Large pale flat edible seed grown in the southern us?

You're describing cottonseed. Here's why:

* Large: Cottonseeds are indeed relatively large compared to other common seeds.

* Pale: They have a pale, off-white color.

* Flat: They are somewhat flattened in shape.

* Edible: While not a common food in the US, cottonseed is used in various animal feeds and some human food products.

* Grown in the Southern US: Cotton is a major crop in the Southern US.

Let me know if you have other clues to help narrow down the answer!