onion

Onion, also known as onion, onion, jade onion and onion head, is a biennial herb belonging to Allium of Liliaceae. There are many opinions about the origin of onions, but most people think that onions are more likely to be produced in the plateau areas of Central Asia in southwest Asia, Iran in Asia Minor and Afghanistan, because wild types of onions can still be found in these areas. The origin of onion has a history of more than 5,000 years. It spread to Egypt in 1000 BC, then to the Mediterranean region, to the United States in the 16th century, to Japan in the 17th century and to China in the early 20th century. Onion is widely distributed in China, cultivated in north and south, and the planting area is still expanding. It is one of the main vegetables in China at present. China has become one of the four countries (China, Indian, American and Japanese) with large onion production. China's planting areas are mainly Shandong, Gansu, Inner Mongolia, Xinjiang and other places. Onion is native to continental climate zone, where the climate changes drastically, the air is dry, and the soil moisture changes obviously seasonally. Therefore, in the process of system development, due to long-term adaptation to this special environment, onion not only undergoes corresponding changes in morphology-shortened stem disc, moisture-loving root system, drought-tolerant leaf shape, bulbs with storage function, but also has certain physiological adaptability. In the vegetative growth period, it requires cool temperature, moderate intensity of light, loose, fertile soil with strong water retention, low air humidity and high soil humidity, and shows the characteristics of cold resistance, humidity and fertilizer, and is not resistant to high temperature, strong light, drought and barren. Enter the dormant period when the temperature is high and the sunshine is long. The edible part of onion is the underground hypertrophy bulb (onion head). According to its skin color, it can be divided into three kinds: white skin, yellow skin and red skin: white skin has small bulbs, white or slightly green appearance, tender meat, spicy juice and light leaves, and good quality, which is suitable for raw food. Chinese people are often afraid of its unique spicy aroma, but abroad it is known as the "queen of vegetables" and its nutritional value is not low. Quality requirements of onion: the onion is fat, the skin is shiny, not rotten, without mechanical damage and soil, and the fresh onion has no leaves; After storage, it is not soft, not bolting, with compact scales, less water content and strong spicy and sweet taste. When you cut onions, you will leave tears.
Reprinted with attribution： https://cnlocality.com/(Chinese Specialty Products)