India, June 18 -- In November 1900, an interesting exchange of letters debating the protection of India from famines was published in the "Agricultural Ledger". These letters were written by two men with very different ideas, and their subject was a root vegetable called cassava.

It started when Robert Thomson, an experienced tropical planter, reached out to Dr George Watt, the Scottish botanist and the author of "The Dictionary of Economic Products of India". Thomson urged the government to introduce several varieties of cassava from Colombia to India, arguing that if it were grown instead of or alongside rice, it could completely wipe out the threat of famine.

Thomson believed that rice was a thirsty crop that needed 50 to 60 inches o...