Crossing plants. How to cross plants at home. Crossing plants - crossing technology and advantages of hybrid varieties How to create a new type of plant

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 very large number 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 peel no longer surprises 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. This purple potatoes with the usual taste looks great in the form of puree, indescribable rich 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. Besides, exotic look 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, the inside is 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 crunchy 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 is good for gastrointestinal diseases, for removing heavy metals and radioactive substances from the body, and improving 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 commonly 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 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 and protects against colds. Animals are dipped into the same bath, and then the plants are watered with water.

How to obtain high-quality seed material for vegetables at home, what is the difference between varieties and hybrids? You will find answers to these and other questions about seed production in the material below.

Obtaining seeds from tomatoes, peppers, eggplants

Tomatoes and other nightshades are self-pollinating crops (i.e. fruits are set by pollination with their own pollen). To obtain your own seeds, you need to have between one variety (or hybrid) open ground There was a spatial isolation of about 50 m, and if the place was protected by trees and shrubs - at least 30 cm.

Currently, in many vegetable crops, breeders develop hybrids (F1) rather than varieties. Such hybrids are called heterotic. Heterosis is a method of producing first generation (F1) hybrids that are superior to the parental forms (paternal and maternal) when crossed. Heterotic hybrids are more productive, resistant to diseases and pests, and have many other beneficial properties compared to varieties. However, seeds should not be taken from their fruits, since when such seeds are sown the next year, splitting will occur, and the offspring will show signs of maternal and paternal plants (plants will have different heights, colors and shapes of fruits, ripen later or earlier, etc. .).

Varieties compared to hybrids have the main thing positive attribute- they will not split if the conditions for obtaining pure seeds are met.

Tomato, pepper, eggplant are heat-loving crops; they do not tolerate early spring frosts. To obtain seeds, it is necessary to grow high-quality seedlings. At the time of planting, seedlings should have a height of 25-35 cm, 7-8 leaves, and flower buds. Before landing on permanent place straight plants are selected.

Plants are planted in a greenhouse or in open ground. In the south (Volgograd region, Krasnodar and Stavropol territories) these crops grow well in open ground and produce a full harvest of seeds and fruits. But in the Non-Black Earth Region and in the northern regions they must be grown in a greenhouse.

Seed plants require increased fertilizing with mineral and organic fertilizers, more frequent watering. After planting, the plants are tied to a support. For better fruit set, it is recommended to gently tap the stem with a stick so that the pollen gets onto the stigma of the flower. Then there will be much more seeds in the fruits.

The first fruits on the plant have the strongest and most viable seeds. Seeds must be isolated from fruits that have ripened directly on the plant.

Well-ripened tomato fruits are washed with water, cut crosswise, the seeds are removed along with the pulp into a cup or jar, and left for 2-3 days. After the seeds have fermented, wash them with water and dry them. Then the well-dried seeds are poured into paper bags and stored until sowing.

It should be remembered that in order to obtain pepper seeds, you must follow the main rule - plant sweet varieties separately from hot varieties (i.e., you must maintain spatial isolation: on open area- 2000 m, on protected - 1000 m). Otherwise, sweet pepper varieties - their fruits and seeds - will become spicy. It is best to grow one variety or type of pepper (either sweet or hot) in a summer cottage.

Getting your own hybrid seeds

When producing your own hybrid seeds of tomato and other nightshade crops, the most important thing is the technique of pollinating the flowers. One variety is pre-selected - the paternal form. From 8 to 10 am, ripe anthers (stamens with pollen) are found on blooming flowers, they are torn off with tweezers and placed in a glass jar.

Then another variety is selected - the mother form. On this variety, carefully open the unopened buds with tweezers (they will open tomorrow or the day after tomorrow), tear off the stamens and apply pollen of the paternal form to the stigma of the pistil, having previously opened the anthers with tweezers. To pollinate one flower, it is recommended to apply pollen from 2-3 anthers (the guarantee of fruit set increases and more seeds are formed in the fruit).

After applying pollen to the stigma, the flowers are isolated from insects (they put a bag of nonwoven material), a label is hung on the peduncle (the paternal and maternal form and the date of pollination are recorded on it).

The next day, the bags can be removed from the flowers. Within a few days it will become clear how the crossing went: if the ovary begins to increase in size, then pollination was successful.

In this way, you can get your own hybrid seeds, i.e. first generation hybrid (F1).

The yield of seeds from one fruit of sweet pepper is 150-250 pcs., hot pepper - 300-700 pcs., eggplant - 600-1300 pcs., tomato - 600-1800 pcs. Tomato seeds remain viable for up to 7-8 years, pepper and eggplant seeds for 2-3 years.

Own pea and bean seeds

Vegetable peas and beans are self-pollinating plants. Using this property to obtain your own seeds, you can plant several varieties, keeping a distance of 20-50 cm between them.

Pea seeds are sown in the ground in late April - early May, and beans - in late May - early June. The distance in the row between plants is 10-12 cm (for beans) and 5-6 (for peas), between rows - 20-30 cm.

After the emergence of seedlings, they are loosened and fertilized with mineral or organic fertilizers before or during flowering.

To obtain seeds, plants that are typical for the variety, healthy and uniform, are selected. Selection and cleaning should be carried out starting from the emergence of seedlings, then during the period of flowering and formation of beans.

Remove plants after yellowing. They are carefully pulled out, tied and dried under a canopy for ripening. Then the completely dried pods with seeds are threshed (cleaned). From one seed plant you can get 30-40 pieces. vegetable bean seeds, 100 or more pcs. vegetable pea seeds.

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 for those drinking in the shade of the colonnade mineral waters(hydrocarbonate-sulfate-chloride-sodium - for the information of those gathering in Karlovy Vary) were delivered daily 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 commonality 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 that 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.

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 genera of the same 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 cultivation, 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 mostly 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 in size several times the parent forms. This phenomenon is called heterosis. In the sexually produced offspring of hybrids, 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 various types with each other, it was possible to obtain forms that were 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

the development stage of the hybrid is favored by 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 subsequently crosses with it 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 the pollen of 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 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 green, 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 graft mentor, when, for example, by grafting several cuttings of an old variety (graft 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, have 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 that are of interest both in themselves and for further crossings again with wheat to obtain hybrids with high qualities wheat grains 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 times or requirements 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 point: 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.

Appearance of flowers different plants may differ significantly, but 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 plant 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 point is that you will need to find out whether you actually withdrew new variety or you are following a path already trodden by someone. 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 himself.

In the 30s last century N.I. Vavilov noted that the problem of creating disease-resistant varieties of agricultural crops can be solved 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. On at the moment In breeding for resistance, all generally accepted modern methods of breeding work are used: 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 in 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 selection, different selection methods can be used and analytical methods, which 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 a plant population of the first group, the unit of analysis is an individual plant, the other - a 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 that meet the requirements for the future variety are selected from the initial population in the field, immediately assessing a set of traits (including resistance to certain diseases). The harvest of all selected plants is combined and sown next year in the form of one plot. 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 large quantities 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 primarily 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 are selected from the initial population, 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 more 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 transmit from wild plants cultural ecological plasticity, resistance to adverse environmental factors, 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). Required condition is that the maternal forms for each subsequent backcross are selected from stable hybrid plants previous crossings detected on 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 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 genetic mutations (changes in the molecular structure of a gene), chromosomal (changes in the structure of chromosomes) or genomic (changes in sets of chromosomes) occur in plant organisms.

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. For humans, the quality of proteins in edible foods (including people) should be obtained from food is also very important required quantities 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 essential properties. 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 receiving much more high yields 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. To obtain high yields, each crop requires optimal conditions growth. 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 crosses and selections produced improved triticale lines for specific areas. In the mid-1980s. This crop, due to its high yield, resistance to climatic factors and excellent straw remaining after harvest, quickly gained popularity in France, the largest grain producer 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, helminthosporium blight, a fungal disease of corn caused by Helminthosporium maydis (pictured above), destroyed approximately 15% of the U.S. 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. Nutritional value tomatoes was 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, there is 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 in natural conditions It is impossible to crossbreed 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 can 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 livestock 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 people need products. In the same row is the creation 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 due to the variability that occurred in the characteristics of land organisms from Noah’s Ark and aquatic life survivors outside the ark, while adapting 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!

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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 terms of flowering 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.

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 plant 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.

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. Competition in the field of creating new varieties is very high.