(1) common onion common onion most widely cultivated in our country, its plant is tall, no tiller before shooting, after shooting only in the flower shoots at the base of a lateral bud, seed maturity to grow a new plant. Individual plants can be divided into two single plants, but there is still an outer leaf sheath wrapped together when harvested. The common onion can be further divided into three types of long white onion, short white onion and chicken leg onion according to the white onion morphology.
①Long white onion. Long white onion neighboring leaf distance is long, generally 2 ~ 3 cm apart, leaf spread is small, long white onion, thickness uniformity, white onion height is greater than the plant height 1 / 3, long and thick ratio of 10 or more. The height of the whole plant is more than 1.3 meters, and it is a single plant without tillers. The lower part of the onion white is firm, the upper part is flabby, generally the mouth of the leaf sheath is loose, the leaf blade is thin and fleshy, the leaf blade is 4 to 6, and the windproof ability is poor. Higher yield, requiring better cultivation conditions. Long white onion high water content, less crude fiber, mostly sweet and spicy type taste, suitable for raw food, fried food.
②Short white onions. Short white onion white short, up and down the thickness of more uniform, long and thick ratio of less than 10. Leaf spacing is closer, generally 1.5 ~ 2 cm, leaf spread is larger, leaf sheath mouth tight, giving a feeling of seemingly overlapping leaves, the general short white onion leaf body is short and thick, leaf blade 6 ~ 8, leaf meat is thicker, and the leaf surface wax layer is more resistant to wind, resistance to pests and diseases, taste spicy, strong flavor, excellent seasoning. Short white onions are resistant to storage and transportation.
③Chicken leg onion. As the name suggests, the chicken leg onion base dilated chicken leg, some were garlic, plant thin and slender, white onion small, outer layer of light red or light yellow, similar to the skin of the onion head. Onion leaves are small, 4 to 6, slow growth, low yield, but the chicken leg onion flavor spicy aroma, far more than the high white onion and short white onion, onion white solid, storage resistance is very strong, is the onion varieties with a unique flavor of the treasures. (2) divided onion divided onion is also called tiller onion, this type of onion in the nutrient growth period, whenever the plant grows 5 ~ 8 leaves, that is, a tiller, from a plant into a similar size of 2 ~ 3 plants. Under the condition of abundant nutritive growth time, it can tiller 2 to 3 times a year, *** forming 6 to 10 plants. Tiller onion single plant size and weight, the varieties vary greatly, the varieties with short planting intervals, the plant is smaller, the pseudostem is about 20 centimeters long, about 1 to 1.5 centimeters thick, the leaf is smaller than the ordinary onion and tender, suitable for white onion and tender leaves and cultivation. Tiller shallots are produced more in the southern region of China, and their yield per unit area is lower, but the price is often much higher than ordinary shallots. Tiller onion is very suitable for production in greenhouses, in recent years, many areas will also be soilless culture technology for tiller onion production. (3) building onions building onions, also known as dragon claw onions, Gansu Province, Longnan region, also known as red onions, old onions, building onions and ordinary onions, the same, through the vernalization of shoots, but the flower organs degradation, no normal inflorescences, but in the disk of the occurrence of aerial small scale buds. Scale buds have no dormant period, and develop into young plants with two to three leaflets on the disk. Six to sixteen young plants may grow on the same disk. Individuals of the earliest development of the formation of young plants, can be in the disk again shoots, and in the top of the occurrence of young plants, the floor onion so named. There are two varieties of onions, tillers and non-tillers. The onion is propagated by aerial young plants, and the reproduction coefficient is low. However, the seedling period is short and cold-resistant, so it is suitable for cultivation in alpine mountainous areas where the growing period is short. The edible method of onion is the same as other onions, which can be eaten raw, fried, and used as seasoning. (4) fine scallions fine scallions, also known as scallions, four seasons onions, for the lily family onion perennial herbs, for biennial cultivation, edible young leaves and pseudostems. The product is tender, with a special flavor, mostly used for seasoning. Fine scallion leaves thin cylindrical, 30-40 cm long, light green. Leaf sheath base slightly hypertrophied, long ovate, pseudostem length 8 ~ 10 cm, thickness 0.6 cm, skin gray-white, sometimes reddish, tillering force is strong, each stem has a strong vitality of the buds, in the appropriate conditions can quickly grow into a dense bush, the root system is cross-connected. Growing the second year of shoots, flowering stems slender, cymes, small flowers lavender, not easy to bear seeds, and other onions are not easy to hybridize. China south of the Yangtze River has a small number of cultivation. Fine scallions cold, fertilizer, wide adaptability to the soil, but heat and drought resistance is weak. (5) leek onion leek onion alias flat onion, flat-leafed onion, garlic seedlings, belongs to the lily family onion biennial herbs. Root system for fleshy string-like fibrous roots, thicker and shorter, attached to the shortened stem disk, weak root division, less root hairs, weak absorption, root length of 30 ~ 40 cm. The leaf blade is flat and plump, banded, with wax powder on the surface, and the leaf blade is 3-4 centimeters wide, with multilayered leaf sheaths clasping into a pseudostem. The plant height is generally 50 cm, the pseudostem is 22-26 cm long, and the adult plant of long pseudostem type varieties can reach 1.3-1.5 meters in height, and the pseudostem is 80-100 cm long. Leek cold, heat resistance are strong, suitable for growth in the day temperature of 15 ~ 25 ℃, the night temperature of 12 ~ 13 ℃ environmental conditions, drought, waterlogging tolerance is poor. Wide adaptability to soil, sandy soil, clay soil can be cultivated. Suitable for cultivation in rich organic matter, fertile, loose soil. (6) Hu onion Hu onion, also known as fire onion, green onion, garlic onion, petal onion, for the lily family onion biennial herbaceous plants. Young leaves and bulbs for seasoning, bulbs can also be used as pickling raw materials. Hu onion native to Central Asia, Hu onion in Cuba is the main cultivation of onion species, Japan is also cultivated. China's South China, such as Guangzhou, cultivated more, less cultivated in the north. Onion stems shortened disc-shaped, leaves by the leaf sheath and conical tubular leaf blade composition, inserted on the stem disc, the leaves are shorter and softer, generally 25 centimeters long, lime green, less wax powder. Tiller strong, can form bulbs, bulbs long ovate, bulb outer skin purple-red, inner white. Multiple bulbs are densely clustered, connected at the base, and the joints are crowded into a rhombic shape. The plant produces flowering stems in late spring, which are hollow and have lavender flowers. In the south does not bear seeds, in Beijing cultivation can obtain a small number of seeds, seeds shield-shaped, such as onion seeds, black and shiny. Onions like cool, cold resistance, intolerant of heat.