Onion cultivation in India – a way forward

Abstract

The adoption of onion in India is carried through from very early times before Christian era. In India, there are reports of onion in writing from 6th century BC. Originally, native of Central Asia of temperate region with perennial/ biennial habit and long day bulbing characters, it has established well in India under tropical and short day (11-11.5 hours) photoperiodic conditions. During acclimatization of different kinds of vegetable crops and their varieties, farmers applied selection pressure involuntarily to meet the market preferences. In case of onion, ability to produce seeds indigenously has played an important role in the adaptation. In course of adaptation and diversification, out breeding mechanisms present in onion has promoted selections suited to diverse environments. This kind of adaptation made onion to behave as annual. The phenomenon resulted in loss of short dormancy of onion bulbs. This fascinating aspect of onion domestication in Western India had gone unnoticed and unrecorded. In the centre of origin and area between 35 and 400N latitude, onion is biennial in seed production and requires more than 14 hours day length for bulb production. In subtropical and tropical parts of India between 12 and 250N latitude, it is biennial but able to produce bulbs under comparatively shorter photoperiod (11-11.5 hours) in winter season. The concentration of onion growing in Western Maharashtra and Gujarat is very significant, where two crops – one in rainy season (kharif) and other in winter season (rabi) – are regularly grown. The tropicalization progresses further southwards towards Bellary region in Northern Karnataka and finally a vegetatively propagated multiplier onion (aggregatum) type got established in Tamil Nadu (6 – 8 0N latitude). The adoption to hardy conditions of high rainfall, high temperature and short day photoperiod typical of rainy (kharif) season of Western India has not been chronologically documented.