Is there corn during Buddha's time?

Sace dhavati te cittam
kamesu ca bhavesu ca
khippam nigganha satiya
kitthadam viya duppasum.

If your mind runs wild among
sensual pleasures and things that arise,
quickly restrain it with mindfulness
as one pulls the cow from the corn.

- Theragatha, verse 446.

I came across this verse many times as I was working on the Chinese translation of Gemstone of the Good Dhamma.

I did not see any problem with it until I remembered something I had read about corn. Corn is native to America. It was only introduced to the rest of the world after the Europeans got in touch with America in the 14th/15th century.

So theoretically, corn was not know in India during Buddha's time.

I checked a Pali-English dictionary. It explains kittha as corn.

I am wondering if kittha is really corn as we know it today or something else...