The  onion (Allium  cepa  L.) is  an  indispensable element  of  almost every  culture  as a  vegetable.  It consumed as raw or a component of meals in many different cultures around the world. Also, unlike many other vegetable species, consumption of onion is not limited to a particular season.

Academic studies on onions are quite difficult due to some features such as multiple flower structure, prolonged flowering  period, long isolation distance for  control of  fertility, the strong effect  of environmental factors on some morphological features, difficulty in maintaining genetic resources etc. In addition to these, at least two years are  needed from  seed sowing  to seed  harvesting. The  onion bulbs  harvested in the previous season should be stored under appropriate conditions and plantation should be established again in the second year for seed production.