US, WASHINGTON (ORDO NEWS) — Throughout the civilized history of mankind, rice has been one of the main sources of food. He retained this significance even now, being a key culture for more than half of the inhabitants of the Earth. It is believed that its cultivation began 9,000 years ago, in the Yangtze River Valley, and then spread to the west – up to the Middle East and Africa, and then America – and also to the east, to Japan and the tropical islands of the Pacific Ocean.
Scientists have followed this movement, using new sequencing data for complete genomes for more than 1400 existing rice varieties today, estimating the time of their appearance and the area of cultivation. It turned out that the key “trigger” that triggered the spread of rice was the climatic catastrophe of the 12th century BC. Michael Purugganan and his colleagues write about this in an article published in the journal Nature Plants .
For millennia , rice cultivation has been limited to China, where various varieties of round-grain “Japanese” were grown. However, around 2200 BC , a global cooling and a series of severe droughts occurred on the planet , which led to the death of many ancient communities, including the Egyptian Ancient Kingdom and the Akkadian Empire. “The dramatic climate changes have forced plants, including cultivated ones, to adapt quickly,” the scientists emphasize.
According to Purugganan and his coauthors, it was during this period that new varieties of “Japanese” began to appear, adapted for cultivation in both a more moderate and hotter climate. These varieties spread to the north of China, to Korea and Japan, as well as to southern countries. About 2500 years ago, “Japan” reached South-West Asia, where it quickly diversified with a number of new tropical varieties.
The history of “indica” developed later. Domestication of the long-grain variety occurred about 4000 years ago, in the lower Ganges valley. Only about 2000 years ago, with the development of global retail chains, it spread to China. “These genomics have given us a basic model of where and when, in what parts of Asia, rice appeared,” the authors of the work say . “Archeology pointed out the places where it was cultivated, and climate modeling provided the ecological context for everything that happened.”
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