I get some rice from Harvestcrafts gardens. I turn them into seeds.
If I plant them right off - the plants despawn after a few seconds.
If I analyze them first turning them into Agricraft seeds the cannot be planted on crops.
All other seeds I'v tried (and that is almost 100% of them) works both planting them as they are and turning them into agricraft seeds.

If you are on version 1.3.1 then this is irrelevant and you will have to update.
If you are on version 1.4.0-alpha, then that means you have to plant rice on water pads.