Centers of origin of cultivated plants description. Centers of origin of plants

plant breeding

Breeding is the science of creating new and improving existing breeds of animals, plant varieties, strains of microorganisms.

Selection is based on methods such as hybridization and selection. Theoretical basis breeding is genetics.

Breeds, varieties, strains are populations of organisms artificially created by man with hereditarily fixed features: productivity, morphological, physiological characteristics.

Development pioneer scientific foundations breeding work was N. I. Vavilov and his students. N. I. Vavilov believed that the basis of selection is right choice for the work of the original individuals, their genetic diversity and influence environment on the manifestation of hereditary traits during hybridization of these individuals.

For successful work the breeder needs varietal diversity source material, for this purpose N.I. Vavilov collected a collection of varieties cultivated plants and their wild ancestors from all over the globe. By 1940, the All-Union Institute of Plant Growing had 300,000 specimens.

In search of starting material for obtaining new plant hybrids, N. I. Vavilov organized in the 20-30s. 20th century dozens of expeditions around the world. During these expeditions, N. I. Vavilov and his students collected more than 1,500 species of cultivated plants and a huge number of their varieties. Analyzing the collected material, N. I. Vavilov noticed that in some areas there is a very large variety of varieties of certain types of cultivated plants, while in other areas there is no such diversity.

Centers of origin of cultivated plants

N. I. Vavilov suggested that the region of the greatest genetic diversity any kind of cultivated plant is the center of its origin and domestication. In total, N. I. Vavilov established 8 centers of ancient agriculture, where people first began to grow wild plant species.

1. The Indian (South Asian) center includes the Indian subcontinent, South China, and Southeast Asia. This center is home to rice, citrus fruits, cucumbers, eggplants, sugar cane and many other types of cultivated plants.

2. The Chinese (East Asian) center includes Central and Eastern China, Korea, and Japan. Millet, soybeans, buckwheat, radishes, cherries, plums, and apple trees were cultivated in this center.

3. The Southwest Asian center covers the countries of Asia Minor, Central Asia, Iran, Afghanistan, Northwest India. This is the birthplace of soft varieties of wheat, rye, legumes (peas, beans), flax, hemp, garlic, grapes.

5. The Mediterranean Center includes European, African and Asian countries located along the coast mediterranean sea. Here is the birthplace of cabbage, olives, parsley, sugar beet, clover.

6. The Abyssinian center is located in a relatively small area of ​​modern Ethiopia and on the southern coast of the Arabian Peninsula. This center is the birthplace of durum wheat, sorghum, bananas, and coffee. Apparently, of all the centers of ancient agriculture, the Abyssinian center is the most ancient.

7. The Central American center is Mexico, the islands of the Caribbean Sea and part of the countries of Central America. Here is the birthplace of corn, pumpkin, cotton, tobacco, red pepper.

8. The South American center covers the western coast of South America. This is the birthplace of potatoes, pineapple, cinchona, tomatoes, beans.

All these centers coincide with the places of existence of the great civilizations of antiquity - Ancient Egypt, China, Japan, Ancient Greece, Rome, Mayan and Aztec states.

Centers of origin of cultivated plants

9. Basic plant breeding methods

1. Mass selection for cross-pollinated plants (rye, corn, sunflower). Selection results are unstable due to random cross-pollination.

2. Individual selection for self-pollinating plants (wheat, barley, peas). The offspring from one individual is homozygous and is called a pure line.

3. Inbreeding (closely related crossing) is used for self-pollination of cross-pollinated plants (for example, to obtain corn lines). Inbreeding leads to "depression" as recessive unfavorable genes become homozygous!

Aa x Aa, AA + 2Aa + aa

4. Heterosis (" life force") - a phenomenon in which hybrid individuals significantly exceed parental forms in their characteristics (yield increase up to 30%).

Stages of obtaining heterotic plants

1. Selection of plants that give maximum effect heterosis;

2. Preservation of lines by inbreeding;

3. Obtaining seeds as a result of crossing two inbred lines.

Two main hypotheses explain the effect of heterosis:

Dominance hypothesis - heterosis depends on the number of dominant genes in the homozygous or heterozygous state: the more pairs of genes will have dominant genes, the greater the effect of heterosis.

Overdominance hypothesis - a heterozygous state for one or more pairs of genes gives the hybrid superiority over parental forms (overdominance).

Cross-pollination of self-pollinators is used to produce new varieties.

Cross-pollination of self-pollinators makes it possible to combine properties different varieties.

6. Polyploidy. Polyploids are plants that have an increase in the chromosome set, a multiple of the haploid one. In plants, polyploids are larger vegetative organs, have more large fruits and seeds.

Natural polyploids - wheat, potatoes, etc., varieties of polyploid buckwheat, sugar beet have been bred.

The classic method for obtaining polyploids is the treatment of seedlings with colchicine. Colchicine destroys the spindle and the number of chromosomes in the cell doubles.

7. Experimental mutagenesis is based on the discovery of the effects of various radiations to produce mutations and on the use of chemical mutagens.

8. Remote hybridization - crossing plants belonging to different species. But distant hybrids are usually sterile, since they have impaired meiosis.

In 1924, the Soviet scientist G.D. Karpechenko received a prolific intergeneric hybrid. He crossed radish (2n = 18 rare chromosomes) and cabbage (2n = 18 cabbage chromosomes). The hybrid has 2n = 18 chromosomes: 9 rare and 9 cabbage, but it is sterile, does not form seeds.

With the help of colchicine, G.D. Karpechenko obtained a polyploid containing 36 chromosomes; during meiosis, rare (9 + 9) chromosomes were conjugated with rare, cabbage (9 + 9) with cabbage. Fertility has been restored.

In this way, wheat-rye hybrids (triticale), wheat-couch grass hybrids, etc. were subsequently obtained.

9. Use of somatic mutations.

Via vegetative propagation a beneficial somatic mutation can be saved. In addition, only with the help of vegetative propagation, the properties of many varieties of fruit and berry crops are preserved.

10 . Technological scheme for obtaining potato concentrate

Simplified technological scheme obtaining potato concentrate, reduced the energy consumption and labor intensity of its production, scientists from the Republican Unitary Enterprise "Scientific and Practical Center of the National Academy of Sciences of Belarus for Food" (patent of the Republic of Belarus for the invention No. 15570, IPC (2006.01): A23L2 / 385; inventors: Z. Lokis, V. Litvyak, T. Tananayko, D. Khlimankov, A. Pushkar, L. Sergeenko, applicant and patentee: the above-mentioned RUE). The invention is intended to provide a potato concentrate used in the formulations of non-alcoholic, low-alcohol and alcoholic beverages with improved organoleptic characteristics.

The proposed method for obtaining potato concentrate includes several stages: preparation of potato raw materials, which are fresh potatoes and (or) good-quality dry and mashed potato waste; its thermal and subsequent two-stage treatment with amylolytic enzymes; separating the resulting precipitate by filtration; concentration of the filtrate by evaporation; acidifying it with one or more organic acids; subsequent thermostating.

After thermostating, water and (or) water-alcohol infusions of aromatic plants are added to the resulting concentrate. a certain amount to a final solids content of 70±2%. The range of these plants is wide: cumin, echinacea purpurea, hyssop officinalis, coriander, sweet clover, oregano, immortelle, balsamic tansy, peppermint, tarragon tarragon and others.

24-08-2011, 23:48

VI. Central Asiatic Center. This is a vast territory, including Asia Minor and the Arabian Peninsula, Iran, and in our country - all of Transcaucasia and the mountainous part of the Turkmen SSR.
In terms of the diversity of species and ecotypes of wheat, the Western Asian center stands out among all others. An exceptional wealth of cultivated wheat species is concentrated here. The Armenian SSR stands out especially in this regard. In Transcaucasia, 18 species of wheat out of 23 found on the globe were found, including 8 that are not found anywhere else. Almost the entire species potential of the genus Triticum L. is concentrated in this region of the Central Asian region. (The Swedish geneticist D. McKay proposed a new classification of wheat. As a result of genetic analysis, he found that the genus of wheat consists of only 5 species instead of 23, as was commonly believed so far. But even in this case, four species of this genus come from Transcaucasia.) Form-building processes continue here and at the present time, and new forms appear in populations that are of interest for selection. In the local Transcaucasian population of Zanduri, three out of five types of wheat according to McKay's classification were found. Of the 650 known varieties of wheat, more than 200 have been discovered in Armenia, and many wild einkorns and two-grains have also been found. Formation was widespread in this area in durum and Persian wheat. Here P. M. Zhukovsky discovered a very valuable species - Timofeev's wheat (Triticum timopheevii Zhuk.), which has a complex resistance to diseases and pests. Rust resistance is passed on to many Mexican cultivars from this species. Research recent years found to be an important source of CMS.
Asia Minor and Transcaucasia are the main homeland of rye. This culture is represented here by a huge number of forms not found in Europe. Expeditions of the VIR discovered black-eared, red-eared, ligulose, exceptionally drought-resistant, as well as self-fertile forms, several species of wild rye that are not found in any other region of the globe. Natural polyploid forms of wheat and different types wild vegetation. From here come blue alfalfa, lupine, sainfoin, vetch. All the variety of melon species is concentrated in this center. All European types of fruit crops and grapes come from the Near East Asian center of morphogenesis.
VII. Mediterranean center. Some subspecies of durum wheat, spelt, sandy oats, vetch, and beets are concentrated here. This area is a secondary center of origin for wheat and grain legumes. In this center, the influence of a higher agricultural culture and the improvement of plants by man had a particularly strong effect. The Mediterranean forms of barley, beans, chickpeas, peas, lentils have a much larger grain than the forms of these crops from Central Asia, where the primary center of their origin is located.
VIII. African Center. Territorially very large. It includes the Abyssinian General Center as an autonomous entity. Many peculiar botanical forms of wheat are concentrated here. Durum wheat is distinguished by a special richness of forms. Abyssinian oats, an endemic tetraploid species (2n = 28), were found in this center. Ethiopia (formerly Abyssinia) is the center of origin of cultivated barley, represented by an unusually large variety of forms. More varieties of barley have been found here than in all other countries of the world combined, of which 16 varieties were not previously known and are not found anywhere else, forms of barley with yellow, green, black and purple grains have been found. Forms of barley originating from Ethiopia serve as a source of resistance to a dangerous viral disease of this crop - yellow dwarfism. Among the barley forms of this country, the Swedish scientists Hagberg and Karlsson in 1968 isolated the CI 3947 line from the world collection of US barley with a high protein content (up to 19%) and a high content of lysine (more than 4%), as well as other essential amino acids. This line, called Highproly, has become the main source for the creation of high-lysine barley varieties. Many forms of barley from Ethiopia are characterized by dominant traits, which, according to the theory of N. I. Vavilov, indicates their primary origin in the indicated gene center.
In this area there is an autonomous center of origin of peculiar forms of flax, used exclusively for seeds, from which flour is made. Unlike European spinning and oilseed forms, flax from the Abyssinian General Center - bread plant. Ethiopia is one of the centers of origin of many legumes- peas, chickpeas, lentils, ranks, lupine.
All species of the genus sorghum originate from Africa. Here is the primary genecenter of this culture. From here come several types of African cotton, African rice, watermelon, date palm. It is the primary genetic center of the castor bean and South African rye, and the secondary center of origin of the peanut.
IX. European-Siberian Center. Here is the primary and secondary center of origin of sugar beet, the primary gene center of red clover, some species and subspecies of alfalfa, Amur grapes, wild apple tree, wild pear. In the northwestern part of Russia, the primary genetic center of fiber flax has historically developed. In the USSR, in the Kuban, a secondary, unique in terms of breeding potential, sunflower gene center was formed. The gryzovy sunflower by Russian folk selection was turned into an oilseed, and then, as a result of the work of VNIIMK, into a high-oilseed, i.e., in fact, into a culture that was new in terms of production value.
X. Central American Center (Mexico, Guatemala, Costa Rica, Honduras, Panama). This is the main center of origin of corn and the nearest wild species- teosinte and trypsacum. From here, corn spread throughout the world. In the wild, it existed here more than 70 thousand years ago. American bean and pumpkin species, wild tuberous potato species (they have come a long way from diploid to hexaploid species) have developed in this center. This is the birthplace of cocoa. The American upland cotton originating from here became the basis of world cotton growing.
XI. South American (Andean) center. The morphogenesis of cultivated plants in this focus was greatly influenced by the giant mountain system of the Cordilleras and the Andes, where many endemic species arose. In this region of the globe, potatoes were introduced into the culture. From here came the Egyptian cotton South America several centuries ago, it came to Egypt and later became known as Egyptian, thus, it is the second homeland and the secondary general center of the origin of cotton. The sunflower has two subgenera - South American and North American, each of which is represented by a large number herbaceous and shrub species. Peru is home to 17 shrub species of the South American sunflower group.
XII. North American Center. It is the primary genetic center of origin for about 50 herbaceous sunflower species, several wild potato and tobacco species, more than 40 wild lupine species, and one wild cotton species. North America is also home to the primary gene center for endemic grape varieties.

If you set the task: "Name the centers of origin of cultivated plants," then many people who are not associated with hybridization will not be able to cope with it. The article contains explanatory information.

Terminology

The centers of origin of cultivated plants are special geographical "foci". They concentrate the genetic diversity of agricultural varieties. Centers of origin are primary - these include areas where wild and domesticated forms originally grew, and secondary. The latter are the centers that were formed from the subsequent distribution of semi-cultivated, cultivated plant species and their further selection.

Historical information

Such a phenomenon as crop production arose long before the advent of our era. Initially, development took place, regardless of the types of surrounding flora, in five geographically isolated territories of the planet. In general, the floristic structure of the species that were attempted to be domesticated was endemic to most areas. This forced the use of local flora. Human civilization continued its development... The heyday of sea and land communications between peoples living in different geographical areas began. These processes were able to accelerate the spread of fruits and seeds of endemic domesticated plants. For this reason, it is not at all easy to establish the homeland of a particular cultural species. The progress of domestication, which took place in different geographical conditions of certain territories, was subject to the laws of evolution. For example, plants experienced such phenomena as random crossing, a multiple increase in the number of chromosomes against the background of natural hybridization. Mutations of various types also took place.

Research Conclusions

Based on the discovery of Charles Darwin about the geographical centers of origin of different biological species, a certain direction has been formed in the study of hybridization. In the 19th century, A. Decandol published his research, in which he singled out the centers of origin of cultivated plants and the territories of their initial occurrence. In his writings, these areas referred to vast continents, as well as to other large-scale areas. For almost fifty years after the publication of Decandole's work, knowledge of the centers of origin of cultivated plants has expanded significantly. Several monographs were published that covered agricultural varieties of different countries, as well as materials on individual species. Later, N. I. Vavilov took up this issue in earnest. On the basis of information about the world's flora resources, he identified the main centers of origin of cultivated plants. There are seven in total: East Asian, Mediterranean, Central American, South Asian, Southwest Asian, Ethiopian, and Indian. In each of them, a certain percentage of the entire variety of agricultural varieties grows.

Making adjustments

Some researchers, such as A. I. Kuptsov and P. M. Zhukovsky, continued the work of N. I. Vavilov. They made certain changes to his conclusions. Thus, the South-West Asian center was divided into the Central Asian and Central Asian ones, while Indo-China and tropical India act as two independent geographical centers. The Yellow River basin is considered the basis of the East Asian center. Previously, it was the Yangtze, but the Chinese, as a people engaged in agriculture, settled in this territory much later. New Guinea and Western Sudan were also singled out as areas of agriculture.

notice, that fruit crops, including walnuts and berries, have an extensive habitat. They extend far beyond the borders of the territories of origin. This phenomenon is more consistent with the teachings of Decandole than with the others. The reason is substantiated mainly by the forest origin, and not by the foothills, which corresponds to the field and vegetable varieties. Selection is also key. The centers of origin of cultivated plants are now more clearly defined. Among them, the European-Siberian and Australian centers are distinguished. The North American center was also formed.

General information

In past certain types plants were introduced into culture outside the main foci. However, their number is relatively small. Previously, the main centers of ancient agricultural cultures were considered to be the valleys of the Nile, Euphrates, Tigris, Ganges and others. major rivers. According to Vavilov's research, many agricultural varieties appeared in the mountainous zones of the tropics and subtropics. The original centers of origin of cultivated plants are closely related to floristic diversity and ancient civilizations.

Chinese section

This area includes the mountainous territories of the western and central parts of the country, with low-lying areas adjacent to them. The basis of this center is the latitudes of the temperate zone, located on the Yellow River. The local conditions are characterized by such characteristics as a moderate, very high degree of moisture and a high temperature regime. The hearth is a natural habitat for soybeans, angular beans, kaoliang, millet, rice, oats, paisa, chumiza, Tibetan barley and many other plants.

Southeast Asian section

The Indo-Malaysian center of origin of agricultural crops is complemented by the Indian region. It includes such territories as Indochina, the entire Malay Archipelago and the Philippines. The Hindustan and Chinese centers of origin of cultivated plants had some impact on the area. Local conditions are characterized by year-round vegetation, extremely high humidity and temperature. The area is a natural habitat for nutmeg, cardamom, orange, bergamot, black pepper, mangosteen, betel, lime and many other species.

Indian section

It is also called the Hindustan Hearth and includes the Indian state of Assam, Burma, and the entire Hindustan peninsula, except for the northwestern states of India. The local climate favors a long growing season, high level temperature and humidity. The area was influenced by the Indo-Malay center. Citrus fruits, rice and many other representatives of the flora grow in this area.

Central Asian section

This focus includes the lands of the Western Tien Shan, Tajikistan, the northern part of Pakistan, Uzbekistan, Afghanistan and the northwestern part of India. Local conditions are characterized by a moderate growing season, high temperatures with strong seasonal and daily fluctuations, and very low levels of moisture. This area has experienced a strong impact of the Near East and Chinese centers. For this reason, it is a secondary focus for most of the local fruit varieties.

Western Asian section

The outbreak is located in its region includes the territories of mountainous Turkmenistan, the entire Transcaucasia, Iran and inner part Asia Minor. The local climate is characterized by long dry periods, high temperatures and very low levels of humidity. This area has experienced the impact of the Central Asian and Mediterranean centers. The boundaries of these three foci are closely intertwined, so it is almost impossible to establish them.

South American Center of Origin of Cultivated Plants

These territories include the mountainous zones and plateaus of Bolivia, Ecuador, Colombia and Peru. Local conditions are characterized by insufficient moisture and very high temperature. The Central American center had some influence on this area.

The success of breeding work largely depends on the quality of the source material, mainly on its genetic diversity. The more diverse the source material for selection, the more possibilities it provides for hybridization and selection. Breeders, using the biological, genetic and ecological diversity of the plant world, have created a huge number of different varieties of cultivated plants.

Modern cultivated plants are grown simultaneously in different countries, on different continents. However, each of these plants has its own historical homeland - center of origin . It was there that the wild-growing ancestors of a cultivated plant were or are still located, and its genotype and phenotype were formed there.

The doctrine of centers of origin of cultivated plants created by the outstanding Russian scientist N.I. Vavilov.

N.I. Vavilov initially singled out 8 centers of origin of cultivated plants with a number of subcenters, but in later works he enlarged them into 7 main primary centers (see Table 4 and Fig. 42).

Rice. 42. The main geographical centers of origin of cultivated plants: I - South Asian tropical; II - East Asian; III - Southwest Asian; IV - Mediterranean; V - Abyssinian; VI - Central American; VII - Andean (South American)

Most of the centers coincide with the ancient centers of agriculture, and these are predominantly mountainous rather than flat areas. The scientist singled out primary and secondary centers of origin of cultivated plants. Primary centers are the home of cultivated plants and their wild ancestors. Secondary centers are areas where new forms originate, no longer from wild ancestors, but from previous cultural forms concentrated in one geographical place, often far from the primary center.

Not all cultivated plants are cultivated in their places of origin. Migrations of peoples, navigation, trade, economic and natural factors at all times contributed to the numerous movement of plants to other parts of the Earth.

In other habitats, plants changed and gave rise to new forms of cultivated plants. Their diversity is explained by mutations and recombinations that appear in connection with the growth of plants in new conditions.

The study of the origin of cultivated plants led N.I. Vavilov to the conclusion that the centers of shaping of the most important plant crops are largely associated with foci human culture and with pet diversity centers. Numerous zoological studies have confirmed this conclusion.

The doctrine of the origin and evolution of cultivated plants is considered one of the essential branches of breeding. N.I. Vavilov wrote that all breeding work, starting from the source material, establishing the main areas of origin of species and ending with the creation of new varieties, is, in essence, a new stage in the evolution of plants, and the selection itself can be considered as evolution directed by the will of man.

All cultivated plants on which humanity today feeds have descended from wild plant species that ancient man used for food. Then people noticed that these plants are much more profitable to grow themselves. Then agriculture was born. The moment of the emergence of agriculture is a fundamental turning point in history human society. The cultivation of the land allowed man to multiply the amount of food, because now he not only hunted and collected what he could find in nature, but began to produce food himself. This moment is also called neolithic revolution. It first began in the Middle East, about 10,000 years ago, and came to America the latest. However, many peoples of the Earth, such as the American Indians, Pygmies or Aborigines, have not switched to agriculture to this day, preferring to remain hunters and gatherers in the same way as their ancestors did tens of thousands of years ago.
Modern plants and their fruits that we eat are not at all the same as they were thousands of years ago, when they were first discovered by man. Harvest after harvest, he selected the most perfect plants, as he noticed that their properties are transferred to plants grown from selected seeds. So, at first unconsciously, and then deliberately, for thousands of years, artificial selection and selection was carried out - the breeding of new varieties of plants. In recent decades, people have learned to change plants at the genetic level without selection, but through modern technologies genetic engineering. Plants with altered genes are called genetically modified. They have significantly better performance in terms of productivity and adaptability to adverse environmental factors than their predecessors, bred by conventional selection. However, how safe genetically modified plants are when eaten remains to be seen.

Of course different plants happened in different regions planets. Scientists began to study the geography of their origin after the discovery by Charles Darwin of the laws of evolution and selection. Darwin put forward the idea that all species had centers of origin where they first arose. In 1883 A. Decandol published a work in which he established geographical areas origin of the main cultivated plants. However, the most complete and holistic theory of the centers of origin of cultivated plant species was formulated by Nikolai Ivanovich Vavilov (pictured) in the course of research in the 20-30s of the last century. To do this, he had to travel around almost all the Earth - in America, and. In the course of his expeditions, Vavilov collected the richest collection of cultivated plants, found family ties between them, predicted the properties of these crops that were previously unknown, but genetically incorporated, possible for breeding. Unfortunately, the science of genetics, without which it would have been impossible to make all these discoveries or develop the productivity of agriculture, was recognized in the Soviet Union as false and ideologically hostile. Since she argued that the properties of living beings, including humans, are determined by heredity, which contradicted the ideas of universal equality promoted by the communist regime. N.I. Vavilov, like many other Soviet scientists of those times, was repressed in 1940 and died in prison in 1943.

During the study, N.I. Vavilov, 7 main geographical centers of origin of cultivated plants were identified.

South Asian tropical center (about 33% of the total number of cultivated plant species). (cucumber, lemon, jute, mango, rice, banana, coconut tree, black pepper)
East Asian center (20% of cultivated plants). (millet, soy, radish, Walnut, mandarin, persimmon, bamboo, ginseng)
Southwest Asian center (4% of cultivated plants). (wheat, barley, rye, plum, hazelnut, date palm)
Mediterranean center (approximately 11% of cultivated plant species). (oats, flax, laurel, grapes, cabbage, zucchini, parsley, celery, peas, beans, carrots, beets, radishes, mint, cumin, horseradish, dill)
Ethiopian center (about 4% of cultivated plants). (coffee, sorghum, cotton, sesame, watermelon)
Central American center (about 10%). (corn, beans, pumpkin, cocoa, pepper, sunflower, tobacco, Jerusalem artichoke, papaya)
Andean (South American) center (about 8%) (potato, tomato, pineapple, hevea, peanuts)