Prof Javed Asgraf at JNU Delhi has argued thsi issue in several fo his papers and also another author who worte the book American discoverers ( I forget teh name just now but can send it later) also pointed out thsi possibility about maize.
there rae picytures of scuptures ( I have one inmy office) of Budhdhist period in which corn is shown. It obviously was here in such a case.
anil k gupta
-----Original Message-----
From: Jibunnessa <ycrnn14@UCL.AC.UK>
Date: Wednesday, May 13, 1998 5:27 AM

Dear All

Thought you might find this interesting!


  The evidence of maize in archaeological sites in
  China and its depiction in Hoysala Temples in India,
  both dated before the 15th century A.D., suggests
  that this domesticated crop was diffused by human
  action before the arrival of Columbus in the New
  World. The implications of this evidence are of
  great magnitude, since the presence of maize in Asia
  indicates that humans were able to migrate between
  both hemispheres; more than likely through trans-
  oceanic means of travel.

This comes from an article by Carl Johannessen and
Anne Z. Parker, "Maize Ears Sculptured in 12th and
13th Century A.D. India as Indicators of Pre-Columbian
Diffusion," Economic Botany 43 (2), 1989, pp. 164-180.

Just in case anyone is REALLY interested, I've attached
some (what I think) useful WEB pages.  The first is
Carl Johannessen's own page at University of Oregon.
The second from the University of Ohio, also talks about
the same thing, and has a rather useful bibliography.
The last is an article from the Maize Genetics Cooperation
Newsletter, called, "Antiquity of Maize in India".  It's
by M. Kumar and JKS Sachan from Rajendra Agricultural
University in India.  They also suggest that maize being
grown in the very remote Northeastern Himalayan tracts
adjoining Burma and Tibet, could be further evidence of
possible pre-Columbian introduction.

I hope this stimulates interest!

I'd be interested to hear what people think.

And anyone who knows any more about the subject, I'd be
grateful for some illumination and further leads.

All the best