Drought is one of the most important global problems for agriculture. Plants adapt and respond to water stress by inducing different defense mechanisms by changing their cellular metabolism. The present study is aimed to gauge the effect of drought (with holding watering for six days) by screening the nine cultivars of onion seedlings, by monitoring the following parameters like chlorophyll content, relative water content (RWC), quantitative analysis of proteins, sugars, proline, phenols, flavonoids, and tannins. Drought stress decreased the chlorophyll content in all the cultivars. Relative water content was maintained in Arka lalima under stress when compared with other cultivars. Protein, sugars, and proline content increased in all cultivars under drought conditions. Maximum proline levels were examined in prema 178, arka kirthaman and arka lalima under stress conditions. Secondary metabolites such as flavonoids, phenols and tannins levels enhanced in stressed seedlings. Among all nine cultivars of onion arka kirthaman, arka lalima and prema 178 showed highest response to drought stress when compared to the control. Further physiological and molecular investigation is needed to know the drought tolerance mechanism in onion cultivars.
