The research, published by Professor John Dodson and Professor Xiaoqiang Li, shows there are no modern wild varieties of the wheat and barley, which were found in the region in a domesticated form, and carbon dated to 2,650BC.
It is now thought they originated in the Middle East, which showed exchanges between China hundreds of years before the Silk Road, previously thought to be the earliest contact, around 200BC.
Professor Dodson, from the Australian Nuclear Science and Technology Organisation, has told Radio Australia's Connect Asia program,
"Certainly an exchange of technology," he said.
"There could have been trade, so I guess we're saying certainly a trade in technology and ideas".
Professor Dodson says a major archaeological find in the region in 1987, the Xinjiang mummies, may be evidence of those who brought the wheat from the Middle East.
Archaeologists discovered around 100 perfectly preserved corpses in a dry, hilly region in China's far northwest, which dated at 4,000 years old, and showed Caucasian features.
Professor Dodson says the fact that the mummies were of ordinary families, not royalty, also gives insights into past relationships between China and the west.
"The clothing they wore was of a style that was only recognised from Turkey and areas like that, so this seems to be pretty strong evidence that there were people making that journey east 4,000 years ago," he said.
"The intriguing thing is that there might be a link between those people bringing in Middle East agricultural practices - there may be a good strong link there between these wheat grains and these barley grains that we're finding".
You can find the full interview with Professor Dodson at the Connect Asia website: http://radioaustralia.net.au/connectasia