Potato onion (Multiplier onion) 497
30.3 Production.......................................................................................
The potato or multiplier onion is also known as underground onion. It forms closely
packed clusters of bulbs underground, rather than on the surface like the shallot. It is
difficult to obtain reliable data regarding total area and production of potato onion
because in many countries it is grown only domestically. However, in Thailand,
Indonesia, the Philippines, Sri Lanka and India, potato onions are grown on a commercial
scale for export and for internal consumption. The Food and Agriculture Organization
(FAO) Production Yearbook contains production figures for all onions combined.
According to the FAO website (www.fao.org), the total area under onion during 2004
was about 3.07 million hectares (ha), production was about 53.59 million tonnes and
productivity was 17.46 tonnes/ha. Compared to 1994 figures, there has been an
increase of 43.34% in area, 56% in production and 9% in productivity. In India, it is
estimated that out of a total onion production of approximately 6 million tonnes,
about 1.2 million tonnes is potato onion.
Several varieties of potato onion have been developed in India. The varieties CO1,
CO2, CO3, CO4 (Fig. 30.1) and CO On5 were developed at the Tamil Nadu Agricultural
University. The variety Agrifound Red (Fig. 30.2) was developed at the National
Horticultural Research and Development Foundation. Bulblets of traditional potato
onion varieties are much smaller than those of Agrifound Red (Fig. 30.3). The growing
period is normally 60–65 days, and almost all varieties of potato onions are propagated
vegetatively. The variety CO On5 has a longer growing period of 90 days, and also
has the ability to flower and set seeds, so it can be propagated vegetatively or by
seed. CO On5 is planted in March and harvested in July.
For other varieties, grown in the South, the bulblets are planted in April–May and
October–November. The bulblets are planted on both sides of ridges and spacing is
45 cm ¥ 10 cm. Fertilizers and manures are applied as required. Thrips, insect and
leaf spot are the most common insects and diseases for potato onion crops. Thrips is
controlled by administering Methyl demeton 25EC (1 ml / litre of water), and leaf
Fig. 30.1 Variety CO4 developed by T.N.A.U., Coimbatore, India.