I think Virtualfan bascially said that the fertility techs help crops grow better too. Then there were several apparently unrelated comments. Then someone said that Virtualfan meant fertility affects crops in real life but not in the game. (I'm not sure that is what Virtualfan meant, but that is neither here nor there.)

In the game, the fertility techs only affect the childbearing capabilities of the tribe, as well as the ability to solve a certain puzzle. It should have no affect whatsoever on food production.

Those stats are affected by the farming techs. The reason you have so much food when you get the last fertility tech is that you are at a more advanced stage of the game, and have more people capable of collecting foodstuffs, and the foods are of a higher quality (point value).

I beleive my information is correct, and I hope I done a good job communicating it.