Politically incorrect so it ain't so.
The Sumerians who did the job were migratory pastoralists with great herds of sheep, goats, cattle and other animals.
They were replaced by Semites once all the heavy hauling had been done.
Agriculture was developed extensively in Syria (and along the Mediterranean Coast), Eastern Anatolia and later in Mesopotamia by the Semitic newcomers.
We are talking about thousands of years of work BTW ~ didn't happen overnight.
Oh, yes, the singular Semitic-speaking contribution to government was the creation of the First Nation ~ aka "Egypt". Not at all a casual undertaking and well worth praise, but even Egypt used a writing concept first developed by the Sumerians. East Asian developments lagged the West (meaning Mesopotamia and Eastern Mediterranean) by maybe a thousand years.
Recent discoveries in the Aleutians suggest that Japonica rice may well have been developed there first (along with the same heated floor/foundation system typical of ancient Korean settlements). Japonica was then taken to Asia by Aleuts and then propagated in China. Indicum was developed later along the upper reaches of the Ganges, but it's a separate species. American Indian "wild rice" is yet another group of species (somewhat related to Indicum and Japonica). As usual American Indians were developing many times more species of plants into useful agricultural products than Old World populations.