I've heard a similar theory: the end of the ice age resulted in an increase in the human population in the middle-east. Though these hunter-gatherers knew about plants and may have cultivated them as a sideline, the hunter-gatherer life was fairly easy (you needed to hunt/gather about 4 hours a day to feed your family), so they had no reason to become farmers. However, a long drought came along and there were too many humans around to be supported by hunting and gathering, so humans were gradually forced to turn to farming to survive.
Early farming was NOT an improvement in the quality of life for those involved- farming at that point took a lot more work and led to a less-varied diet, but humans were forced to farm out of necessity.
Forced because of a drought? After tens of thousands of years of simply moving on to another location when conditions changed all of a sudden we thought to grow food?
Ha! More than likely somebody was good a brewing the local ale and beer and found that when he spilled a little of the grain it grew where he had been working the season before. The next logical step would be to place it somewhere specific and THEN if there were a drought add a little water leading to irrigation.
Food was a by-product of getting sloshed. ;)