Crossing plants at home. How to cross plants at home Are plants of different species crossed?

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Non-specialists are often suspicious of hybrid plants, unaware that many of the crops they grow on their garden plots, is the result of many years of work by breeders.

What is plant crossing

Hybridization or crossing of plants is one of the main methods of plant breeding. The essence of the method is to cross two plants of different varieties, species or genera.

The result, which directly depends on the selection of parent plants, is the production of new varieties and species.

For example, few people know that such crops as plums or garden strawberries did not exist in nature. The plum was obtained by crossing sloe and cherry plum, and garden strawberries, or strawberries as they are incorrectly called, are the result of crossing wild species of strawberries - Virginia and Chilean.

Crossbreeding technology

Crossing technology consists of the artificial or natural transfer of pollen from a plant of one variety or species to another, carried out under careful control.

During this period, it is important to isolate the flowers to prevent the entry of foreign pollen.

1. Choose two plants of different varieties or species.
2. On the mother plant, select the most conveniently located flowers.
3. Carefully open the unopened buds (one day before blooming).
4. Using tweezers, carefully remove all stamens with pollen.
5. Wrap flowers with removed stamens in white thin material to avoid unplanned pollination.
6. The day before removing the stamens from one plant from the second (paternal) buds about to open, collect pollen in a glass jar.
7. Cover the jar with gauze or a light transparent cloth and place it in a dry place.

The day after the stamens are removed from the mother plant, fertilization is carried out:

• The best time is the first half of the day before twelve o'clock.
• Shake the jar of pollen.
• The pollen that has settled on the walls of the jar is carefully applied to the stigma of the mother plant with a cotton swab or other improvised means (you can even use your finger).
• Cover the fertilized flower again with a light, thin cloth or gauze.
• Repeat fertilization for 3 days.

Fertilized flowers must be covered for the entire growth period until the fruit ripens. It is recommended to remove excess flowers. After harvesting ripe fruits, they must be stored for from several weeks to several months, depending on the time of ripening and the shelf life of the crop.

Seeds stone fruits are sown immediately on the beds; summer-ripening pome seeds, after three days of drying, are sown in the sand on the beds in the fall. The seeds of plants that ripen in the fall are collected when the fruits begin to deteriorate, but no later than April. After collecting and drying, they are sown in prepared containers.

Spatial and temporal isolation during crossing

When crossing cross-pollinating crops, spatial isolation can be used: the plants are grown in different areas remote from the plants of the given variety. Such crops include carrots, cabbage, beets, etc.

In dioecious plants such as spinach, when growing in one area, one of the varieties should have the male plants removed.

Crossing cross-pollinating crops in isolated areas greatly minimizes labor costs: pollination occurs naturally - by wind or insects. In addition, in one isolated area it is possible to place several plants of the same variety, thus increasing the number of hybrid seeds obtained. A significant disadvantage of this method is the impossibility of completely eliminating the ingress of foreign pollen. In addition, with natural cross-pollination, approximately half of the plants are fertilized with pollen from their own variety.

In regions with a warm climate, where the growing season is quite long, for plants with quickly fading flowers, isolation at time intervals can be used: different combinations of crossings are carried out in the same area. Different terms flowering excludes unplanned cross-pollination.

In breeding practice, in the absence of sufficient space for organizing individual areas, insulating structures are used:

• The design is made in the form of a frame, which is covered with light transparent fabric.
• To isolate individual shoots or inflorescences, small “houses” are made of parchment paper or gauze, which are covered with a wire frame.

For insect-pollinated plants, when constructing insulators, it is better to use materials such as cambric or gauze; for wind-pollinated crops, parchment paper.

Benefits of Crossbreeding

The process of hybridization - crossing plants - is aimed at obtaining plant varieties that have advantageous properties of the parent varieties, such as:

• High yield
• Disease resistance
• Frost resistance
• Drought resistance
• Short ripening times

For example, if the father and mother plants are resistant to various diseases, then the resulting hybrid will inherit resistance to both diseases.

Hybrid plant varieties have better vitality; they are less susceptible to changes in temperature, humidity, and changes in climatic conditions than their non-hybrid counterparts.

More information can be found in the video.

Man, in his quest to improve nature, moves further and further. Thanks to modern advances in genetics, farmers are getting more and more unusual and interesting hybrids that can satisfy the wildest desires of consumers.
In addition, globalization leads to the spread of plant species that are not typical for a given climate zone. In our country, pineapples and bananas have long since become exotic; hybrid nectarines and miniols, etc., have become commonplace.

Yellow watermelon (38 kcal, vitamins A, C)

It's the usual striped watermelon on the outside, but bright yellow on the inside. Another feature is the very small number of seeds. This watermelon is the result of crossing a wild one (yellow inside, but completely tasteless) with a cultivated watermelon. The result was juicy and tender, but less sweet than red.
They are grown in Spain (round varieties) and Thailand (oval). There is a variety “Lunny” bred by breeder Sokolov from Astrakhan. This variety has a very sweet taste with some exotic notes, similar to the taste of mango or lemon, or pumpkin.
There is also a Ukrainian hybrid based on watermelon (“kavuna”) and pumpkin (“garbuza”) - “Kavbuz”. It is more like a pumpkin with a watermelon flavor and is ideal for making porridge.

Purple potatoes (72 kcal, vitamin C, B vitamins, potassium, iron, magnesium and zinc)

Potatoes with pink, yellow or purple skins no longer surprise anyone. But scientists from Colorado State University managed to get potatoes with purple colors inside. The variety is based on Andean highland potatoes, and the color is due to the high content of anthocyanins. These substances are the strongest antioxidants, the properties of which are preserved even after cooking.
They called the variety “Purple Majesty”; it is already actively sold in England and is being started in Scotland, whose climate is most suitable for the variety. The variety was popularized by the English cook Jamie Oliver. These purple potatoes with a familiar taste look great mashed, indescribably rich in color, baked, and of course fries.

Romanesco cabbage (25 kcal, carotene, vitamin C, mineral salts, zinc)

The ethereal appearance of this close relative of broccoli and cauliflower perfectly illustrates the concept of “fractal.” Its soft green inflorescences are cone-shaped and arranged in a spiral on the head of cabbage. This cabbage comes from Italy, it has been widely sold for about 10 years, and its popularization was facilitated by Dutch breeders, who slightly improved the vegetable, known to Italian housewives since the 16th century.

Romanesco has little fiber and a lot of useful substances, making it easily digestible. Interestingly, when preparing this cabbage, there is no characteristic cabbage smell, which children do not like so much. In addition, the exotic appearance of the space vegetable makes you want to try it. Romanesco is prepared like regular broccoli - boiled, stewed, added to pasta and salads.

Pluot (57 kcal, fiber, vitamin C)

By crossing plant species such as plums (plum) and apricots (apricot), two hybrids were obtained: pluot, which looks more like a plum, and aprium, which looks more like an apricot. Both hybrids are named after the first syllables of the English names of the parent species.
Externally, pluot fruits are colored pink, green, burgundy or purple, interior - from white to rich plum. These hybrids were bred at Dave Wilson Nursery in 1989. Now in the world there are already two varieties of aprium, eleven varieties of pluot, one nectaplama (a hybrid of nectarine and plum), and one pichplama (a hybrid of peach and plum).
Plouts are used for making juice, desserts, homemade preparations and wine. This fruit tastes much sweeter than both plum and apricot.

Watermelon radish (20 kcal, folic acid, vitamin C)

Watermelon radishes live up to their name - they are bright crimson inside and covered with white-green skin on the outside, just like a watermelon. In shape and size too (diameter 7-8 cm) it resembles a medium-sized radish or turnip. It tastes quite ordinary - bitter near the skin and sweetish in the middle. True, it is harder, not as juicy and crispy as regular one.
It looks wonderful in a salad, simply sliced ​​with sesame seeds or salt. It is also recommended to puree it, bake it, and add it to vegetables for frying.

Yoshta (40 kcal, anthocyanins with antioxidant properties, vitamins C, P)

Crossing such plant species as currants (johannisbeere) and gooseberries (stachelbeere) produced the yoshtu berry with fruits close to black in color, the size of a cherry, with a sweet and sour, slightly astringent taste, pleasantly reminiscent of currants.
Michurin also dreamed of creating currants the size of gooseberries, but not prickly. He managed to develop the “Black Moor” gooseberry, which is dark purple in color. By 1939, in Berlin, Paul Lorenz was also breeding similar hybrids. Due to the war, these works were stopped. It was only in 1970 that Rudolf Bauer managed to get the ideal plant. Now there are two varieties of yoshta: “Black” (brown-burgundy color) and “Red” (faded red color).
During the season, 7-10 kg of berries are obtained from the yoshta bush. They are used in homemade preparations, desserts, and for flavoring soda. Yoshta helps well with gastrointestinal diseases, for elimination from the body heavy metals and radioactive substances, improve blood circulation.

Broccolini (43 kcal, calcium, vitamins A, C, iron, fiber, folic acid)

In the cabbage family, as a result of crossing ordinary broccoli and Chinese broccoli (gailan), a new cabbage was obtained that looks like asparagus on the top with a broccoli head.
Broccolini is a little sweet, does not have a sharp cabbage spirit, with a peppery note, delicate in taste, reminiscent of asparagus and broccoli at the same time. It contains many useful substances and is low in calories.
In the USA, Brazil, Asian countries, Spain, broccolini is usually used as a side dish. It is served fresh, drizzled with butter or lightly fried in oil.

Nashi (46 kcal, antioxidants, phosphorus, calcium, fiber)

Another result of plant crossings is Nashi. It was obtained from apples and pears in Asia several centuries ago. There it is called Asian, water, sand or Japanese pear. The fruit looks like a round apple, but tastes like a juicy, crisp pear. The color of Nashi ranges from pale green to orange. Unlike regular pears, nashi are harder, so they are better stored and transported.
Nashi is quite juicy, so it is best used in salads or solo. Also good as an appetizer with wine along with cheese and grapes. Currently, about 10 popular commercial varieties are grown in Australia, the USA, New Zealand, France, Chile and Cyprus.

Yuzu (30 kcal, vitamin C)

Yuzu (Japanese lemon) is a hybrid of mandarin and ornamental citrus (ichang papeda). The fruit is the size of a green or yellow color with lumpy skin, it has a sour taste and bright aroma. The Japanese have been using it since the 7th century, when Buddhist monks brought this fruit from the mainland to the islands. Yuzu is popular in Chinese and Korean cooking.
It has a completely unusual aroma - citrus, with floral shades and notes of pine. Most often used for flavoring, the zest is used as a seasoning. This seasoning is added to meat and fish dishes, miso soup, and noodles. Jams, alcoholic and non-alcoholic drinks, desserts, and syrups are also prepared with zest. The juice is similar to lemon juice (sour and aromatic, but softer) and is the basis of ponzu sauce, and is also used as vinegar.
It also has cult significance in Japan. On December 22, the winter solstice, it is customary to take baths with these fruits, which symbolize the sun. Its aroma drives away evil forces, protects against colds. Animals are dipped into the same bath, and then the plants are watered with water.

Yellow beets (50 kcal, folic acid, potassium, vitamin A, fiber)

These beets differ from ordinary ones only in color and in the fact that they do not dirty your hands when cooking. It tastes just as sweet, aromatic, and is good baked and even in chips. Yellow beet leaves can be used fresh in salads.

But man is just learning to transform plant species, and nature has been creating such a miracle for a long time!

All about front gardens, flower beds and flower beds - in photographs and articles

Breeding our own flower varieties

We will tell you how to cross two varieties of the same plant species with each other - this method is called hybridization. Let these be plants of different colors or different shapes of petals and leaves. Or perhaps they will differ in flowering time or requirements for external conditions?

Choose plants that bloom quickly to speed up the experiment. It’s also better to start by choosing unpretentious flowers– for example, foxgloves, calendulas or delphiniums.

Progress of the experiment and observation diary

First, formulate your goals - what you want to get from the experiment. What desirable traits should new varieties have?

Keep a notebook-diary where you write down your goals and record the progress of the experiment from beginning to end.

Be sure to describe in detail the original plants and then the resulting hybrids. Here are the most important point: plant health, growth rate, size, color, aroma, flowering time.

Flower structure

In our article, we will take the hellebore flower as an example; you can see it in the diagram and in the photographs.

The appearance of flowers can vary significantly from plant to plant, but the structure of the flowers is basically the same.

Pollination of a flower

1. Start by choosing two plants. There will be one pollinator, and the other - seed plant. Choose healthy and vigorous plants.

2. Keep a close eye on the seed plant. Select an unopened bud with which you will carry out all the manipulations, and mark it. Moreover, it will have to isolate before opening– tying it in a light linen bag. As soon as the flower begins to open, cut off all the stamens to prevent accidental pollination.

3. Once the flower of the seed plant has fully opened, transfer pollen to it from a pollinating plant. Pollen can be transferred using a cotton swab, a brush, or by tearing out the stamens of a pollinating flower and bringing them directly to the seed. Apply pollen to the stigma of the flower of a seed plant.

4.Put on the flower of the seed plant linen bag. Don’t forget to make the necessary notes in your observation diary about the time of pollination.

5. To be on the safe side, repeat the pollination operation after some time - for example, after a couple of days (depending on the timing of flowering).

Choose two flowers - one will serve as a pollinator, the other will become a seed plant.

As soon as the flower of the seed plant opens, cut off all its stamens.

Apply pollen taken from a pollinating flower to the pistil of a seed plant flower.

A pollinated flower must be marked.

Obtaining hybrids

1. If pollination was successful, then soon the flower will begin to fade, and the ovary will increase. Do not remove the bag from the plant until the seeds are ripe.

2. Plant the resulting seeds as seedlings. When will you receive it? young hybrid plants, then give them a separate place in the garden or transplant them into boxes.

3. Now wait for the hybrids to bloom. Don't forget to write down all your observations in your diary. Among the first, and even the second generation, there may be flowers that exactly repeat the parental properties without changes. Such specimens are immediately rejected. Check in with your goals and select among the new plants received those that most closely match the desired characteristics. You can also pollinate them by hand, or isolate them.

The flower of the seed plant should be protected with a textile bag.

When you receive the seeds, plant them as seedlings. Place young plants in boxes.

Keep a close eye on your new hybrid and write down your observations in your diary.

If you decide to seriously develop new varieties, then you will need the advice of a specialist breeder. The fact is that you will need to find out whether you really have developed a new variety or are you following a path already trodden by someone else. Competition in the field of creating new varieties is very high.

For those who have decided to experiment with hybridization as a home hobby, we wish you to get a lot of pleasure from this activity, make many joyful discoveries and finally give all your gardener friends a new variety of some wonderful flower named after itself.

It is called sexual crossing of two individuals that differ from each other in a greater or lesser number of characteristics. They may belong to two varieties, races, varieties of the same species, two species of the same genus, or different kinds one family. In most cases, the closer the individuals being crossed are to each other, the greater the chance of obtaining viable and fertile offspring.

Sexual hybridization is of great importance and application in practical plant growing. Very many of our cultivated plants, as already indicated, are sexual hybrids, partly obtained naturally in nature and taken from there into culture, partly bred through artificial crossings.

The ability for sexual hybridization in some families or individual genera and species turns out to be greater, in others less. Sometimes hybridization between morphologically closely related species fails, while between more distant ones it succeeds.

Sexual hybridization occurs most easily between varieties and varieties belonging to the same species. Hybrids between species are obtained for the most part small in number, poorly viable and infertile in the future; hybrids between genera are obtained much less frequently and in most cases are subsequently infertile.

Research by I.V. Michurin showed that the sterility of hybrids in many cases is temporary.

Often, when crossing, the first generation of hybrids is distinguished by extremely powerful development, exceeding its parent forms by several times in size. This phenomenon is called heterosis. In the sexually produced offspring of hybrids, the plants usually return to the previous size of their ancestors. But if such giant hybrids can reproduce vegetatively, then the resulting gigantism will also manifest itself in vegetatively bred offspring. In this way they can be derived large varieties root and tuber crops, ornamental trees and herbaceous plants with very large flowers etc. It is also possible to annually breed new annual heterotic plants to increase their production, for example in tobacco, tomatoes, corn, etc.

In some cases of infertility of hybrids, it is possible to restore their fertility through systematic subsequent crossings.

When crossing sexual hybrids of different species with each other, it was possible to obtain forms that are hybrids between 3, 4 or more species.

The issue of dominance - the predominance of certain characteristics of the parents or their ancestors in a hybrid - is the most important issue in the matter of selection, in the development of new varieties.

I.V. Michurin believed that the hybrid does not represent something in between producers. The heredity of a hybrid consists only of those characteristics of the producing plants and their ancestors, which in the early

stages of hybrid development are favored external conditions. The dominance of certain traits also depends on the unequal strength of producers in the sense of transmitting their traits to their offspring. The following traits are transmitted to a greater extent: 1) species growing in the wild; 2) a variety that is older in origin; 3) an individually older plant; 4) older flowers in the crown. The mother plant, all other things being equal, will more fully transfer its properties than the father's, but if the conditions for growing hybrids are more favorable for the father's plant, then its characteristics may dominate.

Plants weakened by drought or cold spring have a weaker power to transmit their hereditary properties.

To overcome the incompatibility of distant systematic species, I. V. Michurin developed a number of effective and very interesting methods from a general biological point of view.

The intermediary method is that if two species do not cross with each other, then one of them is crossed with some third species, with which both of these species can be crossed. The resulting hybrid - the "intermediary" - has a greater ability to cross, and it can be successfully crossed with the second of the species that were planned for crossing. I.V. Michurin used this method when crossing wild almond (Amygdalus nana) with peach; the middleman here was a hybrid obtained from crossing wild almonds with the North American David's peach ( Prunus davidiana). Further research has shown that such complex hybrid forms have a wide ability to interbreed with species with which their original parent forms do not interbreed.

The “vegetative rapprochement” method, used by I.V. Michurin to overcome uncrossability, consists in the fact that a young seedling of one of the plants to be crossed is grafted into the crown of another, adult plant with which it is desirable to cross it. This seedling, unstable as an unformed organism, gradually changes until the time of flowering under the influence of a more powerful rootstock, approaches it in properties and crosses with it in the future better than the original form without grafting. I.V. Michurin used this method, for example, when hybridizing apple and mountain ash with pear.

The method of using a pollen mixture, which also facilitates crossing, consists of mixing a small amount of pollen from the mother (pollinated) plant with pollen from the pollinating plant. Presumably, pollen from one's own species makes the stigma more susceptible to pollination by foreign pollen. These methods are currently widely used in breeding work with a variety of plants. Mixing pollen of a third type or variety is also used, which can also stimulate pollination with pollen, without this technique it does not give results.

A major role in the works of I.V. Michurin was played by the education of young hybrid seedlings with unstable heredity. Distant hybridization without further directed education often does not give the desired results. Targeted effects on hybrids are achieved various methods, including through vaccinations, or the mentor method, in which the hybrid is repeatedly induced to enhance certain properties. The mentor method is based on the mutual influence of the rootstock and scion. It was used by I.V. Michurin in two versions. With the so-called

In a stand mentor, cuttings of a young hybrid seedling are grafted into the crown of one of its adult producers whose quality (for example, frost resistance) it is desirable to enhance in the hybrid. The grafted hybrid, under the powerful influence of the rootstock (stand-up mentor), acquires to a greater extent the property desired by the hybridizer (in this example, frost resistance). Or, for example, the eyes were taken from a seedling, a hybrid between the Renclod green plum and the sloe, and grafted: one onto the Renclod, the other onto the sloe. In the first case, a plant later turned out with signs of renclod (Renclad thorn), in the second case, with signs of sloe (Thorn sweet). The opposite effect of the scion on the rootstock is reflected in the so-called grafting mentor, when, for example, by grafting several cuttings of an old variety (grafting mentor), characterized by abundant fruiting, into the crown of a young seedling, it is possible to accelerate and improve the fruiting of the rootstock; with other combinations of grafted plants, this method succeeded, on the contrary, in delaying the ripening of fruits, extending their ability to remain in storage, etc.

These new principles and methods of work, discovered by I. V. Michurin, are important. Selection of pairs for hybridization through preliminary biological analysis of the parents, targeted education of hybrids, acceleration of the development time of new varieties - all this is now widely used in the development of new varieties of cultivated plants.

By crossing durum wheat ( Triticum durum) with soft ( Triticum vulgare) some new valuable varieties of wheat have been obtained. Rye-wheat hybrids have been obtained, which are of interest both in themselves and for further crossings again with wheat in order to obtain hybrids with high quality wheat grain and cold resistance of rye. Work is underway to cross wheat with wild wheatgrass (N.V. Tsitsin), with perennial wild rye. By crossing potatoes with their wild relatives, potato varieties were obtained that are resistant to infection by a fungus dangerous to potatoes - late blight. Work is underway on crossing annual sunflowers with perennials, sugar cane, which has a very long growing season, with its wild relatives, which have a shorter growing season, bred watermelons with drought-resistant wild relatives, etc. Systematic management of the development of plants (and animals) and the creation of new their forms, based on a deep study of complex biological relationships and the discovery of the laws of life, constitute theoretical basis Soviet selection.

We will tell you how to cross two varieties of the same plant species with each other - this method is called hybridization. Let these be plants of different colors or different shapes of petals and leaves. Or perhaps they will differ in flowering time or requirements for external conditions?

Choose plants that bloom quickly to speed up the experiment. It is also better to start by choosing unpretentious flowers - for example, foxgloves, calendulas or delphiniums.

Progress of the experiment and observation diary

First, formulate your goals - what you want to get from the experiment. What desirable traits should new varieties have?

Keep a notebook-diary where you write down your goals and record the progress of the experiment from beginning to end.

Be sure to describe in detail the original plants and then the resulting hybrids. Here are the most important points: plant health, growth rate, size, color, aroma, flowering time.

Flower structure

In our article, we will use a flower as an example; you can see it in the diagram and in the photographs.

The appearance of flowers can vary significantly from plant to plant, but is generally the same.

Pollination of a flower

1. Start by choosing two plants. There will be one pollinator, and the other - seed plant. Choose healthy and vigorous plants.

2. Keep a close eye on the seed plant. Select an unopened bud with which you will carry out all the manipulations, and mark it. Moreover, it will have to isolate before opening– tying it in a light linen bag. As soon as the flower begins to open, cut off all the stamens to prevent accidental pollination.

3. Once the flower of the seed plant has fully opened, transfer pollen to it from a pollinating plant. Pollen can be transferred using a cotton swab, a brush, or by tearing out the stamens of a pollinating flower and bringing them directly to the seed. Apply pollen to the stigma of the flower of a seed plant.

4.Put on the flower of the seed plant linen bag. Don’t forget to make the necessary notes in your observation diary about the time of pollination.

5. To be on the safe side, repeat the pollination operation after some time - for example, after a couple of days (depending on the timing of flowering).

Choose two flowers - one will serve as a pollinator, the other will become a seed plant.	As soon as the flower of the seed plant opens, cut off all its stamens.
Apply pollen taken from a pollinating flower to the pistil of a seed plant flower.	A pollinated flower must be marked.

Obtaining hybrids

1. If pollination was successful, then soon the flower will begin to fade, and the ovary will increase. Do not remove the bag from the plant until the seeds are ripe.

2. Plant the resulting seeds as seedlings. When will you receive it? young hybrid plants, then give them a separate place in the garden or transplant them into boxes.

3. Now wait for the hybrids to bloom. Don't forget to write down all your observations in your diary. Among the first, and even the second generation, there may be flowers that exactly repeat the parental properties without changes. Such specimens are immediately rejected. Check in with your goals and select among the new plants received those that most closely match the desired characteristics. You can also pollinate them by hand, or isolate them.

If you decide to seriously develop new varieties, then you will need the advice of a specialist breeder. The fact is that you will need to find out whether you really have developed a new variety or are you following a path already trodden by someone else. Competition in the field of creating new varieties is very high.

For those who have decided to experiment with hybridization as a home hobby, we wish you to get a lot of pleasure from this activity, make many joyful discoveries and finally give all your gardener friends a new variety of some wonderful flower named after itself.

In the 30s last century N.I. Vavilov noted that the problem of creating disease-resistant varieties of agricultural crops can be resolved in two ways: selection in the narrow sense of the word (selection of resistant plants among existing forms) and through hybridization (crossing different plants with each other). Methods for plant selection for immunity to pathogenic organisms are not specific. They are modifications of conventional breeding methods. The main difficulties in creating immune varieties are the need to simultaneously take into account the characteristics of plants and the pests that damage them. Currently, all generally accepted modern methods are used in breeding for resistance. breeding work: hybridization, selection, as well as polyploidy, experimental mutagenesis, biotechnology and genetic engineering.

One of the main difficulties in plant selection for immunity is the genetic linkage of plant traits that reflect their phylogenetic history under conditions natural ecosystems. In the process of spontaneous domestication and the formation of highly productive and high-quality forms of plants, their immune system was weakened. In cases where selection is carried out without attention to immunity, the weakening of the latter continues to occur in our time.

The most important task of selection, genetics, molecular biology and is the search for ways to combine high productivity and other economically valuable properties of plants with signs of their immunity. It is desirable that the basis of immunity be polygenic.

The issue is most easily resolved when, from a population of an existing variety, it is possible to isolate plants that are characterized by high immune resistance to one specific pathogen. For such identification, different selection methods and analytical methods can be used that take into account the heterosis of the variety population.

When drawing up breeding programs, the type of pollination of a plant population is very important (cross-pollination, self-pollination, or the population belongs to an intermediate group). Breeding work for immunity to a pathogen should be carried out taking into account the following factors: in the plant population of the first group, the unit of analysis is the individual plant, the other - the population (variety or line).

Traditional breeding methods in creating genotypes resistant to diseases and pests

Selection. Both in nature in general and in human breeding activities, selection is the main process of obtaining new forms (formation of species and varieties, creation of breeds, varieties). Selection is most effective when working with self-pollinating crops, as well as plants that reproduce vegetatively (clonal selection).

In breeding for resistance, selection is effectively used both on its own (it is the main method when working with necrotrophic pathogens) and as a component of the selection process, which is generally impossible to do without in any selection methods. In practical breeding for resistance, two types of selection are used: mass and individual.

Mass selection is the oldest method of selection, thanks to which varieties of the so-called folk selection were created, and is still a valuable source material for modern breeders. This is a type of selection in which a large number of plants are selected from the initial population in the field that meet the requirements for the future variety, immediately assessing a set of traits (including resistance to certain diseases). The harvest of all selected plants is combined and sown in next year in the form of one section. The result of mass selection is the offspring of the total mass of the best plants selected for a certain trait(s).

The main advantages of mass selection are its simplicity and the ability to quickly improve a large amount of material. The disadvantages include the fact that the material selected by mass selection cannot be tested with the offspring and its genetic value determined, and therefore, it is impossible to isolate breeding-valuable forms from the population of a variety or hybrid and use them for further work.

Individual selection (pedigree) - one of the most effective modern methods selection for resistance. Hybridization, artificial mutagenesis, biotechnology and Genetic Engineering are first suppliers of material for individual selection - the next stage of breeding work, selects the most valuable from the provided material.

The essence of the method is that individual resistant plants, the offspring of each of which are subsequently propagated and studied separately.

Both individual and mass selection can be one-time or reusable.

One-time selection mainly used in the selection of self-pollinating crops. One-time individual selection involves sequential study at all stages of the breeding process of a plant selected once for a specific trait. One-time mass selection is most often and most effectively used to improve the health of a variety in seed production. That's why it is also called health-improving.

Multiple selections are more suitable and effective in the selection of cross-pollinating crops; their effectiveness is determined primarily by the degree of heterozygosity of the source material. Through repeated mass selection, resistance to necrotrophs is maintained - pathogens such as fusarium, gray and white rot, etc. Using this method, highly resistant to and were created.

Hybridization. Currently, one of the most used methods in breeding for resistance is hybridization - crossing genotypes with different hereditary abilities with each other and obtaining hybrids that combine the properties of the parent forms.

In breeding for disease resistance, hybridization is appropriate and effective if at least one parent form is a carrier of hereditary factors that can provide genetic protection of the future variety or hybrid from potentially dangerous strains and races of the pathogen.

As noted earlier, such hereditary factors (effective resistance genes) were formed in the centers of related evolution of host plants and their pathogens. Many of them have already been transferred to cultivated plants from their wild relatives using distant hybridization. These are now known as crop resistance genes.

But the indisputable fact is that today most of these genes are widely used in breeding and have mostly lost their effectiveness, overcome as a result of pathogen variability. That's why intraspecific hybridization (between plants of the same species) when creating disease-resistant varieties or hybrids in some cases is unpromising. To obtain positive results, the breeder, when involving certain parental forms in crossings, must be confident in the high efficiency of their resistance genes to the population of the pathogen in the place of future cultivation of the variety (hybrid).

Against this background, everything higher value in selection for resistance acquires distant hybridization (between plants from different botanical taxa). After all, plants of wild and primitive species are characterized by the most pronounced immunity. The genomes of wild relatives of cultivated plants have been and remain the main natural source of resistance genes, including complex immunity. Crossing cultivated plants of existing varieties with wild species usually improves immunogenetic properties. And if earlier the use of distant hybridization was not very popular due to the difficulties associated with the imbalance of the genomes of parental forms and the linkage of resistance with economically undesirable traits, now methods have been developed to resolve problematic issues.

Distant hybridization makes it possible to transfer environmental plasticity and resistance to adverse factors from wild plants to cultivated ones. external environment, to diseases and other valuable properties and qualities. Varieties and new forms of grain, vegetable, industrial and other crops have been created on the basis of distant hybridization. For example, the source of wheat immunity genes to, and is endemic to Transcaucasia Triticum dicoccoides Korn.

As world practice shows, a very effective type of hybridization in the selection of self-pollinating crops for resistance is backcrosses (backcrosses) when a hybrid is crossed with one of the parent forms. This method is also called the method of “repairing” varieties, since it allows you to improve a certain variety for one or another characteristic it lacks (in particular, resistance to a certain disease). But it should be borne in mind that the use of this method does not allow exceeding the productivity of the variety that is being “repaired” (and according to the requirements of the State Service for the Protection of Rights to Plant Varieties of Ukraine, a variety cannot be registered if its productivity does not exceed the standard).

As a rule, when backcrossing, the donor variety of disease resistance is used as the maternal form, and an unstable but highly productive variety (recipient for resistance) is used as the parental form. As a result of their crossing, hybrids are obtained, which are re-crossed with the parent form (backcrossed). A prerequisite is that the maternal forms for each subsequent backcross are selected from resistant hybrid plants of the previous cross that were found against an infectious background. Progeny are selected according to the phenotype of the recipient variety. Backcrosses are carried out until the genotype and phenotype of the recipient are almost completely restored, while simultaneously acquiring resistance to the disease characteristic of the donor.

Increasing the efficiency of plant selection for immunity to pests can be achieved by using pre-created so-called immunity synthetics (known, for example, for corn). The mentioned synthetics are created on the basis of crossing 8-10 immune lines, characterized by different environmental plasticity and composition of immune factors. Many of the synthetics are good sources for creating immune lines for the further breeding of simple and double interline hybrids.

Mutagenesis. Unlike hybridization methods, which are quite labor-intensive and require many years of work to achieve the final result, experimental (artificial) mutagenesis allows, in a short period, to increase plant variability and obtain resistance mutations that do not occur in nature.

The method of experimental (artificial) mutagenesis is based on the targeted effect on plants of various physical and chemical mutagens (ionizing, ultraviolet, laser radiation, chemicals), as a result of which gene mutations occur in plant organisms (changes molecular structure gene), chromosomal (changes in chromosome structures) or genomic (changes in chromosome sets).

The most valuable in breeding terms are gene mutations, which, unlike chromosomal ones, do not lead to sterility of pollen, infertility or non-constancy of mutant lines. Resistance gene mutations are most often associated with either the replacement of a base in a certain section of the DNA of a chromosome, or its loss, addition, or movement. As a result, a change in the genetic code occurs and, accordingly, a change in the physiological and biochemical mechanisms of the cell, which leads to inhibition of the growth, development and reproduction of the pathogen.

The method of artificial mutagenesis in breeding for disease resistance is used in many countries, but it cannot be considered the main method for obtaining resistant forms of plants. This method is most effectively used when working on resistance with crops that reproduce vegetatively, since propagation by seeds entails complex splitting in the offspring due to high degree heterozygosity.

There appears to be further improvement of existing crops grown on already developed lands. Hybrids are something that could play a key role in food supply. After all, most of the areas suitable for agriculture are already occupied. However, increasing the amount of water, fertilizers and other chemicals used on them is economically impossible in many places. That is why the improvement of existing crops is of utmost importance. And hybrids are plants obtained precisely as a result of such an improvement.

The goal is not only to increase yields, but also to increase protein and other nutrient content. The quality of proteins in edible foods is also very important for humans (and people too) must receive from food the required quantities of all essential (i.e. those that they are not able to synthesize themselves) amino acids. Eight of the 20 amino acids necessary for a person, come with food. The remaining 12 can be developed by him himself. However, plants with improved protein composition as a result of selection inevitably require more nitrogen and other nutrients than the original forms, and therefore cannot always be grown on infertile lands, where the need for such crops is especially great.

New properties

Quality includes not only yield, composition and quantity of proteins. Varieties are being created that are more resistant to diseases and pests, thanks to the fruits they contain, are more attractive in shape or color of the fruit (for example, bright red apples), better able to withstand transportation and storage (for example, tomato hybrids with increased shelf life), and also have other significant properties for a given crop.

Activities of breeders

Breeders carefully analyze the available genetic diversity. Over the course of several decades, they have developed thousands of improved lines of important agricultural plants. As a rule, it is necessary to obtain and evaluate thousands of hybrids in order to select those few that will actually surpass in their properties those already widely bred. For example, in the USA from the 1930s to the 1980s. increased almost eightfold, although breeders used only a small part of the genetic diversity of this crop. More and more hybrids are appearing. This allows for more efficient use of cultivated areas.

Hybrid corn

Increased corn productivity has been made possible mainly through the use of hybrid seeds. Inbred lines of this crop (themselves hybrid in origin) were used as parental forms. From the seeds obtained as a result of crossing between them, very powerful corn hybrids develop. The crossed lines are sown in alternating rows, and panicles (male inflorescences) are cut off by hand from the plants of one of them. Therefore, all the seeds on these specimens turn out to be hybrid. And they have very beneficial properties for humans. By carefully selecting inbred lines, powerful hybrids can be obtained. These are plants that will be suitable for growing in any desired location. Because the traits of hybrid plants are the same, they are easier to harvest. And the yield of each of them is much higher than that of unimproved specimens. In 1935, corn hybrids accounted for less than 1% of all corn grown in the United States, but now virtually all of it. Now obtaining significantly higher yields of this crop is much less labor-intensive than before.

Successes of international breeding centers

Over the past few decades, much effort has been made to increase yields of wheat and other grains, especially in warm climates. Impressive successes have been achieved in international breeding centers located in the subtropics. When the new hybrids of wheat, corn and rice were grown in Mexico, India and Pakistan, it led to a dramatic increase in agricultural productivity called the Green Revolution.

Green revolution

The fertilizers and irrigation products developed during this process were used in many developing countries. Each crop requires optimal growing conditions to obtain high yields. Fertilization, mechanization and irrigation are essential components of the Green Revolution. Due to the distribution of credits, only relatively wealthy landowners were able to grow new plant (cereal) hybrids. In many regions, the Green Revolution has accelerated the concentration of land in the hands of the wealthiest few owners. This redistribution of property does not necessarily provide jobs or food for the majority of the population in these regions.

Triticale

Traditional breeding methods can sometimes produce surprising results. For example, the hybrid of wheat (Triticum) and rye (Secale) triticale (scientific name Triticosecale) is becoming increasingly important in many areas and appears to be very promising. It was created by doubling the number of chromosomes in a sterile wheat-rye hybrid in the mid-1950s. J. O'Mara at the University of St. Iowa using colchicine, a substance that interferes with the formation of the cell plate. Triticale combines the high yield of wheat with the unpretentiousness of rye. The hybrid is relatively resistant to linear rust, a fungal disease that is one of the main wheat yields. Further crossings and selection produced improved triticale lines for specific areas. In the mid-1980s. this crop, thanks to its high yield, resistance to climatic factors and excellent straw remaining after harvesting, quickly gained popularity in France, largest producer grain within the EEC. The role of triticale in the human diet is rapidly growing.

Conservation and use of crop genetic diversity

Intensive programs of crossing and selection lead to a narrowing of the genetic diversity of cultivated plants for all their traits. For obvious reasons, it is mainly aimed at increasing productivity, and among the very homogeneous offspring of specimens selected strictly for this trait, disease resistance is sometimes lost. Within a culture, plants become more and more uniform, since certain of their characteristics are more pronounced than others; Therefore, crops in general are more vulnerable to pathogens and pests. For example, in 1970 helminthosporiosis, fungal disease A corn disease caused by Helminthosporium maydis (pictured above) has destroyed approximately 15% of the US corn crop, causing losses of approximately $1 billion. These losses appear to be due to the emergence of a new race of fungus, which is very dangerous to some of the main lines of corn that were widely used in the production of hybrid seeds. Many commercially valuable lines of this plant had identical cytoplasm, since the same pistillate plants are repeatedly used in the production of hybrid corn.

To prevent such damage, it is necessary to grow in isolation and preserve different lines of important crops, which, even if the sum of their traits is not of economic interest, may contain genes useful in ongoing pest and disease control.

Tomato hybrids

Tomato breeders have achieved amazing success in increasing genetic diversity by attracting wild forms. The creation of a collection of lines of this culture, carried out by Charles Rick and his collaborators at the University of California at Davis, made it possible to effectively combat many of its serious diseases, in particular those caused by imperfect fungi Fusarium and Verticillum, as well as some viruses. The nutritional value of tomatoes has been significantly increased. In addition, plant hybrids have become more resistant to salinity and other unfavorable conditions. This occurred mainly through the systematic collection, analysis and use of wild tomato lines for breeding.

As you can see, interspecific hybrids are very promising in agriculture. Thanks to them, it is possible to improve the yield and quality of plants. It should be noted that crossing is used not only in agriculture, but also in animal husbandry. As a result, for example, a mule appeared (its photo is presented above). This is also a hybrid, a cross between a donkey and a mare.

Oleg asks
Answered by Elena Titova, 12/01/2013

Oleg asks: “Hello, Elena! Please tell me, is the crossing of different types of plants, vegetables and fruits by scientists not an interference in God’s creation and a sin? Doesn’t successful such crossings jeopardize Creationism? After all, if you manage to cross different plants, then with Over time, it will be possible to cross different animals, a cat with a dog, for example. So, is there a possibility that from one simpler living creature a more complex one emerged, and so on until the appearance of man?”

Greetings, Oleg!

Scientists-breeders mainly carry out intraspecific crossings (hybridization) to produce desirable traits (for humans, of course) in animals, plants and microorganisms, thereby achieving the creation of new or improved breeds, varieties, strains.

Within a species, crossing of individuals is relatively easy due to the similarity of their genetic material and anatomical and physiological characteristics. Although this is not always the case, for example, under natural conditions it is impossible to cross a tiny Chihuahua dog and a huge mastiff.

But already on the way of crossing individuals different types(and even more so of different genera), molecular genetic barriers arise that prevent the development of full-fledged organisms. And they are more pronounced the further the species and genera being crossed are separated from each other. Due to significantly different genomes of the parents, hybrids may develop unbalanced sets of chromosomes, unfavorable combinations of genes, the processes of cell division and formation of gametes (sex cells) may be disrupted, the death of the zygote (fertilized egg), etc. may occur. Hybrids may be partially or completely sterile (sterile) ), with reduced viability up to lethality (although in some cases in the first generation there is a sharp increase in viability - heterosis), developmental anomalies, in particular, reproductive organs, or so-called chimeric tissues (genetically heterogeneous), etc. may appear. Apparently, this is why the Lord warned His people: “... do not mix your cattle with another breed; do not sow your field with two kinds [of seeds]” ().

Under natural conditions, cases of interspecific crossing are extremely rare.

Examples of artificial distant hybridization are: mule (horse + donkey), bester (beluga + sterlet), liger (lion + tigress), tigon (tiger + lioness), leopon (lion + female leopard), plumcat (plum + apricot), clementine (orange + tangerine), etc. In some cases, scientists are able to remove the negative consequences of distant hybridization, for example, fertile hybrids of wheat and rye (triticale), radish and cabbage (raphanobrassica) have been obtained.

And now your questions. Is artificial hybridization interfering with God's creation? In a certain sense, yes, if a person creates an option that is different from natural, which can be compared, say, with women using decorative cosmetics to improve their appearance. Is artificial hybridization a sin? Is eating meat a sin? The Lord, out of our hardness of heart, allows the killing of living beings for food. Probably, also due to our hardness of heart, he allows selective experimentation for the sake of improvement consumer properties products people need. In the same series is the creation of medicines (in this case, laboratory animals are used and killed). As sad as it may be, all this is the reality of a society where sin reigns and the “prince of this world” rules.

Do successful crossbreeding jeopardize creationism? Not in any way. Against.

You know that everything reproduces “according to its kind.” The biblical “genus” is not a biological species of modern taxonomy. After all, a rich diversity of species appeared after the Flood as a result of the variability that occurred in the characteristics of land organisms from Noah’s Ark and aquatic inhabitants that survived outside the Ark, as they adapted to new environmental conditions. It is difficult to delineate a biblical “genus,” the genetic potential of which is significant and was given initially at creation. It may include modern taxa such as species and genus, but probably not higher than (sub)family. It is possible, for example, that the big cats of the modern systematic genera of the cat family go back to one original “genus”, and the small cats to one or two others. It is clear that the species and genera separated from the biblical “genus” include their own, to some extent, depleted and altered (in relation to the original) genetic material. The combination of these not entirely complementary parts (in interspecific and intergeneric crosses) encounters obstacles at the molecular genetic level, which means it does not allow the formation of a full-fledged organism, although in rare cases this can happen within the biblical “genus”.

What does this mean? That in principle there can be no crossings between “cats and dogs” and “up to humans.”

One more moment. Compare 580 thousand nucleotide pairs, 482 genes in the DNA of a single-cell mycoplasma and 3.2 billion nucleotide pairs, about 30 thousand genes in human DNA. If you imagine a hypothetical path “from amoeba to man,” think about where the new genetic information came from? There is nowhere for it to come from naturally. We know that information only comes from an intelligent source. So who is the Author of amoeba and man?

God's blessings!

Often, non-specialists are suspicious of hybrid plants, not realizing that many of the crops they grow in their gardens are the result of many years of work by breeders.

In dioecious plants such as spinach, when growing in one area, one of the varieties should have the male plants removed.

Crossing cross-pollinating crops in isolated areas greatly minimizes labor costs: pollination occurs naturally - by wind or insects. In addition, in one isolated area it is possible to place several plants of the same variety, thus increasing the number of hybrid seeds obtained. A significant disadvantage of this method is the impossibility of completely eliminating the ingress of foreign pollen. In addition, with natural crossover, approximately half of the plants are fertilized with pollen of their own variety.

In regions with a warm climate, where the growing season is quite long, for plants with quickly fading flowers, isolation at time intervals can be used: different combinations of crossings are carried out in the same area. Different flowering times eliminate unplanned cross-pollination.

In breeding practice, in the absence of sufficient space for organizing individual areas, insulating structures are used:

• The design is made in the form of a frame, which is covered with light transparent fabric.
• To isolate individual shoots or inflorescences, small “houses” are made of parchment paper or gauze, which are used to cover a wire frame.

For insect-pollinated plants, when constructing insulators, it is better to use materials such as cambric or gauze; for wind-pollinated crops, parchment paper.

The process of hybridization - crossing plants - is aimed at obtaining plant varieties that have advantageous properties of the parent varieties, such as:

• High yield
• Resistant to
• Frost resistance
• Drought resistance
• Short ripening times

For example, if the paternal and maternal plants have resistance to different diseases, then the resulting hybrid will inherit resistance to both diseases.

Hybrid plant varieties have better vitality; they are less susceptible to changes in temperature, humidity, and changes in climatic conditions than their non-hybrid counterparts.

More information can be found in the video.

We will tell you how to cross two varieties of the same plant species with each other - this method is called hybridization. Let these be plants of different colors or different shapes of petals and leaves. Or perhaps they will differ in flowering time or requirements for external conditions?

Choose plants that bloom quickly to speed up the experiment. It is also better to start by choosing unpretentious flowers - for example, foxgloves, calendulas or delphiniums.

Progress of the experiment and observation diary

First, formulate your goals - what you want to get from the experiment. What desirable traits should new varieties have?

Keep a notebook-diary where you write down your goals and record the progress of the experiment from beginning to end.

Be sure to describe in detail the original plants and then the resulting hybrids. Here are the most important points: plant health, growth rate, size, color, aroma, flowering time.

Flower structure

In our article, we will use a flower as an example; you can see it in the diagram and in the photographs.

The appearance of flowers can vary significantly from plant to plant, but is generally the same.

Pollination of a flower

1. Start by choosing two plants. There will be one pollinator, and the other - seed plant. Choose healthy and vigorous plants.

2. Keep a close eye on the seed plant. Select an unopened bud with which you will carry out all the manipulations, and mark it. Moreover, it will have to isolate before opening– tying it in a light linen bag. As soon as the flower begins to open, cut off all the stamens to prevent accidental pollination.

3. Once the flower of the seed plant has fully opened, transfer pollen to it from a pollinating plant. Pollen can be transferred using a cotton swab, a brush, or by tearing out the stamens of a pollinating flower and bringing them directly to the seed. Apply pollen to the stigma of the flower of a seed plant.

4.Put on the flower of the seed plant linen bag. Don’t forget to make the necessary notes in your observation diary about the time of pollination.

5. To be on the safe side, repeat the pollination operation after some time - for example, after a couple of days (depending on the timing of flowering).

Choose two flowers - one will serve as a pollinator, the other will become a seed plant.	As soon as the flower of the seed plant opens, cut off all its stamens.
Apply pollen taken from a pollinating flower to the pistil of a seed plant flower.	A pollinated flower must be marked.

Obtaining hybrids

1. If pollination was successful, then soon the flower will begin to fade, and the ovary will increase. Do not remove the bag from the plant until the seeds are ripe.

2. Plant the resulting seeds as seedlings. When will you receive it? young hybrid plants, then give them a separate place in the garden or transplant them into boxes.

3. Now wait for the hybrids to bloom. Don't forget to write down all your observations in your diary. Among the first, and even the second generation, there may be flowers that exactly repeat the parental properties without changes. Such specimens are immediately rejected. Check in with your goals and select among the new plants received those that most closely match the desired characteristics. You can also pollinate them by hand, or isolate them.

The flower of the seed plant should be protected with a textile bag.

When you receive the seeds, plant them as seedlings. Place young plants in boxes.

Keep a close eye on your new hybrid and write down your observations in your diary.

If you decide to seriously develop new varieties, then you will need the advice of a specialist breeder. The fact is that you will need to find out whether you really have developed a new variety or are you following a path already trodden by someone else. Competition in the field of creating new varieties is very high.

For those who have decided to experiment with hybridization as a home hobby, we wish you to get a lot of pleasure from this activity, make many joyful discoveries and finally give all your gardener friends a new variety of some wonderful flower named after itself.

In Goethe's times, as Goethe himself recalled, in Carlsbad - don't look on the map, now it's Karlovy Vary - vacationers on the waters liked to identify plants in bouquets according to Linnaeus. These bouquets were delivered daily to those drinking mineral waters in the shade of the colonnade (bicarbonate-sulfate-chloride-sodium - for the information of those gathering in Karlovy Vary) by a young handsome gardener, arousing increased interest among pale, lonely ladies.

The correct identification of each plant was a matter of honor and success for the gardener, who encouraged innocent botanical hobbies for a modest fee. It is difficult to say why - whether because of jealousy towards the gardener, or towards Linnaeus, but the poet severely disagreed with Linnaeus on the principles of plant taxonomy. Linnaeus, as is known, looked for differences in plants, but Goethe began to look for what was common and with this, it must be said, took the first step towards the genetic systematization of plants.

Women's passion for botany was understandable: Linnaeus' system was amazingly simple and understandable. This is not a “Determinant” higher plants European part of the USSR" by Stankov-Taliev, more than a thousand pages long, leading students to a pre-infarction state.

Linnaeus, who had never liked arithmetic, nevertheless laid it, one might say, as the basis of his system. He divided plants into 24 classes, of which 13 were distinguished by the number of stamens. Plants with one stamen in each flower are placed in the first class, with two - in the second, and so on until the tenth class, which includes plants with ten stamens. The 11th class included plants with 11-20 stamens; 20 or more stamens in a flower indicated that they belonged to the 12th and 13th classes. These two classes were distinguished by the level of location of the base of the stamens relative to the place of attachment of the pistil. Plants of classes 14 and 15 have stamens of unequal length. In flowers of classes 15-20, the stamens of plants are fused with each other or with the pistil. Class 21 included monoecious plants, which have partly staminate and partly fertile (pistillate) flowers. Class 22 includes dioecious plants, which develop only staminate flowers on some plants, and only fertile flowers on others. Class 23 included plants with a chaotic scattering of male and female flowers (including sometimes joint flowers) on the plant. In the 24th class, “secret” plants were united - all flowerless plants, from ferns to algae. The latter were called “cryptogamy” for the reason that botanists did not know how they reproduce. It is now that biologists know their organization and reproduction better than flowering plants.

Linnaeus classified 20 of the 23 classes as glaucous bisexual flowers. It was these that he considered the rule in the plant kingdom, the rest - a curious exception. It seems logical, it’s more convenient for plants - the stamens and pistils are nearby, which means the marriage goes without a hitch; the result of love - the fruit and seed appear as a result of self-pollination, encrypted by biologists with the Latin word autogamia.

After Linnaeus, it became clear that some plants only have seemingly bisexual flowers. Although they have stamens and pistils nearby in the flowers, the pollen cells in the anthers are underdeveloped and the whole plant looks like a eunuch - it’s disgusting to watch. Other flowers cannot fertilize themselves, but their pollen is capable of producing offspring when pollinating the pistils of foreign plants.

Since botanists have long been accustomed to call everything by Latin names, they called the collection of stamens of a flower androecium, and the collection of pistils (or simply pistil) - gynoecium. But since no scientist will ever stop at what has already been achieved, botanists subsequently, depending on the structure of the flowers, divided them into bisexual (containing an androecium and gynoecium) and unisexual (containing either an androecium or gynoecium). If male and female flowers bloom on the same plant, it is called monoecious (corn), but if on different ones, it is called dioecious (hemp). Polygamous species have bisexual and unisexual flowers on one plant (melon, sunflower). However, apparently, in defiance of botanical scientists, nature sometimes exposes to their inquisitive eye all forms of transition from one sexual type of flower and plant to another, even barren flowers, completely devoid of stamens and with underdeveloped pistils.

The weed plant chickweed, or stomper, which is extremely annoying to gardeners, has ten stamens in two five-membered whorls, of which usually 5 internal ones, with some addition of those from the outer whorl, are wrinkled and devoid of pollen. The flower heads of the burnet (Poterium polygamum) contain, in addition to purely fertile and purely staminate flowers, also true bisexual flowers. They represent all the examples of the transition from true bisexual to purely maternal type flowers. By the way, this botanical genus is exceptional among Rosaceae for its tendency to wind pollination.

The degrees of separation among pseudobisexual fertile and staminate flowers are also unusually varied. Thistle, asparagus, persimmon, grapes, some scabioses, saxifrage, and valerian have flowers that seem to be bisexual at first glance. They have well-developed pistils and visible stamens, the anthers of which may or may not contain pollen. In the latter case, these are pseudobisexual flowers. What to do, “false Dmitry” is found in nature. The same can be said about part of the flowers in the racemes of horse chestnuts and some types of sorrel, as well as in the flowers in the center of the coltsfoot baskets and marigolds, which have the appearance of true bisexual flowers, but whose ovaries do not produce viable seeds, since the stigma unable to pass pollen tubes through itself.

In the racemes of sycamore (one of the maple species) one can notice all possible transitions from pseudobisexual staminate flowers with well-developed large ovaries to those in which the pistils are underdeveloped or completely absent. Transitions from true bisexual flowers to barren flowers can be found in several species of steppe hyacinth.

Three-domed species are also known: some plants bear only male flowers, others only female ones, and still others bear bisexual flowers (resinous flowers). Among the oddities of plants, one can note the change in sex with age or in certain years. The cordate grape, which in its homeland is typically dioecious, is represented in the Vienna Botanical Garden by bushes with staminate flowers. But in some years, vine bushes confuse tour guides because, in addition to staminate ones, they produce true bisexual flowers.

In many plants, self-fertilization is prevented by the non-simultaneous maturation of stamens and pistils in a flower - dichogamy (sunflower, raspberry, pear, apple, plum), in which a distinction is made between proterandry, when the stamens mature before the pistils mature, and protogyny, when the pistils mature before the stamens.

Mainly proterandric are Asteraceae, Lamiaceae, Malvaceae, Cloveaceae and Legumes; The following are proterogynic: rushes and ozhikas, kirkazonaceae and daphniaceae, honeysuckles, globulariaceae, nightshades, rosaceae and cruciferous plants. All monoecious plants are proterogynous: sedges, cattails, burrs, aroids with monoecious flowers, corn, monoecious stinging nettle, urut, burnet, cocklebur, squirting cucumber, euphorbia plants, alder, birch, Walnut, plane tree, elm, oak, hazel, beech. In the trees and shrubs mentioned here, the anthers begin to shed dust with a delay of 2-3 days. For alpine green alder this difference is 4-5 days, and for small cattail it is even nine.

For the most part, dioecious plants are proterogynic. In large willow thickets along the banks of our rivers, which are not poisoned by chemicals, some species are still represented by numerous shrubs. Some of them bear staminate flowers, others - pistillate flowers. They are practically in the same conditions, but, despite the same external conditions in the same area, bushes with pistillate flowers always deftly outstrip their “men” with staminate flowers in flowering. In belotal, purple vine, basket willow and willow, the stigmas in their maturation are 2-3 days ahead of the opening of the staminate flowers. It’s the same with alpine willows - check it out if you happen to visit the Alps. But here the time difference is limited to only one day, from which it is reasonable to conclude that our willows are the most proterogynous willows in the world.

In hemp plants growing nearby, at the beginning of flowering you can notice stigmas, ready to receive pollen, although not a single staminate flower has yet opened - they will open only after 4-5 days. In the woodleaf, or hen, growing in deciduous forests and shrubs, maternal and paternal individuals are located nearby. Nevertheless, their pistillate flowers open two days before their staminate flowers. The same is true for hops and many other dioecious plants.

In a few plants, self-fertilization is difficult because the stamens and pistils are arranged in such a way that it is difficult for pollen to reach the stigma of its flower. For example, with heterostyly, some individuals have flowers with long pistils and short stamens, while others have the opposite. Heterostylous (variegated) include some gentianaceae (for example, watch, or trefoil), buckwheat, various types of sloth, numerous primroses (for example, prolomnik, turcha, primula, or primrose), as well as many borage (forget-me-nots, lungwort, etc.) .

Vakhta has very elegant shaggy white-pink star-shaped flowers, collected in a brush on a leafless stem. Some flowers have a low style and an anther attached above it, while others, on the contrary, have high styles and anthers attached underneath. The stigmas of the plant mature before the stamens. Insects visiting watch flowers touch either the pistils or the stamens with the same part of their body, carrying out strictly cross-pollination. However, during prolonged bad weather, the flower is closed and forced to self-fertilize.

Primrose, better known to children as rams, is one of the first spring flowers to bloom. Hence the Latin name primus - first. Only bumblebees and butterflies pollinate the plant. Due to the difference in columnarity, the pistils of some flowers can only be pollinated by pollen from other flowers. If a bumblebee lands on a flower with a low pistil, its head touches the high-standing stamens. Flying to a flower with a high pistil, it touches the stigma with its head and produces cross-pollination.

The phenomenon of heterocolumnarity was first discovered on the flowers of the bog grass, and then on other plants. Turchi's superiority in this regard seems even incredible, considering that the entire plant is immersed in water, and only in July do flowers appear above the water. Another remarkable thing about turkish grass is that it has no roots, and its suction functions are performed by the cells of the skin of the leaves.

In buckwheat, according to the sworn assurance of geneticists, long columnarity is controlled by the recessive allele s, and short columnarity by the dominant allele S (we remind you that an allele is one of the forms of the state of the same gene). Since pollination does not occur within one type of flower, an equal ratio of plants with genotypes Ss and ss is always maintained in populations; this can be seen from the Punnett lattice, known from school course biology:

that is, a 1:1 split, as in humans, into boys (AT) and girls (XX) in the offspring.

According to the structure of the flower, buckwheat is adapted to cross-pollination mainly by insects (flies, bumblebees and especially bees), which are attracted by nectar, and only partly by the wind. During normal (legitimate) pollination, when pollen from short stamens falls on the stigmas of short styles and, accordingly, pollen from long stamens falls on the stigmas of long styles, the largest number of seeds are set.

Weeping grass (Lythrum salicaria) is one of our most interesting plants. The fact is that weeping grass flowers have pistils of three various sizes and 12 stamens, equally spaced in two circles. In some flowers the pistil is above both circles of stamens, in others it is between them and in others it is below both circles. Consequently, the stamens are located at different heights in the same way as the pistils, allowing for cross-pollination. An insect, flying in for nectar, smears itself with pollen and deposits it on the stigma of the pistil, which is the same length as the stamen from which the pollen was removed. Fertilization occurs normally when pollen is transferred from a stamen that is the same length as the pistil. Pollen grains from stamens of three different heights differ from each other in size and partly in color, and accordingly, the length of the papillae on the stigmas of three different heights is also different, because the stigmas must catch different pollen. The pollination process was first studied in detail by Charles Darwin.

In some plants, the stamens and pistils are arranged in strict order, presenting themselves to insects for “unloading” pollen or “loading” stigma. In our common rue, found on the slopes and hills in the forests of the Southern Crimea, the flower contains ten anthers supported by straight, star-shaped threads. First, one filament rises, placing the anther it supports in the middle of the flower along a line leading to the nectar, which is secreted by a fleshy ring at the base of the pistil. She maintains this position for about a day, then returns to her previous position. While the first stamen bends, another one rises - and everything repeats. This continues until all ten anthers, one after the other, stand in the middle of the flower. When, finally, the tenth stamen bends back, the stigma appears in the center of the flower, which at this time has become receptive to pollination.

In the bisexual flowers of the nettle family, the stigma develops even before the flower opens and is the first to protrude from the greenish bud of the flower. The anthers on bent legs, as if on springs, are covered with interlocking small greenish integumentary leaves. But before they allow the anthers to rise from their “knees”, straighten up and scatter their pollen in the form of a cloud in the air, the stigma withers and the style is separated along with the stigma from the ovary. So by the time the pollen is released from the anthers, the ovary ends in a point - the dried base of the fallen style.

Usually in plants this all happens differently: first, the anthers and stamens fall off in the flower, and only after that the stigma acquires the ability to receive pollen. In balsam flowers, the anthers are fused together and form something like a cap over the stigma. After the flower has opened and made itself accessible to flying insects, the anthers immediately crack, and a cap formed by the opened anthers appears before us. But then the threads of the stamens separate, and the cap falls out of the flower. Only now do the stigmas appear, fully ripe. The same can be observed in large-flowered species of crane grass and geranium.

In the bisexual flowers of Tradescantia, bred at home and misunderstoodly called “woman's gossip,” the anthers open a little earlier than the stigmas become receptive to pollen. But as soon as the stigma is ready for pollination, the stamens curl into a spiral, and soon after this the integumentary leaves fade, covering the anthers on curled threads. The style protrudes, and the stigmas are receptive to pollen throughout the next day. These flowers are visited by insects with short proboscis to feast on the juice of the crushed integumentary leaves that hide the stamens, while they touch the stigmas and pollinate them with pollen brought from other flowers. Pollination of one's anthers by pollen is no longer possible.

Dichogamy botanists, who rely in their research only on morphoecological differences, without taking into account the content of genomes, are obliged to the abundance of sedge species, endlessly rediscovered, and even rediscovered. Moreover, the so-called “species” of sedges easily interbreed with each other, producing many intermediate forms that are readily accepted as new “species” (the authors of the species are attracted by the opportunity to immortalize their name in Latin transcription). Imperfect (incomplete) dichogamy in botanical genera with monoecious flowers ensures, for example, in sedges, first the so-called interspecific, and later intraspecific crossing. This is understandable, since the stigma of the very first flowering plant of a proterogynic species can only be pollinated by the pollen of other “species” that flowered even earlier.

Lysenko believed that “dialectical materialism, developed and raised to a new height by the works of Comrade Stalin, for Soviet biologists, for the Michurinists, is the most valuable, most powerful theoretical weapon in solving deep questions of biology, including the question of the origin of some species from others.” . That is why he gave a super-dialectical definition of species at this new height: “A species is a special, qualitatively defined state of living forms of matter. An essential characteristic of species of plants, animals and microorganisms is certain intraspecific relationships between individuals.” That's it.

Not all botanists want to see that in the dialectical unity of form and content, content is decisive. The content of a species is the unity of the genetic structure of the populations that make it up. Outwardly, it manifests itself in phenotypic similarity, free interbreeding, and especially in the ability to produce fertile offspring when crossed. Hereditary information is what qualitatively determines the species and constitutes its content. It is difficult to say whether life arose simultaneously with heredity (I suspect that it did), but one thing is certain: with the advent of discrete heredity, species appeared on the globe.

Taking into account the formulations known to science, the definition of a species can be as follows: species - a qualitatively isolated at a given stage of the evolutionary process, a complex and mobile community of organisms, characterized by unity of origin, common genetic constitution, hereditary stability and fertility of offspring. Most of the identified “species” of sedges and willows do not correspond to this definition.

When identifying “good” or true species based on crossability and the formation of fertile offspring, one must not forget about the phenomenon of self-incompatibility - the impossibility of self-fertilization in some hermaphroditic organisms or cross-fertilization between individuals of a species with the same genetic factors of incompatibility. The main function of self-incompatibility systems is to prevent self-fertilization and promote interbreeding between unrelated individuals.

There are gametophytic, sporophytic and heteromorphic self-incompatibility. Gametophytic self-incompatibility is the most common (cereals, beets, alfalfa, fruits, potatoes, etc.). This system is characterized by the independent action in pollen and style of two alleles of the S. incompatibility locus present in each individual. For example, pollen from a plant with the genotype S 1 S 2 behaves as S 1 or S 2 depending on which allele the pollen grain contains. None of the alleles exhibit dominance or any other form of inter-allelic interaction. The same complete independence of action is observed in the column.

The incompatibility reaction manifests itself in the pistil style: the growth of pollen tubes carrying a given allele stops in the styles containing the identical allele. If all alleles involved in hybridization are different, for example S 1 S 2 XS 3 S 4, then all pollen tubes are compatible, the ovary is normal and 4 cross-compatible genotypes are formed in the offspring. In the vast majority of species studied, gametophytic incompatibility is controlled by one or two loci.

Sporophytic incompatibility was first described in guayule. In sporophytic self-incompatibility, the behavior of each pollen grain depends on the genotype of the style. Thus, if S 1 is dominant over S 2 , all pollen from plant S 1 S 2 will react as S 1 and will be able to penetrate into styles carrying the S 2 allele, regardless of the genotype of the pollen tube - S 1 or S 2 .

Heteromorphic incompatibility arises on the basis of heterostyly, which we have already described earlier.

One of the plant's adaptations for cross-fertilization is male sterility. In recent decades, male sterility in cultivated plants has aroused great interest among breeders and seed growers, as it makes it possible to obtain first-generation heterotic hybrids on a large scale, which give yield increases of up to 40 percent compared to conventional varieties, are characterized by early and uniform ripening, high uniformity and resistance to adverse environmental factors.

To date, cytoplasmic male sterility (CMS) and genetic male sterility (GMS), controlled by genes in the cell nucleus, have been described. Cytoplasmic male sterility in plants is caused by the interaction of sterile cytoplasm (S) with 1-3 pairs of recessive nuclear genes (rf). In the presence of dominant nuclear (RF) genes, pollen fertility is restored. CMS is widely used to produce heterotic hybrids on an industrial scale in corn, sorghum, sugar beets, onions, and carrots. Usually,

To use CMS in seed production of first generation hybrids (they are designated F 1), fertile sterility fixers with the Nrfrf genotype (N - normal cytoplasm), their sterile analogues - Srfrf and fertility restorers - RfRf are used.

Genetic male sterility is used to obtain heterotic seeds in tomatoes, peppers, and barley. When producing hybrid seeds based on one recessive GMS gene, splitting in Fi occurs according to Mendel in the ratio of 3 fertile: 1 sterile plant, since, unlike CMS, male sterility is transmitted through both female and male gametes.

Crossings, as is known, are widely used in plant breeding and seed production. The possibility of artificially producing hybrids was first suggested by the German scientist R. Camerarius in 1694, and, as often happens, no one believed him. Only in 1760, the German botanist and honorary member of the St. Petersburg Academy of Sciences Joseph Kölreuter obtained a hybrid of Peruvian paniculata tobacco with shag. From this year, scientists begin conscious hybridization.

Depending on the degree of relatedness of the crossed forms, intraspecific and distant - interspecific and intergeneric hybridization are distinguished. If two parental forms are involved in the crossing, we speak of simple, or pair, hybridization, if more than two - of complex. There are direct (A×B) and reverse (B×A) crosses, which are generally called reciprocal. Crossing hybrids with one of the parents, for example (A×B)×A or (A×B)×B, is called backcross, or return.

To designate hybrids and parental forms, the following symbols are used: P - parental form; F 1 - first generation hybrid; F 2 - second, etc.; B 1, or BC 1, is the first generation of backcross; B 2, or BC 2 - second, etc. The maternal form is indicated by the symbol ♀, the paternal form by ♂. However, most often they do without the latter, placing the maternal form in the first place in the records of crossing combinations, and the paternal form in second.

The method and technique of crossing depend on the biology of flowering and pollination, fertilization, the structural features of flowers (bisexual, dioecious), the location of the latter on the plant and in the inflorescence, the method of pollination, the duration of the viability of the pistil and pollen, and the conditions of crossing.

Breeders use forced, limited-free and free crossings, which often require castration of plants. Castration consists of removing immature anthers or damaging them by pruning, thermal sterilization (hot air or water) or chemical castration - the use of specially selected gametocides.

In forced crossing, castrated and isolated mother plants are pollinated with pollen from the father plant. In free crossing, the parent forms are sown in alternating rows. Castrated, male-sterile or biologically female mother plants are pollinated by pollen from nearby father plants.

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