild: the lion's modern range includes mainly central and southern Africa (although India has the last surviving population of Asiatic lions), while the tiger exclusively Asian look. Therefore, crossing of species occurs when animals live for a long time in the same enclosure or cage (for example, in a zoo or circus), but only 1-2% of pairs produce offspring, which is why there are no more than two dozen ligers in the world today.

6. Do you think mass selection can be used when breeding animals? Prove your opinion.

Not used. mass selection is selection by phenotype. Individual - by genotype. Producers in animals are individuals with a well-defined pedigree, i.e. the genotype for the desired traits is quite well known. And the characteristics of animals - it takes time to reach sexual maturity, a small number of offspring (compared to plants - now can be considered a solved problem - artificial insemination, surrogate females) and the impossibility of asexual reproduction.

7. Using additional literature and Internet resources, prepare a message or presentation about the history of selection from ancient times to the present.

Selection as a method of developing breeds of domestic animals and varieties of cultivated plants has existed for a long time. About 8000-9000 years ago, with the advent of agriculture in the Middle East, and later in Europe and Asia, the development of crop and livestock farming began. Since that time, people began to engage in artificial selection in order to breed animal breeds and plant varieties with economically valuable qualities. The first breeding activities, known almost 6000 years ago in Elam (Mesopotamia), can be judged by the image of the pedigree of horses found on a signet. There is also information that the Arabs long before new era used artificial pollination of date palms. In the Roman Empire, documents have been preserved from detailed description techniques used in animal breeding. In the works of scientists of Ancient China and Ancient Rome, there are indications of the importance of selecting ears in cereals and recommendations are given for carrying out such selection.

At first, breeding activities were limited to selection. It was of an unconscious nature and lasted for a long time (10-15 years). Breeders, without having theoretical basis, were guided by experience and intuition. They took into account beneficial features parental individuals, but could not purposefully carry out selection. The results of crossing often turned out to be unexpected, and the expected trait was not found in the offspring. Nevertheless, unknown breeders left a legacy of many valuable varieties of cultivated plants and breeds of domestic animals. For example, a number of the best varieties of cotton now cultivated in Russia and the USA were borrowed from the peasants of old Mexican villages. Using the method of unconscious selection, varieties of fiber flax were bred in some areas of Pskov: low-growing plants were used for household needs, and seeds of tall ones were used for sowing. There are known varieties of winter (for example, Krymka, Poltavka, Sandomirka) and spring (Ulka, Girka, Syr-Bidai, etc.) wheat with valuable economic qualities, bred in ancient times.

However, selection for economically useful traits and properties without taking into account the mechanisms of their heritability and variability often gave undesirable results. For example, selection for the appearance of fine-wool sheep for polling led to the appearance of cryptorchidism; getting rid of piebald hair on the neck of Romanov sheep weakened their vitality; An increase in hair growth in sheep was accompanied by a decrease in their weight. It was not possible to develop a pure line of Wyandottes (a breed of chickens) with a rose-shaped comb; Despite the culling of chicks with leaf-shaped combs, they appeared in the offspring. Obviously, the breed consisted of generalozygotes for this gene, since homozygotes had reduced fertility.

All this indicated that the desired result cannot be obtained without theoretical knowledge. From the end of the 18th - beginning of the 19th century. The work of breeders was already of a scientific nature. The main task breeding began to study the genetics of traits such as animal productivity and plant yield. Solving selection problems is impossible without knowledge related to genetic analysis, i.e. without knowledge of the type of inheritance of traits (dominant or recessive), the type of dominance, the nature of inheritance (autosomal or sex-linked, independent or linked), the type and nature of gene interaction in ontogenesis . Breeders should pay main attention to the problems of the relationship between the genotype and the environment, since the expressivity and penetrance of the studied traits largely depends on the factors of the latter.

8. Are there breeding stations or centers in your region? What research are they doing? What are their achievements? Together with your teacher, organize an excursion to such a station.

Yu-U Research Institute of Horticulture and Potato Growing, Chelyabinsk

Eh, apple, ranetochka...

In 1931, on the initiative of I.V. Michurin, the first scientific research institution for horticulture in the Southern Urals was created - the Ural Zonal Fruit and Berry Experimental Station. The organizer of this station was Valery Pavlovich Yarushin.

And already in next year scientific research began on the selection and selection of varieties suitable for cultivation in the harsh conditions of the Chelyabinsk and Kurgan regions, including those then included in the Kamyshlovsky and Kamensk-Uralsky regions of the now Sverdlovsk region. Scientists began to survey and collect the best forms of fruit and berry crops east of the Ural Range. In 1934, station employees registered a large tract of wild cherries - 2270 hectares - in the Karagai forest dacha (Annensky Bor). In the same year, a scientific expedition led by Doctor of Agricultural Sciences E. P. Syubarova (BelSRRI of Fruit Growing) and Chelyabinsk scientist M. N. Salamatov examined thickets of wild steppe cherries in the Verkhneufaleysky and Poltava districts of the Chelyabinsk region. At the same time, extensive collections of plums were imported from Far East, from Canada, North America, central Russia, Volga region, Karzin plums from Siberia. From the selected material in 1937, scientists identified varieties and proposed the first Ural assortment of berry crops.

In those years, both among the people and agronomic science, it was believed that due to the harsh climate with frosty and long winters, gardening in the Urals was impossible. It took South Ural scientists only twenty years - by breeding standards, a very short period of time - to refute this widespread opinion. Thanks to the selection and study of new varieties of fruit and berry crops at the Chelyabinsk experimental station, horticulture began to develop rapidly in our country.

The first collective gardens in the region appeared soon after the war. In 1948, Traktorosad, Druzhba in the Metallurgical District, Lokomotiv in the Sovetsky District, and Magnitogorsk Gardens were formed metallurgical plant. Their appearance was preceded by a long and viscous struggle in the corridors of the then government with opponents of the creation of such gardens. Nevertheless, collective gardening has developed and is still developing. Currently, gardeners produce the bulk of fruits and vegetables.

By the beginning of the 50s, our scientists collected and studied 442 apple tree varieties, including 210 varieties of Ural-Siberian selection. The first varieties of fruit and berry experimental station officially issued with copyright certificates were apple trees. The basis of the pre-war assortment was local ranetki. They are distinguished by their adaptability to the Ural and Siberian climate, high yield and small fruit size weighing from 15 to 50 g. The older generation still remembers these bright, beautiful Ranetka apples - Lyubimets, Anisik Omsky, Ponikloe. They seemed like the ultimate dream then, especially for children. But by the 60s, the institute already had 25 zoned varieties: 14 apple trees, 4 pears, 4 plums and 3 berry crops.

In 1964, the Ural Zonal Fruit and Berry Experimental Station was renamed the Chelyabinsk Fruit and Vegetable Breeding Station named after. I. V. Michurina. By that time, the specialized trust “Plodoprom”, headed by Vsevolod Ivanovich Nazarov, was already successfully operating in the region. Close cooperation science and production, the passion and enthusiasm of their employees raised South Ural horticulture to unprecedented heights. With the support of regional leaders, fruit nurseries were created: "Smolinsky" in the suburbs of Chelyabinsk, "Michurinsky" in Kartaly, "Raduzhny" in Magnitogorsk, "Tyubelyassky" in the mining zone. State variety testing sites were organized at the Smolinsky and Michurinsky fruit nurseries.

It was then, in the 50-60s, that small gardens from 20 to 100 hectares were established on collective and state farms located under the MTS. Some of them have survived to this day. At the peak of the development of horticulture in the region, public gardens occupied an area of 8 thousand hectares, and the industry itself was generally profitable.

In the fifties, work on scientific support for potato growing also began in our region. By the beginning of the 80s, the Chelyabinsk fruit and vegetable breeding station named after. I.V. Michurina had 29 of her own varieties of fruit and berry crops and potatoes, included in the State Register of Breeding Achievements approved for use.

Station scientists began to use the world collection of forms of fruit and berry crops and potatoes from the All-Union Institute of Plant Growing and other research institutions, including foreign ones, in plant breeding. The genetic fund was involved in the selection process, new breeding technologies were introduced that made it possible to shorten the selection process, and the training of highly qualified personnel increased. Scientific developments South Ural scientists began to be implemented in the farms of Chelyabinsk, Kurgan, Kustanai, Orenburg and other regions, in the Republic of Bashkortostan.

New name - new goals

In November 1991, by decision of the Government of the Russian Federation, the Chelyabinsk Fruit and Vegetable Experimental Station named after. I.V. Michurina was transformed into the South Ural Research Institute of Fruit and Vegetable and Potato Growing. Not only the name has changed. More serious goals and directions of research activities were set for the institute. In addition to the selection of fruit and berry crops and potatoes, life required the creation of new resource-saving, environmentally friendly technologies for the selection and cultivation of these crops, scientific research on hybridization, as well as the production of elite seedlings of new promising varieties of horticultural crops and potato seeds on a healthy, virus-free basis using biotechnology.

Over the entire period of the institute’s activities, starting with the Ural Zonal Fruit and Berry Station, Chelyabinsk breeders have created more than 200 varieties of fruit and berry crops, 18 varieties of potatoes, developed technologies for industrial and amateur gardening, technologies for the production of potatoes with a yield of up to 70 t/ha.

IN State Register selection achievements approved for use, 110 varieties were introduced in different years. The level of research work is evidenced by the fact that today the institute has more than 100 copyright certificates and patents for varieties and inventions.

For the first time in the Southern Urals, models of intensive varieties of fruit and berry crops, potatoes until 2020 have been created, selection schemes have been developed for productivity, winter hardiness, incl. resistance of flowers to spring frosts, product quality, immunity. The Institute has a rich genetic fund of horticultural crops, which numbers 64 thousand hybrid plants, incl. 39 - fruit crops, 25 thousand seedlings of berry crops. The volume of hybrid crosses amounts to 45 thousand flowers.

Scientific research on selection and agricultural technology of horticultural crops and potatoes is carried out in creative collaboration with leading research institutes and experimental stations in Russia, near and far abroad.

Today the institute has a breeding garden with an area of more than 100 hectares. This is where the main scientific activity South Ural breeders.

Apple tree. For the first time in the world practice of horticulture, the institute's breeders, using an originally developed method, developed varieties of natural dwarfs with a tree height of 1.5-2.5 m. When propagated on clonal vegetatively propagated dwarf rootstocks, they become natural dwarfs (0.8-1.5 m).

Pear is an amazing crop in the Urals. Fruits every year. The fruits are tasty, sweet, suitable for processing. Involvement of selected forms of Ussuri pear in breeding made it possible to create varieties characterized by high winter hardiness and productivity, high taste qualities of fruits, monogenic resistance to scab and field resistance to pear gall mite.

Apricot and plum. Local varieties have been bred and selected forms have been identified, characterized by increased winter hardiness of fruit buds and high quality fruits

Cherry. Experimental data have been accumulated to create genotypes resistant to coccomycosis. Isolation of donors with a gene for mono-resistance to coccomycosis and identification of forms of steppe cherry with field resistance to coccomycosis continues. For this purpose and to replenish the collection, expeditions were carried out to examine wild cherry plants in the territory of Bashkiria, Chelyabinsk and Kurgan regions. Forms of steppe and forest cherries have been selected that are resistant to coccomycosis, large-fruited, good taste fruits

Berry crops. Research is being conducted on the selection of new varieties that are resistant to adverse environmental factors, highly winter-hardy, with increased resistance of flowers to spring frosts, highly productive, and with excellent fruit quality. Models of the optimal variety of berry crops have been compiled, taking into account the technological requirements of breeding for 2020-2025. Technologies for cultivating rose hips, gooseberries, honeysuckle, currants, and technologies for propagating currants in film greenhouses have been developed.

Bring back its former glory

The reforms carried out in the Russian agricultural sector since the early 90s have turned out to be destructive for horticulture. As a branch of the national economy, it virtually ceased to exist. Only in the Chelyabinsk region the share of industrial gardening decreased from 65% to 1%. There are almost no fruit-bearing plantings left, experimental production fruit nurseries have practically ceased their activities, and their products satisfy market demand by only 12-15%.

There is no targeted program for the development of industrial horticulture in the region, based on reliable materials from the inventory of plantings and new developments of scientific institutions in recent years.

This is not science's fault. Scientists from the South Ural Research Institute of Horticulture and Potato Growing have more than once proposed to form the scientific basis for the revival of the industry. However, the state of the macroeconomy and bureaucratic conservatism do not provide an opportunity to move forward. The expectation is that collective amateur gardening (i.e. private sector) will make up for the losses of industrial gardening, is not justified. Yes, and he cannot justify himself. Despite the fact that UUNIIPOK annually produces more than 60 thousand seedlings of fruit and berry crops for the population, the private sector suffers from a lack of planting material, especially new varieties, the need for which is met by 47-50%. Small producers of seedlings - private traders - are trying to fill this niche. But the quality of their planting material often does not stand up to criticism in all respects.

Is it realistic to revive community gardening in the new economic conditions?

Quite, say South Ural scientists and breeders. But for this, at the state and regional level, in their opinion, it is necessary to resolve the most pressing issues:

From the areas under gardens from the beginning of territory preparation until the plantings begin to bear fruit, cancel the land tax

Allocate on a repayable basis capital investments for planting perennial plants

On industrial enterprises region to organize the production of special equipment for gardening

Laws are needed to protect domestic producers in their own market

Encourage small businesses to organize processing of horticultural products

In the vocational education system it is necessary to organize training for horticulture

The unification of the scientific potential of Ural agricultural scientists is also very important. For these purposes, it is necessary to create a Ural Scientific and Methodological Center with its location in Chelyabinsk. The benefits of such a union are enormous. Proof of this is the potato coordinating council, created in April 2000 at the initiative of the State Scientific Institution YuUNIPOK on a voluntary basis. Over the 8 years of joint work, potato growing institutes have carried out a powerful mobilization of the gene pool, expanded collections, agreed on crossing combinations, and regularly exchange information, source and breeding material. The practice of the coordinating council has shown that this form of work is extremely effective, viable and therefore deserves development and improvement.

Work has also begun to unite horticultural institutions. A multilateral agreement was signed between six scientific institutions Ural and adjacent regions - State Scientific Institution YuUNIIPOK, BashNIISKH, Udmurt Research Institute of Agriculture, Kostanay Research Institute of Agriculture, Kazakh Research Institute of Agriculture, Karabalyk Experimental Station.

Agricultural science today is going through difficult times, but it is alive and ready to contribute to the revival of agricultural production, including the South Ural industrial horticulture.

HETEROSIS

(from the Greek heteroiosis - change, transformation), “hybrid power”, the superiority of hybrids in a number of characteristics and properties over the parent forms. The term "G." proposed by J. Schell in 1914. As a rule, G. is characteristic of first-generation hybrids obtained by crossing unrelated forms: decomp. lines, breeds (varieties) and even species. In further generations (crossing hybrids with each other), its effect weakens and disappears. The hypothesis of “overdominance”, or monogenic G., assumes that heterozygotes by definition. gene are superior in their characteristics to the corresponding homozygotes. A phenomenon that illustrates this hypothesis is interallelic complementation. A number of other hypotheses are based on the assumption that the hybrid has a larger number of dominant alleles of different genes compared to the parental forms and the interaction between these alleles. Synthetic hypotheses are based on both intragenic and intergenic interactions. The importance of heterozygosity as the basis of genetics is also evidenced by the fact that in natural populations individuals are heterozygous for a large number of genes. Moreover, many remain in the heterozygous state. alleles that, when homozygous, exhibit adverse effects on vital signs. G. has important in agriculture practice (in agricultural animals and plants, corn often leads to an increase in productivity and yield: the production of simple and double interline hybrids of corn made it possible to increase the gross grain yield by 20-30%), but its use is often not effective enough, because . The problem of consolidating G. in a number of generations has not yet been solved. Vegetative propagation of heterotic forms, polyploidy, etc. are considered as approaches to solving this problem. irregular forms of sexual reproduction (apomixis, parthenogenesis, etc.).

Source: “Biological Encyclopedic Dictionary.” Ch. ed. M. S. Gilyarov; Editorial team: A. A. Babaev, G. G. Vinberg, G. A. Zavarzin and others - 2nd ed., corrected. - M.: Sov. Encyclopedia, 1986.)

heterosis

(hybrid power, hybrid strength), superiority of first generation hybrids over parental forms in viability, yield, fertility and a number of other characteristics. To obtain the effect of hybrid power, it is important to choose unrelated forms as parents, representing different lines, breeds, even species. In practice, the best parental pairs, which produce the most valuable hybrids, are selected as a result of numerous crosses, making it possible to identify the most successful compatibility different lines. When successive generations are crossed with each other, heterosis weakens and dies out.
The basis of heterosis is sharp increase heterozygosity in first generation hybrids and superiority heterozygotes for certain genes over the corresponding ones homozygous. Thus, the phenomenon of hybrid power is opposite to the result of inbreeding - inbreeding which has adverse consequences for the offspring. The genetic mechanism of heterosis (it is not fully understood) is also associated with the presence in the hybrid, compared to the parents, of a larger number of dominant genes that interact with each other in a favorable direction.
Heterosis is widely used in agricultural practice to increase agricultural productivity. crops and agricultural productivity animals. In the 1930s US breeders have dramatically increased corn yields by using hybrid seeds. One of the important tasks selection– search for ways to “consolidate” heterosis, i.e. preserving it over generations.