I think it will eventually be discovered that farming was there, almost all the way along.
The mystery of farming 'being invented' all over the place is just another indication of sciences' near total myopia where diffusionism is concerned.
Farming requires water sources. Primitive farming, even more so, and flowing water would be preferred in primitive conditions, as the easy means of getting the water to the crop would necessitate gravitational systems.
Hence, farming is always, or nearly always a product of bottom land, near creeks and rivers. The unfortunate circumstance is that the natural meandering of rivers within their bottoms has a tendency to wash the evidence of thousands of years away every time the bed changes course.
Farming requires hunting and gathering, and hunter/gatherers require farms and townships. And they all require trade and trade routes.
It has ever been thus.