Scientific Name Allium cepa.
Family: Amaryllidaceae.
Chromosome Number: 2n = 16.
India is the second largest onion growing country in the world. Indian onions are famous for their pungency and are available round the year. Indian onions have two crop cycles, first harvesting starts in November to January and the second harvesting from January to May.
Location
Maharashtra, Madhya Pradesh, Karnataka, Gujarat, Bihar, Rajasthan, Andhra Pradesh, Haryana, West Bengal, and Uttar Pradesh in the country. These States account for almost 90% of the total onion production of the country.
Soil Type
● Soils should be light, deep, friable and highly fertile.
● Sandy soil needs more and frequent irrigation and favour early maturity.
● In general, sandy loam to clay loam soil is recommended.
● The optimum pH range is between 6.0 and 7.5.
Varieties
● Bulb onion: N 53, Arka Kalyan, Agri found dark red, Arka Pragati, Agri found light red.
● Multiplier onion: CO 1, CO 2, good genotype locally available.
Propagation
● The common method of propagation is by seeds. However, the multiplier onion is propagated by bulblets (Sets).
Seed Rate
● 8-10 kg seeds/ha (bulb onion)
● 1.0-1.2 t/ha (multiplier onion)
Seed Treatment
● Seeds must be treated with fungicides before storage. The seeds may be treated with captan or Thiram @ 4 g/kg of seeds.
● The seeds can also be treated with halogen mixture @ 5g/kg of seed and it is an eco-friendly seed treatment.
Nursery
Raise seedlings in a 3 m x 1.5 m nursery bed and incorporate 200 kg well decomposed FYM.
Nursery of 0.05 ha is needed for raising seedlings for 1 ha of land.
Land Preparation
Plough the land to a fine tilth and form ridges and furrows at 45 cm spacing. Sow the bulbs on both the sides of the ridges at 10 cm apart.
Transplanting
● The planting time of kharif onion is different in different kharif onion producing states, which starts from the first week of June to the second week of August.
● In Maharashtra, it is planted from mid-June to mid-July. During kharif season, flat beds should be avoided to prevent water logging as it favours anthracnose disease which is most devastating during kharif season.
● BBF is the best method for kharif onion production because the excess water can be drained out through the furrow.
Sowing Time
● Kharif: May-June.
● Late Kharif: August-September
● Sow the seeds in a raised nursery bed in line spaced at 5-7 cm distance. Seedlings of 6-7 weeks old are suitable for planting.
● Best time for transplanting of kharif onions is July-August.
Spacing
● Bulb onion – 15 cm x 10 cm.
● Multiplier onion – 20 cm x 10 cm.
Manure & Fertilizers
● 2 tonnes FYM/ha
● 125:60:90 kg N: P2O5: K2O/ha
● Full quantity of P2O5, K2O and half N should be applied as basal and other half N in two equal splits at 30 and 45 DAT.
● The recommended dose of fertilizers for kharif onion is 75 kg nitrogen, 40 kg phosphorus, and 40 kg potassium per hectare.
Weed Management
● Fluchloralin 45% must be sprayed @ 1000ml per acre of land before sowing (or)
● Spray pendimethalin 30% @1.3 to 1.6 litres per acre or oxyfluorfen 23.5% @ 200ml/acre before sowing (or)
● Spray oxyfluorfen 23.5% @ 200 ml per acre 2-3 days after planting, care should be taken that enough moisture is present in the soil.
Water Management
● Irrigation should be given at the time of planting of seedlings and on the third day and later at weekly intervals.
● Irrigation should be stopped 15 days before harvest.
Harvesting
● Onion crops should be harvested after 50% top fall, which is an indicator of crop maturity.
● However, in kharif season, bulbs mature in about 90-110 days, but plants remain in the active growth stage and there will not be any top fall.
● The curing of kharif onion is important for better shelf life but high humidity and cloudy weather do not facilitate curing and results in more losses due to bruising, rotting and sprouting.
Average Yield
● Irrigated onion crop in rabi season gives a yield of 25-30 t/ha while under rainfed conditions it yields only about 0.7-1.0 t/ha.
● Onion raised as an intercrop in sugarcane and turmeric, in alleys of young fruit garden and banana garden, gives a yield of 5-9 t/ha.
Storage
● Onions are stored in a well-ventilated place with a lot of aeration and sunlight.
● Onion bulbs are packed in perforated gunny bags and stalked in a vertical column, one above the other.
● However, the height of such a vertical column should not exceed more than 5 feet and should have sufficient space all around and bottom.