Onion a bulbous herb, Allium cepa, of the family Alliaceae. The plant is characterised by an edible bulb composed of food storage leaves. The above-ground green leaves are typically long and tubular, and are also eaten. In Bangladesh onion is grown in an area of about 34,455 hectares and total onion production is about 1,38,000 m tons. It possibly originated in Western Asia. The pungency, which varies with cultivar, is due to a volatile oil known as allyl-propyl disulphide.

Onions can be grown on all types of soils. The optimum time of transplanting in Bangladesh is December or the 1st week of January. Onion bulbs reach maturity when plants cease to produce new leaves. The average yield is 4-5 m tons/ha. Tahirpur and Faridpuri are two important varieties; the bangladesh agricultural research institute has recently released one variety called BARI Piaj-1. Onion is grown in all districts, but Faridpur is the largest producer of onion. It is used as a fresh vegetable; as a spice and as an ingredient of curry, sauce, soup, pickles, seasoning food, etc. [AKM Matiar Rahman]