Onion is an herbaceous biennial plant grown for its edible bulb.

The origin of Onion is somewhere in South East Asia.

Major Onion growing countries in the world are China, India, USA, Iran, Russia, Turkey, Egypt and Pakistan.

Major Onion growing states of India are Maharashtra, Karnataka, Gujarat, Bihar, Madhya Pradesh and Andhra Pradesh

• Kingdom:  Plantae
• Division: Magnoliophyta
• Class: Liliopsida
• Order:  Liliales
• Family: Liliaceae
• Genus: Allium
• Species: cepa

Bulbs and shoots are the most economically important parts of Onion cultivation

Onions are hardy, cool season vegetables that grow best at temperatures of 12 to 24 °C .

They require a fertile, well-draining soil such as clay or silt loams with a pH of 5.5–6.5.

The plants do not do well in acidic soils.

Onions should be set out in full sun for optimum bulb development. 

Onions are biennial vegetables and if they are left in the ground for a second year, they will produce flowers and set seed

• The major challenges involve Biotic and Abiotic causes.
• Biotic Causes:
  • Major Pests: Bulb Mites, Leaf Miner, Onion Maggot and Thrips.
    
  • Major Diseases: Black Mold, Botrytis Leaf Blight, Downy Mildew, Damping Off and Purple Blotch.
• Abiotic Causes:
  • Bolting
  • Splitting
  • Doubling of bulbs