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The main centers of origin of cultivated plants
If you set the task: "What are the centers of origin of cultivated plants," then many people who are not connected 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 "centers". In them the genetic varieties of agricultural varieties are concentrated. The centers of origin of cultivated plants are primary - they include areas where wild and domesticated forms grew originally, and secondary. The latter are the centers that were formed from the subsequent distribution of semi-cultural, cultivated plant species and their further selection.
Historical background
Such phenomena as crop production, arose long before the onset of our era. Initially, the development took place, regardless of the species of the surrounding flora, on five geographically isolated territories of the planet. In general, the floral structure of species that were attempted to domesticate was endemic for most areas. This forced to resort to the use of the local flora. Human civilization continued its development ... There was a period of flowering of sea and land communications between peoples living in different geographical areas. These processes were able to accelerate the spread of fruits and seeds of endemic domesticated plants. For this reason, it is not easy to establish the birthplace of one or another cultural form. The progress of domestication, which took place in different geographical conditions of certain territories, was subject to the laws of evolution. For example, with plants occurred such phenomena as random crossing, a multiple increase in the number of chromosomes against a background of natural hybridization. There were also mutations of various types.
Research findings
On the basis of the discovery of Charles Darwin on the geographical centers of origin of different biological species, a certain direction has been formed in the study of hybridization. In the XIX century, A. Decandol published his research, in which he singled out the centers of origin of cultivated plants and the territories of their original origin. In his works, these areas belonged to vast continents, as well as to other large-scale regions. For nearly fifty years after the publication of the work of the Decandol, knowledge of the centers of origin of cultivated plants has expanded significantly. Several monographs were published that covered agricultural varieties from different countries, as well as materials on individual species. Later, NI Vavilov dealt with this issue closely. Based on information about the world's resources of the flora, he identified the main centers of origin of cultivated plants. There are seven in total: East Asian, Mediterranean, Central American, South Asian, South-West Asian, Ethiopic and Indian. In each of them, a certain percentage of the diversity of species of agricultural varieties grows.
Making adjustments
Some researchers, such as AI Kuptsov and PM Zhukovsky, continued the work of NI Vavilov. They made some changes to his conclusions. Thus, the South-West Asian Center was divided into the Near East and Central Asia, and Indochina and tropical India act as two independent geographical centers. The Yellow River basin is considered the backbone of the East Asian Center. Before, it was the Yangtze, but in this territory the Chinese - as people engaged in agriculture - settled much later. New Guinea and Western Sudan have also been identified as areas of agriculture.
It should be noted that fruit crops, including walnut and berry crops, have an extensive habitat. They extend far beyond the boundaries of the territories of origin. This phenomenon is more consistent with the teachings of De Candolle, rather than with the rest. The reason is based mainly on forest origin, and not foothill, which corresponds to field and vegetable varieties. Also, the key factor is breeding. The centers of origin of cultivated plants are now defined more clearly. Among them are the European-Siberian and Australian centers. Formed and the North American Center.
General information
In the past, certain plant species were introduced into culture outside the main foci. However, their number is relatively small. Earlier the main centers of ancient agricultural cultures were considered to be the valleys of the Nile, the Euphrates, the Tigris, the Ganges and other large rivers. According to Vavilov's research, many agricultural varieties appeared in the temperate zones of the temperate zone, the tropics and subtropics. The original centers of origin of cultivated plants are closely related to floristic diversity and the oldest civilizations.
Chinese site
This area includes mountainous areas of the western and central part of the country, with adjacent lowland areas. The center of this center is the latitudes of the temperate belt, located on the Yellow River. The local conditions are characterized by such characteristics as a moderate vegetation period, a very high degree of moistening and a high temperature regime. The hearth is a natural habitat for soy, angular beans, kaolian, millet, rice, oats, piza, chumise, Tibetan barley and many other plants.
South-East Asian section
The Indo-Malaysian focus of the origin of agricultural crops is supplemented 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 influence on this area. Local conditions are characterized by year-round vegetation, extremely high humidity and temperature. The region is a natural habitat for nutmeg, clove, cardamom, orange, bergamot, black pepper, mangosteen, betel, lime and many other species.
Indian site
It is also called the Hindustan hearth and includes the Indian state of Assam, Burma and the entire Hindustan peninsula, with the exception of the northwestern states of India. The local climate contributes to a prolonged vegetation, a high level of temperature and humidity. The area was influenced by the Indo-Malayan Center. In this territory grow citrus, sugar cane, rice and many other representatives of the flora.
The Central Asian section
This center includes the lands of the Western Tien Shan, Tajikistan, northern Pakistan, Uzbekistan, Afghanistan and north-western India. Local conditions are characterized by a moderate duration of vegetation, high temperatures with strong seasonal and daily fluctuations and very low level of moistening. This area has experienced a strong impact of the Asiatic and Chinese centers. For this reason, it is a secondary focus for most of the local fruit varieties.
The front Asian section
The outbreak is located in the Near East. It includes the territory of the mountainous Turkmenia, the entire Transcaucasus, the Fertile Crescent, Iran and the interior of Asia Minor. The climate here is characterized by the duration of dry periods, high temperatures and very low humidity. This region has experienced the impact of the Central Asian and Mediterranean centers. The boundaries of these three centers are closely intertwined, so it is almost impossible to establish them.
South American Center for the Origin of Cultivated Plants
These areas include the highlands and highlands of Bolivia, Ecuador, Colombia and Peru. Local conditions are characterized by insufficient moisture and very high temperatures. The Central American Center exerted some influence on this area.
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